vps_web/app.py

# -*- coding: utf-8 -*-
"""云服务器价格对比 - Flask 应用"""
import io
import json
import os
import re
from time import monotonic
from datetime import datetime, timezone
from email.utils import format_datetime
from urllib.parse import urlencode
from xml.sax.saxutils import escape as xml_escape
from flask import (
    Flask,
    abort,
    jsonify,
    make_response,
    redirect,
    render_template,
    request,
    send_file,
    send_from_directory,
    session,
    url_for,
)
from werkzeug.middleware.proxy_fix import ProxyFix
from sqlalchemy import text, func, or_
from sqlalchemy.orm import joinedload
from markupsafe import Markup, escape
try:
    import markdown as py_markdown
except Exception:
    py_markdown = None
try:
    import bleach
except Exception:
    bleach = None
from config import Config
from extensions import db
from openpyxl import Workbook
from openpyxl import load_workbook

app = Flask(__name__)
app.config.from_object(Config)
# 部署在 Nginx 等反向代理后时，信任 X-Forwarded-* 头（HTTPS、真实 IP）
app.wsgi_app = ProxyFix(app.wsgi_app, x_for=1, x_proto=1, x_host=1)
db.init_app(app)

from models import (
    VPSPlan,
    Provider,
    PriceHistory,
    User,
    ForumPost,
    ForumComment,
    ForumCategory,
    ForumReport,
    ForumNotification,
    ForumPostLike,
    ForumPostBookmark,
)  # noqa: E402


def _ensure_mysql_columns():
    """为已有 MySQL 表添加缺失列，避免 1054 Unknown column。"""
    try:
        engine = db.engine
        if engine.dialect.name != "mysql":
            return
        with engine.connect() as conn:
            for col, spec in [
                ("traffic", "VARCHAR(64) NULL"),
                ("countries", "VARCHAR(255) NULL"),
                ("provider_id", "INT NULL"),
            ]:
                try:
                    conn.execute(text("ALTER TABLE vps_plans ADD COLUMN {} {}".format(col, spec)))
                    conn.commit()
                except Exception:
                    conn.rollback()
            for col, spec in [
                ("name", "VARCHAR(128) NULL"),
                ("region", "VARCHAR(128) NULL"),
                ("price_cny", "DOUBLE NULL"),
                ("price_usd", "DOUBLE NULL"),
            ]:
                try:
                    conn.execute(text("ALTER TABLE vps_plans MODIFY COLUMN {} {}".format(col, spec)))
                    conn.commit()
                except Exception:
                    conn.rollback()
    except Exception:
        pass  # 表不存在或非 MySQL 时忽略


def _ensure_forum_columns():
    """为已有论坛表补齐后续新增字段。"""
    try:
        engine = db.engine
        dialect = engine.dialect.name
        with engine.connect() as conn:
            if dialect == "mysql":
                alters = [
                    "ALTER TABLE forum_posts ADD COLUMN category VARCHAR(32) NOT NULL DEFAULT '综合讨论'",
                    "ALTER TABLE forum_posts ADD COLUMN view_count INT NOT NULL DEFAULT 0",
                ]
            else:
                alters = [
                    "ALTER TABLE forum_posts ADD COLUMN category TEXT DEFAULT '综合讨论'",
                    "ALTER TABLE forum_posts ADD COLUMN view_count INTEGER DEFAULT 0",
                ]
            for sql in alters:
                try:
                    conn.execute(text(sql))
                    conn.commit()
                except Exception:
                    conn.rollback()
    except Exception:
        pass


def _ensure_forum_manage_columns():
    """为用户与论坛帖子补齐管理字段（封禁/置顶/精华/锁帖）。"""
    try:
        engine = db.engine
        dialect = engine.dialect.name
        with engine.connect() as conn:
            if dialect == "mysql":
                alters = [
                    "ALTER TABLE users ADD COLUMN is_banned TINYINT(1) NOT NULL DEFAULT 0",
                    "ALTER TABLE users ADD COLUMN banned_at DATETIME NULL",
                    "ALTER TABLE users ADD COLUMN banned_reason VARCHAR(255) NULL",
                    "ALTER TABLE forum_posts ADD COLUMN is_pinned TINYINT(1) NOT NULL DEFAULT 0",
                    "ALTER TABLE forum_posts ADD COLUMN is_featured TINYINT(1) NOT NULL DEFAULT 0",
                    "ALTER TABLE forum_posts ADD COLUMN is_locked TINYINT(1) NOT NULL DEFAULT 0",
                ]
            else:
                alters = [
                    "ALTER TABLE users ADD COLUMN is_banned INTEGER DEFAULT 0",
                    "ALTER TABLE users ADD COLUMN banned_at DATETIME",
                    "ALTER TABLE users ADD COLUMN banned_reason TEXT",
                    "ALTER TABLE forum_posts ADD COLUMN is_pinned INTEGER DEFAULT 0",
                    "ALTER TABLE forum_posts ADD COLUMN is_featured INTEGER DEFAULT 0",
                    "ALTER TABLE forum_posts ADD COLUMN is_locked INTEGER DEFAULT 0",
                ]
            for sql in alters:
                try:
                    conn.execute(text(sql))
                    conn.commit()
                except Exception:
                    conn.rollback()
    except Exception:
        pass


DEFAULT_FORUM_CATEGORIES = [
    "综合讨论",
    "VPS 评测",
    "优惠活动",
    "运维经验",
    "新手提问",
]


def _ensure_forum_categories_seed():
    """初始化论坛默认分类。"""
    try:
        if ForumCategory.query.count() > 0:
            return
        for idx, name in enumerate(DEFAULT_FORUM_CATEGORIES, start=1):
            db.session.add(ForumCategory(
                name=name,
                sort_order=idx * 10,
                is_active=True,
            ))
        db.session.commit()
    except Exception:
        db.session.rollback()


def _ensure_price_history_baseline():
    """为历史数据补首条价格快照，便于后续计算涨跌。"""
    try:
        missing = (
            db.session.query(VPSPlan)
            .outerjoin(PriceHistory, PriceHistory.plan_id == VPSPlan.id)
            .filter(PriceHistory.id.is_(None))
            .all()
        )
        if not missing:
            return
        for p in missing:
            if p.price_cny is None and p.price_usd is None:
                continue
            db.session.add(PriceHistory(
                plan_id=p.id,
                price_cny=p.price_cny,
                price_usd=p.price_usd,
                currency=(p.currency or "CNY"),
                source="bootstrap",
            ))
        db.session.commit()
    except Exception:
        db.session.rollback()


# 启动时自动创建表（若不存在），并为已有表补列
with app.app_context():
    db.create_all()
    _ensure_mysql_columns()
    _ensure_forum_columns()
    _ensure_forum_manage_columns()
    _ensure_forum_categories_seed()
    _ensure_price_history_baseline()

ADMIN_PASSWORD = app.config["ADMIN_PASSWORD"]
SITE_URL = app.config["SITE_URL"]
SITE_NAME = app.config["SITE_NAME"]

# 国家/区域标签，供后台表单选择
COUNTRY_TAGS = [
    "中国大陆", "中国香港", "中国台湾", "美国", "日本", "新加坡", "韩国",
    "德国", "英国", "法国", "荷兰", "加拿大", "澳大利亚", "印度", "其他",
]

PRICE_SOURCE_LABELS = {
    "manual": "手工编辑",
    "import": "Excel 导入",
    "bootstrap": "基线",
}

FORUM_REPORT_REASONS = [
    "垃圾广告",
    "辱骂攻击",
    "违法违规",
    "虚假信息",
    "其他",
]

FORUM_REPORT_STATUS_LABELS = {
    "pending": "待处理",
    "processed": "已处理",
    "rejected": "已驳回",
}

FORUM_NOTIFICATION_TYPE_LABELS = {
    "post_commented": "帖子新评论",
    "thread_replied": "主题新回复",
    "report_processed": "举报处理结果",
    "content_removed": "内容处理通知",
}


# 论坛高频数据短时缓存（进程内）
_FORUM_CACHE_TTL_CATEGORIES = 20.0
_FORUM_CACHE_TTL_SIDEBAR = 15.0
_FORUM_CACHE_TTL_NOTIF_COUNT = 30.0
_FORUM_CATEGORY_CACHE = {}
_FORUM_SIDEBAR_CACHE = {"expires_at": 0.0, "data": None}
_NOTIF_COUNT_CACHE = {}  # user_id -> (count, expires_at)

_MARKDOWN_ALLOWED_TAGS = [
    "p", "br", "hr",
    "h1", "h2", "h3", "h4",
    "strong", "em", "del",
    "ul", "ol", "li",
    "blockquote",
    "pre", "code",
    "a",
    "table", "thead", "tbody", "tr", "th", "td",
]
_MARKDOWN_ALLOWED_ATTRS = {
    "a": ["href", "title", "target", "rel"],
    "code": ["class"],
    "pre": ["class"],
}
_MARKDOWN_EXTENSIONS = [
    "fenced_code",
    "tables",
    "sane_lists",
    "nl2br",
]


FORUM_NOTIFICATION_TYPE_LABELS_EN = {
    "post_commented": "New comment",
    "thread_replied": "New reply",
    "report_processed": "Report update",
    "content_removed": "Content moderation",
}

# Sitemap 单个文件最大帖子条数（按语言拆分后可稳定低于 50k URL 上限）
SITEMAP_POSTS_PER_FILE = 25000

FORUM_CATEGORY_SEO_COPY = {
    "综合讨论": {
        "zh": "围绕 VPS 选型、采购和实践经验的综合讨论区。",
        "en": "General discussions about VPS planning, buying, and operations.",
    },
    "VPS 评测": {
        "zh": "集中查看 VPS 评测、性能体验与线路反馈。",
        "en": "Hands-on VPS reviews, benchmarks, and network feedback.",
    },
    "优惠活动": {
        "zh": "跟踪厂商促销、折扣活动与限时优惠。",
        "en": "Track provider promotions, discounts, and limited-time deals.",
    },
    "运维经验": {
        "zh": "分享部署、监控、故障排查与稳定性实践。",
        "en": "Operations playbooks for deployment, monitoring, and troubleshooting.",
    },
    "新手提问": {
        "zh": "面向新手的配置建议与入门答疑。",
        "en": "Beginner-friendly Q&A for VPS setup and decision making.",
    },
}


def _get_lang():
    lang = (
        request.args.get("lang")
        or request.form.get("lang")
        or session.get("lang")
        or "zh"
    )
    lang = (lang or "zh").strip().lower()
    if lang not in ("zh", "en"):
        lang = "zh"
    session["lang"] = lang
    return lang


def _pick_lang(zh_text, en_text, lang=None):
    active_lang = lang or _get_lang()
    return en_text if active_lang == "en" else zh_text


def _lang_url(lang_code):
    target_lang = (lang_code or "").strip().lower()
    if target_lang not in ("zh", "en"):
        target_lang = "zh"
    params = {}
    if request.view_args:
        params.update(request.view_args)
    params.update(request.args.to_dict(flat=True))
    params["lang"] = target_lang
    try:
        if request.endpoint:
            return url_for(request.endpoint, **params)
    except Exception:
        pass
    return "{}?{}".format(request.path, urlencode(params))


def _site_root_url():
    return (SITE_URL or "").rstrip("/")


def _absolute_url_for(endpoint, **values):
    return "{}{}".format(_site_root_url(), url_for(endpoint, **values))


def _public_url(endpoint, lang="zh", **params):
    values = {}
    for key, value in params.items():
        if value is None:
            continue
        if isinstance(value, str) and not value.strip():
            continue
        values[key] = value
    if (lang or "zh").strip().lower() == "en":
        values["lang"] = "en"
    else:
        values.pop("lang", None)
    return _absolute_url_for(endpoint, **values)


def _alternate_lang_links(endpoint, **params):
    return {
        "zh-CN": _public_url(endpoint, lang="zh", **params),
        "en-US": _public_url(endpoint, lang="en", **params),
        "x-default": _public_url(endpoint, lang="zh", **params),
    }


def _iso8601_utc(dt):
    if not dt:
        return None
    if dt.tzinfo is None:
        aware = dt.replace(tzinfo=timezone.utc)
    else:
        aware = dt.astimezone(timezone.utc)
    return aware.strftime("%Y-%m-%dT%H:%M:%SZ")


def _rfc2822_utc(dt):
    if not dt:
        return None
    if dt.tzinfo is None:
        aware = dt.replace(tzinfo=timezone.utc)
    else:
        aware = dt.astimezone(timezone.utc)
    return format_datetime(aware, usegmt=True)


def _plain_excerpt(text, limit=160):
    raw = " ".join((text or "").split())
    if len(raw) <= limit:
        return raw
    return "{}…".format(raw[:max(limit - 1, 0)].rstrip())


def _estimate_reading_minutes(text, lang="zh"):
    raw = " ".join((text or "").split())
    if not raw:
        return 1
    # 对中英混合文本做轻量估算：中文按字、英文按词处理。
    token_count = len(re.findall(r"[A-Za-z0-9_]+|[\u4e00-\u9fff]", raw))
    if lang == "en":
        rate = 220
    else:
        rate = 320
    minutes = (token_count + rate - 1) // rate
    return max(1, int(minutes))


def _forum_category_description(category_name, lang):
    category = (category_name or "").strip()
    if not category:
        return _pick_lang(
            "聚合 VPS 评测、运维经验与采购讨论，帮助团队完成云资源选型。",
            "A VPS community for reviews, operations knowledge, and procurement discussions.",
            lang,
        )
    preset = FORUM_CATEGORY_SEO_COPY.get(category) or {}
    if lang == "en":
        return preset.get("en") or "Community topics tagged '{}' for VPS reviews, operations, and buying decisions.".format(category)
    return preset.get("zh") or "浏览“{}”分类下的 VPS 讨论、评测与采购经验。".format(category)


def _forum_index_keywords(lang, active_tab="latest", selected_category=None):
    if lang == "en":
        keywords = [
            "VPS forum",
            "VPS community",
            "cloud server reviews",
            "VPS buying guide",
            "VPS operations",
        ]
        tab_map = {
            "latest": "latest VPS topics",
            "new": "new VPS posts",
            "hot": "popular VPS discussions",
        }
    else:
        keywords = [
            "VPS论坛",
            "VPS社区",
            "云服务器评测",
            "VPS采购建议",
            "VPS运维经验",
        ]
        tab_map = {
            "latest": "最新帖子",
            "new": "新帖",
            "hot": "热门讨论",
        }
    tab_keyword = tab_map.get(active_tab)
    if tab_keyword:
        keywords.append(tab_keyword)
    if selected_category:
        keywords.append(selected_category)
    return ", ".join(dict.fromkeys(keywords))


def _forum_breadcrumb_schema(lang, selected_category=None, post=None, post_url=None):
    items = [
        {
            "@type": "ListItem",
            "position": 1,
            "name": _pick_lang("首页", "Home", lang),
            "item": _public_url("index", lang=lang),
        },
        {
            "@type": "ListItem",
            "position": 2,
            "name": _pick_lang("论坛", "Forum", lang),
            "item": _public_url("forum_index", lang=lang),
        },
    ]
    if selected_category:
        items.append({
            "@type": "ListItem",
            "position": len(items) + 1,
            "name": selected_category,
            "item": _public_url("forum_index", lang=lang, category=selected_category),
        })
    if post and post_url:
        items.append({
            "@type": "ListItem",
            "position": len(items) + 1,
            "name": post.title,
            "item": post_url,
        })
    return {
        "@type": "BreadcrumbList",
        "itemListElement": items,
    }


def _sitemap_alternates(endpoint, **params):
    links = _alternate_lang_links(endpoint, **params)
    return [{"hreflang": k, "href": v} for k, v in links.items()]


def _build_sitemap_urlset_xml(url_items):
    lines = [
        '<?xml version="1.0" encoding="UTF-8"?>',
        '<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9" '
        'xmlns:xhtml="http://www.w3.org/1999/xhtml">',
    ]
    for item in url_items:
        lines.append("  <url>")
        lines.append("    <loc>{}</loc>".format(xml_escape(item["loc"])))
        if item.get("lastmod"):
            lines.append("    <lastmod>{}</lastmod>".format(item["lastmod"]))
        if item.get("changefreq"):
            lines.append("    <changefreq>{}</changefreq>".format(item["changefreq"]))
        if item.get("priority"):
            lines.append("    <priority>{}</priority>".format(item["priority"]))
        for alt in item.get("alternates") or []:
            href = alt.get("href")
            hreflang = alt.get("hreflang")
            if not href or not hreflang:
                continue
            lines.append(
                '    <xhtml:link rel="alternate" hreflang="{}" href="{}" />'.format(
                    xml_escape(hreflang),
                    xml_escape(href),
                )
            )
        lines.append("  </url>")
    lines.append("</urlset>")
    return "\n".join(lines)


def _build_sitemap_index_xml(entries):
    lines = [
        '<?xml version="1.0" encoding="UTF-8"?>',
        '<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">',
    ]
    for item in entries:
        lines.append("  <sitemap>")
        lines.append("    <loc>{}</loc>".format(xml_escape(item["loc"])))
        if item.get("lastmod"):
            lines.append("    <lastmod>{}</lastmod>".format(item["lastmod"]))
        lines.append("  </sitemap>")
    lines.append("</sitemapindex>")
    return "\n".join(lines)


def _latest_forum_content_datetime():
    return db.session.query(func.max(func.coalesce(ForumPost.updated_at, ForumPost.created_at))).scalar()


def _forum_sitemap_total_pages():
    total_posts = ForumPost.query.count()
    return max((total_posts + SITEMAP_POSTS_PER_FILE - 1) // SITEMAP_POSTS_PER_FILE, 1)


def _should_noindex_path(path):
    target = path or ""
    if target.startswith("/admin"):
        return True
    if target.startswith("/api/"):
        return True
    if target in {"/login", "/register", "/profile", "/me", "/notifications"}:
        return True
    if target.startswith("/notification/"):
        return True
    if target == "/forum/post/new":
        return True
    if target == "/forum/report":
        return True
    if target.startswith("/forum/post/") and target.endswith("/edit"):
        return True
    if target.startswith("/forum/comment/") and target.endswith("/edit"):
        return True
    return False


@app.after_request
def _append_response_headers(response):
    response.headers.setdefault("Referrer-Policy", "strict-origin-when-cross-origin")
    response.headers.setdefault("X-Content-Type-Options", "nosniff")
    response.headers.setdefault("X-Frame-Options", "SAMEORIGIN")
    if _should_noindex_path(request.path):
        response.headers["X-Robots-Tag"] = "noindex, nofollow, noarchive"
    return response


def _notification_type_label(notif_type, lang=None):
    active_lang = lang or _get_lang()
    if active_lang == "en":
        return FORUM_NOTIFICATION_TYPE_LABELS_EN.get(notif_type, notif_type or "Notification")
    return FORUM_NOTIFICATION_TYPE_LABELS.get(notif_type, notif_type or "通知")


@app.template_global("l")
def _template_pick_lang(zh_text, en_text):
    active_lang = session.get("lang", "zh")
    if active_lang not in ("zh", "en"):
        active_lang = "zh"
    return en_text if active_lang == "en" else zh_text


@app.template_global("lang_url")
def _template_lang_url(lang_code):
    return _lang_url(lang_code)


def _render_markdown_html(text):
    raw = (text or "").strip()
    if not raw:
        return Markup("")
    if py_markdown is None or bleach is None:
        # 依赖缺失时回退为安全纯文本显示，避免服务启动失败。
        return Markup("<p>{}</p>".format(str(escape(raw)).replace("\n", "<br>")))
    html = py_markdown.markdown(raw, extensions=_MARKDOWN_EXTENSIONS)
    clean_html = bleach.clean(
        html,
        tags=_MARKDOWN_ALLOWED_TAGS,
        attributes=_MARKDOWN_ALLOWED_ATTRS,
        protocols=["http", "https", "mailto"],
        strip=True,
    )
    return Markup(clean_html)


