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


class Comment(models.Model):
    """Model for comments."""

    AI_STATUS_CHOICES = [
        ('pending', '待审核'),
        ('approved', '通过'),
        ('rejected', '拒绝'),
    ]

    TARGET_TYPE_CHOICES = [
        ('article', '文章'),
        ('service', '特色服务'),
    ]

    content = models.TextField(verbose_name='评论内容')
    target_type = models.CharField(
        max_length=20,
        choices=TARGET_TYPE_CHOICES,
        verbose_name='评论对象类型'
    )
    target_id = models.PositiveIntegerField(verbose_name='评论对象ID')
    author = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
        related_name='comments',
        verbose_name='评论者'
    )
    ai_status = models.CharField(
        max_length=20,
        choices=AI_STATUS_CHOICES,
        default='pending',
        verbose_name='AI审核状态'
    )
    ai_rejection_reason = models.TextField(null=True, blank=True, verbose_name='AI拒绝原因')
    created_at = models.DateTimeField(auto_now_add=True, verbose_name='创建时间')

    class Meta:
        db_table = 'comments'
        verbose_name = '评论'
        verbose_name_plural = '评论'
        ordering = ['-created_at']

    def __str__(self):
        return f'{self.author.username} on {self.target_type} {self.target_id}'

    def approve_ai(self):
        """Approve comment by AI."""
        self.ai_status = 'approved'
        self.save()

    def reject_ai(self, reason):
        """Reject comment by AI."""
        self.ai_status = 'rejected'
        self.ai_rejection_reason = reason
        self.save()


class Rating(models.Model):
    """Model for ratings."""

    TARGET_TYPE_CHOICES = [
        ('region', '城市'),
        ('service', '特色服务'),
    ]

    user = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
        related_name='ratings',
        verbose_name='用户'
    )
    target_type = models.CharField(
        max_length=20,
        choices=TARGET_TYPE_CHOICES,
        verbose_name='评分对象类型'
    )
    target_id = models.PositiveIntegerField(verbose_name='评分对象ID')
    score = models.PositiveSmallIntegerField(verbose_name='评分值')
    created_at = models.DateTimeField(auto_now_add=True, verbose_name='创建时间')

    class Meta:
        db_table = 'ratings'
        verbose_name = '评分'
        verbose_name_plural = '评分'
        unique_together = ['user', 'target_type', 'target_id']
        ordering = ['-created_at']

    def __str__(self):
        return f'{self.user.username} rated {self.target_type} {self.target_id}: {self.score}'


class Like(models.Model):
    """Model for likes."""

    TARGET_TYPE_CHOICES = [
        ('article', '文章'),
        ('service', '特色服务'),
    ]

    user = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
        related_name='likes',
        verbose_name='用户'
    )
    target_type = models.CharField(
        max_length=20,
        choices=TARGET_TYPE_CHOICES,
        verbose_name='点赞对象类型'
    )
    target_id = models.PositiveIntegerField(verbose_name='点赞对象ID')
    created_at = models.DateTimeField(auto_now_add=True, verbose_name='创建时间')

    class Meta:
        db_table = 'likes'
        verbose_name = '点赞'
        verbose_name_plural = '点赞'
        unique_together = ['user', 'target_type', 'target_id']
        ordering = ['-created_at']

    def __str__(self):
        return f'{self.user.username} likes {self.target_type} {self.target_id}'


class Favorite(models.Model):
    """Model for favorites."""

    TARGET_TYPE_CHOICES = [
        ('region', '城市'),
        ('service', '特色服务'),
    ]

    user = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
        related_name='favorites',
        verbose_name='用户'
    )
    target_type = models.CharField(
        max_length=20,
        choices=TARGET_TYPE_CHOICES,
        verbose_name='收藏对象类型'
    )
    target_id = models.PositiveIntegerField(verbose_name='收藏对象ID')
    created_at = models.DateTimeField(auto_now_add=True, verbose_name='创建时间')

    class Meta:
        db_table = 'favorites'
        verbose_name = '收藏'
        verbose_name_plural = '收藏'
        unique_together = ['user', 'target_type', 'target_id']
        ordering = ['-created_at']

    def __str__(self):
        return f'{self.user.username} favorited {self.target_type} {self.target_id}'