from django.db import models
from django_ckeditor_5.fields import CKEditor5Field

from users.models import User, Department


# Create your models here.

from django.db import models
from django.core.exceptions import ValidationError

class Section(models.Model):
    name = models.CharField('板块名称', max_length=100, unique=True)
    code = models.SlugField('唯一标识', max_length=50, unique=True, help_text='用于模板或URL识别，建议英文')
    parent = models.ForeignKey(
        'self',
        on_delete=models.CASCADE,
        null=True,
        blank=True,
        related_name='subsections',
        verbose_name='所属主板块'
    )
    order = models.PositiveSmallIntegerField('排序权重', default=0)
    enabled = models.BooleanField('启用状态', default=True)

    class Meta:
        verbose_name = '板块'
        verbose_name_plural = '板块管理'
        ordering = ('order', 'name')

    def __str__(self):
        if self.parent:
            return f"{self.parent.name} → {self.name}"
        return self.name

    def clean(self):
        super().clean()
        # 禁止子板块再设父级（即最多两级）
        if self.parent and self.parent.parent:
            raise ValidationError('子板块不能再设置子级，最多只允许一级嵌套。')
        # 防止自引用
        if self.pk and self.parent and self.parent.pk == self.pk:
            raise ValidationError('板块不能以自身为父级。')

    @property
    def is_sub(self):
        """是否为子板块"""
        return self.parent is not None

    @property
    def is_main(self):
        """是否为主板块（无父级）"""
        return self.parent is None


class Carousel(models.Model):
    title = models.CharField("轮播标题", max_length=100)
    image = models.ImageField("图片", upload_to='carousel/')
    link_url = models.URLField("跳转链接", blank=True)
    order = models.IntegerField("排序", default=0)
    active = models.BooleanField("启用", default=True)

    class Meta:
        verbose_name = "轮播图"
        verbose_name_plural = "轮播管理"


class Article(models.Model):
    title = models.CharField("标题", max_length=200)
    section = models.ForeignKey(Section, on_delete=models.CASCADE, verbose_name="所属板块")
    author = models.ForeignKey(User, on_delete=models.SET_NULL, null=True, verbose_name="作者")
    content = CKEditor5Field("正文")  # 需安装 django-ckeditor
    cover = models.ImageField("封面图", upload_to='articles/', blank=True)
    is_published = models.BooleanField("已发布", default=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:
        verbose_name = "文章"
        verbose_name_plural = "文章管理"

    def __str__(self):
        return self.title


class Notice(models.Model):
    title = models.CharField("通知标题", max_length=200)
    content = CKEditor5Field("通知内容")
    publisher = models.ForeignKey(User, on_delete=models.SET_NULL, null=True, verbose_name="发布人")
    target_departments = models.ManyToManyField(Department, blank=True, verbose_name="接收部门")  # 可指定发给哪些部门
    require_sign = models.BooleanField("是否需要签收", default=False)
    is_published = models.BooleanField("已发布", default=True)
    created_at = models.DateTimeField("发布时间", auto_now_add=True)
    updated_at = models.DateTimeField("更新时间", auto_now=True)

    class Meta:
        verbose_name = "通知"
        verbose_name_plural = "通知管理"

    def __str__(self):
        return self.title


class NoticeReceipt(models.Model):
    """签收记录"""
    notice = models.ForeignKey(Notice, on_delete=models.CASCADE, related_name='receipts')
    user = models.ForeignKey(User, on_delete=models.CASCADE, verbose_name="签收人")
    signed_at = models.DateTimeField("签收时间", auto_now_add=True)

    class Meta:
        unique_together = ('notice', 'user')  # 防止重复签收
        verbose_name = "签收记录"
        verbose_name_plural = "签收管理"

    def __str__(self):
        return f"{self.user.cname} 已签收《{self.notice.title}》"