@app.template_filter("markdown_html")
def markdown_html_filter(text):
    return _render_markdown_html(text)


def _get_current_user():
    user_id = session.get("user_id")
    if not user_id:
        return None
    user = db.session.get(User, user_id)
    if not user:
        session.pop("user_id", None)
    return user


def _is_banned_user(user):
    return bool(user and bool(user.is_banned))


def _user_ban_message(user):
    if not user:
        return "账号状态异常"
    reason = (user.banned_reason or "").strip()
    if reason:
        return "账号已被封禁：{}".format(reason)
    return "账号已被封禁"


def _is_valid_username(username):
    if not username:
        return False
    if len(username) < 3 or len(username) > 20:
        return False
    return all(ch.isalnum() or ch == "_" for ch in username)


def _safe_next_url(default_endpoint):
    nxt = (request.values.get("next") or "").strip()
    if nxt.startswith("/") and not nxt.startswith("//"):
        return nxt
    return url_for(default_endpoint)


def _safe_form_next_url(default_url):
    nxt = (request.form.get("next") or request.args.get("next") or "").strip()
    if nxt.startswith("/") and not nxt.startswith("//"):
        return nxt
    return default_url


def _create_notification(
    user_id,
    notif_type,
    message,
    actor_id=None,
    post_id=None,
    comment_id=None,
    report_id=None,
):
    """创建站内通知（由调用方控制事务提交）。"""
    if not user_id or not message:
        return
    db.session.add(ForumNotification(
        user_id=user_id,
        actor_id=actor_id,
        notif_type=notif_type,
        post_id=post_id,
        comment_id=comment_id,
        report_id=report_id,
        message=message[:255],
        is_read=False,
    ))
    _NOTIF_COUNT_CACHE.pop(user_id, None)


def _notification_target_url(notification):
    # 避免通知列表页按条检查帖子存在性导致 N+1 查询。
    if notification.post_id:
        return url_for("forum_post_detail", post_id=notification.post_id)
    return url_for("user_notifications")


def _load_forum_categories(active_only=True):
    """读取论坛分类（默认只读启用项）。"""
    try:
        q = ForumCategory.query
        if active_only:
            q = q.filter_by(is_active=True)
        return q.order_by(ForumCategory.sort_order.asc(), ForumCategory.id.asc()).all()
    except Exception:
        return []


def _get_forum_category_names(active_only=True):
    cache_key = "active" if active_only else "all"
    now_ts = monotonic()
    cached = _FORUM_CATEGORY_CACHE.get(cache_key)
    if cached and cached[0] > now_ts:
        return list(cached[1])

    rows = _load_forum_categories(active_only=active_only)
    names = [x.name for x in rows if x.name]
    if names:
        _FORUM_CATEGORY_CACHE[cache_key] = (now_ts + _FORUM_CACHE_TTL_CATEGORIES, tuple(names))
        return names
    # 若全部被停用，前台仍回退到已存在分类，避免下拉为空。
    if active_only:
        rows = _load_forum_categories(active_only=False)
        names = [x.name for x in rows if x.name]
        if names:
            _FORUM_CATEGORY_CACHE[cache_key] = (now_ts + _FORUM_CACHE_TTL_CATEGORIES, tuple(names))
            return names
    fallback = list(DEFAULT_FORUM_CATEGORIES)
    _FORUM_CATEGORY_CACHE[cache_key] = (now_ts + _FORUM_CACHE_TTL_CATEGORIES, tuple(fallback))
    return fallback


def _get_notifications_unread_count(user_id):
    """已登录用户未读通知数，短时缓存减少每次请求的 count 查询。"""
    if not user_id:
        return 0
    now_ts = monotonic()
    entry = _NOTIF_COUNT_CACHE.get(user_id)
    if entry is not None and entry[1] > now_ts:
        return entry[0]
    count = ForumNotification.query.filter_by(user_id=user_id, is_read=False).count()
    _NOTIF_COUNT_CACHE[user_id] = (count, now_ts + _FORUM_CACHE_TTL_NOTIF_COUNT)
    return count


@app.context_processor
def inject_global_user():
    lang = _get_lang()
    current_user = _get_current_user()
    notifications_unread_count = _get_notifications_unread_count(current_user.id if current_user else None)
    return {
        "current_user": current_user,
        "admin_logged_in": bool(session.get("admin_logged_in")),
        "forum_categories": _get_forum_category_names(active_only=True),
        "forum_report_reasons": FORUM_REPORT_REASONS,
        "notifications_unread_count": notifications_unread_count,
        "lang": lang,
    }


def _humanize_time(dt, lang=None):
    if not dt:
        return ""
    active_lang = lang or session.get("lang", "zh")
    if dt.tzinfo is None:
        # 兼容历史“无时区”时间：按 UTC 解释后与当前 UTC 进行比较，避免 utcnow 弃用告警
        dt = dt.replace(tzinfo=timezone.utc)
        now = datetime.now(timezone.utc)
    else:
        now = datetime.now(dt.tzinfo)
    delta = now - dt
    seconds = int(delta.total_seconds())
    if seconds < 0:
        return dt.strftime("%Y-%m-%d")
    if seconds < 60:
        return "just now" if active_lang == "en" else "刚刚"
    if seconds < 3600:
        mins = seconds // 60
        return "{}m ago".format(mins) if active_lang == "en" else "{} 分钟前".format(mins)
    if seconds < 86400:
        hours = seconds // 3600
        return "{}h ago".format(hours) if active_lang == "en" else "{} 小时前".format(hours)
    if seconds < 86400 * 14:
        days = seconds // 86400
        return "{}d ago".format(days) if active_lang == "en" else "{} 天前".format(days)
    return dt.strftime("%Y-%m-%d")


def _build_forum_post_cards(rows, lang=None):
    """将论坛查询结果行转换为列表卡片数据。"""
    active_lang = lang or _get_lang()
    cards = []
    for post, reply_count, latest_activity, author_name, like_count, bookmark_count in rows:
        latest_activity = latest_activity or post.created_at
        username = author_name or _pick_lang("用户", "User", active_lang)
        cards.append({
            "post": post,
            "reply_count": int(reply_count or 0),
            "view_count": int(post.view_count or 0),
            "like_count": int(like_count or 0),
            "bookmark_count": int(bookmark_count or 0),
            "latest_activity": latest_activity,
            "latest_activity_text": _humanize_time(latest_activity, lang=active_lang),
            "author_name": username,
            "author_initial": (username[0] if username else "?").upper(),
        })
    return cards


def _build_forum_url(tab="latest", category=None, q=None, page=1, per_page=20, lang=None):
    """构建论坛列表页链接，并尽量保持 URL 简洁。"""
    params = {}
    if (tab or "latest") != "latest":
        params["tab"] = tab
    if category:
        params["category"] = category
    if q:
        params["q"] = q
    if page and int(page) > 1:
        params["page"] = int(page)
    if per_page:
        size = int(per_page)
        if size != 20:
            params["per_page"] = size
    active_lang = (lang or "").strip().lower()
    if active_lang == "en":
        params["lang"] = "en"
    return url_for("forum_index", **params)


def _query_forum_post_rows(active_tab="latest", selected_category=None, search_query=None, author_id=None):
    """论坛列表查询：支持最新/新帖/热门 + 分类过滤 + 关键词搜索。"""
    comment_stats_subq = (
        db.session.query(
            ForumComment.post_id.label("post_id"),
            func.count(ForumComment.id).label("comment_count"),
            func.max(ForumComment.created_at).label("latest_comment_at"),
        )
        .group_by(ForumComment.post_id)
        .subquery()
    )
    comment_count_expr = func.coalesce(comment_stats_subq.c.comment_count, 0)
    latest_activity_expr = func.coalesce(comment_stats_subq.c.latest_comment_at, ForumPost.created_at)
    like_stats_subq = (
        db.session.query(
            ForumPostLike.post_id.label("post_id"),
            func.count(ForumPostLike.id).label("like_count"),
        )
        .group_by(ForumPostLike.post_id)
        .subquery()
    )
    bookmark_stats_subq = (
        db.session.query(
            ForumPostBookmark.post_id.label("post_id"),
            func.count(ForumPostBookmark.id).label("bookmark_count"),
        )
        .group_by(ForumPostBookmark.post_id)
        .subquery()
    )
    like_count_expr = func.coalesce(like_stats_subq.c.like_count, 0)
    bookmark_count_expr = func.coalesce(bookmark_stats_subq.c.bookmark_count, 0)
    q = (
        db.session.query(
            ForumPost,
            comment_count_expr.label("comment_count"),
            latest_activity_expr.label("latest_activity"),
            User.username.label("author_name"),
            like_count_expr.label("like_count"),
            bookmark_count_expr.label("bookmark_count"),
        )
        .outerjoin(comment_stats_subq, comment_stats_subq.c.post_id == ForumPost.id)
        .outerjoin(like_stats_subq, like_stats_subq.c.post_id == ForumPost.id)
        .outerjoin(bookmark_stats_subq, bookmark_stats_subq.c.post_id == ForumPost.id)
        .outerjoin(User, User.id == ForumPost.user_id)
    )
    if selected_category:
        q = q.filter(ForumPost.category == selected_category)
    if author_id is not None:
        q = q.filter(ForumPost.user_id == author_id)
    if search_query:
        pattern = "%{}%".format(search_query)
        q = q.filter(
            or_(
                ForumPost.title.ilike(pattern),
                ForumPost.content.ilike(pattern),
                User.username.ilike(pattern),
            )
        )
    if active_tab == "hot":
        q = q.order_by(
            ForumPost.is_pinned.desc(),
            comment_count_expr.desc(),
            like_count_expr.desc(),
            ForumPost.view_count.desc(),
            latest_activity_expr.desc(),
            ForumPost.id.desc(),
        )
    elif active_tab == "new":
        q = q.order_by(ForumPost.is_pinned.desc(), ForumPost.created_at.desc(), ForumPost.id.desc())
    else:
        q = q.order_by(ForumPost.is_pinned.desc(), latest_activity_expr.desc(), ForumPost.id.desc())
    return q


def _forum_sidebar_data():
    now_ts = monotonic()
    cached = _FORUM_SIDEBAR_CACHE.get("data")
    if cached is not None and _FORUM_SIDEBAR_CACHE.get("expires_at", 0.0) > now_ts:
        return dict(cached)

    category_counts = (
        db.session.query(ForumPost.category, func.count(ForumPost.id))
        .group_by(ForumPost.category)
        .order_by(func.count(ForumPost.id).desc())
        .all()
    )
    active_users = (
        db.session.query(User.username, func.count(ForumPost.id).label("post_count"))
        .outerjoin(ForumPost, ForumPost.user_id == User.id)
        .group_by(User.id)
        .order_by(func.count(ForumPost.id).desc(), User.created_at.asc())
        .limit(6)
        .all()
    )
    data = {
        "total_users": User.query.count(),
        "total_posts": ForumPost.query.count(),
        "total_comments": ForumComment.query.count(),
        "category_counts": list(category_counts),
        "active_users": list(active_users),
    }
    _FORUM_SIDEBAR_CACHE["data"] = data
    _FORUM_SIDEBAR_CACHE["expires_at"] = now_ts + _FORUM_CACHE_TTL_SIDEBAR
    return dict(data)


def _count_forum_posts(selected_category=None, search_query=None, author_id=None):
    """论坛列表总数查询：避免对重查询语句直接 count 导致慢查询。"""
    q = (
        db.session.query(func.count(ForumPost.id))
        .select_from(ForumPost)
        .outerjoin(User, User.id == ForumPost.user_id)
    )
    if selected_category:
        q = q.filter(ForumPost.category == selected_category)
    if author_id is not None:
        q = q.filter(ForumPost.user_id == author_id)
    if search_query:
        pattern = "%{}%".format(search_query)
        q = q.filter(
            or_(
                ForumPost.title.ilike(pattern),
                ForumPost.content.ilike(pattern),
                User.username.ilike(pattern),
            )
        )
    return int(q.scalar() or 0)


def _currency_symbol(currency):
    return "¥" if (currency or "CNY").upper() == "CNY" else "$"


def _format_money(currency, value):
    return "{}{:.2f}".format(_currency_symbol(currency), float(value))


def _format_history_time(dt):
    return dt.strftime("%Y-%m-%d %H:%M") if dt else ""


def _pick_price_pair(latest, previous=None):
    if previous is None:
        if latest.price_cny is not None:
            return "CNY", float(latest.price_cny), None
        if latest.price_usd is not None:
            return "USD", float(latest.price_usd), None
        return None, None, None
    if latest.price_cny is not None and previous.price_cny is not None:
        return "CNY", float(latest.price_cny), float(previous.price_cny)
    if latest.price_usd is not None and previous.price_usd is not None:
        return "USD", float(latest.price_usd), float(previous.price_usd)
    return None, None, None


def _build_price_trend(latest, previous=None):
    currency, current_value, previous_value = _pick_price_pair(latest, previous)
    if currency is None or current_value is None:
        return None
    source = PRICE_SOURCE_LABELS.get(latest.source or "", latest.source or "未知来源")
    meta = "当前 {} · {} · {}".format(
        _format_money(currency, current_value),
        _format_history_time(latest.captured_at),
        source,
    )
    if previous_value is None:
        return {
            "direction": "new",
            "delta_text": "首次记录",
            "meta_text": meta,
        }
    diff = current_value - previous_value
    if abs(diff) < 1e-9:
        return {
            "direction": "flat",
            "delta_text": "→ 持平",
            "meta_text": meta,
        }
    direction = "up" if diff > 0 else "down"
    arrow = "↑" if diff > 0 else "↓"
    sign = "+" if diff > 0 else "-"
    delta_text = "{} {}{}{:,.2f}".format(arrow, sign, _currency_symbol(currency), abs(diff))
    if abs(previous_value) > 1e-9:
        pct = diff / previous_value * 100
        delta_text += " ({:+.2f}%)".format(pct)
    return {
        "direction": direction,
        "delta_text": delta_text,
        "meta_text": meta,
    }


def _build_plan_trend_map(plans):
    plan_ids = [p.id for p in plans if p.id is not None]
    if not plan_ids:
        return {}
    rows = (
        PriceHistory.query
        .filter(PriceHistory.plan_id.in_(plan_ids))
        .order_by(PriceHistory.plan_id.asc(), PriceHistory.captured_at.desc(), PriceHistory.id.desc())
        .all()
    )
    grouped = {}
    for row in rows:
        bucket = grouped.setdefault(row.plan_id, [])
        if len(bucket) < 2:
            bucket.append(row)
    result = {}
    for plan_id, bucket in grouped.items():
        latest = bucket[0] if bucket else None
        previous = bucket[1] if len(bucket) > 1 else None
        trend = _build_price_trend(latest, previous) if latest else None
        if trend:
            result[plan_id] = trend
    return result


def _build_post_plan_recommendations(post, lang="zh", limit=5):
    if not post:
        return [], _pick_lang("暂无推荐方案", "No recommended plans yet.", lang)

    raw_text = "{}\n{}".format(post.title or "", post.content or "")
    text_lower = raw_text.lower()
    matched_provider_ids = []
    matched_provider_names = []
    provider_rows = Provider.query.order_by(Provider.id.asc()).limit(200).all()
    for provider in provider_rows:
        name = (provider.name or "").strip()
        if not name:
            continue
        if name.lower() in text_lower:
            matched_provider_ids.append(provider.id)
            matched_provider_names.append(name)

    matched_regions = []
    for region in COUNTRY_TAGS:
        item = (region or "").strip()
        if item and item in raw_text:
            matched_regions.append(item)
        if len(matched_regions) >= 3:
            break

    price_score_expr = func.coalesce(VPSPlan.price_cny, VPSPlan.price_usd * 7.2, 999999.0)
    base_query = (
        VPSPlan.query
        .options(joinedload(VPSPlan.provider_rel))
        .filter(or_(VPSPlan.price_cny.isnot(None), VPSPlan.price_usd.isnot(None)))
    )
    scoped_query = base_query
    if matched_provider_ids:
        scoped_query = scoped_query.filter(
            or_(
                VPSPlan.provider_id.in_(matched_provider_ids),
                VPSPlan.provider.in_(matched_provider_names),
            )
        )
    if matched_regions:
        region_conds = []
        for region in matched_regions:
            region_conds.append(VPSPlan.countries.ilike("%{}%".format(region)))
            region_conds.append(VPSPlan.region.ilike("%{}%".format(region)))
        scoped_query = scoped_query.filter(or_(*region_conds))

    ordered_scoped = scoped_query.order_by(
        price_score_expr.asc(),
        VPSPlan.vcpu.desc(),
        VPSPlan.memory_gb.desc(),
        VPSPlan.id.desc(),
    )
    picked = ordered_scoped.limit(limit).all()
    seen_ids = {p.id for p in picked if p and p.id is not None}
    if len(picked) < limit:
        fallback_rows = (
            base_query
            .order_by(
                price_score_expr.asc(),
                VPSPlan.vcpu.desc(),
                VPSPlan.memory_gb.desc(),
                VPSPlan.id.desc(),
            )
            .limit(max(limit * 2, 12))
            .all()
        )
        for row in fallback_rows:
            if not row or row.id in seen_ids:
                continue
            picked.append(row)
            seen_ids.add(row.id)
            if len(picked) >= limit:
                break

    items = []
    for plan in picked[:limit]:
        if plan.price_cny is not None:
            price_label = _format_money("CNY", plan.price_cny)
        elif plan.price_usd is not None:
            price_label = _format_money("USD", plan.price_usd)
        else:
            price_label = _pick_lang("待更新", "TBD", lang)
        items.append({
            "id": plan.id,
            "provider": plan.provider_name or plan.provider or _pick_lang("未知厂商", "Unknown Provider", lang),
            "name": plan.display_name or _pick_lang("未命名方案", "Unnamed Plan", lang),
            "region": (plan.countries or plan.region or _pick_lang("区域未标注", "Region not specified", lang)).strip(),
            "price_label": price_label,
            "official_url": (plan.official_url or (plan.provider_rel.official_url if plan.provider_rel else "") or "").strip(),
        })

    if matched_provider_ids and matched_regions:
        context_text = _pick_lang(
            "依据帖子中的厂商与区域关键词推荐",
            "Recommended based on provider and region keywords in this topic",
            lang,
        )
    elif matched_provider_ids:
        context_text = _pick_lang(
            "依据帖子中的厂商关键词推荐",
            "Recommended based on provider keywords in this topic",
            lang,
        )
    elif matched_regions:
        context_text = _pick_lang(
            "依据帖子中的区域关键词推荐",
            "Recommended based on region keywords in this topic",
            lang,
        )
    else:
        context_text = _pick_lang(
            "按价格与规格综合排序推荐",
            "Recommended by a combined price/spec ranking",
            lang,
        )
    return items, context_text


def _build_post_detail_url(post_id, lang="zh", comment_page=1):
    """构建帖子详情页 URL（用于评论分页链接）。"""
    page_num = 1
    try:
        page_num = int(comment_page or 1)
    except Exception:
        page_num = 1
    if page_num < 1:
        page_num = 1
    params = {"post_id": post_id}
    if page_num > 1:
        params["cp"] = page_num
    if (lang or "zh").strip().lower() == "en":
        params["lang"] = "en"
    return url_for("forum_post_detail", **params)


def _build_post_comment_page_links(post_id, total_pages, current_page, lang="zh"):
    total = int(total_pages or 1)
    current = int(current_page or 1)
    if total <= 1:
        return []
    candidates = {1, total}
    for n in range(current - 2, current + 3):
        if 1 <= n <= total:
            candidates.add(n)
    ordered = sorted(candidates)
    links = []
    prev = None
    for page in ordered:
        if prev is not None and page - prev > 1:
            links.append({"is_gap": True, "label": "…"})
        links.append({
            "is_gap": False,
            "page": page,
            "url": _build_post_detail_url(post_id, lang=lang, comment_page=page),
            "active": page == current,
        })
        prev = page
    return links


def _build_post_resource_links(post, lang="zh"):
    if not post:
        return []
    category_name = (post.category or "").strip()
    links = []
    if category_name:
        links.append({
            "title": _pick_lang("继续看同分类主题", "More in This Category", lang),
            "description": _pick_lang("同一分类下的最新讨论与经验汇总。", "Browse latest discussions in the same category.", lang),
            "url": _build_forum_url(category=category_name, lang=lang),
            "track_label": "resource_category",
        })
    links.extend([
        {
            "title": _pick_lang("论坛热门讨论", "Hot Forum Topics", lang),
            "description": _pick_lang("优先阅读互动度高的帖子，快速获取高信号观点。", "Prioritize high-engagement threads for stronger signals.", lang),
            "url": _build_forum_url(tab="hot", lang=lang),
            "track_label": "resource_hot",
        },
        {
            "title": _pick_lang("论坛最新动态", "Latest Forum Activity", lang),
            "description": _pick_lang("追踪最新发布和最近活跃的主题。", "Track newly posted and recently active topics.", lang),
            "url": _build_forum_url(tab="latest", lang=lang),
            "track_label": "resource_latest",
        },
        {
            "title": _pick_lang("VPS 价格总览", "VPS Pricing Console", lang),
            "description": _pick_lang("按价格、地区、配置进行方案筛选。", "Filter plans by price, region, and specs.", lang),
            "url": url_for("index", lang="en") if lang == "en" else url_for("index"),
            "track_label": "resource_pricing",
        },
        {
            "title": _pick_lang("论坛 RSS 订阅", "Forum RSS Feed", lang),
            "description": _pick_lang("通过订阅持续跟进论坛更新。", "Follow forum updates through RSS subscription.", lang),
            "url": url_for("forum_feed", lang="en") if lang == "en" else url_for("forum_feed"),
            "track_label": "resource_feed",
        },
    ])
    deduped = []
    seen = set()
    for item in links:
        u = item.get("url")
        if not u or u in seen:
            continue
        seen.add(u)
        deduped.append(item)
    return deduped[:6]


def _build_post_faq_items(post, comments_count=0, read_minutes=1, plan_reco_context="", lang="zh"):
    if not post:
        return []
    post_excerpt = _plain_excerpt(post.content or "", limit=180) or _pick_lang(
        "本帖围绕 VPS 选型与采购决策展开讨论。",
        "This topic discusses VPS shortlisting and procurement decisions.",
        lang,
    )
    comments_val = max(int(comments_count or 0), 0)
    read_val = max(int(read_minutes or 1), 1)
    recommendation_line = (plan_reco_context or "").strip() or _pick_lang(
        "按价格与规格综合排序推荐方案。",
        "Plans are recommended by combined price and spec ranking.",
        lang,
    )
    return [
        {
            "question": _pick_lang("这篇帖子主要讨论什么？", "What does this topic focus on?", lang),
            "answer": post_excerpt,
        },
        {
            "question": _pick_lang("我应该先看正文还是先看评论？", "Should I read content or comments first?", lang),
            "answer": _pick_lang(
                "建议先用约 {} 分钟读完正文，再结合 {} 条评论验证观点。".format(read_val, comments_val),
                "Read the main post first in about {} minutes, then validate points with {} comments.".format(read_val, comments_val),
                lang,
            ),
        },
        {
            "question": _pick_lang("下一步如何落地选型？", "What is the next step for shortlisting?", lang),
            "answer": _pick_lang(
                "{} 随后进入价格页按地区、预算和配置筛选，再到厂商官网确认条款。".format(recommendation_line),
                "{} Then use the pricing page filters (region, budget, specs) and confirm terms on official provider sites.".format(recommendation_line),
                lang,
            ),
        },
    ]


