from django.contrib import admin
from django.contrib.auth.admin import UserAdmin as BaseUserAdmin
from django.utils.html import format_html
from import_export.admin import ImportExportModelAdmin

from .models import Department, Role, Menu
from .models import User


# ========== 菜单管理 ==========
@admin.register(Menu)
class MenuAdmin(admin.ModelAdmin):
    list_display = (
        'name', 'code', 'menu_type_display', 'path', 'permission_code', 'parent_link', 'order_num', 'status')
    list_filter = ('menu_type', 'status', 'parent')
    search_fields = ('name', 'code', 'permission_code')
    ordering = ('order_num', 'id')
    list_editable = ('order_num', 'status')  # 允许在列表页直接编辑
    list_per_page = 20

    # 自定义字段：显示菜单类型
    def menu_type_display(self, obj):
        types = {0: '目录', 1: '菜单', 2: '按钮'}
        return types.get(obj.menu_type, '未知')

    menu_type_display.short_description = '类型'

    # 自定义字段：父菜单链接（可点击）
    def parent_link(self, obj):
        if obj.parent:
            url = f"/admin/users/menu/{obj.parent.id}/change/"
            return format_html('<a href="{}">{}</a>', url, obj.parent.name)
        return '-'

    parent_link.short_description = '父菜单'


# ========== 角色管理 ==========
class RoleMenuInline(admin.TabularInline):
    """
    内联管理：在角色编辑页直接分配菜单
    """
    model = Role.menus.through  # 使用自动创建的中间表
    verbose_name = "菜单权限"
    verbose_name_plural = "菜单权限"
    extra = 1  # 默认显示1个空行

    # 优化显示：只显示关键字段
    def formfield_for_foreignkey(self, db_field, request, **kwargs):
        if db_field.name == "menu":
            # 可以在这里过滤菜单选项，例如只显示状态为True的
            kwargs["queryset"] = Menu.objects.filter(status=True)
        return super().formfield_for_foreignkey(db_field, request, **kwargs)


@admin.register(Role)
class RoleAdmin(admin.ModelAdmin):
    list_display = ('name', 'code', 'description', 'user_count', 'menu_count', 'status', 'created_at')
    list_filter = ('status', 'created_at')
    search_fields = ('name', 'code', 'description')
    ordering = ('-created_at',)
    list_per_page = 20

    # 使用内联管理菜单权限
    inlines = [RoleMenuInline]

    # 排除 menus 字段，因为已经在内联中处理
    exclude = ('menus',)

    # 自定义字段：关联用户数量
    def user_count(self, obj):
        count = obj.users.count()
        if count:
            url = f"/admin/users/user/?roles__id__exact={obj.id}"
            return format_html('<a href="{}">{}</a>', url, count)
        return 0

    user_count.short_description = '用户数'

    # 自定义字段：关联菜单数量
    def menu_count(self, obj):
        count = obj.menus.count()
        if count:
            url = f"/admin/users/menu/?roles__id__exact={obj.id}"
            return format_html('<a href="{}">{}</a>', url, count)
        return 0

    menu_count.short_description = '菜单数'


# ========== 用户管理 ==========
class UserRoleInline(admin.TabularInline):
    """
    内联管理：在用户编辑页直接分配角色
    """
    model = User.roles.through
    verbose_name = "角色"
    verbose_name_plural = "角色"
    extra = 1


@admin.register(User)
class UserAdmin(BaseUserAdmin, ImportExportModelAdmin):
    list_display = ('username', 'cname', 'dept', 'phone', 'is_active', 'is_staff')
    list_filter = ('is_active', 'is_staff', 'dept')
    search_fields = ('username', 'cname', 'phone',)
    fieldsets = (
        (None, {'fields': ('username', 'password')}),
        ('个人信息', {'fields': ('cname', 'dept')}),
        ('权限', {'fields': ('is_active', 'is_staff', 'is_superuser', 'groups', 'user_permissions')}),
        ('重要日期', {'fields': ('last_login', 'date_joined')}),
    )
    add_fieldsets = (
        (None, {
            'classes': ('wide',),
            'fields': ('username', 'cname', 'password1', 'password2', 'dept'),
        }),
    )
    ordering = ('username', '-date_joined',)
    filter_horizontal = ('groups', 'user_permissions', 'roles')  # 如果 roles 是 ManyToMany
    list_per_page = 20
    # 使用内联管理角色
    inlines = [UserRoleInline]

    # 排除 roles 字段，因为已经在内联中处理
    exclude = ('roles',)

    # 自定义字段：显示所有角色名称
    def role_names(self, obj):
        roles = obj.roles.all()
        if roles:
            names = ', '.join([role.name for role in roles])
            return names[:50] + '...' if len(names) > 50 else names
        return '-'

    role_names.short_description = '角色'


# ========== 部门管理 ==========
@admin.register(Department)
class DepartmentAdmin(admin.ModelAdmin):
    list_display = ('name_with_indent', 'parent_link', 'order', 'user_count')
    list_editable = ('order',)
    ordering = ('order', 'id')
    list_per_page = 30

    def get_queryset(self, request):
        # 优化查询，避免 N+1
        return super().get_queryset(request).select_related('parent')

    def name_with_indent(self, obj):
        """根据层级缩进显示部门名称"""
        level = 0
        current = obj.parent
        while current:
            level += 1
            current = current.parent
        indent = "=>" * level
        return format_html('{}{}', indent, obj.name)

    name_with_indent.short_description = "部门名称"
    name_with_indent.allow_tags = True

    def parent_link(self, obj):
        if obj.parent:
            url = f"/admin/users/department/{obj.parent.id}/change/"
            return format_html('<a href="{}">{}</a>', url, obj.parent.name)
        return '-'

    parent_link.short_description = "上级部门"

    def user_count(self, obj):
        count = obj.user_set.count()
        if count:
            url = f"/admin/users/user/?department__id__exact={obj.id}"
            return format_html('<a href="{}">{}</a>', url, count)
        return 0

    user_count.short_description = "用户数"