from django.contrib.auth.models import PermissionsMixin, AbstractUser
from django.db import models

from common.base import BaseEntity


# Create your models here.
class Role(BaseEntity):
    """角色模型"""
    name = models.CharField(max_length=50, unique=True, verbose_name="角色名称")
    code = models.CharField(max_length=50, unique=True, verbose_name="角色编码")
    description = models.CharField(max_length=200, blank=True, verbose_name="描述")
    status = models.BooleanField(default=True, verbose_name="状态")
    # 直接关联菜单（多对多）
    menus = models.ManyToManyField(
        'Menu',
        blank=True,
        related_name='roles',
        verbose_name="菜单权限"
    )

    class Meta:
        verbose_name = "角色"
        verbose_name_plural = verbose_name


class Department(BaseEntity):
    name = models.CharField("部门名称", max_length=100, unique=True)
    parent = models.ForeignKey('self', on_delete=models.CASCADE, null=True, blank=True, verbose_name="上级部门")
    order = models.IntegerField("排序", default=0)

    class Meta:
        verbose_name = "部门"
        verbose_name_plural = "部门管理"

        # 👇 核心：添加部分唯一约束
        constraints = [
            models.UniqueConstraint(
                fields=['parent'],
                condition=models.Q(parent__isnull=True),
                name='unique_root_department'
            )
        ]

    def __str__(self):
        return self.name

    @property
    def is_root(self):
        return self.parent is None


class User(AbstractUser, PermissionsMixin, BaseEntity):
    username = models.CharField("英文名/账号", max_length=30, unique=True)
    cname = models.CharField("中文名", max_length=30, blank=True)
    phone = models.CharField(max_length=20, blank=True, verbose_name="手机号")
    avatar = models.CharField(max_length=255, blank=True, verbose_name="头像")
    dept = models.ForeignKey('Department', on_delete=models.SET_NULL, null=True, blank=True, verbose_name="所属部门")
    is_active = models.BooleanField(default=True, verbose_name="状态")
    # 直接在这里定义多对多关系 👈
    roles = models.ManyToManyField(
        Role,
        blank=True,
        related_name='users',
        verbose_name="角色"
    )

    USERNAME_FIELD = 'username'
    REQUIRED_FIELDS = []

    def __str__(self):
        return f"{self.cname} ({self.username})"


class Menu(BaseEntity):
    """菜单模型"""
    MENU_TYPE_CHOICES = [
        (0, '目录'),
        (1, '菜单'),
        (2, '按钮'),
    ]

    name = models.CharField(max_length=50, verbose_name="菜单名称")
    code = models.CharField(max_length=50, unique=True, verbose_name="菜单编码")
    path = models.CharField(max_length=200, blank=True, verbose_name="路由路径")
    component = models.CharField(max_length=200, blank=True, verbose_name="组件路径")
    icon = models.CharField(max_length=50, blank=True, verbose_name="图标")
    parent = models.ForeignKey('self', null=True, blank=True, on_delete=models.CASCADE, verbose_name="父菜单")
    menu_type = models.IntegerField(choices=MENU_TYPE_CHOICES, default=1, verbose_name="菜单类型")
    order_num = models.IntegerField(default=0, verbose_name="显示顺序")
    permission_code = models.CharField(max_length=100, blank=True, verbose_name="权限标识")
    status = models.BooleanField(default=True, verbose_name="状态")

    class Meta:
        verbose_name = "菜单"
        verbose_name_plural = verbose_name

    def __str__(self):
        return self.name