def _build_post_howto_schema(post, canonical_url, lang="zh", read_minutes=1, comments_count=0):
    if not post or not canonical_url:
        return None
    comments_val = max(int(comments_count or 0), 0)
    read_val = max(int(read_minutes or 1), 1)
    pricing_url = _public_url("index", lang=lang)
    post_new_url = _public_url("forum_post_new", lang=lang)
    steps = [
        {
            "@type": "HowToStep",
            "position": 1,
            "name": _pick_lang("阅读主题与核心需求", "Read the topic and core requirement", lang),
            "text": _pick_lang(
                "先阅读标题和正文，明确业务目标、预算和区域要求。",
                "Read title and content first to identify workload goals, budget, and region requirements.",
                lang,
            ),
            "url": canonical_url,
        },
        {
            "@type": "HowToStep",
            "position": 2,
            "name": _pick_lang("核对评论反馈", "Validate with comments", lang),
            "text": _pick_lang(
                "结合约 {} 条评论判断观点可靠性与落地风险。".format(comments_val),
                "Use around {} comments to validate reliability and delivery risks.".format(comments_val),
                lang,
            ),
            "url": "{}#comments-panel".format(canonical_url),
        },
        {
            "@type": "HowToStep",
            "position": 3,
            "name": _pick_lang("进入价格页筛选方案", "Filter plans on pricing page", lang),
            "text": _pick_lang(
                "按地区、价格和配置过滤候选 VPS，建立短名单。",
                "Filter candidates by region, price, and specs to build a shortlist.",
                lang,
            ),
            "url": pricing_url,
        },
        {
            "@type": "HowToStep",
            "position": 4,
            "name": _pick_lang("补充需求并确认采购", "Publish requirement and finalize", lang),
            "text": _pick_lang(
                "若信息仍不足，可发布新主题补充业务约束并确认采购方案。",
                "If signal is still insufficient, publish a follow-up topic and finalize the buying plan.",
                lang,
            ),
            "url": post_new_url,
        },
    ]
    return {
        "@type": "HowTo",
        "@id": "{}#howto".format(canonical_url),
        "name": _pick_lang("如何从论坛主题完成 VPS 选型", "How to shortlist VPS from a forum topic", lang),
        "description": _pick_lang(
            "从阅读帖子到筛选方案再到确认采购的标准流程。",
            "A practical workflow from reading a discussion to shortlisting and procurement.",
            lang,
        ),
        "inLanguage": "en-US" if lang == "en" else "zh-CN",
        "totalTime": "PT{}M".format(max(3, read_val + 2)),
        "step": steps,
    }


def admin_required(f):
    from functools import wraps
    @wraps(f)
    def wrapped(*args, **kwargs):
        if not session.get("admin_logged_in"):
            return redirect(url_for("admin_login"))
        return f(*args, **kwargs)
    return wrapped


def user_login_required(f):
    from functools import wraps
    @wraps(f)
    def wrapped(*args, **kwargs):
        user = _get_current_user()
        if not user:
            return redirect(url_for("user_login", next=request.path))
        if _is_banned_user(user):
            session.pop("user_id", None)
            return redirect(url_for("user_login", next=request.path, error=_user_ban_message(user)))
        return f(*args, **kwargs)
    return wrapped


def _ensure_forum_interaction_user(user, post_id=None):
    """校验当前登录用户是否可进行论坛互动动作。"""
    if not _is_banned_user(user):
        return None
    text = _user_ban_message(user)
    if post_id:
        return _forum_redirect_with_error(post_id, text)
    return redirect(url_for("forum_index", error=text))


def _can_edit_post(user, post):
    if not user or not post:
        return False
    return post.user_id == user.id


def _can_edit_comment(user, comment):
    if not user or not comment:
        return False
    return comment.user_id == user.id


def _forum_redirect_with_error(post_id, text_msg):
    return redirect(url_for("forum_post_detail", post_id=post_id, error=text_msg))


def _forum_redirect_with_msg(post_id, text_msg):
    return redirect(url_for("forum_post_detail", post_id=post_id, msg=text_msg))


# 首页多语言文案（中文 / English）
I18N = {
    "zh": {
        "meta_title": "全球 VPS 价格与配置对比 | 云价眼",
        "meta_description": "面向技术与采购团队的云服务器价格情报平台：统一对比主流厂商 VPS 月付价格、配置与区域，支持快速筛选并直达官方购买页。",
        "meta_keywords": "VPS价格对比,云服务器采购,云主机报价,云厂商比价,企业云成本,阿里云腾讯云DigitalOceanVultr",
        "og_title": "云价眼 | 全球 VPS 价格与配置决策台",
        "og_description": "为团队采购与技术选型提供可比价的云服务器数据视图，快速定位成本与性能平衡点。",
        "og_locale": "zh_CN",
        "schema_webapp_description": "面向团队采购与技术选型的 VPS 价格与配置对比平台。",
        "schema_table_about": "云价眼 - 全球 VPS 价格与配置决策台",
        "schema_table_name": "VPS 价格与配置对比表",
        "schema_table_description": "主流云厂商 VPS 方案的配置、区域与月付价格数据",
        "tagline": "面向团队采购的云服务器价格情报",
        "hero_kicker": "企业云资源采购情报",
        "hero_title": "全球 VPS 价格与配置决策台",
        "hero_lede": "聚合主流云厂商公开报价，统一月付口径与配置维度，帮助技术与采购团队更快完成方案筛选与预算评估。",
        "hero_trust_1": "主流云厂商持续收录",
        "hero_trust_2": "统一月付与配置口径",
        "hero_trust_3": "直达官方购买与文档",
        "metric_total_plans": "可比较方案",
        "metric_providers": "覆盖厂商",
        "metric_regions": "覆盖区域",
        "metric_lowest": "筛选后最低月价",
        "filters_title": "采购筛选控制台",
        "filters_subtitle": "按厂商、区域、资源规格与预算快速收敛候选方案。",
        "table_caption": "价格与配置根据筛选条件实时刷新，用于初步比选与预算评估。",
        "filter_provider": "供应商",
        "filter_region": "区域市场",
        "filter_memory": "内存 ≥",
        "filter_price": "价格区间",
        "filter_currency": "计价货币",
        "search_placeholder": "搜索供应商、方案或区域...",
        "all": "全部",
        "unlimited": "不限",
        "btn_reset": "清空筛选",
        "btn_visit": "查看官网",
        "th_provider": "供应商",
        "th_country": "区域",
        "th_config": "实例规格",
        "th_vcpu": "vCPU",
        "th_memory": "内存",
        "th_storage": "存储",
        "th_bandwidth": "带宽",
        "th_traffic": "流量",
        "th_price": "月付参考价",
        "th_action": "官方链接",
        "disclaimer": "* 数据来自公开页面与规则换算，可能存在时差或促销偏差；下单前请以厂商官网实时价格与条款为准。",
        "footer_note": "仅作采购调研参考 · 请以各云厂商官网实时价格为准",
        "contact_label": "联系我们",
        "empty_state": "未找到匹配的方案",
        "load_error": "数据加载失败，请刷新页面重试",
        "search_label": "关键词检索",
        "result_count_pattern": "当前筛选：{visible} / {total} 个方案",
        "price_under50": "< ¥50",
        "price_50_100": "¥50-100",
        "price_100_300": "¥100-300",
        "price_300_500": "¥300-500",
        "price_over500": "> ¥500",
        "cny": "人民币 (¥)",
        "usd": "美元 ($)",
        "no_js_note": "已显示基础数据表；开启 JavaScript 后可使用实时筛选、排序和动态统计。",
        "faq_title": "常见问题（采购前必看）",
        "faq_intro": "以下信息用于预算与方案初筛，正式采购前请再次核对厂商官网。",
        "faq_q1": "价格和配置数据多久更新一次？",
        "faq_a1": "平台持续维护公开报价源，后台更新后会同步刷新展示与 API 缓存。",
        "faq_q2": "表格价格能直接作为合同报价吗？",
        "faq_a2": "不能。页面数据用于调研与比选，实际价格、账单周期与折扣条款请以厂商官网和销售合同为准。",
        "faq_q3": "如何快速筛选适合企业业务的方案？",
        "faq_a3": "建议先按区域和预算过滤，再结合 vCPU、内存、存储和带宽指标缩小候选范围，最后进入厂商官网确认 SLA 与网络质量。",
        "cta_title": "需要更深度的采购建议？",
        "cta_lede": "在社区论坛提交需求场景，或直接联系站点维护者获取更新建议。",
        "cta_primary": "进入社区论坛",
        "cta_secondary": "联系维护者",
    },
    "en": {
        "meta_title": "Global VPS Pricing & Configuration Comparison | VPS Price",
        "meta_description": "Pricing intelligence for engineering and procurement teams: compare VPS monthly costs, specs, and regions across major providers with normalized criteria.",
        "meta_keywords": "VPS pricing comparison,cloud server procurement,provider pricing benchmark,cloud cost planning,infrastructure buying",
        "og_title": "VPS Price | Global VPS Pricing Decision Console",
        "og_description": "A procurement-ready view of VPS pricing and specs across major providers for faster, more confident infrastructure decisions.",
        "og_locale": "en_US",
        "schema_webapp_description": "A pricing and configuration comparison platform for VPS procurement and technical planning.",
        "schema_table_about": "VPS Price - Global VPS Pricing Decision Console",
        "schema_table_name": "VPS Pricing and Configuration Table",
        "schema_table_description": "Comparable monthly pricing, specs, and region data across mainstream VPS providers",
        "tagline": "Cloud pricing intelligence for engineering and procurement teams",
        "hero_kicker": "Enterprise Infrastructure Intelligence",
        "hero_title": "Global VPS Pricing Decision Console",
        "hero_lede": "Aggregate public VPS offers, normalize monthly pricing and specs, and help engineering and procurement teams shortlist options faster.",
        "hero_trust_1": "Major providers continuously tracked",
        "hero_trust_2": "Normalized monthly pricing and specs",
        "hero_trust_3": "Direct links to official purchase pages",
        "metric_total_plans": "Comparable Plans",
        "metric_providers": "Providers Covered",
        "metric_regions": "Regions Covered",
        "metric_lowest": "Lowest Monthly Price",
        "filters_title": "Procurement Filter Console",
        "filters_subtitle": "Narrow candidates by provider, region, resource profile, and budget range.",
        "table_caption": "Pricing and specs refresh in real time based on active filters for quicker shortlist decisions.",
        "filter_provider": "Provider",
        "filter_region": "Region",
        "filter_memory": "Memory ≥",
        "filter_price": "Price range",
        "filter_currency": "Currency",
        "search_placeholder": "Search provider, plan, or region...",
        "all": "All",
        "unlimited": "Any",
        "btn_reset": "Clear filters",
        "btn_visit": "Visit Site",
        "th_provider": "Provider",
        "th_country": "Region",
        "th_config": "Plan Spec",
        "th_vcpu": "vCPU",
        "th_memory": "Memory",
        "th_storage": "Storage",
        "th_bandwidth": "Bandwidth",
        "th_traffic": "Traffic",
        "th_price": "Monthly Price",
        "th_action": "Official Link",
        "disclaimer": "* Data is compiled from public sources and normalization rules. Final billing terms and live pricing are determined by each provider.",
        "footer_note": "For research and shortlisting only. Always verify latest pricing on official provider websites.",
        "contact_label": "Contact",
        "empty_state": "No matching plans found",
        "load_error": "Failed to load data. Please refresh.",
        "search_label": "Keyword Search",
        "result_count_pattern": "Showing {visible} of {total} plans",
        "price_under50": "< 50",
        "price_50_100": "50-100",
        "price_100_300": "100-300",
        "price_300_500": "300-500",
        "price_over500": "> 500",
        "cny": "CNY (¥)",
        "usd": "USD ($)",
        "no_js_note": "Base table data is already visible. Enable JavaScript for live filters, sorting, and dynamic metrics.",
        "faq_title": "FAQ for Procurement Teams",
        "faq_intro": "Use these answers for shortlisting. Re-check vendor websites before placing orders.",
        "faq_q1": "How often are pricing and spec records updated?",
        "faq_a1": "The platform continuously maintains public pricing sources. Admin updates refresh both page rendering and API cache.",
        "faq_q2": "Can listed prices be treated as final contract quotes?",
        "faq_a2": "No. This site is for research and shortlisting. Final pricing, billing cycles, and discounts are defined by each provider and contract.",
        "faq_q3": "How should we shortlist plans for business workloads?",
        "faq_a3": "Start with region and budget filters, then narrow by vCPU, memory, storage, and bandwidth. Validate SLA and network quality on the provider site.",
        "cta_title": "Need Deeper Buying Guidance?",
        "cta_lede": "Post your workload requirements in the community forum or contact the site maintainer directly.",
        "cta_primary": "Open Community Forum",
        "cta_secondary": "Contact Maintainer",
    },
}


def _query_plans_for_display():
    """查询 VPS 方案列表并预加载 provider，避免 to_dict() 时 N+1。"""
    return (
        VPSPlan.query
        .options(joinedload(VPSPlan.provider_rel))
        .order_by(VPSPlan.provider, VPSPlan.price_cny)
        .all()
    )


# /api/plans 短期缓存（秒）
_API_PLANS_CACHE_TTL = 60
_API_PLANS_CACHE = {"data": None, "expires_at": 0.0}


def _invalidate_plans_cache():
    """后台增删改方案后调用，使 /api/plans 缓存失效。"""
    _API_PLANS_CACHE["expires_at"] = 0.0


def _build_home_faq_items(t):
    return [
        {"question": t["faq_q1"], "answer": t["faq_a1"]},
        {"question": t["faq_q2"], "answer": t["faq_a2"]},
        {"question": t["faq_q3"], "answer": t["faq_a3"]},
    ]


def _build_home_schema(lang, t, canonical_url, plans_data, faq_items):
    in_language = "en-US" if lang == "en" else "zh-CN"
    site_root = _site_root_url()
    logo_url = _absolute_url_for("static", filename="img/site-logo.svg")
    og_image_url = _absolute_url_for("static", filename="img/site-logo-mark.svg")
    item_list = []
    for idx, plan in enumerate(plans_data[:30], start=1):
        provider_name = (plan.get("provider") or "").strip()
        plan_name = (plan.get("name") or "").strip()
        product_name = "{} {}".format(provider_name, plan_name).strip() or "VPS Plan {}".format(idx)
        product = {
            "@type": "Product",
            "name": product_name,
            "brand": {"@type": "Brand", "name": provider_name or SITE_NAME},
        }
        region_name = (plan.get("countries") or "").strip()
        if region_name:
            product["category"] = region_name
        official_url = (plan.get("official_url") or "").strip()
        if official_url:
            product["url"] = official_url
        offer = {"@type": "Offer", "url": official_url or canonical_url}
        if plan.get("price_cny") is not None:
            offer["price"] = float(plan["price_cny"])
            offer["priceCurrency"] = "CNY"
        elif plan.get("price_usd") is not None:
            offer["price"] = float(plan["price_usd"])
            offer["priceCurrency"] = "USD"
        if "price" in offer:
            product["offers"] = offer
        item_list.append({
            "@type": "ListItem",
            "position": idx,
            "item": product,
        })

    faq_entities = [
        {
            "@type": "Question",
            "name": item["question"],
            "acceptedAnswer": {"@type": "Answer", "text": item["answer"]},
        }
        for item in faq_items
    ]

    return {
        "@context": "https://schema.org",
        "@graph": [
            {
                "@type": "Organization",
                "@id": "{}#org".format(site_root),
                "name": SITE_NAME,
                "url": site_root,
                "logo": logo_url,
            },
            {
                "@type": "WebSite",
                "@id": "{}#website".format(site_root),
                "url": site_root,
                "name": SITE_NAME,
                "inLanguage": in_language,
            },
            {
                "@type": "WebPage",
                "@id": "{}#home".format(canonical_url),
                "url": canonical_url,
                "name": t["meta_title"],
                "description": t["meta_description"],
                "inLanguage": in_language,
                "primaryImageOfPage": og_image_url,
            },
            {
                "@type": "ItemList",
                "name": t["schema_table_name"],
                "description": t["schema_table_description"],
                "itemListElement": item_list,
            },
            {
                "@type": "FAQPage",
                "mainEntity": faq_entities,
            },
        ],
    }


@app.route("/")
def index():
    lang = _get_lang()
    t = I18N[lang]
    plans = _query_plans_for_display()
    plans_data = [p.to_dict() for p in plans]
    canonical_url = _public_url("index", lang=lang)
    alternate_links = _alternate_lang_links("index")
    faq_items = _build_home_faq_items(t)
    seo = {
        "title": t["meta_title"],
        "description": t["meta_description"],
        "keywords": t["meta_keywords"],
        "canonical_url": canonical_url,
        "robots": "index,follow,max-image-preview:large,max-snippet:-1,max-video-preview:-1",
        "og_type": "website",
        "og_url": canonical_url,
        "og_title": t["og_title"],
        "og_description": t["og_description"],
        "og_locale": t["og_locale"],
        "og_image": _absolute_url_for("static", filename="img/site-logo-mark.svg"),
        "twitter_card": "summary_large_image",
        "twitter_title": t["og_title"],
        "twitter_description": t["og_description"],
        "alternate_links": alternate_links,
    }
    home_schema = _build_home_schema(
        lang=lang,
        t=t,
        canonical_url=canonical_url,
        plans_data=plans_data,
        faq_items=faq_items,
    )
    return render_template(
        "index.html",
        site_url=_site_root_url(),
        site_name=SITE_NAME,
        initial_plans_json=plans_data,
        faq_items=faq_items,
        seo=seo,
        seo_schema=home_schema,
        lang=lang,
        t=t,
    )


@app.route("/assets/<path:filename>")
def legacy_assets(filename):
    """
    兼容历史内容中的 /assets/* 链接：
    - 若 static/assets 下存在目标文件则直接返回
    - 否则回退到站点标识图，避免前端出现 404 噪音
    """
    assets_dir = os.path.join(app.static_folder or "", "assets")
    candidate = os.path.normpath(os.path.join(assets_dir, filename))
    assets_dir_abs = os.path.abspath(assets_dir)
    candidate_abs = os.path.abspath(candidate)
    if candidate_abs.startswith(assets_dir_abs + os.sep) and os.path.isfile(candidate_abs):
        rel_path = os.path.relpath(candidate_abs, assets_dir_abs)
        return send_from_directory(assets_dir_abs, rel_path)
    return redirect(url_for("static", filename="img/site-logo-mark.svg"), code=302)


@app.route("/api/plans")
def api_plans():
    now_ts = monotonic()
    cached = _API_PLANS_CACHE.get("data")
    if cached is not None and _API_PLANS_CACHE.get("expires_at", 0.0) > now_ts:
        resp = jsonify(cached)
        resp.headers["Cache-Control"] = "public, max-age=%d" % _API_PLANS_CACHE_TTL
        return resp
    plans = _query_plans_for_display()
    data = [p.to_dict() for p in plans]
    _API_PLANS_CACHE["data"] = data
    _API_PLANS_CACHE["expires_at"] = now_ts + _API_PLANS_CACHE_TTL
    resp = jsonify(data)
    resp.headers["Cache-Control"] = "public, max-age=%d" % _API_PLANS_CACHE_TTL
    return resp


@app.route("/api/event/track", methods=["POST"])
def api_event_track():
    payload = {}
    if request.is_json:
        payload = request.get_json(silent=True) or {}
    if not payload:
        payload = request.form.to_dict(flat=True)
    event_name = (payload.get("event_name") or "").strip().lower()
    if not re.match(r"^[a-z0-9_]{3,64}$", event_name or ""):
        return ("", 204)

    whitelist = {
        "post_detail_cta_pricing",
        "post_detail_cta_new_topic",
        "post_detail_jump_comments",
        "post_detail_related_click",
        "post_detail_plan_click",
        "post_detail_comment_submit",
        "post_detail_sidebar_compare",
        "post_detail_resource_click",
    }
    if event_name not in whitelist:
        return ("", 204)

    label = " ".join((payload.get("label") or "").strip().split())[:120]
    page_path = " ".join((payload.get("page_path") or "").strip().split())[:255]
    post_id = payload.get("post_id")
    try:
        post_id = int(post_id) if post_id is not None else None
    except Exception:
        post_id = None
    if not page_path:
        referer = (request.headers.get("Referer") or "").strip()
        page_path = referer[:255]
    user = _get_current_user()
    event_data = {
        "event_name": event_name,
        "label": label,
        "post_id": post_id,
        "user_id": user.id if user else None,
        "page_path": page_path,
        "endpoint_path": request.path,
        "referer": (request.headers.get("Referer") or "")[:255],
        "ip": (request.headers.get("X-Forwarded-For") or request.remote_addr or "")[:120],
        "at": _iso8601_utc(datetime.now(timezone.utc)),
    }
    app.logger.info("forum_track_event %s", json.dumps(event_data, ensure_ascii=False))
    return ("", 204)


