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


MSG_TYPE_CHOICES = [
    ('reply', '回复'),
    ('at_me', '@我'),
    ('like', '点赞'),
]

TARGET_TYPE_CHOICES = [
    ('comment', '评论'),
    ('article', '文章'),
]

SYSTEM_CATEGORY_CHOICES = [
    ('system', '系统通知'),
    ('activity', '活动通知'),
    ('security', '安全提醒'),
    ('update', '功能更新'),
]


class Message(models.Model):
    recipient = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
        related_name='messages',
        verbose_name='接收者'
    )
    sender = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.SET_NULL,
        related_name='sent_messages',
        verbose_name='发送者',
        null=True,
        blank=True
    )
    msg_type = models.CharField(max_length=20, choices=MSG_TYPE_CHOICES, verbose_name='消息类型')
    title = models.CharField(max_length=200, verbose_name='标题')
    content = models.TextField(verbose_name='内容')
    extra_info = models.CharField(max_length=500, blank=True, default='', verbose_name='附加信息')
    target_link = models.CharField(max_length=500, blank=True, default='', verbose_name='跳转链接')
    target_type = models.CharField(max_length=20, blank=True, default='', choices=TARGET_TYPE_CHOICES, verbose_name='目标类型')
    target_id = models.PositiveIntegerField(null=True, blank=True, verbose_name='目标ID')
    is_read = models.BooleanField(default=False, verbose_name='是否已读')
    created_at = models.DateTimeField(auto_now_add=True, verbose_name='创建时间')

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

    def __str__(self):
        return f'{self.get_msg_type_display()} - {self.title}'


class SystemMessage(models.Model):
    title = models.CharField(max_length=200, verbose_name='标题')
    content = models.TextField(verbose_name='摘要')
    detail = models.TextField(verbose_name='详情正文')
    category = models.CharField(max_length=20, choices=SYSTEM_CATEGORY_CHOICES, verbose_name='分类')
    icon_name = models.CharField(max_length=50, blank=True, default='', verbose_name='图标名称')
    icon_color = models.CharField(max_length=20, blank=True, default='#1890ff', verbose_name='图标颜色')
    is_global = models.BooleanField(default=True, verbose_name='是否全局广播')
    created_at = models.DateTimeField(auto_now_add=True, verbose_name='创建时间')

    class Meta:
        verbose_name = '系统消息'
        verbose_name_plural = '系统消息'
        ordering = ['-created_at']

    def __str__(self):
        return self.title


class SystemMessageRead(models.Model):
    user = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
        related_name='system_message_reads',
        verbose_name='用户'
    )
    system_message = models.ForeignKey(
        SystemMessage,
        on_delete=models.CASCADE,
        related_name='read_records',
        verbose_name='系统消息'
    )
    read_at = models.DateTimeField(auto_now_add=True, verbose_name='阅读时间')

    class Meta:
        verbose_name = '系统消息已读'
        verbose_name_plural = '系统消息已读'
        unique_together = ['user', 'system_message']

    def __str__(self):
        return f'{self.user} read {self.system_message}'