"""
User models for authentication and profile management.
"""
from django.db import models
from django.contrib.auth.models import AbstractBaseUser, BaseUserManager, PermissionsMixin


class UserManager(BaseUserManager):
    """Custom user manager."""
    
    def create_user(self, open_id, password=None, **extra_fields):
        """Create and save a regular user."""
        if not open_id:
            raise ValueError('The open_id must be set')
        user = self.model(open_id=open_id, **extra_fields)
        if password:
            user.set_password(password)
        else:
            user.set_unusable_password()
        user.save(using=self._db)
        return user
    
    def create_superuser(self, open_id, password=None, **extra_fields):
        """Create and save a superuser."""
        extra_fields.setdefault('is_staff', True)
        extra_fields.setdefault('is_superuser', True)
        extra_fields.setdefault('role', 'admin')
        return self.create_user(open_id, password=password, **extra_fields)


class User(AbstractBaseUser, PermissionsMixin):
    """Custom user model matching the original schema."""
    
    class Role(models.TextChoices):
        USER = 'user', '普通用户'
        ADMIN = 'admin', '管理员'
    
    id = models.AutoField(primary_key=True)
    open_id = models.CharField('OpenID', max_length=64, unique=True)
    name = models.CharField('用户名', max_length=255, blank=True, null=True)
    email = models.EmailField('邮箱', max_length=320, blank=True, null=True)
    avatar = models.TextField('头像', blank=True, null=True)
    login_method = models.CharField('登录方式', max_length=64, blank=True, null=True)
    role = models.CharField(
        '角色',
        max_length=10,
        choices=Role.choices,
        default=Role.USER
    )
    stripe_customer_id = models.CharField('Stripe客户ID', max_length=255, blank=True, null=True)
    stripe_account_id = models.CharField('Stripe账户ID', max_length=255, blank=True, null=True)
    
    # Django auth fields
    is_active = models.BooleanField('是否激活', default=True)
    is_staff = models.BooleanField('是否员工', default=False)
    
    created_at = models.DateTimeField('创建时间', auto_now_add=True)
    updated_at = models.DateTimeField('更新时间', auto_now=True)
    last_signed_in = models.DateTimeField('最后登录时间', auto_now=True)
    
    objects = UserManager()
    
    USERNAME_FIELD = 'open_id'
    REQUIRED_FIELDS = []
    
    class Meta:
        db_table = 'users'
        verbose_name = '用户'
        verbose_name_plural = '用户'
        indexes = [
            models.Index(fields=["role", "is_active"]),
            models.Index(fields=["created_at"]),
        ]
    
    def __str__(self):
        return self.name or self.open_id
    
    @property
    def is_admin(self):
        return self.role == self.Role.ADMIN


class FriendRequest(models.Model):
    """Friend request and relationship status."""

    class Status(models.TextChoices):
        PENDING = "pending", "待处理"
        ACCEPTED = "accepted", "已通过"
        REJECTED = "rejected", "已拒绝"
        CANCELED = "canceled", "已取消"

    requester = models.ForeignKey(
        User,
        related_name="sent_friend_requests",
        on_delete=models.CASCADE,
    )
    receiver = models.ForeignKey(
        User,
        related_name="received_friend_requests",
        on_delete=models.CASCADE,
    )
    status = models.CharField(
        "状态",
        max_length=10,
        choices=Status.choices,
        default=Status.PENDING,
    )
    accepted_at = models.DateTimeField("通过时间", blank=True, null=True)
    created_at = models.DateTimeField("创建时间", auto_now_add=True)
    updated_at = models.DateTimeField("更新时间", auto_now=True)

    class Meta:
        db_table = "friend_requests"
        verbose_name = "好友请求"
        verbose_name_plural = "好友请求"
        unique_together = ("requester", "receiver")
        constraints = [
            models.CheckConstraint(
                check=~models.Q(requester=models.F("receiver")),
                name="no_self_friend_request",
            )
        ]
        indexes = [
            models.Index(fields=["receiver", "status"]),
            models.Index(fields=["requester", "status"]),
        ]

    def __str__(self):
        return f"{self.requester_id}->{self.receiver_id} ({self.status})"