# ---------- 前台用户与论坛 ----------
@app.route("/register", methods=["GET", "POST"])
def user_register():
    lang = _get_lang()
    current = _get_current_user()
    if current:
        if _is_banned_user(current):
            session.pop("user_id", None)
        else:
            return redirect(url_for("forum_index"))
    error = None
    if request.method == "POST":
        username = (request.form.get("username") or "").strip()
        password = request.form.get("password") or ""
        confirm_password = request.form.get("confirm_password") or ""

        if not _is_valid_username(username):
            error = _pick_lang(
                "用户名需为 3-20 位，仅支持字母、数字、下划线",
                "Username must be 3-20 chars (letters, numbers, underscore).",
                lang,
            )
        elif len(password) < 6:
            error = _pick_lang("密码至少 6 位", "Password must be at least 6 characters.", lang)
        elif password != confirm_password:
            error = _pick_lang("两次输入的密码不一致", "Passwords do not match.", lang)
        elif User.query.filter(func.lower(User.username) == username.lower()).first():
            error = _pick_lang("用户名已存在", "Username already exists.", lang)
        else:
            user = User(username=username)
            user.set_password(password)
            user.last_login_at = datetime.now(timezone.utc)
            db.session.add(user)
            db.session.commit()
            session["user_id"] = user.id
            return redirect(_safe_next_url("forum_index"))

    return render_template("auth/register.html", error=error)


@app.route("/login", methods=["GET", "POST"])
def user_login():
    lang = _get_lang()
    current = _get_current_user()
    if current:
        if _is_banned_user(current):
            session.pop("user_id", None)
        else:
            return redirect(url_for("forum_index"))
    error = (request.args.get("error") or "").strip() or None
    if request.method == "POST":
        username = (request.form.get("username") or "").strip()
        password = request.form.get("password") or ""
        user = User.query.filter(func.lower(User.username) == username.lower()).first()
        if not user or not user.check_password(password):
            error = _pick_lang("用户名或密码错误", "Invalid username or password.", lang)
        elif _is_banned_user(user):
            error = _user_ban_message(user)
        else:
            user.last_login_at = datetime.now(timezone.utc)
            db.session.commit()
            session["user_id"] = user.id
            return redirect(_safe_next_url("forum_index"))
    return render_template("auth/login.html", error=error)


@app.route("/logout")
def user_logout():
    session.pop("user_id", None)
    return redirect(url_for("forum_index"))


@app.route("/profile")
def user_profile_redirect():
    return redirect(url_for("user_profile"))


@app.route("/me", methods=["GET", "POST"])
@user_login_required
def user_profile():
    lang = _get_lang()
    user = _get_current_user()
    tab = (request.args.get("tab") or "posts").strip().lower()
    if tab not in {"posts", "comments", "likes", "bookmarks", "settings"}:
        tab = "posts"

    if request.method == "POST":
        action = (request.form.get("action") or "").strip().lower()
        if action == "profile":
            username = (request.form.get("username") or "").strip()
            if username == user.username:
                return redirect(url_for("user_profile", tab="settings", msg=_pick_lang("资料未变更", "No changes detected.", lang)))
            if not _is_valid_username(username):
                return redirect(url_for(
                    "user_profile",
                    tab="settings",
                    error=_pick_lang(
                        "用户名需为 3-20 位，仅支持字母、数字、下划线",
                        "Username must be 3-20 chars (letters, numbers, underscore).",
                        lang,
                    ),
                ))
            exists = (
                User.query
                .filter(func.lower(User.username) == username.lower(), User.id != user.id)
                .first()
            )
            if exists:
                return redirect(url_for("user_profile", tab="settings", error=_pick_lang("用户名已存在", "Username already exists.", lang)))
            user.username = username
            db.session.commit()
            return redirect(url_for("user_profile", tab="settings", msg=_pick_lang("用户名已更新", "Username updated.", lang)))

        if action == "password":
            current_password = request.form.get("current_password") or ""
            new_password = request.form.get("new_password") or ""
            confirm_password = request.form.get("confirm_password") or ""
            if not user.check_password(current_password):
                return redirect(url_for("user_profile", tab="settings", error=_pick_lang("当前密码错误", "Current password is incorrect.", lang)))
            if len(new_password) < 6:
                return redirect(url_for("user_profile", tab="settings", error=_pick_lang("新密码至少 6 位", "New password must be at least 6 characters.", lang)))
            if new_password != confirm_password:
                return redirect(url_for("user_profile", tab="settings", error=_pick_lang("两次新密码输入不一致", "New passwords do not match.", lang)))
            user.set_password(new_password)
            db.session.commit()
            return redirect(url_for("user_profile", tab="settings", msg=_pick_lang("密码已更新", "Password updated.", lang)))

        return redirect(url_for("user_profile", tab="settings", error=_pick_lang("未知操作", "Unknown action.", lang)))

    my_post_rows = (
        _query_forum_post_rows(active_tab="latest", author_id=user.id)
        .limit(60)
        .all()
    )
    my_post_cards = _build_forum_post_cards(my_post_rows, lang=lang)
    my_comment_rows = (
        db.session.query(
            ForumComment,
            ForumPost.id.label("post_id"),
            ForumPost.title.label("post_title"),
        )
        .join(ForumPost, ForumComment.post_id == ForumPost.id)
        .filter(ForumComment.user_id == user.id)
        .order_by(ForumComment.created_at.desc(), ForumComment.id.desc())
        .limit(120)
        .all()
    )
    my_comment_items = [
        {
            "comment": c,
            "post_id": post_id,
            "post_title": post_title,
        }
        for c, post_id, post_title in my_comment_rows
    ]
    my_like_rows = (
        db.session.query(
            ForumPostLike,
            ForumPost.id.label("post_id"),
            ForumPost.title.label("post_title"),
            ForumPost.category.label("post_category"),
            ForumPost.created_at.label("post_created_at"),
        )
        .join(ForumPost, ForumPostLike.post_id == ForumPost.id)
        .filter(ForumPostLike.user_id == user.id)
        .order_by(ForumPostLike.created_at.desc(), ForumPostLike.id.desc())
        .limit(120)
        .all()
    )
    my_like_items = [
        {
            "like": like_row,
            "post_id": post_id,
            "post_title": post_title,
            "post_category": post_category,
            "post_created_at": post_created_at,
        }
        for like_row, post_id, post_title, post_category, post_created_at in my_like_rows
    ]
    my_bookmark_rows = (
        db.session.query(
            ForumPostBookmark,
            ForumPost.id.label("post_id"),
            ForumPost.title.label("post_title"),
            ForumPost.category.label("post_category"),
            ForumPost.created_at.label("post_created_at"),
        )
        .join(ForumPost, ForumPostBookmark.post_id == ForumPost.id)
        .filter(ForumPostBookmark.user_id == user.id)
        .order_by(ForumPostBookmark.created_at.desc(), ForumPostBookmark.id.desc())
        .limit(120)
        .all()
    )
    my_bookmark_items = [
        {
            "bookmark": bookmark_row,
            "post_id": post_id,
            "post_title": post_title,
            "post_category": post_category,
            "post_created_at": post_created_at,
        }
        for bookmark_row, post_id, post_title, post_category, post_created_at in my_bookmark_rows
    ]
    stats = {
        "post_count": ForumPost.query.filter_by(user_id=user.id).count(),
        "comment_count": ForumComment.query.filter_by(user_id=user.id).count(),
        "like_count": ForumPostLike.query.filter_by(user_id=user.id).count(),
        "bookmark_count": ForumPostBookmark.query.filter_by(user_id=user.id).count(),
        "report_count": ForumReport.query.filter_by(reporter_id=user.id).count(),
        "pending_report_count": ForumReport.query.filter_by(reporter_id=user.id, status="pending").count(),
        "notification_count": ForumNotification.query.filter_by(user_id=user.id).count(),
        "unread_notification_count": ForumNotification.query.filter_by(user_id=user.id, is_read=False).count(),
    }
    return render_template(
        "forum/profile.html",
        profile_user=user,
        active_tab=tab,
        my_post_cards=my_post_cards,
        my_comment_items=my_comment_items,
        my_like_items=my_like_items,
        my_bookmark_items=my_bookmark_items,
        stats=stats,
        message=request.args.get("msg") or "",
        error=request.args.get("error") or "",
    )


@app.route("/notifications")
@user_login_required
def user_notifications():
    lang = _get_lang()
    user = _get_current_user()
    status = (request.args.get("status") or "all").strip().lower()
    if status not in {"all", "unread", "read"}:
        status = "all"
    q = (
        ForumNotification.query
        .filter_by(user_id=user.id)
        .options(joinedload(ForumNotification.actor_rel))
    )
    if status == "unread":
        q = q.filter_by(is_read=False)
    elif status == "read":
        q = q.filter_by(is_read=True)
    rows = q.order_by(ForumNotification.created_at.desc(), ForumNotification.id.desc()).limit(300).all()
    items = []
    for n in rows:
        items.append({
            "notification": n,
            "type_label": _notification_type_label(n.notif_type, lang=lang),
            "actor_name": n.actor_rel.username if n.actor_rel else "",
            "target_url": _notification_target_url(n),
            "time_text": _humanize_time(n.created_at, lang=lang),
        })
    status_rows = (
        db.session.query(ForumNotification.is_read, func.count(ForumNotification.id))
        .filter_by(user_id=user.id)
        .group_by(ForumNotification.is_read)
        .all()
    )
    read_count = 0
    unread_count = 0
    for is_read, count_val in status_rows:
        if bool(is_read):
            read_count = int(count_val or 0)
        else:
            unread_count = int(count_val or 0)
    return render_template(
        "forum/notifications.html",
        active_status=status,
        notification_items=items,
        unread_count=unread_count,
        read_count=read_count,
        total_count=unread_count + read_count,
        message=request.args.get("msg") or "",
        error=request.args.get("error") or "",
    )


@app.route("/notification/<int:notification_id>/go")
@user_login_required
def user_notification_go(notification_id):
    lang = _get_lang()
    user = _get_current_user()
    n = ForumNotification.query.get_or_404(notification_id)
    if n.user_id != user.id:
        return redirect(url_for("user_notifications", error=_pick_lang("无权访问该通知", "Permission denied for this notification.", lang)))
    if not n.is_read:
        n.is_read = True
        db.session.commit()
    return redirect(_notification_target_url(n))


@app.route("/notification/<int:notification_id>/read", methods=["POST"])
@user_login_required
def user_notification_read(notification_id):
    lang = _get_lang()
    user = _get_current_user()
    n = ForumNotification.query.get_or_404(notification_id)
    if n.user_id != user.id:
        return redirect(url_for("user_notifications", error=_pick_lang("无权操作该通知", "Permission denied for this notification.", lang)))
    if not n.is_read:
        n.is_read = True
        db.session.commit()
        _NOTIF_COUNT_CACHE.pop(user.id, None)
    next_url = (request.form.get("next") or "").strip()
    if next_url.startswith("/") and not next_url.startswith("//"):
        return redirect(next_url)
    return redirect(url_for("user_notifications", msg=_pick_lang("已标记为已读", "Marked as read.", lang)))


@app.route("/notifications/read-all", methods=["POST"])
@user_login_required
def user_notifications_read_all():
    lang = _get_lang()
    user = _get_current_user()
    unread = ForumNotification.query.filter_by(user_id=user.id, is_read=False)
    updated = unread.update({"is_read": True}, synchronize_session=False)
    db.session.commit()
    if updated:
        _NOTIF_COUNT_CACHE.pop(user.id, None)
    msg = _pick_lang("已全部标记为已读", "All notifications marked as read.", lang) if updated else _pick_lang("没有未读通知", "No unread notifications.", lang)
    return redirect(url_for("user_notifications", msg=msg))


@app.route("/forum")
def forum_index():
    lang = _get_lang()
    per_page_options = [10, 20, 30, 50]
    active_tab = (request.args.get("tab") or "latest").strip().lower()
    if active_tab not in {"latest", "new", "hot"}:
        active_tab = "latest"
    selected_category = (request.args.get("category") or "").strip() or None
    if selected_category and len(selected_category) > 32:
        selected_category = selected_category[:32]
    search_query = (request.args.get("q") or "").strip()
    if len(search_query) > 80:
        search_query = search_query[:80]
    page = request.args.get("page", type=int) or 1
    if page < 1:
        page = 1
    per_page = request.args.get("per_page", type=int) or 20
    if per_page not in per_page_options:
        per_page = 20

    rows_query = _query_forum_post_rows(
        active_tab=active_tab,
        selected_category=selected_category,
        search_query=search_query or None,
    )
    total_posts = _count_forum_posts(
        selected_category=selected_category,
        search_query=search_query or None,
    )
    total_pages = max((total_posts + per_page - 1) // per_page, 1)
    if page > total_pages:
        page = total_pages
    rows = rows_query.offset((page - 1) * per_page).limit(per_page).all()
    post_cards = _build_forum_post_cards(rows, lang=lang)

    sidebar = _forum_sidebar_data()
    category_count_map = {name: int(count or 0) for name, count in (sidebar.get("category_counts") or [])}
    category_names = list(_get_forum_category_names(active_only=True))
    for name in category_count_map.keys():
        if name and name not in category_names:
            category_names.append(name)
    if selected_category and selected_category not in category_names:
        category_names.insert(0, selected_category)

    tab_defs = [
        ("latest", _pick_lang("最新", "Latest", lang)),
        ("new", _pick_lang("新帖", "New", lang)),
        ("hot", _pick_lang("热门", "Top", lang)),
    ]
    tab_links = [
        {
            "key": key,
            "label": label,
            "url": _build_forum_url(
                tab=key,
                category=selected_category,
                q=search_query or None,
                page=1,
                per_page=per_page,
            ),
            "active": active_tab == key,
        }
        for key, label in tab_defs
    ]
    category_links = [
        {
            "name": _pick_lang("全部", "All", lang),
            "count": None,
            "url": _build_forum_url(
                tab=active_tab,
                category=None,
                q=search_query or None,
                page=1,
                per_page=per_page,
            ),
            "active": selected_category is None,
        }
    ]
    for name in category_names:
        category_links.append({
            "name": name,
            "count": category_count_map.get(name, 0),
            "url": _build_forum_url(
                tab=active_tab,
                category=name,
                q=search_query or None,
                page=1,
                per_page=per_page,
            ),
            "active": selected_category == name,
        })

    category_nav_url = _build_forum_url(
        tab=active_tab,
        category=selected_category or (category_names[0] if category_names else None),
        q=search_query or None,
        page=1,
        per_page=per_page,
    )

    window_start = max(1, page - 2)
    window_end = min(total_pages, page + 2)
    page_links = [
        {
            "num": num,
            "url": _build_forum_url(
                tab=active_tab,
                category=selected_category,
                q=search_query or None,
                page=num,
                per_page=per_page,
            ),
            "active": num == page,
        }
        for num in range(window_start, window_end + 1)
    ]

    has_filters = bool(selected_category or search_query or active_tab != "latest")
    if search_query and selected_category:
        empty_hint = _pick_lang("当前分类下没有匹配关键词的帖子。", "No posts match your keywords in this category.", lang)
    elif search_query:
        empty_hint = _pick_lang("没有匹配关键词的帖子。", "No posts match your keywords.", lang)
    elif selected_category:
        empty_hint = _pick_lang("该分类暂时没有帖子。", "No posts in this category yet.", lang)
    else:
        empty_hint = _pick_lang("当前没有帖子，点击右上角按钮发布第一条内容。", "No posts yet. Create the first topic from the top-right button.", lang)

    result_start = ((page - 1) * per_page + 1) if total_posts else 0
    result_end = min(page * per_page, total_posts) if total_posts else 0
    canonical_params = {
        "tab": active_tab if active_tab != "latest" else None,
        "category": selected_category,
        "page": page if page > 1 else None,
    }
    canonical_url = _public_url("forum_index", lang=lang, **canonical_params)
    alternate_links = _alternate_lang_links("forum_index", **canonical_params)
    prev_canonical_url = None
    next_canonical_url = None
    if page > 1:
        prev_params = dict(canonical_params)
        prev_page = page - 1
        prev_params["page"] = prev_page if prev_page > 1 else None
        prev_canonical_url = _public_url("forum_index", lang=lang, **prev_params)
    if page < total_pages:
        next_params = dict(canonical_params)
        next_params["page"] = page + 1
        next_canonical_url = _public_url("forum_index", lang=lang, **next_params)

    if selected_category:
        forum_title = _pick_lang(
            "{} 讨论区 | 云价眼论坛".format(selected_category),
            "{} Discussions | VPS Forum".format(selected_category),
            lang,
        )
        forum_heading = _pick_lang(
            "{} · 论坛分类".format(selected_category),
            "{} · Forum Category".format(selected_category),
            lang,
        )
    else:
        forum_title = _pick_lang("VPS 社区论坛 | 云价眼", "VPS Community Forum | VPS Price", lang)
        forum_heading = _pick_lang("VPS 社区论坛", "VPS Community Forum", lang)
    if page > 1:
        forum_title = "{} - {}".format(
            forum_title,
            _pick_lang("第 {} 页".format(page), "Page {}".format(page), lang),
        )
    if search_query:
        forum_description = _pick_lang(
            "论坛搜索结果：{}。该页面主要用于站内检索。".format(search_query),
            "Forum search results for '{}'. This page is intended for on-site search.".format(search_query),
            lang,
        )
        forum_intro = _pick_lang(
            "搜索词：{}。建议进一步按分类或标签缩小结果范围。".format(search_query),
            "Search query: '{}'. Narrow down with categories or topic tags for better results.".format(search_query),
            lang,
        )
    elif selected_category:
        forum_description = _forum_category_description(selected_category, lang)
        forum_intro = forum_description
    else:
        forum_description = _forum_category_description(None, lang)
        tab_intro_map = {
            "latest": _pick_lang(
                "按最新活跃度浏览主题，快速跟进持续更新的讨论。",
                "Browse by latest activity to track ongoing discussions.",
                lang,
            ),
            "new": _pick_lang(
                "查看最近发布的新主题，及时参与新话题。",
                "See newly published topics and join early conversations.",
                lang,
            ),
            "hot": _pick_lang(
                "按热度排序，优先阅读高互动的热门讨论。",
                "Sorted by engagement to surface high-signal discussions.",
                lang,
            ),
        }
        forum_intro = tab_intro_map.get(active_tab) or forum_description

    noindex_listing = bool(search_query or per_page != 20)
    forum_feed_url = _public_url("forum_feed", lang=lang)
    seo = {
        "title": forum_title,
        "description": forum_description,
        "keywords": _forum_index_keywords(lang, active_tab=active_tab, selected_category=selected_category),
        "canonical_url": canonical_url,
        "prev_canonical_url": prev_canonical_url,
        "next_canonical_url": next_canonical_url,
        "robots": "noindex,follow" if noindex_listing else "index,follow,max-image-preview:large,max-snippet:-1,max-video-preview:-1",
        "og_type": "website",
        "og_url": canonical_url,
        "og_title": forum_title,
        "og_description": forum_description,
        "og_image": _absolute_url_for("static", filename="img/site-logo-mark.svg"),
        "twitter_card": "summary_large_image",
        "twitter_title": forum_title,
        "twitter_description": forum_description,
        "alternate_links": alternate_links,
        "feed_url": forum_feed_url,
    }

    list_items = []
    latest_activity_at = None
    for idx, card in enumerate(post_cards, start=1):
        post_obj = card.get("post")
        if not post_obj:
            continue
        post_url = _public_url("forum_post_detail", lang=lang, post_id=post_obj.id)
        list_items.append({
            "@type": "ListItem",
            "position": idx,
            "name": post_obj.title,
            "url": post_url,
        })
        activity_at = card.get("latest_activity") or post_obj.updated_at or post_obj.created_at
        if activity_at and (latest_activity_at is None or activity_at > latest_activity_at):
            latest_activity_at = activity_at

    breadcrumb_schema = _forum_breadcrumb_schema(lang=lang, selected_category=selected_category)
    breadcrumb_schema["@id"] = "{}#breadcrumb".format(canonical_url)
    collection_schema = {
        "@type": "CollectionPage",
        "@id": "{}#collection".format(canonical_url),
        "name": forum_title,
        "description": forum_description,
        "url": canonical_url,
        "inLanguage": "en-US" if lang == "en" else "zh-CN",
        "breadcrumb": {"@id": breadcrumb_schema["@id"]},
        "isPartOf": {"@type": "WebSite", "name": SITE_NAME, "url": _site_root_url()},
    }
    if latest_activity_at:
        collection_schema["dateModified"] = _iso8601_utc(latest_activity_at)
    if not search_query:
        collection_schema["potentialAction"] = {
            "@type": "SearchAction",
            "target": "{}?q={{q}}".format(_public_url("forum_index", lang=lang)),
            "query-input": "required name=q",
        }

    seo_graph = [collection_schema, breadcrumb_schema]
    if list_items:
        item_list_schema = {
            "@type": "ItemList",
            "@id": "{}#items".format(canonical_url),
            "itemListElement": list_items,
        }
        collection_schema["mainEntity"] = {"@id": item_list_schema["@id"]}
        seo_graph.append(item_list_schema)

    seo_schema = {
        "@context": "https://schema.org",
        "@graph": seo_graph,
    }

    return render_template(
        "forum/index.html",
        post_cards=post_cards,
        sidebar=sidebar,
        active_tab=active_tab,
        selected_category=selected_category,
        search_query=search_query,
        tab_links=tab_links,
        category_links=category_links,
        category_nav_url=category_nav_url,
        total_posts=total_posts,
        total_pages=total_pages,
        current_page=page,
        page_links=page_links,
        has_prev=(page > 1),
        has_next=(page < total_pages),
        prev_page_url=_build_forum_url(
            tab=active_tab,
            category=selected_category,
            q=search_query or None,
            page=page - 1,
            per_page=per_page,
        ),
        next_page_url=_build_forum_url(
            tab=active_tab,
            category=selected_category,
            q=search_query or None,
            page=page + 1,
            per_page=per_page,
        ),
        clear_search_url=_build_forum_url(
            tab=active_tab,
            category=selected_category,
            q=None,
            page=1,
            per_page=per_page,
        ),
        clear_all_url=_build_forum_url(tab="latest", category=None, q=None, page=1, per_page=per_page),
        has_filters=has_filters,
        empty_hint=empty_hint,
        result_start=result_start,
        result_end=result_end,
        per_page=per_page,
        per_page_options=per_page_options,
        message=request.args.get("msg") or "",
        error=request.args.get("error") or "",
        forum_heading=forum_heading,
        forum_intro=forum_intro,
        forum_feed_url=forum_feed_url,
        seo=seo,
        seo_schema=seo_schema,
    )


