from django.contrib import admin
from django.contrib.auth.hashers import make_password
from django.contrib import messages
from django.contrib.auth.models import AbstractUser, Group, Permission, User
from django.contrib.auth import get_user_model

UserModel = get_user_model()

# admin.site.unregister(User)  # 如果使用原生用户模型，需要先取消注册
@admin.register(UserModel)
class UserAdmin(admin.ModelAdmin):
    list_display_links = ('username',)
    search_fields = ('username', 'first_name')

    def get_list_display(self, request):
        """列表页展示的字段，管理员添加可见字段"""
        list_display = ('username', 'first_name', 'area', 'is_staff', 'is_superuser_display', 'date_joined', 'last_login')
        return list_display

    # 自定义显示字段
    @admin.display(description='超级管理员')
    def is_superuser_display(self, obj):
        return '是' if obj.is_superuser else ''

    # 列表过滤器功能的字段
    def get_list_filter(self, request):
        if request.user.is_superuser:
            list_filter = ('area',)
            self.list_filter_multiples = ('area',)
            return list_filter
        else:
            return super().get_list_filter(request)

    def get_fieldsets(self, request, obj=None):
        """详情页字段"""
        self.filter_horizontal = ['user_permissions', 'groups']
        fieldsets = [
            ("账号信息", {"fields": [('username', 'password', 'first_name', 'email')]}),
            ("登录权限", {"fields": ['area', 'is_staff', 'is_superuser']}),
            ("使用权限", {"fields": ['user_permissions', 'groups'], "classes": ['collapse']}),
        ]
        return fieldsets

    def get_changeform_initial_data(self, request):
        """详情页中初始值的修改"""
        initial = super().get_changeform_initial_data(request)
        initial['is_staff'] = True
        return initial

    def save_model(self, request, obj, form, change):
        """创建或修改某条数据的功能"""
        if obj.is_superuser:  # 如果是超管，无需配置区域
            obj.area = None
            
        if change:
            # 修改密码
            if obj.password != User.objects.get(pk=obj.pk).password:  # 如果有修改密码行为
                if obj.pk != request.user.pk and request.user.is_superuser is False:  # 如果不是超管，不可以修改其他人密码
                    messages.error(request, '您不是超管，不能修改其他人密码。')
                    return
                obj.password = make_password(obj.password)
        else:  # 如果是创建用户
            obj.password = make_password(obj.password)

        super().save_model(request, obj, form, change)

    def delete_model(self, request, obj):
        """删除时做一些处理"""
        obj.delete()

    def save_related(self, request, form, formsets, change):
        """保存外键和多对多关系数据"""
        super().save_related(request, form, formsets, change)
        obj = form.instance

        # 默认权限（必须先添加数据才能修改权限）
        if not change:  # 如果是新建用户
            if not obj.user_permissions.exists() and not obj.groups.exists():  # 如果没有手动添加权限
                permissions = Permission.objects.filter(content_type__app_label__in=['children', 'women', 'users'])
                obj.user_permissions.add(*permissions)

                user_permissions = Permission.objects.filter(content_type__app_label='auth', content_type__model='user')  # 用户表权限
                obj.user_permissions.add(*user_permissions)

    def get_queryset(self, request):
        """列表页的查询集"""
        qs = super().get_queryset(request)

        if not request.user.is_superuser:
            qs = qs.filter(area=request.user.area, is_superuser=False)

        return qs