from django.db import models
from django.conf import settings


class FriendRequest(models.Model):
    STATUS_CHOICES = [
        ('pending', '待处理'),
        ('accepted', '已接受'),
        ('rejected', '已拒绝'),
        ('cancelled', '已取消'),
    ]

    from_user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name='sent_friend_requests', verbose_name='发送者')
    to_user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name='received_friend_requests', verbose_name='接收者')
    status = models.CharField(max_length=20, choices=STATUS_CHOICES, default='pending', verbose_name='状态')
    message = models.CharField(max_length=200, blank=True, default='', verbose_name='验证消息')
    created_at = models.DateTimeField(auto_now_add=True, verbose_name='创建时间')
    updated_at = models.DateTimeField(auto_now=True, verbose_name='更新时间')

    class Meta:
        verbose_name = '好友请求'
        verbose_name_plural = '好友请求'
        unique_together = ['from_user', 'to_user']
        ordering = ['-created_at']

    def __str__(self):
        return f'{self.from_user} -> {self.to_user} ({self.status})'


class Friendship(models.Model):
    user1 = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name='friendships_as_user1', verbose_name='用户1')
    user2 = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name='friendships_as_user2', verbose_name='用户2')
    created_at = models.DateTimeField(auto_now_add=True, verbose_name='成为好友时间')

    class Meta:
        verbose_name = '好友关系'
        verbose_name_plural = '好友关系'
        unique_together = ['user1', 'user2']
        ordering = ['-created_at']

    def save(self, *args, **kwargs):
        if self.user1_id > self.user2_id:
            self.user1, self.user2 = self.user2, self.user1
        super().save(*args, **kwargs)

    def __str__(self):
        return f'{self.user1} - {self.user2}'


class Conversation(models.Model):
    TYPE_CHOICES = [
        ('private', '私聊'),
    ]
    type = models.CharField(max_length=20, choices=TYPE_CHOICES, default='private', verbose_name='会话类型')
    created_at = models.DateTimeField(auto_now_add=True, verbose_name='创建时间')

    class Meta:
        verbose_name = '会话'
        verbose_name_plural = '会话'
        ordering = ['-created_at']

    def __str__(self):
        return f'Conversation {self.id} ({self.type})'


class ConversationParticipant(models.Model):
    conversation = models.ForeignKey(Conversation, on_delete=models.CASCADE, related_name='participants', verbose_name='会话')
    user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name='chat_participations', verbose_name='用户')
    joined_at = models.DateTimeField(auto_now_add=True, verbose_name='加入时间')
    last_read_at = models.DateTimeField(null=True, blank=True, verbose_name='最后阅读时间')

    class Meta:
        verbose_name = '会话参与者'
        verbose_name_plural = '会话参与者'
        unique_together = ['conversation', 'user']

    def __str__(self):
        return f'{self.user} in {self.conversation}'


class ChatMessage(models.Model):
    MSG_TYPE_CHOICES = [
        ('text', '文本'),
        ('image', '图片'),
        ('file', '文件'),
        ('emoji', '表情'),
        ('sticker', '表情包'),
    ]

    conversation = models.ForeignKey(Conversation, on_delete=models.CASCADE, related_name='messages', verbose_name='会话')
    sender = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name='chat_messages', verbose_name='发送者')
    content = models.TextField(verbose_name='内容')
    msg_type = models.CharField(max_length=20, choices=MSG_TYPE_CHOICES, default='text', verbose_name='消息类型')
    file_url = models.CharField(max_length=500, blank=True, default='', verbose_name='文件URL')
    reply_to = models.ForeignKey('self', on_delete=models.SET_NULL, null=True, blank=True, related_name='replies', verbose_name='引用消息')
    is_recalled = models.BooleanField(default=False, verbose_name='是否撤回')
    created_at = models.DateTimeField(auto_now_add=True, verbose_name='创建时间')

    class Meta:
        verbose_name = '聊天消息'
        verbose_name_plural = '聊天消息'
        ordering = ['created_at']

    def __str__(self):
        return f'{self.sender}: {self.content[:30]}'


class FavoriteSticker(models.Model):
    user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name='favorite_stickers', verbose_name='用户')
    image = models.ImageField(upload_to='chat_stickers/%Y/%m/', verbose_name='表情包图片')
    created_at = models.DateTimeField(auto_now_add=True, verbose_name='收藏时间')

    class Meta:
        verbose_name = '收藏表情'
        verbose_name_plural = '收藏表情'
        ordering = ['-created_at']

    def __str__(self):
        return f'{self.user} favorite sticker {self.id}'