@app.route("/forum/post/new", methods=["GET", "POST"])
@user_login_required
def forum_post_new():
    lang = _get_lang()
    user = _get_current_user()
    blocked_resp = _ensure_forum_interaction_user(user)
    if blocked_resp:
        return blocked_resp
    error = None
    title = ""
    content = ""
    available_categories = _get_forum_category_names(active_only=True)
    category = available_categories[0] if available_categories else "综合讨论"
    if request.method == "POST":
        title = (request.form.get("title") or "").strip()
        content = (request.form.get("content") or "").strip()
        category = (request.form.get("category") or "").strip() or category
        if category not in available_categories:
            category = available_categories[0] if available_categories else "综合讨论"
        if len(title) < 5:
            error = _pick_lang("标题至少 5 个字符", "Title must be at least 5 characters.", lang)
        elif len(title) > 160:
            error = _pick_lang("标题不能超过 160 个字符", "Title must be 160 characters or fewer.", lang)
        elif len(content) < 10:
            error = _pick_lang("内容至少 10 个字符", "Content must be at least 10 characters.", lang)
        else:
            post = ForumPost(
                user_id=user.id,
                category=category,
                title=title,
                content=content,
            )
            db.session.add(post)
            db.session.commit()
            return redirect(url_for("forum_post_detail", post_id=post.id))
    return render_template(
        "forum/post_form.html",
        error=error,
        title_val=title,
        content_val=content,
        category_val=category,
        categories=available_categories,
        page_title=_pick_lang("创建新主题", "Create Topic", lang),
        submit_text=_pick_lang("发布主题", "Publish", lang),
        action_url=url_for("forum_post_new"),
        cancel_url=url_for("forum_index"),
        form_mode="create",
    )


@app.route("/forum/post/<int:post_id>/edit", methods=["GET", "POST"])
@user_login_required
def forum_post_edit(post_id):
    lang = _get_lang()
    post = ForumPost.query.get_or_404(post_id)
    user = _get_current_user()
    blocked_resp = _ensure_forum_interaction_user(user, post_id=post.id)
    if blocked_resp:
        return blocked_resp
    if not _can_edit_post(user, post):
        return _forum_redirect_with_error(post.id, "你没有权限编辑该帖子")

    error = None
    title = post.title or ""
    content = post.content or ""
    available_categories = _get_forum_category_names(active_only=True)
    if post.category and post.category not in available_categories:
        available_categories.insert(0, post.category)
    category = post.category or (available_categories[0] if available_categories else "综合讨论")
    if request.method == "POST":
        title = (request.form.get("title") or "").strip()
        content = (request.form.get("content") or "").strip()
        category = (request.form.get("category") or "").strip() or category
        if category not in available_categories:
            category = available_categories[0] if available_categories else "综合讨论"
        if len(title) < 5:
            error = _pick_lang("标题至少 5 个字符", "Title must be at least 5 characters.", lang)
        elif len(title) > 160:
            error = _pick_lang("标题不能超过 160 个字符", "Title must be 160 characters or fewer.", lang)
        elif len(content) < 10:
            error = _pick_lang("内容至少 10 个字符", "Content must be at least 10 characters.", lang)
        else:
            post.title = title
            post.content = content
            post.category = category
            db.session.commit()
            return _forum_redirect_with_msg(post.id, "帖子已更新")

    return render_template(
        "forum/post_form.html",
        error=error,
        title_val=title,
        content_val=content,
        category_val=category,
        categories=available_categories,
        page_title=_pick_lang("编辑主题", "Edit Topic", lang),
        submit_text=_pick_lang("保存修改", "Save Changes", lang),
        action_url=url_for("forum_post_edit", post_id=post.id),
        cancel_url=url_for("forum_post_detail", post_id=post.id),
        form_mode="edit",
    )


@app.route("/forum/post/<int:post_id>/delete", methods=["POST"])
@user_login_required
def forum_post_delete(post_id):
    post = ForumPost.query.get_or_404(post_id)
    user = _get_current_user()
    blocked_resp = _ensure_forum_interaction_user(user, post_id=post.id)
    if blocked_resp:
        return blocked_resp
    if not _can_edit_post(user, post):
        return _forum_redirect_with_error(post.id, "你没有权限删除该帖子")
    db.session.delete(post)
    db.session.commit()
    return redirect(url_for("forum_index"))


@app.route("/forum/post/<int:post_id>")
def forum_post_detail(post_id):
    lang = _get_lang()
    post = ForumPost.query.get_or_404(post_id)
    comment_per_page = 20
    comment_page = request.args.get("cp", type=int) or 1
    if comment_page < 1:
        comment_page = 1
    current_user = _get_current_user()
    viewed_posts = session.get("viewed_posts") or []
    if post.id not in viewed_posts:
        post.view_count = int(post.view_count or 0) + 1
        viewed_posts.append(post.id)
        session["viewed_posts"] = viewed_posts[-200:]
        db.session.commit()
    comments_query = (
        ForumComment.query
        .options(joinedload(ForumComment.author_rel))
        .filter_by(post_id=post.id)
        .order_by(ForumComment.created_at.asc(), ForumComment.id.asc())
    )
    comments_count = comments_query.count()
    comments_total_pages = max((comments_count + comment_per_page - 1) // comment_per_page, 1)
    if comment_page > comments_total_pages:
        comment_page = comments_total_pages
    comments = (
        comments_query
        .offset((comment_page - 1) * comment_per_page)
        .limit(comment_per_page)
        .all()
    )
    schema_comments = comments
    if comment_page > 1:
        schema_comments = comments_query.limit(20).all()
    like_count = ForumPostLike.query.filter_by(post_id=post.id).count()
    bookmark_count = ForumPostBookmark.query.filter_by(post_id=post.id).count()
    liked_by_me = False
    bookmarked_by_me = False
    can_interact = bool(current_user and not _is_banned_user(current_user))
    if current_user:
        # 一次查询同时得到当前用户是否点赞/收藏，减少请求次数
        rows = db.session.execute(
            text(
                "(SELECT 'like' AS kind FROM forum_post_likes WHERE post_id=:pid AND user_id=:uid LIMIT 1) "
                "UNION ALL "
                "(SELECT 'bookmark' FROM forum_post_bookmarks WHERE post_id=:pid AND user_id=:uid LIMIT 1)"
            ),
            {"pid": post.id, "uid": current_user.id},
        ).fetchall()
        kinds = {row[0] for row in rows}
        liked_by_me = "like" in kinds
        bookmarked_by_me = "bookmark" in kinds
    sidebar = _forum_sidebar_data()
    related_rows = (
        _query_forum_post_rows(active_tab="latest", selected_category=post.category or None)
        .filter(ForumPost.id != post.id)
        .limit(6)
        .all()
    )
    if not related_rows:
        related_rows = (
            _query_forum_post_rows(active_tab="hot")
            .filter(ForumPost.id != post.id)
            .limit(6)
            .all()
        )
    related_cards = _build_forum_post_cards(related_rows, lang=lang)
    plan_recommendations, plan_reco_context = _build_post_plan_recommendations(
        post=post,
        lang=lang,
        limit=5,
    )
    canonical_url = _public_url("forum_post_detail", lang=lang, post_id=post.id)
    post_excerpt = _plain_excerpt(post.content or "", limit=170)
    if not post_excerpt:
        post_excerpt = _pick_lang("论坛主题详情页。", "Discussion topic detail page.", lang)
    post_category = post.category or _pick_lang("综合讨论", "General", lang)
    post_keywords = ", ".join(dict.fromkeys([
        post_category,
        _pick_lang("VPS论坛", "VPS forum", lang),
        _pick_lang("VPS讨论", "VPS discussion", lang),
        _pick_lang("云服务器评测", "cloud server review", lang),
    ]))
    published_time = _iso8601_utc(post.created_at)
    modified_time = _iso8601_utc(post.updated_at or post.created_at)
    read_minutes = _estimate_reading_minutes(post.content or "", lang=lang)
    detail_resource_links = _build_post_resource_links(post=post, lang=lang)
    detail_faq_items = _build_post_faq_items(
        post=post,
        comments_count=comments_count,
        read_minutes=read_minutes,
        plan_reco_context=plan_reco_context,
        lang=lang,
    )
    comment_page_links = _build_post_comment_page_links(
        post_id=post.id,
        total_pages=comments_total_pages,
        current_page=comment_page,
        lang=lang,
    )
    comment_prev_url = None
    comment_next_url = None
    comment_prev_canonical_url = None
    comment_next_canonical_url = None
    if comment_page > 1:
        comment_prev_url = _build_post_detail_url(post.id, lang=lang, comment_page=comment_page - 1)
        prev_cp = (comment_page - 1) if (comment_page - 1) > 1 else None
        comment_prev_canonical_url = _public_url("forum_post_detail", lang=lang, post_id=post.id, cp=prev_cp)
    if comment_page < comments_total_pages:
        comment_next_url = _build_post_detail_url(post.id, lang=lang, comment_page=comment_page + 1)
        comment_next_canonical_url = _public_url("forum_post_detail", lang=lang, post_id=post.id, cp=comment_page + 1)

    query_keys = {str(k or "").strip().lower() for k in request.args.keys()}
    query_keys.discard("")
    indexable_query_keys = {"lang"}
    has_non_canonical_query = any(
        (key not in indexable_query_keys) or key.startswith("utm_")
        for key in query_keys
    )
    forum_feed_url = _public_url("forum_feed", lang=lang)
    seo_title = _pick_lang(
        "{} - 论坛主题 | 云价眼".format(post.title),
        "{} - Forum Topic | VPS Price".format(post.title),
        lang,
    )
    seo = {
        "title": seo_title,
        "description": post_excerpt,
        "keywords": post_keywords,
        "canonical_url": canonical_url,
        "robots": (
            "noindex,follow"
            if has_non_canonical_query
            else "index,follow,max-image-preview:large,max-snippet:-1,max-video-preview:-1"
        ),
        "prev_canonical_url": comment_prev_canonical_url,
        "next_canonical_url": comment_next_canonical_url,
        "og_type": "article",
        "og_url": canonical_url,
        "og_title": seo_title,
        "og_description": post_excerpt,
        "og_image": _absolute_url_for("static", filename="img/site-logo-mark.svg"),
        "twitter_card": "summary_large_image",
        "twitter_title": seo_title,
        "twitter_description": post_excerpt,
        "article_published_time": published_time,
        "article_modified_time": modified_time,
        "article_section": post_category,
        "feed_url": forum_feed_url,
        "alternate_links": _alternate_lang_links("forum_post_detail", post_id=post.id),
    }
    author_name = (
        post.author_rel.username
        if post.author_rel and post.author_rel.username
        else _pick_lang("已注销用户", "Deleted user", lang)
    )
    post_schema = {
        "@type": "DiscussionForumPosting",
        "@id": "{}#topic".format(canonical_url),
        "headline": post.title,
        "description": post_excerpt,
        "articleSection": post_category,
        "keywords": post_keywords,
        "mainEntityOfPage": canonical_url,
        "url": canonical_url,
        "datePublished": published_time,
        "dateModified": modified_time,
        "author": {"@type": "Person", "name": author_name},
        "publisher": {
            "@type": "Organization",
            "name": SITE_NAME,
            "url": _site_root_url(),
            "logo": {
                "@type": "ImageObject",
                "url": _absolute_url_for("static", filename="img/site-logo.svg"),
            },
        },
        "commentCount": comments_count,
        "interactionStatistic": [
            {
                "@type": "InteractionCounter",
                "interactionType": "https://schema.org/ViewAction",
                "userInteractionCount": int(post.view_count or 0),
            },
            {
                "@type": "InteractionCounter",
                "interactionType": "https://schema.org/CommentAction",
                "userInteractionCount": comments_count,
            },
            {
                "@type": "InteractionCounter",
                "interactionType": "https://schema.org/LikeAction",
                "userInteractionCount": int(like_count or 0),
            },
        ],
        "inLanguage": "en-US" if lang == "en" else "zh-CN",
        "isPartOf": {"@type": "WebSite", "name": SITE_NAME, "url": _site_root_url()},
    }

    comment_entities = []
    for c in schema_comments[:20]:
        author = c.author_rel.username if c.author_rel and c.author_rel.username else _pick_lang("匿名用户", "Anonymous", lang)
        text_excerpt = _plain_excerpt(c.content or "", limit=220)
        if not text_excerpt:
            continue
        comment_item = {
            "@type": "Comment",
            "text": text_excerpt,
            "dateCreated": _iso8601_utc(c.created_at),
            "author": {"@type": "Person", "name": author},
        }
        if c.id:
            comment_item["url"] = "{}#comment-{}".format(canonical_url, c.id)
        comment_entities.append(comment_item)
    if comment_entities:
        post_schema["comment"] = comment_entities

    breadcrumb_schema = _forum_breadcrumb_schema(
        lang=lang,
        selected_category=post.category,
        post=post,
        post_url=canonical_url,
    )
    breadcrumb_schema["@id"] = "{}#breadcrumb".format(canonical_url)
    post_schema["breadcrumb"] = {"@id": breadcrumb_schema["@id"]}
    faq_schema = None
    if detail_faq_items:
        faq_schema = {
            "@type": "FAQPage",
            "@id": "{}#faq".format(canonical_url),
            "inLanguage": "en-US" if lang == "en" else "zh-CN",
            "mainEntity": [
                {
                    "@type": "Question",
                    "name": item.get("question"),
                    "acceptedAnswer": {
                        "@type": "Answer",
                        "text": item.get("answer"),
                    },
                }
                for item in detail_faq_items
                if item.get("question") and item.get("answer")
            ],
        }
        if not faq_schema["mainEntity"]:
            faq_schema = None
    howto_schema = _build_post_howto_schema(
        post=post,
        canonical_url=canonical_url,
        lang=lang,
        read_minutes=read_minutes,
        comments_count=comments_count,
    )
    seo_graph = [post_schema, breadcrumb_schema]
    if faq_schema:
        seo_graph.append(faq_schema)
    if howto_schema:
        seo_graph.append(howto_schema)

    seo_schema = {
        "@context": "https://schema.org",
        "@graph": seo_graph,
    }
    return render_template(
        "forum/post_detail.html",
        post=post,
        comments=comments,
        like_count=like_count,
        bookmark_count=bookmark_count,
        liked_by_me=liked_by_me,
        bookmarked_by_me=bookmarked_by_me,
        can_interact=can_interact,
        sidebar=sidebar,
        related_cards=related_cards,
        plan_recommendations=plan_recommendations,
        plan_reco_context=plan_reco_context,
        detail_resource_links=detail_resource_links,
        detail_faq_items=detail_faq_items,
        comments_count=comments_count,
        read_minutes=read_minutes,
        comment_page=comment_page,
        comments_total_pages=comments_total_pages,
        comment_page_links=comment_page_links,
        comment_prev_url=comment_prev_url,
        comment_next_url=comment_next_url,
        message=request.args.get("msg") or "",
        error=request.args.get("error") or "",
        seo=seo,
        seo_schema=seo_schema,
    )


@app.route("/forum/post/<int:post_id>/like", methods=["POST"])
@user_login_required
def forum_post_like_toggle(post_id):
    post = ForumPost.query.get_or_404(post_id)
    user = _get_current_user()
    blocked_resp = _ensure_forum_interaction_user(user, post_id=post.id)
    if blocked_resp:
        return blocked_resp

    exists = ForumPostLike.query.filter_by(post_id=post.id, user_id=user.id).first()
    if exists:
        db.session.delete(exists)
        db.session.commit()
        return redirect(_safe_form_next_url(url_for("forum_post_detail", post_id=post.id, msg="已取消点赞")))
    db.session.add(ForumPostLike(post_id=post.id, user_id=user.id))
    db.session.commit()
    return redirect(_safe_form_next_url(url_for("forum_post_detail", post_id=post.id, msg="已点赞该帖子")))


@app.route("/forum/post/<int:post_id>/bookmark", methods=["POST"])
@user_login_required
def forum_post_bookmark_toggle(post_id):
    post = ForumPost.query.get_or_404(post_id)
    user = _get_current_user()
    blocked_resp = _ensure_forum_interaction_user(user, post_id=post.id)
    if blocked_resp:
        return blocked_resp

    exists = ForumPostBookmark.query.filter_by(post_id=post.id, user_id=user.id).first()
    if exists:
        db.session.delete(exists)
        db.session.commit()
        return redirect(_safe_form_next_url(url_for("forum_post_detail", post_id=post.id, msg="已取消收藏")))
    db.session.add(ForumPostBookmark(post_id=post.id, user_id=user.id))
    db.session.commit()
    return redirect(_safe_form_next_url(url_for("forum_post_detail", post_id=post.id, msg="已收藏该帖子")))


@app.route("/forum/post/<int:post_id>/comment", methods=["POST"])
@user_login_required
def forum_post_comment(post_id):
    post = ForumPost.query.get_or_404(post_id)
    user = _get_current_user()
    blocked_resp = _ensure_forum_interaction_user(user, post_id=post.id)
    if blocked_resp:
        return blocked_resp
    if post.is_locked:
        return _forum_redirect_with_error(post.id, "该帖子已锁定，暂不允许新增评论")
    content = (request.form.get("content") or "").strip()
    if len(content) < 2:
        return redirect(url_for("forum_post_detail", post_id=post.id, error="评论至少 2 个字符"))
    comment = ForumComment(
        post_id=post.id,
        user_id=user.id,
        content=content,
    )
    db.session.add(comment)
    db.session.flush()

    actor_name = user.username or "用户"
    post_title = post.title or "主题"
    if post.user_id and post.user_id != user.id:
        _create_notification(
            user_id=post.user_id,
            notif_type="post_commented",
            message="{} 评论了你的帖子《{}》".format(actor_name, post_title),
            actor_id=user.id,
            post_id=post.id,
            comment_id=comment.id,
        )

    participant_rows = (
        db.session.query(ForumComment.user_id)
        .filter(
            ForumComment.post_id == post.id,
            ForumComment.user_id.isnot(None),
            ForumComment.user_id != user.id,
        )
        .distinct()
        .limit(50)
        .all()
    )
    for (uid,) in participant_rows:
        if not uid:
            continue
        if uid == post.user_id or uid == user.id:
            continue
        _create_notification(
            user_id=uid,
            notif_type="thread_replied",
            message="{} 在你参与的主题《{}》有新回复".format(actor_name, post_title),
            actor_id=user.id,
            post_id=post.id,
            comment_id=comment.id,
        )

    db.session.commit()
    return redirect(url_for("forum_post_detail", post_id=post.id, msg="评论发布成功"))


@app.route("/forum/comment/<int:comment_id>/edit", methods=["GET", "POST"])
@user_login_required
def forum_comment_edit(comment_id):
    comment = ForumComment.query.get_or_404(comment_id)
    user = _get_current_user()
    blocked_resp = _ensure_forum_interaction_user(user, post_id=comment.post_id)
    if blocked_resp:
        return blocked_resp
    if not _can_edit_comment(user, comment):
        return _forum_redirect_with_error(comment.post_id, "你没有权限编辑该评论")

    error = None
    content = comment.content or ""
    if request.method == "POST":
        content = (request.form.get("content") or "").strip()
        if len(content) < 2:
            error = "评论至少 2 个字符"
        else:
            comment.content = content
            db.session.commit()
            return _forum_redirect_with_msg(comment.post_id, "评论已更新")

    return render_template(
        "forum/comment_form.html",
        error=error,
        comment=comment,
        content_val=content,
        action_url=url_for("forum_comment_edit", comment_id=comment.id),
        cancel_url=url_for("forum_post_detail", post_id=comment.post_id),
    )


@app.route("/forum/comment/<int:comment_id>/delete", methods=["POST"])
@user_login_required
def forum_comment_delete(comment_id):
    comment = ForumComment.query.get_or_404(comment_id)
    user = _get_current_user()
    blocked_resp = _ensure_forum_interaction_user(user, post_id=comment.post_id)
    if blocked_resp:
        return blocked_resp
    if not _can_edit_comment(user, comment):
        return _forum_redirect_with_error(comment.post_id, "你没有权限删除该评论")
    post_id = comment.post_id
    db.session.delete(comment)
    db.session.commit()
    return _forum_redirect_with_msg(post_id, "评论已删除")


@app.route("/forum/report", methods=["POST"])
@user_login_required
def forum_report_create():
    user = _get_current_user()
    blocked_resp = _ensure_forum_interaction_user(user)
    if blocked_resp:
        return blocked_resp
    target_type = (request.form.get("target_type") or "").strip().lower()
    target_id = request.form.get("target_id", type=int) or 0
    reason = (request.form.get("reason") or "其他").strip()
    detail = (request.form.get("detail") or "").strip()
    if len(detail) > 500:
        detail = detail[:500]
    if reason not in FORUM_REPORT_REASONS:
        reason = "其他"

    report_post_id = None
    target_owner_id = None
    snapshot_title = None
    snapshot_content = None
    if target_type == "post":
        target_post = db.session.get(ForumPost, target_id)
        if target_post is None:
            return redirect(url_for("forum_index"))
        report_post_id = target_post.id
        target_owner_id = target_post.user_id
        snapshot_title = target_post.title
        snapshot_content = target_post.content
    elif target_type == "comment":
        target_comment = db.session.get(ForumComment, target_id)
        if target_comment is None:
            return redirect(url_for("forum_index"))
        report_post_id = target_comment.post_id
        target_owner_id = target_comment.user_id
        snapshot_title = target_comment.post_rel.title if target_comment.post_rel else None
        snapshot_content = target_comment.content
    else:
        return redirect(url_for("forum_index"))

    if target_owner_id == user.id:
        return _forum_redirect_with_error(report_post_id, "不能举报自己的内容")

    exists = ForumReport.query.filter_by(
        reporter_id=user.id,
        target_type=target_type,
        target_id=target_id,
        status="pending",
    ).first()
    if exists:
        return _forum_redirect_with_msg(report_post_id, "你已举报该内容，请等待处理")

    db.session.add(ForumReport(
        reporter_id=user.id,
        target_type=target_type,
        target_id=target_id,
        reason=reason,
        detail=detail or None,
        snapshot_title=snapshot_title,
        snapshot_content=snapshot_content,
        status="pending",
    ))
    db.session.commit()
    return _forum_redirect_with_msg(report_post_id, "举报已提交，感谢反馈")


@app.route("/forum/feed")
@app.route("/forum/feed.xml/")
@app.route("/forum/feed.xml")
def forum_feed():
    lang = _get_lang()
    latest_activity_expr = func.coalesce(ForumPost.updated_at, ForumPost.created_at)
    rows = (
        db.session.query(
            ForumPost,
            User.username.label("author_name"),
        )
        .outerjoin(User, User.id == ForumPost.user_id)
        .order_by(latest_activity_expr.desc(), ForumPost.id.desc())
        .limit(120)
        .all()
    )

    channel_title = _pick_lang("云价眼论坛最新主题", "VPS Price Forum Latest Topics", lang)
    channel_description = _pick_lang(
        "按最新活跃度输出论坛主题 RSS 订阅，便于跟踪 VPS 讨论更新。",
        "RSS feed of the latest forum activity to track VPS discussions.",
        lang,
    )
    channel_link = _public_url("forum_index", lang=lang)
    self_feed_url = _public_url("forum_feed", lang=lang)
    latest_time = None
    if rows:
        p = rows[0][0]
        latest_time = p.updated_at or p.created_at
    last_build_date = _rfc2822_utc(latest_time or datetime.now(timezone.utc))

    lines = [
        '<?xml version="1.0" encoding="UTF-8"?>',
        '<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">',
        "  <channel>",
        "    <title>{}</title>".format(xml_escape(channel_title)),
        "    <description>{}</description>".format(xml_escape(channel_description)),
        "    <link>{}</link>".format(xml_escape(channel_link)),
        "    <language>{}</language>".format("en-us" if lang == "en" else "zh-cn"),
        "    <lastBuildDate>{}</lastBuildDate>".format(xml_escape(last_build_date)),
        '    <atom:link href="{}" rel="self" type="application/rss+xml" />'.format(xml_escape(self_feed_url)),
    ]
    for post, author_name in rows:
        post_url = _public_url("forum_post_detail", lang=lang, post_id=post.id)
        pub_date = _rfc2822_utc(post.updated_at or post.created_at) or last_build_date
        author = author_name or _pick_lang("匿名用户", "Anonymous", lang)
        summary = _plain_excerpt(post.content or "", limit=260)
        category = post.category or _pick_lang("综合讨论", "General", lang)
        lines.extend([
            "    <item>",
            "      <title>{}</title>".format(xml_escape(post.title or _pick_lang("未命名主题", "Untitled topic", lang))),
            "      <description>{}</description>".format(xml_escape(summary)),
            "      <link>{}</link>".format(xml_escape(post_url)),
            "      <guid>{}</guid>".format(xml_escape(post_url)),
            "      <author>{}</author>".format(xml_escape(author)),
            "      <category>{}</category>".format(xml_escape(category)),
            "      <pubDate>{}</pubDate>".format(xml_escape(pub_date)),
            "    </item>",
        ])
    lines.extend([
        "  </channel>",
        "</rss>",
    ])
    xml = "\n".join(lines)

    resp = make_response(xml)
    resp.mimetype = "application/rss+xml"
    resp.headers["Cache-Control"] = "public, max-age=900"
    return resp


# ---------- 法务页面 ----------
@app.route("/privacy")
def privacy_policy():
    lang = _get_lang()
    page_title = _pick_lang("隐私政策 | 云价眼", "Privacy Policy | VPS Price", lang)
    page_description = _pick_lang(
        "了解云价眼如何收集、使用和保护站点访客与论坛用户数据。",
        "How VPS Price collects, uses, and protects visitor and forum user data.",
        lang,
    )
    canonical_url = _public_url("privacy_policy", lang=lang)
    seo = {
        "title": page_title,
        "description": page_description,
        "canonical_url": canonical_url,
        "robots": "index,follow,max-image-preview:large",
        "og_type": "article",
        "og_url": canonical_url,
        "og_title": page_title,
        "og_description": page_description,
        "og_image": _absolute_url_for("static", filename="img/site-logo-mark.svg"),
        "twitter_card": "summary",
        "twitter_title": page_title,
        "twitter_description": page_description,
        "alternate_links": _alternate_lang_links("privacy_policy"),
    }
    seo_schema = {
        "@context": "https://schema.org",
        "@type": "WebPage",
        "name": page_title,
        "description": page_description,
        "url": canonical_url,
        "inLanguage": "en-US" if lang == "en" else "zh-CN",
    }
    return render_template(
        "privacy.html",
        seo=seo,
        seo_schema=seo_schema,
        updated_on="2026-02-10",
    )


@app.route("/terms")
def terms_of_service():
    lang = _get_lang()
    page_title = _pick_lang("服务条款 | 云价眼", "Terms of Service | VPS Price", lang)
    page_description = _pick_lang(
        "查看云价眼的服务范围、免责声明与论坛使用规范。",
        "Read the VPS Price service scope, disclaimers, and forum usage rules.",
        lang,
    )
    canonical_url = _public_url("terms_of_service", lang=lang)
    seo = {
        "title": page_title,
        "description": page_description,
        "canonical_url": canonical_url,
        "robots": "index,follow,max-image-preview:large",
        "og_type": "article",
        "og_url": canonical_url,
        "og_title": page_title,
        "og_description": page_description,
        "og_image": _absolute_url_for("static", filename="img/site-logo-mark.svg"),
        "twitter_card": "summary",
        "twitter_title": page_title,
        "twitter_description": page_description,
        "alternate_links": _alternate_lang_links("terms_of_service"),
    }
    seo_schema = {
        "@context": "https://schema.org",
        "@type": "WebPage",
        "name": page_title,
        "description": page_description,
        "url": canonical_url,
        "inLanguage": "en-US" if lang == "en" else "zh-CN",
    }
    return render_template(
        "terms.html",
        seo=seo,
        seo_schema=seo_schema,
        updated_on="2026-02-10",
    )


# ---------- SEO ----------
@app.route("/sitemap.xml")
def sitemap():
    latest_forum_dt = _latest_forum_content_datetime()
    sitemap_lastmod = _iso8601_utc(latest_forum_dt)
    total_pages = _forum_sitemap_total_pages()
    entries = [{
        "loc": _absolute_url_for("sitemap_static"),
        "lastmod": sitemap_lastmod,
    }]
    for lang_code in ("zh", "en"):
        for page in range(1, total_pages + 1):
            entries.append({
                "loc": _absolute_url_for("sitemap_forum_page", lang_code=lang_code, page=page),
                "lastmod": sitemap_lastmod,
            })
    xml = _build_sitemap_index_xml(entries)
    resp = make_response(xml)
    resp.mimetype = "application/xml"
    resp.headers["Cache-Control"] = "public, max-age=1800"
    return resp


@app.route("/sitemap-static.xml")
def sitemap_static():
    latest_forum_dt = _latest_forum_content_datetime()
    latest_forum_lastmod = _iso8601_utc(latest_forum_dt)
    urls = []

    def add_page(endpoint, changefreq, priority, params=None, lastmod=None):
        values = params or {}
        alternates = _sitemap_alternates(endpoint, **values)
        for lang_code in ("zh", "en"):
            urls.append({
                "loc": _public_url(endpoint, lang=lang_code, **values),
                "changefreq": changefreq,
                "priority": priority,
                "lastmod": lastmod,
                "alternates": alternates,
            })

    add_page("index", "daily", "1.0")
    add_page("forum_index", "daily", "0.9", lastmod=latest_forum_lastmod)
    add_page("forum_feed", "hourly", "0.4", lastmod=latest_forum_lastmod)
    add_page("forum_index", "daily", "0.8", params={"tab": "new"}, lastmod=latest_forum_lastmod)
    add_page("forum_index", "daily", "0.8", params={"tab": "hot"}, lastmod=latest_forum_lastmod)
    add_page("privacy_policy", "monthly", "0.3", lastmod="2026-02-10T00:00:00Z")
    add_page("terms_of_service", "monthly", "0.3", lastmod="2026-02-10T00:00:00Z")

    category_rows = (
        db.session.query(
            ForumPost.category,
            func.max(func.coalesce(ForumPost.updated_at, ForumPost.created_at)).label("latest_at"),
        )
        .filter(ForumPost.category.isnot(None), ForumPost.category != "")
        .group_by(ForumPost.category)
        .order_by(func.count(ForumPost.id).desc(), ForumPost.category.asc())
        .limit(300)
        .all()
    )
    for category_name, latest_at in category_rows:
        add_page(
            "forum_index",
            "daily",
            "0.75",
            params={"category": category_name},
            lastmod=_iso8601_utc(latest_at),
        )

    xml = _build_sitemap_urlset_xml(urls)
    resp = make_response(xml)
    resp.mimetype = "application/xml"
    resp.headers["Cache-Control"] = "public, max-age=1800"
    return resp


@app.route("/sitemap-forum-<lang_code>-<int:page>.xml")
def sitemap_forum_page(lang_code, page):
    normalized_lang = (lang_code or "").strip().lower()
    if normalized_lang not in {"zh", "en"}:
        abort(404)
    total_pages = _forum_sitemap_total_pages()
    if page < 1 or page > total_pages:
        abort(404)

    offset = (page - 1) * SITEMAP_POSTS_PER_FILE
    rows = (
        db.session.query(ForumPost.id, ForumPost.updated_at, ForumPost.created_at)
        .order_by(ForumPost.updated_at.desc(), ForumPost.id.desc())
        .offset(offset)
        .limit(SITEMAP_POSTS_PER_FILE)
        .all()
    )
    urls = []
    for post_id, updated_at, created_at in rows:
        lastmod = _iso8601_utc(updated_at or created_at)
        urls.append({
            "loc": _public_url("forum_post_detail", lang=normalized_lang, post_id=post_id),
            "changefreq": "weekly",
            "priority": "0.8",
            "lastmod": lastmod,
            "alternates": _sitemap_alternates("forum_post_detail", post_id=post_id),
        })

    xml = _build_sitemap_urlset_xml(urls)
    resp = make_response(xml)
    resp.mimetype = "application/xml"
    resp.headers["Cache-Control"] = "public, max-age=1800"
    return resp


@app.route("/robots.txt")
def robots():
    txt = """User-agent: *
Allow: /
Allow: /forum/feed.xml
Disallow: /admin/
Disallow: /login
Disallow: /register
Disallow: /profile
Disallow: /me
Disallow: /notifications
Disallow: /notification/
Disallow: /forum/post/new
Disallow: /forum/post/*/edit
Disallow: /forum/comment/*/edit
Disallow: /forum/report
Disallow: /api/
Disallow: /*?*q=

Sitemap: {}/sitemap.xml
""".format(_site_root_url())
    resp = make_response(txt)
    resp.mimetype = "text/plain"
    resp.headers["Cache-Control"] = "public, max-age=3600"
    return resp


@app.route("/ads.txt")
def ads_txt():
    content = (os.environ.get("ADS_TXT_CONTENT") or "").strip()
    if content:
        from flask import make_response

        body = content if content.endswith("\n") else "{}\n".format(content)
        resp = make_response(body)
        resp.mimetype = "text/plain"
        resp.headers["Cache-Control"] = "public, max-age=3600"
        return resp
    ads_file = os.path.join(app.static_folder or "", "ads.txt")
    if os.path.isfile(ads_file):
        return send_from_directory(app.static_folder or "", "ads.txt")
    from flask import make_response

    resp = make_response("# Configure ADS_TXT_CONTENT or create static/ads.txt\n")
    resp.mimetype = "text/plain"
    resp.headers["Cache-Control"] = "public, max-age=600"
    return resp


@app.route("/favicon.ico")
def favicon():
    return redirect(url_for("static", filename="img/site-logo-mark.svg"))


# ---------- 后台 ----------
@app.route("/admin/login", methods=["GET", "POST"])
def admin_login():
    if request.method == "POST":
        password = request.form.get("password", "")
        if password == ADMIN_PASSWORD:
            session["admin_logged_in"] = True
            return redirect(url_for("admin_dashboard"))
        return render_template("admin/login.html", error="密码错误")
    return render_template("admin/login.html")


@app.route("/admin/logout")
def admin_logout():
    session.pop("admin_logged_in", None)
    return redirect(url_for("index"))


@app.route("/admin/api/plan/<int:plan_id>")
@admin_required
def admin_api_plan(plan_id):
    plan = VPSPlan.query.get_or_404(plan_id)
    return jsonify({
        "id": plan.id,
        "provider_id": plan.provider_id,
        "countries": plan.countries or "",
        "vcpu": plan.vcpu,
        "memory_gb": plan.memory_gb,
        "storage_gb": plan.storage_gb,
        "bandwidth_mbps": plan.bandwidth_mbps,
        "traffic": plan.traffic or "",
        "price_cny": float(plan.price_cny) if plan.price_cny is not None else None,
        "price_usd": float(plan.price_usd) if plan.price_usd is not None else None,
        "currency": plan.currency or "CNY",
        "official_url": plan.official_url or "",
    })


@app.route("/admin/api/plan/<int:plan_id>/price-history")
@admin_required
def admin_api_plan_price_history(plan_id):
    plan = VPSPlan.query.get_or_404(plan_id)
    rows = (
        PriceHistory.query
        .filter_by(plan_id=plan.id)
        .order_by(PriceHistory.captured_at.desc(), PriceHistory.id.desc())
        .limit(30)
        .all()
    )
    return jsonify([
        {
            "id": r.id,
            "price_cny": float(r.price_cny) if r.price_cny is not None else None,
            "price_usd": float(r.price_usd) if r.price_usd is not None else None,
            "currency": r.currency or "CNY",
            "source": r.source or "",
            "captured_at": r.captured_at.isoformat() if r.captured_at else "",
        }
        for r in rows
    ])


@app.route("/admin")
@admin_required
def admin_dashboard():
    providers = Provider.query.order_by(Provider.name).all()
    plans = _query_plans_for_display()
    plan_trends = _build_plan_trend_map(plans)
    return render_template(
        "admin/dashboard.html",
        providers=providers,
        plans=plans,
        plan_trends=plan_trends,
        country_tags=COUNTRY_TAGS,
    )


# ---------- 厂商管理 ----------
@app.route("/admin/providers")
@admin_required
def admin_providers():
    providers = Provider.query.order_by(Provider.name).all()
    return render_template("admin/providers.html", providers=providers)


@app.route("/admin/provider/new", methods=["GET", "POST"])
@admin_required
def admin_provider_new():
    if request.method == "POST":
        name = request.form.get("name", "").strip()
        official_url = request.form.get("official_url", "").strip() or None
        if not name:
            return render_template("admin/provider_form.html", provider=None, error="请填写厂商名称")
        if Provider.query.filter_by(name=name).first():
            return render_template("admin/provider_form.html", provider=None, error="该厂商名称已存在")
        p = Provider(name=name, official_url=official_url)
        db.session.add(p)
        db.session.commit()
        return redirect(url_for("admin_provider_detail", provider_id=p.id))
    return render_template("admin/provider_form.html", provider=None)


@app.route("/admin/provider/<int:provider_id>")
@admin_required
def admin_provider_detail(provider_id):
    provider = Provider.query.get_or_404(provider_id)
    plans = (
        VPSPlan.query
        .options(joinedload(VPSPlan.provider_rel))
        .filter(
            (VPSPlan.provider_id == provider_id) | (VPSPlan.provider == provider.name)
        )
        .order_by(VPSPlan.price_cny.asc(), VPSPlan.name)
        .all()
    )
    providers = Provider.query.order_by(Provider.name).all()
    plan_trends = _build_plan_trend_map(plans)
    return render_template(
        "admin/provider_detail.html",
        provider=provider,
        plans=plans,
        plan_trends=plan_trends,
        providers=providers,
        country_tags=COUNTRY_TAGS,
    )


@app.route("/admin/provider/<int:provider_id>/edit", methods=["GET", "POST"])
@admin_required
def admin_provider_edit(provider_id):
    provider = Provider.query.get_or_404(provider_id)
    if request.method == "POST":
        provider.name = request.form.get("name", "").strip()
        provider.official_url = request.form.get("official_url", "").strip() or None
        if not provider.name:
            return render_template("admin/provider_form.html", provider=provider, error="请填写厂商名称")
        db.session.commit()
        return redirect(url_for("admin_provider_detail", provider_id=provider.id))
    return render_template("admin/provider_form.html", provider=provider)


@app.route("/admin/provider/<int:provider_id>/delete", methods=["POST"])
@admin_required
def admin_provider_delete(provider_id):
    provider = Provider.query.get_or_404(provider_id)
    # 将该厂商下的配置改为无厂商关联（保留配置，仅清空 provider_id）
    VPSPlan.query.filter_by(provider_id=provider_id).update({"provider_id": None})
    db.session.delete(provider)
    db.session.commit()
    _invalidate_plans_cache()
    return redirect(url_for("admin_providers"))


def _parse_sort_order(raw, default=100):
    s = (raw or "").strip()
    if not s:
        return default
    try:
        return int(s)
    except ValueError:
        return default


def _admin_user_counts(user_ids):
    """批量统计用户维度数据，减少列表页 N+1 查询。"""
    if not user_ids:
        return {
            "posts": {},
            "comments": {},
            "reports": {},
            "unread_notifications": {},
        }

    post_counts = {
        uid: int(cnt or 0)
        for uid, cnt in (
            db.session.query(ForumPost.user_id, func.count(ForumPost.id))
            .filter(ForumPost.user_id.in_(user_ids))
            .group_by(ForumPost.user_id)
            .all()
        )
    }
    comment_counts = {
        uid: int(cnt or 0)
        for uid, cnt in (
            db.session.query(ForumComment.user_id, func.count(ForumComment.id))
            .filter(ForumComment.user_id.in_(user_ids))
            .group_by(ForumComment.user_id)
            .all()
        )
    }
    report_counts = {
        uid: int(cnt or 0)
        for uid, cnt in (
            db.session.query(ForumReport.reporter_id, func.count(ForumReport.id))
            .filter(ForumReport.reporter_id.in_(user_ids))
            .group_by(ForumReport.reporter_id)
            .all()
        )
    }
    unread_notification_counts = {
        uid: int(cnt or 0)
        for uid, cnt in (
            db.session.query(ForumNotification.user_id, func.count(ForumNotification.id))
            .filter(ForumNotification.user_id.in_(user_ids), ForumNotification.is_read.is_(False))
            .group_by(ForumNotification.user_id)
            .all()
        )
    }
    return {
        "posts": post_counts,
        "comments": comment_counts,
        "reports": report_counts,
        "unread_notifications": unread_notification_counts,
    }


def _admin_load_user_options(limit=400):
    return (
        User.query
        .order_by(User.username.asc(), User.id.asc())
        .limit(limit)
        .all()
    )


def _admin_load_post_options(limit=400):
    return (
        ForumPost.query
        .order_by(ForumPost.created_at.desc(), ForumPost.id.desc())
        .limit(limit)
        .all()
    )


def _admin_fill_post_and_user_options(post_options, selected_post_id, user_options, selected_user_id):
    """确保编辑场景中的当前值始终出现在下拉框中。"""
    if selected_post_id and all(p.id != selected_post_id for p in post_options):
        selected_post = db.session.get(ForumPost, selected_post_id)
        if selected_post:
            post_options = [selected_post] + post_options
    if selected_user_id and all(u.id != selected_user_id for u in user_options):
        selected_user = db.session.get(User, selected_user_id)
        if selected_user:
            user_options = [selected_user] + user_options
    return post_options, user_options


# ---------- 论坛分类管理 ----------
@app.route("/admin/forum/categories")
@admin_required
def admin_forum_categories():
    categories = _load_forum_categories(active_only=False)
    posts_by_category = {
        name: count
        for name, count in (
            db.session.query(ForumPost.category, func.count(ForumPost.id))
            .group_by(ForumPost.category)
            .all()
        )
    }
    return render_template(
        "admin/forum_categories.html",
        categories=categories,
        posts_by_category=posts_by_category,
        msg=request.args.get("msg", ""),
        error=request.args.get("error", ""),
    )


@app.route("/admin/forum/category/new", methods=["GET", "POST"])
@admin_required
def admin_forum_category_new():
    error = ""
    name_val = ""
    sort_order_val = 100
    is_active_val = True
    if request.method == "POST":
        name_val = (request.form.get("name") or "").strip()
        sort_order_val = _parse_sort_order(request.form.get("sort_order"), 100)
        is_active_val = bool(request.form.get("is_active"))
        if not name_val:
            error = "请填写分类名称"
        elif len(name_val) > 32:
            error = "分类名称最多 32 个字符"
        elif ForumCategory.query.filter(func.lower(ForumCategory.name) == name_val.lower()).first():
            error = "分类名称已存在"
        else:
            db.session.add(ForumCategory(
                name=name_val,
                sort_order=sort_order_val,
                is_active=is_active_val,
            ))
            db.session.commit()
            return redirect(url_for("admin_forum_categories", msg="已新增分类：{}".format(name_val)))
    return render_template(
        "admin/forum_category_form.html",
        page_title="新增论坛分类",
        submit_text="创建分类",
        action_url=url_for("admin_forum_category_new"),
        error=error,
        name_val=name_val,
        sort_order_val=sort_order_val,
        is_active_val=is_active_val,
        category_id=None,
    )


@app.route("/admin/forum/category/<int:category_id>/edit", methods=["GET", "POST"])
@admin_required
def admin_forum_category_edit(category_id):
    category = ForumCategory.query.get_or_404(category_id)
    error = ""
    name_val = category.name
    sort_order_val = category.sort_order
    is_active_val = bool(category.is_active)
    if request.method == "POST":
        name_val = (request.form.get("name") or "").strip()
        sort_order_val = _parse_sort_order(request.form.get("sort_order"), category.sort_order)
        is_active_val = bool(request.form.get("is_active"))
        if not name_val:
            error = "请填写分类名称"
        elif len(name_val) > 32:
            error = "分类名称最多 32 个字符"
        elif category.is_active and not is_active_val and ForumCategory.query.filter_by(is_active=True).count() <= 1:
            error = "至少保留一个启用分类"
        else:
            exists = (
                ForumCategory.query
                .filter(func.lower(ForumCategory.name) == name_val.lower(), ForumCategory.id != category.id)
                .first()
            )
            if exists:
                error = "分类名称已存在"
            else:
                old_name = category.name
                category.name = name_val
                category.sort_order = sort_order_val
                category.is_active = is_active_val
                if old_name != name_val:
                    ForumPost.query.filter_by(category=old_name).update({"category": name_val})
                db.session.commit()
                return redirect(url_for("admin_forum_categories", msg="已更新分类：{}".format(name_val)))
    return render_template(
        "admin/forum_category_form.html",
        page_title="编辑论坛分类",
        submit_text="保存修改",
        action_url=url_for("admin_forum_category_edit", category_id=category.id),
        error=error,
        name_val=name_val,
        sort_order_val=sort_order_val,
        is_active_val=is_active_val,
        category_id=category.id,
    )


@app.route("/admin/forum/category/<int:category_id>/delete", methods=["POST"])
@admin_required
def admin_forum_category_delete(category_id):
    category = ForumCategory.query.get_or_404(category_id)
    total = ForumCategory.query.count()
    if total <= 1:
        return redirect(url_for("admin_forum_categories", error="至少保留一个分类，无法删除最后一个"))
    if category.is_active and ForumCategory.query.filter_by(is_active=True).count() <= 1:
        return redirect(url_for("admin_forum_categories", error="至少保留一个启用分类，无法删除最后一个启用项"))
    replacement = (
        ForumCategory.query
        .filter(ForumCategory.id != category.id)
        .order_by(ForumCategory.is_active.desc(), ForumCategory.sort_order.asc(), ForumCategory.id.asc())
        .first()
    )
    if replacement is None:
        return redirect(url_for("admin_forum_categories", error="未找到可替代分类"))
    ForumPost.query.filter_by(category=category.name).update({"category": replacement.name})
    db.session.delete(category)
    db.session.commit()
    return redirect(url_for("admin_forum_categories", msg="已删除分类，帖子迁移到：{}".format(replacement.name)))


def _get_report_target_info(report):
    """返回举报目标的展示信息。"""
    info = {
        "exists": False,
        "post_id": None,
        "title": report.snapshot_title or "",
        "content": report.snapshot_content or "",
        "author_name": "",
    }
    if report.target_type == "post":
        post = db.session.get(ForumPost, report.target_id)
        if post:
            info.update({
                "exists": True,
                "post_id": post.id,
                "title": post.title or info["title"],
                "content": post.content or info["content"],
                "author_name": post.author_rel.username if post.author_rel else "",
            })
    elif report.target_type == "comment":
        comment = db.session.get(ForumComment, report.target_id)
        if comment:
            info.update({
                "exists": True,
                "post_id": comment.post_id,
                "title": comment.post_rel.title if comment.post_rel else (info["title"] or ""),
                "content": comment.content or info["content"],
                "author_name": comment.author_rel.username if comment.author_rel else "",
            })
    if info["content"] and len(info["content"]) > 140:
        info["content"] = info["content"][:140] + "..."
    return info


@app.route("/admin/forum/reports")
@admin_required
def admin_forum_reports():
    status = (request.args.get("status") or "pending").strip().lower()
    if status not in {"pending", "processed", "rejected", "all"}:
        status = "pending"
    q = ForumReport.query.order_by(ForumReport.created_at.desc(), ForumReport.id.desc())
    if status != "all":
        q = q.filter_by(status=status)
    reports = q.limit(300).all()
    report_items = []
    for r in reports:
        report_items.append({
            "report": r,
            "target": _get_report_target_info(r),
            "reporter_name": r.reporter_rel.username if r.reporter_rel else "用户",
        })
    grouped = (
        db.session.query(ForumReport.status, func.count(ForumReport.id))
        .group_by(ForumReport.status)
        .all()
    )
    count_map = {k: int(v or 0) for k, v in grouped}
    return render_template(
        "admin/forum_reports.html",
        status=status,
        report_items=report_items,
        status_count_map=count_map,
        status_labels=FORUM_REPORT_STATUS_LABELS,
        msg=request.args.get("msg", ""),
        error=request.args.get("error", ""),
    )


@app.route("/admin/forum/report/<int:report_id>/process", methods=["POST"])
@admin_required
def admin_forum_report_process(report_id):
    report = ForumReport.query.get_or_404(report_id)
    action = (request.form.get("action") or "").strip().lower()
    review_note = (request.form.get("review_note") or "").strip()
    if len(review_note) > 500:
        review_note = review_note[:500]

    if report.status != "pending":
        return redirect(url_for("admin_forum_reports", error="该举报已处理"))

    outcome = ""
    target_owner_id = None
    target_post_id = None
    target_kind_label = "内容"
    if action == "delete_target":
        deleted = False
        if report.target_type == "post":
            target = db.session.get(ForumPost, report.target_id)
            if target:
                target_owner_id = target.user_id
                target_post_id = target.id
                target_kind_label = "帖子"
                db.session.delete(target)
                deleted = True
            outcome = "已删除被举报帖子" if deleted else "目标帖子已不存在"
        elif report.target_type == "comment":
            target = db.session.get(ForumComment, report.target_id)
            if target:
                target_owner_id = target.user_id
                target_post_id = target.post_id
                target_kind_label = "评论"
                db.session.delete(target)
                deleted = True
            outcome = "已删除被举报评论" if deleted else "目标评论已不存在"
        else:
            return redirect(url_for("admin_forum_reports", error="未知举报目标类型"))
        report.status = "processed"
        report.review_note = review_note or outcome
    elif action == "keep":
        report.status = "processed"
        report.review_note = review_note or "审核后保留内容"
        outcome = "已标记为保留"
    elif action == "reject":
        report.status = "rejected"
        report.review_note = review_note or "举报不成立"
        outcome = "已驳回举报"
    else:
        return redirect(url_for("admin_forum_reports", error="未知处理动作"))

    report.reviewed_by = "admin"
    report.reviewed_at = datetime.now(timezone.utc)

    _create_notification(
        user_id=report.reporter_id,
        notif_type="report_processed",
        message="你提交的举报（#{}）处理结果：{}".format(report.id, outcome),
        report_id=report.id,
        post_id=target_post_id,
    )
    if action == "delete_target" and target_owner_id and target_owner_id != report.reporter_id:
        _create_notification(
            user_id=target_owner_id,
            notif_type="content_removed",
            message="你的{}因举报处理已被删除".format(target_kind_label),
            report_id=report.id,
            post_id=target_post_id,
        )

    db.session.commit()
    return redirect(url_for("admin_forum_reports", msg=outcome))


@app.route("/admin/users")
@admin_required
def admin_users():
    keyword = (request.args.get("q") or "").strip()
    if len(keyword) > 50:
        keyword = keyword[:50]
    q = User.query
    if keyword:
        pattern = "%{}%".format(keyword)
        q = q.filter(User.username.ilike(pattern))
    users = q.order_by(User.created_at.desc(), User.id.desc()).limit(300).all()
    user_ids = [u.id for u in users]
    count_maps = _admin_user_counts(user_ids)
    return render_template(
        "admin/users.html",
        users=users,
        keyword=keyword,
        post_count_map=count_maps["posts"],
        comment_count_map=count_maps["comments"],
        report_count_map=count_maps["reports"],
        unread_notification_count_map=count_maps["unread_notifications"],
        msg=request.args.get("msg", ""),
        error=request.args.get("error", ""),
    )


@app.route("/admin/user/new", methods=["GET", "POST"])
@admin_required
def admin_user_new():
    error = ""
    username_val = ""
    if request.method == "POST":
        username_val = (request.form.get("username") or "").strip()
        password = request.form.get("password") or ""
        confirm_password = request.form.get("confirm_password") or ""

        if not _is_valid_username(username_val):
            error = "用户名需为 3-20 位，仅支持字母、数字、下划线"
        elif len(password) < 6:
            error = "密码至少 6 位"
        elif password != confirm_password:
            error = "两次输入的密码不一致"
        elif User.query.filter(func.lower(User.username) == username_val.lower()).first():
            error = "用户名已存在"
        else:
            user = User(username=username_val)
            user.set_password(password)
            db.session.add(user)
            db.session.commit()
            return redirect(url_for("admin_users", msg="已新增用户：{}".format(username_val)))

    return render_template(
        "admin/user_form.html",
        page_title="新增用户",
        submit_text="创建用户",
        action_url=url_for("admin_user_new"),
        error=error,
        username_val=username_val,
        user_id=None,
    )


@app.route("/admin/user/<int:user_id>/edit", methods=["GET", "POST"])
@admin_required
def admin_user_edit(user_id):
    user = User.query.get_or_404(user_id)
    error = ""
    username_val = user.username or ""
    if request.method == "POST":
        username_val = (request.form.get("username") or "").strip()
        new_password = request.form.get("new_password") or ""
        confirm_password = request.form.get("confirm_password") or ""

        if not _is_valid_username(username_val):
            error = "用户名需为 3-20 位，仅支持字母、数字、下划线"
        elif (
            User.query
            .filter(func.lower(User.username) == username_val.lower(), User.id != user.id)
            .first()
        ):
            error = "用户名已存在"
        elif new_password and len(new_password) < 6:
            error = "新密码至少 6 位"
        elif new_password and new_password != confirm_password:
            error = "两次新密码输入不一致"
        else:
            old_username = user.username
            user.username = username_val
            changed = False
            if old_username != username_val:
                changed = True
            if new_password:
                user.set_password(new_password)
                changed = True
            if changed:
                db.session.commit()
                return redirect(url_for("admin_users", msg="已更新用户：{}".format(username_val)))
            return redirect(url_for("admin_users", msg="未检测到变更"))

    return render_template(
        "admin/user_form.html",
        page_title="编辑用户",
        submit_text="保存修改",
        action_url=url_for("admin_user_edit", user_id=user.id),
        error=error,
        username_val=username_val,
        user_id=user.id,
    )


@app.route("/admin/user/<int:user_id>/delete", methods=["POST"])
@admin_required
def admin_user_delete(user_id):
    user = User.query.get_or_404(user_id)
    if User.query.count() <= 1:
        return redirect(url_for("admin_users", error="至少保留一个用户，无法删除最后一个"))

    username = user.username or "用户"
    try:
        # 其他用户已收到的通知可能引用该用户为 actor，删除前置空避免外键冲突。
        ForumNotification.query.filter_by(actor_id=user.id).update({"actor_id": None}, synchronize_session=False)
        db.session.delete(user)
        db.session.commit()
        return redirect(url_for("admin_users", msg="已删除用户：{}".format(username)))
    except Exception:
        db.session.rollback()
        return redirect(url_for("admin_users", error="删除失败，请稍后重试"))


@app.route("/admin/user/<int:user_id>/ban", methods=["POST"])
@admin_required
def admin_user_ban(user_id):
    user = User.query.get_or_404(user_id)
    reason = (request.form.get("reason") or "").strip()
    if len(reason) > 255:
        reason = reason[:255]
    if user.is_banned:
        return redirect(url_for("admin_users", msg="用户已处于封禁状态：{}".format(user.username)))

    user.is_banned = True
    user.banned_at = datetime.now(timezone.utc)
    user.banned_reason = reason or "管理员封禁"
    db.session.commit()
    return redirect(url_for("admin_users", msg="已封禁用户：{}".format(user.username)))


@app.route("/admin/user/<int:user_id>/unban", methods=["POST"])
@admin_required
def admin_user_unban(user_id):
    user = User.query.get_or_404(user_id)
    if not user.is_banned:
        return redirect(url_for("admin_users", msg="用户未被封禁：{}".format(user.username)))

    user.is_banned = False
    user.banned_at = None
    user.banned_reason = None
    db.session.commit()
    return redirect(url_for("admin_users", msg="已解封用户：{}".format(user.username)))


@app.route("/admin/forum/posts")
@admin_required
def admin_forum_posts():
    keyword = (request.args.get("q") or "").strip()
    if len(keyword) > 80:
        keyword = keyword[:80]
    selected_category = (request.args.get("category") or "").strip() or None
    selected_author_id = request.args.get("author_id", type=int)

    comment_stats_subq = (
        db.session.query(
            ForumComment.post_id.label("post_id"),
            func.count(ForumComment.id).label("comment_count"),
        )
        .group_by(ForumComment.post_id)
        .subquery()
    )
    like_stats_subq = (
        db.session.query(
            ForumPostLike.post_id.label("post_id"),
            func.count(ForumPostLike.id).label("like_count"),
        )
        .group_by(ForumPostLike.post_id)
        .subquery()
    )
    bookmark_stats_subq = (
        db.session.query(
            ForumPostBookmark.post_id.label("post_id"),
            func.count(ForumPostBookmark.id).label("bookmark_count"),
        )
        .group_by(ForumPostBookmark.post_id)
        .subquery()
    )
    q = (
        db.session.query(
            ForumPost,
            func.coalesce(comment_stats_subq.c.comment_count, 0).label("comment_count"),
            User.username.label("author_name"),
            func.coalesce(like_stats_subq.c.like_count, 0).label("like_count"),
            func.coalesce(bookmark_stats_subq.c.bookmark_count, 0).label("bookmark_count"),
        )
        .outerjoin(comment_stats_subq, comment_stats_subq.c.post_id == ForumPost.id)
        .outerjoin(like_stats_subq, like_stats_subq.c.post_id == ForumPost.id)
        .outerjoin(bookmark_stats_subq, bookmark_stats_subq.c.post_id == ForumPost.id)
        .outerjoin(User, User.id == ForumPost.user_id)
    )
    if selected_category:
        q = q.filter(ForumPost.category == selected_category)
    if selected_author_id:
        q = q.filter(ForumPost.user_id == selected_author_id)
    if keyword:
        pattern = "%{}%".format(keyword)
        q = q.filter(
            or_(
                ForumPost.title.ilike(pattern),
                ForumPost.content.ilike(pattern),
                User.username.ilike(pattern),
            )
        )
    rows = q.order_by(ForumPost.is_pinned.desc(), ForumPost.created_at.desc(), ForumPost.id.desc()).limit(400).all()

    category_names = list(_get_forum_category_names(active_only=False))
    for (name,) in db.session.query(ForumPost.category).distinct().all():
        if name and name not in category_names:
            category_names.append(name)
    if selected_category and selected_category not in category_names:
        category_names.insert(0, selected_category)

    author_rows = (
        db.session.query(
            User.id,
            User.username,
            func.count(ForumPost.id).label("post_count"),
        )
        .outerjoin(ForumPost, ForumPost.user_id == User.id)
        .group_by(User.id)
        .order_by(func.count(ForumPost.id).desc(), User.username.asc())
        .limit(300)
        .all()
    )

    return render_template(
        "admin/forum_posts.html",
        rows=rows,
        category_names=category_names,
        author_rows=author_rows,
        keyword=keyword,
        selected_category=selected_category,
        selected_author_id=selected_author_id,
        msg=request.args.get("msg", ""),
        error=request.args.get("error", ""),
    )


@app.route("/admin/forum/post/<int:post_id>/moderate", methods=["POST"])
@admin_required
def admin_forum_post_moderate(post_id):
    post = ForumPost.query.get_or_404(post_id)
    action = (request.form.get("action") or "").strip().lower()
    if action == "pin":
        post.is_pinned = True
    elif action == "unpin":
        post.is_pinned = False
    elif action == "feature":
        post.is_featured = True
    elif action == "unfeature":
        post.is_featured = False
    elif action == "lock":
        post.is_locked = True
    elif action == "unlock":
        post.is_locked = False
    else:
        return redirect(url_for("admin_forum_posts", error="未知帖子管理动作"))
    db.session.commit()
    return redirect(url_for("admin_forum_posts", msg="已更新帖子 #{} 状态".format(post.id)))


@app.route("/admin/forum/post/new", methods=["GET", "POST"])
@admin_required
def admin_forum_post_new():
    error = ""
    users = _admin_load_user_options(limit=400)
    categories = _get_forum_category_names(active_only=False)
    if not categories:
        categories = list(DEFAULT_FORUM_CATEGORIES)
    selected_author_id = request.args.get("author_id", type=int) or (users[0].id if users else None)
    selected_category = request.args.get("category") or (categories[0] if categories else "综合讨论")
    is_pinned_val = False
    is_featured_val = False
    is_locked_val = False
    title_val = ""
    content_val = ""

    if request.method == "POST":
        selected_author_id = request.form.get("author_id", type=int)
        selected_category = (request.form.get("category") or "").strip() or selected_category
        is_pinned_val = bool(request.form.get("is_pinned"))
        is_featured_val = bool(request.form.get("is_featured"))
        is_locked_val = bool(request.form.get("is_locked"))
        title_val = (request.form.get("title") or "").strip()
        content_val = (request.form.get("content") or "").strip()

        author = db.session.get(User, selected_author_id or 0)
        if not author:
            error = "请选择有效作者"
        elif selected_category not in categories:
            error = "请选择有效分类"
        elif len(title_val) < 5:
            error = "标题至少 5 个字符"
        elif len(title_val) > 160:
            error = "标题不能超过 160 个字符"
        elif len(content_val) < 10:
            error = "内容至少 10 个字符"
        else:
            db.session.add(ForumPost(
                user_id=author.id,
                category=selected_category,
                title=title_val,
                content=content_val,
                is_pinned=is_pinned_val,
                is_featured=is_featured_val,
                is_locked=is_locked_val,
            ))
            db.session.commit()
            return redirect(url_for("admin_forum_posts", msg="已新增帖子"))

    if not users:
        error = error or "当前没有可用用户，请先在用户管理中新增用户"
    return render_template(
        "admin/forum_post_form.html",
        page_title="后台新增帖子",
        submit_text="创建帖子",
        action_url=url_for("admin_forum_post_new"),
        cancel_url=url_for("admin_forum_posts"),
        error=error,
        users=users,
        categories=categories,
        selected_author_id=selected_author_id,
        selected_category=selected_category,
        is_pinned_val=is_pinned_val,
        is_featured_val=is_featured_val,
        is_locked_val=is_locked_val,
        title_val=title_val,
        content_val=content_val,
        post_id=None,
    )


@app.route("/admin/forum/post/<int:post_id>/edit", methods=["GET", "POST"])
@admin_required
def admin_forum_post_edit(post_id):
    post = ForumPost.query.get_or_404(post_id)
    error = ""
    users = _admin_load_user_options(limit=400)
    categories = _get_forum_category_names(active_only=False)
    if post.category and post.category not in categories:
        categories.insert(0, post.category)

    selected_author_id = post.user_id
    selected_category = post.category or (categories[0] if categories else "综合讨论")
    is_pinned_val = bool(post.is_pinned)
    is_featured_val = bool(post.is_featured)
    is_locked_val = bool(post.is_locked)
    title_val = post.title or ""
    content_val = post.content or ""

    if request.method == "POST":
        selected_author_id = request.form.get("author_id", type=int)
        selected_category = (request.form.get("category") or "").strip() or selected_category
        is_pinned_val = bool(request.form.get("is_pinned"))
        is_featured_val = bool(request.form.get("is_featured"))
        is_locked_val = bool(request.form.get("is_locked"))
        title_val = (request.form.get("title") or "").strip()
        content_val = (request.form.get("content") or "").strip()

        author = db.session.get(User, selected_author_id or 0)
        if not author:
            error = "请选择有效作者"
        elif selected_category not in categories:
            error = "请选择有效分类"
        elif len(title_val) < 5:
            error = "标题至少 5 个字符"
        elif len(title_val) > 160:
            error = "标题不能超过 160 个字符"
        elif len(content_val) < 10:
            error = "内容至少 10 个字符"
        else:
            post.user_id = author.id
            post.category = selected_category
            post.is_pinned = is_pinned_val
            post.is_featured = is_featured_val
            post.is_locked = is_locked_val
            post.title = title_val
            post.content = content_val
            db.session.commit()
            return redirect(url_for("admin_forum_posts", msg="已更新帖子 #{}".format(post.id)))

    if not users:
        error = error or "当前没有可用用户，请先在用户管理中新增用户"
    return render_template(
        "admin/forum_post_form.html",
        page_title="后台编辑帖子",
        submit_text="保存修改",
        action_url=url_for("admin_forum_post_edit", post_id=post.id),
        cancel_url=url_for("admin_forum_posts"),
        error=error,
        users=users,
        categories=categories,
        selected_author_id=selected_author_id,
        selected_category=selected_category,
        is_pinned_val=is_pinned_val,
        is_featured_val=is_featured_val,
        is_locked_val=is_locked_val,
        title_val=title_val,
        content_val=content_val,
        post_id=post.id,
    )


@app.route("/admin/forum/post/<int:post_id>/delete", methods=["POST"])
@admin_required
def admin_forum_post_delete(post_id):
    post = ForumPost.query.get_or_404(post_id)
    db.session.delete(post)
    db.session.commit()
    return redirect(url_for("admin_forum_posts", msg="已删除帖子 #{}".format(post_id)))


@app.route("/admin/forum/comments")
@admin_required
def admin_forum_comments():
    keyword = (request.args.get("q") or "").strip()
    if len(keyword) > 80:
        keyword = keyword[:80]
    selected_author_id = request.args.get("author_id", type=int)
    selected_post_id = request.args.get("post_id", type=int)

    q = (
        db.session.query(
            ForumComment,
            ForumPost.title.label("post_title"),
            User.username.label("author_name"),
        )
        .join(ForumPost, ForumComment.post_id == ForumPost.id)
        .outerjoin(User, User.id == ForumComment.user_id)
    )
    if selected_post_id:
        q = q.filter(ForumComment.post_id == selected_post_id)
    if selected_author_id:
        q = q.filter(ForumComment.user_id == selected_author_id)
    if keyword:
        pattern = "%{}%".format(keyword)
        q = q.filter(
            or_(
                ForumComment.content.ilike(pattern),
                ForumPost.title.ilike(pattern),
                User.username.ilike(pattern),
            )
        )
    rows = q.order_by(ForumComment.created_at.desc(), ForumComment.id.desc()).limit(500).all()

    author_rows = (
        db.session.query(
            User.id,
            User.username,
            func.count(ForumComment.id).label("comment_count"),
        )
        .outerjoin(ForumComment, ForumComment.user_id == User.id)
        .group_by(User.id)
        .order_by(func.count(ForumComment.id).desc(), User.username.asc())
        .limit(300)
        .all()
    )
    post_rows = (
        db.session.query(
            ForumPost.id,
            ForumPost.title,
        )
        .order_by(ForumPost.created_at.desc(), ForumPost.id.desc())
        .limit(300)
        .all()
    )
    if selected_post_id and all(pid != selected_post_id for pid, _ in post_rows):
        selected_post = db.session.get(ForumPost, selected_post_id)
        if selected_post:
            post_rows = [(selected_post.id, selected_post.title)] + post_rows

    return render_template(
        "admin/forum_comments.html",
        rows=rows,
        author_rows=author_rows,
        post_rows=post_rows,
        keyword=keyword,
        selected_author_id=selected_author_id,
        selected_post_id=selected_post_id,
        msg=request.args.get("msg", ""),
        error=request.args.get("error", ""),
    )


@app.route("/admin/forum/comment/new", methods=["GET", "POST"])
@admin_required
def admin_forum_comment_new():
    error = ""
    post_options = _admin_load_post_options(limit=400)
    user_options = _admin_load_user_options(limit=400)
    selected_post_id = request.args.get("post_id", type=int) or (post_options[0].id if post_options else None)
    selected_user_id = request.args.get("user_id", type=int) or (user_options[0].id if user_options else None)
    post_options, user_options = _admin_fill_post_and_user_options(
        post_options,
        selected_post_id,
        user_options,
        selected_user_id,
    )

    content_val = ""
    if request.method == "POST":
        selected_post_id = request.form.get("post_id", type=int)
        selected_user_id = request.form.get("user_id", type=int)
        content_val = (request.form.get("content") or "").strip()
        post_options, user_options = _admin_fill_post_and_user_options(
            post_options,
            selected_post_id,
            user_options,
            selected_user_id,
        )
        target_post = db.session.get(ForumPost, selected_post_id or 0)
        target_user = db.session.get(User, selected_user_id or 0)
        if not target_post:
            error = "请选择有效帖子"
        elif not target_user:
            error = "请选择有效用户"
        elif len(content_val) < 2:
            error = "评论至少 2 个字符"
        else:
            db.session.add(ForumComment(
                post_id=target_post.id,
                user_id=target_user.id,
                content=content_val,
            ))
            db.session.commit()
            return redirect(url_for("admin_forum_comments", post_id=target_post.id, msg="已新增评论"))

    if not post_options:
        error = error or "暂无可评论的帖子，请先新增帖子"
    elif not user_options:
        error = error or "当前没有可用用户，请先在用户管理中新增用户"
    return render_template(
        "admin/forum_comment_form.html",
        page_title="后台新增评论",
        submit_text="创建评论",
        action_url=url_for("admin_forum_comment_new"),
        cancel_url=url_for("admin_forum_comments"),
        error=error,
        post_options=post_options,
        user_options=user_options,
        selected_post_id=selected_post_id,
        selected_user_id=selected_user_id,
        content_val=content_val,
        comment_id=None,
    )


@app.route("/admin/forum/comment/<int:comment_id>/edit", methods=["GET", "POST"])
@admin_required
def admin_forum_comment_edit(comment_id):
    comment = ForumComment.query.get_or_404(comment_id)
    error = ""
    post_options = _admin_load_post_options(limit=400)
    user_options = _admin_load_user_options(limit=400)
    selected_post_id = comment.post_id
    selected_user_id = comment.user_id
    post_options, user_options = _admin_fill_post_and_user_options(
        post_options,
        selected_post_id,
        user_options,
        selected_user_id,
    )
    content_val = comment.content or ""
    if request.method == "POST":
        selected_post_id = request.form.get("post_id", type=int)
        selected_user_id = request.form.get("user_id", type=int)
        content_val = (request.form.get("content") or "").strip()
        post_options, user_options = _admin_fill_post_and_user_options(
            post_options,
            selected_post_id,
            user_options,
            selected_user_id,
        )
        target_post = db.session.get(ForumPost, selected_post_id or 0)
        target_user = db.session.get(User, selected_user_id or 0)
        if not target_post:
            error = "请选择有效帖子"
        elif not target_user:
            error = "请选择有效用户"
        elif len(content_val) < 2:
            error = "评论至少 2 个字符"
        else:
            comment.post_id = target_post.id
            comment.user_id = target_user.id
            comment.content = content_val
            db.session.commit()
            return redirect(url_for("admin_forum_comments", post_id=target_post.id, msg="已更新评论 #{}".format(comment.id)))

    if not post_options:
        error = error or "暂无可评论的帖子，请先新增帖子"
    elif not user_options:
        error = error or "当前没有可用用户，请先在用户管理中新增用户"
    return render_template(
        "admin/forum_comment_form.html",
        page_title="后台编辑评论",
        submit_text="保存修改",
        action_url=url_for("admin_forum_comment_edit", comment_id=comment.id),
        cancel_url=url_for("admin_forum_comments", post_id=selected_post_id),
        error=error,
        post_options=post_options,
        user_options=user_options,
        selected_post_id=selected_post_id,
        selected_user_id=selected_user_id,
        content_val=content_val,
        comment_id=comment.id,
    )


@app.route("/admin/forum/comment/<int:comment_id>/delete", methods=["POST"])
@admin_required
def admin_forum_comment_delete(comment_id):
    comment = ForumComment.query.get_or_404(comment_id)
    post_id = comment.post_id
    db.session.delete(comment)
    db.session.commit()
    return redirect(url_for("admin_forum_comments", post_id=post_id, msg="已删除评论 #{}".format(comment_id)))


@app.route("/admin/plan/new", methods=["GET", "POST"])
@admin_required
def admin_plan_new():
    provider_id = request.args.get("provider_id", type=int)
    if request.method == "POST":
        return _save_plan(None)
    providers = Provider.query.order_by(Provider.name).all()
    return render_template(
        "admin/plan_form.html",
        plan=None,
        country_tags=COUNTRY_TAGS,
        providers=providers,
        preselected_provider_id=provider_id,
    )


@app.route("/admin/plan/<int:plan_id>/edit", methods=["GET", "POST"])
@admin_required
def admin_plan_edit(plan_id):
    plan = VPSPlan.query.get_or_404(plan_id)
    if request.method == "POST":
        return _save_plan(plan)
    return redirect(url_for("admin_dashboard"))


def _parse_optional_int(s):
    s = (s or "").strip()
    if not s:
        return None
    try:
        return int(s)
    except ValueError:
        return None


def _parse_optional_float(s):
    s = (s or "").strip()
    if not s:
        return None
    try:
        return float(s)
    except ValueError:
        return None


def _save_plan(plan):
    provider_id = request.form.get("provider_id", type=int)
    countries = request.form.get("countries", "").strip() or None
    vcpu = _parse_optional_int(request.form.get("vcpu"))
    memory_gb = _parse_optional_int(request.form.get("memory_gb"))
    storage_gb = _parse_optional_int(request.form.get("storage_gb"))
    bandwidth_mbps = _parse_optional_int(request.form.get("bandwidth_mbps"))
    traffic = request.form.get("traffic", "").strip() or None
    price_cny = _parse_optional_float(request.form.get("price_cny"))
    price_usd = _parse_optional_float(request.form.get("price_usd"))
    currency = request.form.get("currency", "CNY").strip() or "CNY"
    official_url = request.form.get("official_url", "").strip() or None

    provider = None
    if provider_id:
        provider = db.session.get(Provider, provider_id)
    if not provider:
        providers = Provider.query.order_by(Provider.name).all()
        return render_template(
            "admin/plan_form.html",
            plan=plan,
            country_tags=COUNTRY_TAGS,
            providers=providers,
            preselected_provider_id=provider_id,
            error="请选择厂商",
        )

    if plan is None:
        plan = VPSPlan(
            provider_id=provider.id,
            provider=provider.name,
            region=None,
            name=None,
            vcpu=vcpu,
            memory_gb=memory_gb,
            storage_gb=storage_gb,
            bandwidth_mbps=bandwidth_mbps,
            traffic=traffic,
            price_cny=price_cny,
            price_usd=price_usd,
            currency=currency,
            official_url=official_url,
            countries=countries,
        )
        db.session.add(plan)
    else:
        plan.provider_id = provider.id
        plan.provider = provider.name
        plan.region = None
        plan.name = None
        plan.vcpu = vcpu
        plan.memory_gb = memory_gb
        plan.storage_gb = storage_gb
        plan.bandwidth_mbps = bandwidth_mbps
        plan.traffic = traffic
        plan.price_cny = price_cny
        plan.price_usd = price_usd
        plan.currency = currency
        plan.official_url = official_url
        plan.countries = countries

    db.session.flush()
    _record_price_history(plan, source="manual")
    db.session.commit()
    _invalidate_plans_cache()
    # 若从厂商详情页进入添加，保存后返回该厂商详情
    from_provider_id = request.form.get("from_provider_id", type=int)
    if from_provider_id:
        return redirect(url_for("admin_provider_detail", provider_id=from_provider_id))
    return redirect(url_for("admin_dashboard"))


@app.route("/admin/plan/<int:plan_id>/delete", methods=["POST"])
@admin_required
def admin_plan_delete(plan_id):
    plan = VPSPlan.query.get_or_404(plan_id)
    PriceHistory.query.filter_by(plan_id=plan_id).delete()
    db.session.delete(plan)
    db.session.commit()
    _invalidate_plans_cache()
    return redirect(url_for("admin_dashboard"))


# ---------- Excel 导出 / 导入 ----------
EXCEL_HEADERS = [
    "厂商", "厂商官网", "国家", "vCPU", "内存GB", "存储GB", "带宽Mbps", "流量",
    "月付人民币", "月付美元", "货币", "配置官网",
]


@app.route("/admin/export/excel")
@admin_required
def admin_export_excel():
    wb = Workbook()
    ws = wb.active
    ws.title = "配置"
    ws.append(EXCEL_HEADERS)
    plans = _query_plans_for_display()
    for p in plans:
        provider_url = (p.provider_rel.official_url if p.provider_rel else "") or ""
        ws.append([
            p.provider_name,
            provider_url or "",
            p.countries or "",
            p.vcpu if p.vcpu is not None else "",
            p.memory_gb if p.memory_gb is not None else "",
            p.storage_gb if p.storage_gb is not None else "",
            p.bandwidth_mbps if p.bandwidth_mbps is not None else "",
            p.traffic or "",
            p.price_cny if p.price_cny is not None else "",
            p.price_usd if p.price_usd is not None else "",
            p.currency or "CNY",
            p.official_url or "",
        ])
    buf = io.BytesIO()
    wb.save(buf)
    buf.seek(0)
    return send_file(
        buf,
        mimetype="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
        as_attachment=True,
        download_name="vps_配置_导出.xlsx",
    )


def _num(v):
    if v is None or v == "":
        return None
    try:
        return int(float(v))
    except (ValueError, TypeError):
        return None


def _float(v):
    if v is None or v == "":
        return None
    try:
        return float(v)
    except (ValueError, TypeError):
        return None


def _opt_text(v):
    if v is None:
        return None
    s = str(v).strip()
    return s or None


def _safe_str(v):
    if v is None:
        return ""
    return str(v).strip()


def _eq_optional(a, b):
    if a is None and b is None:
        return True
    if a is None or b is None:
        return False
    if isinstance(a, float) or isinstance(b, float):
        return abs(float(a) - float(b)) < 1e-9
    return a == b


def _record_price_history(plan, source):
    if plan is None:
        return
    if plan.price_cny is None and plan.price_usd is None:
        return
    if plan.id is None:
        db.session.flush()
    latest = (
        PriceHistory.query
        .filter_by(plan_id=plan.id)
        .order_by(PriceHistory.captured_at.desc(), PriceHistory.id.desc())
        .first()
    )
    currency = _opt_text(plan.currency) or "CNY"
    if latest:
        same_currency = _safe_str(latest.currency).upper() == _safe_str(currency).upper()
        if same_currency and _eq_optional(latest.price_cny, plan.price_cny) and _eq_optional(latest.price_usd, plan.price_usd):
            return
    db.session.add(PriceHistory(
        plan_id=plan.id,
        price_cny=plan.price_cny,
        price_usd=plan.price_usd,
        currency=currency,
        source=source,
    ))


def _display_val(v):
    if v is None or v == "":
        return "—"
    if isinstance(v, float):
        s = "{:.2f}".format(v).rstrip("0").rstrip(".")
        return s if s else "0"
    return str(v)


def _row_identity_key(row):
    return (
        _safe_str(row.get("厂商")),
        _num(row.get("vCPU")),
        _num(row.get("内存GB")),
        _num(row.get("存储GB")),
        _num(row.get("带宽Mbps")),
        _safe_str(row.get("国家")),
        _safe_str(row.get("流量")),
    )


def _plan_identity_key(plan):
    return (
        _safe_str(plan.provider_name),
        plan.vcpu,
        plan.memory_gb,
        plan.storage_gb,
        plan.bandwidth_mbps,
        _safe_str(plan.countries),
        _safe_str(plan.traffic),
    )


def _plan_diff(plan, row):
    """返回导入行相对于现有 plan 的差异列表。"""
    fields = [
        ("国家", "countries", _opt_text(row.get("国家"))),
        ("vCPU", "vcpu", _num(row.get("vCPU"))),
        ("内存GB", "memory_gb", _num(row.get("内存GB"))),
        ("存储GB", "storage_gb", _num(row.get("存储GB"))),
        ("带宽Mbps", "bandwidth_mbps", _num(row.get("带宽Mbps"))),
        ("流量", "traffic", _opt_text(row.get("流量"))),
        ("月付人民币", "price_cny", _float(row.get("月付人民币"))),
        ("月付美元", "price_usd", _float(row.get("月付美元"))),
        ("货币", "currency", _opt_text(row.get("货币")) or "CNY"),
        ("配置官网", "official_url", _opt_text(row.get("配置官网"))),
    ]
    diffs = []
    for label, attr, new_value in fields:
        old_value = getattr(plan, attr)
        if not _eq_optional(old_value, new_value):
            diffs.append({
                "label": label,
                "old": old_value,
                "new": new_value,
                "old_display": _display_val(old_value),
                "new_display": _display_val(new_value),
            })
    return diffs


def _upsert_provider_from_row(row):
    provider_name = _safe_str(row.get("厂商"))
    if not provider_name:
        return None
    imported_provider_url = _opt_text(row.get("厂商官网"))
    provider = Provider.query.filter_by(name=provider_name).first()
    if not provider:
        provider = Provider(name=provider_name, official_url=imported_provider_url)
        db.session.add(provider)
        db.session.flush()
    elif imported_provider_url and provider.official_url != imported_provider_url:
        provider.official_url = imported_provider_url
    return provider


def _fill_plan_from_row(plan, row, provider):
    plan.provider_id = provider.id
    plan.provider = provider.name
    plan.region = None
    plan.name = None
    plan.vcpu = _num(row.get("vCPU"))
    plan.memory_gb = _num(row.get("内存GB"))
    plan.storage_gb = _num(row.get("存储GB"))
    plan.bandwidth_mbps = _num(row.get("带宽Mbps"))
    plan.traffic = _opt_text(row.get("流量"))
    plan.price_cny = _float(row.get("月付人民币"))
    plan.price_usd = _float(row.get("月付美元"))
    plan.currency = _opt_text(row.get("货币")) or "CNY"
    plan.official_url = _opt_text(row.get("配置官网"))
    plan.countries = _opt_text(row.get("国家"))


@app.route("/admin/import", methods=["GET", "POST"])
@admin_required
def admin_import():
    if request.method == "GET":
        return render_template("admin/import.html")
    f = request.files.get("file")
    if not f or not f.filename:
        return render_template("admin/import.html", error="请选择 Excel 文件")
    if not f.filename.lower().endswith(".xlsx"):
        return render_template("admin/import.html", error="请上传 .xlsx 文件")
    try:
        wb = load_workbook(io.BytesIO(f.read()), read_only=True, data_only=True)
        ws = wb.active
        rows = list(ws.iter_rows(min_row=2, values_only=True))
    except Exception as e:
        return render_template("admin/import.html", error="解析失败: {}".format(str(e)))
    headers = EXCEL_HEADERS
    parsed = []
    for row in rows:
        if not any(cell is not None and str(cell).strip() for cell in row):
            continue
        d = {}
        for i, h in enumerate(headers):
            if i < len(row):
                v = row[i]
                if v is not None and hasattr(v, "strip"):
                    v = v.strip()
                d[h] = v
            else:
                d[h] = None
        parsed.append(d)
    if not parsed:
        return render_template("admin/import.html", error="文件中没有有效数据行")
    plans = VPSPlan.query.all()
    plan_index = {}
    for p in plans:
        key = _plan_identity_key(p)
        if key not in plan_index:
            plan_index[key] = p
    seen_row_keys = set()
    preview_items = []
    for row in parsed:
        key = _row_identity_key(row)
        provider_name = key[0]
        if not provider_name:
            continue
        if key in seen_row_keys:
            continue
        seen_row_keys.add(key)
        matched = plan_index.get(key)
        if not matched:
            preview_items.append({
                "action": "add",
                "row": row,
                "changes": [],
                "provider_url_changed": False,
            })
            continue
        changes = _plan_diff(matched, row)
        imported_provider_url = _opt_text(row.get("厂商官网"))
        old_provider_url = _opt_text(matched.provider_rel.official_url if matched.provider_rel else None)
        provider_url_changed = bool(imported_provider_url and imported_provider_url != old_provider_url)
        if changes or provider_url_changed:
            preview_items.append({
                "action": "update",
                "plan_id": matched.id,
                "row": row,
                "changes": changes,
                "provider_url_changed": provider_url_changed,
                "provider_url_old": old_provider_url,
                "provider_url_new": imported_provider_url,
            })
    session["import_preview"] = preview_items
    return redirect(url_for("admin_import_preview"))


@app.route("/admin/import/preview", methods=["GET", "POST"])
@admin_required
def admin_import_preview():
    preview_items = session.get("import_preview") or []
    add_count = sum(1 for x in preview_items if x.get("action") == "add")
    update_count = sum(1 for x in preview_items if x.get("action") == "update")
    if request.method == "GET":
        return render_template(
            "admin/import_preview.html",
            rows=list(enumerate(preview_items)),
            add_count=add_count,
            update_count=update_count,
        )
    selected = request.form.getlist("row_index")
    if not selected:
        return render_template(
            "admin/import_preview.html",
            rows=list(enumerate(preview_items)),
            add_count=add_count,
            update_count=update_count,
            error="请至少勾选一行",
        )
    indices = sorted(set(int(x) for x in selected if x.isdigit()))
    add_applied = 0
    update_applied = 0
    for i in indices:
        if i < 0 or i >= len(preview_items):
            continue
        item = preview_items[i]
        row = item.get("row") or {}
        provider = _upsert_provider_from_row(row)
        if not provider:
            continue
        action = item.get("action")
        if action == "update":
            plan = db.session.get(VPSPlan, item.get("plan_id"))
            if not plan:
                plan = VPSPlan()
                db.session.add(plan)
                add_applied += 1
            else:
                update_applied += 1
            _fill_plan_from_row(plan, row, provider)
        else:
            plan = VPSPlan()
            _fill_plan_from_row(plan, row, provider)
            db.session.add(plan)
            add_applied += 1
        _record_price_history(plan, source="import")
    db.session.commit()
    _invalidate_plans_cache()
    session.pop("import_preview", None)
    msg = "已新增 {} 条，更新 {} 条配置".format(add_applied, update_applied)
    return redirect(url_for("admin_dashboard") + "?" + urlencode({"msg": msg}))


if __name__ == "__main__":
    app.run(debug=True, port=5001)