import { useState, useEffect } from 'react'
import { rolesApi, type RoleInfo, type Permission } from '@/api'
import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/components/ui/card'
import { Button } from '@/components/ui/button'
import { Badge } from '@/components/ui/badge'
import { Checkbox } from '@/components/ui/checkbox'
import {
  Table,
  TableBody,
  TableCell,
  TableHead,
  TableHeader,
  TableRow,
} from '@/components/ui/table'
import { RefreshCw, Loader2, Users, Check } from 'lucide-react'

// 角色颜色映射
const roleColors: Record<string, { bg: string; text: string; border: string }> = {
  super_admin: { bg: 'bg-purple-100', text: 'text-purple-700', border: 'border-purple-300' },
  admin: { bg: 'bg-red-100', text: 'text-red-700', border: 'border-red-300' },
  moderator: { bg: 'bg-orange-100', text: 'text-orange-700', border: 'border-orange-300' },
  user: { bg: 'bg-blue-100', text: 'text-blue-700', border: 'border-blue-300' },
}

// 角色名称映射
const roleNameMap: Record<string, string> = {
  super_admin: '超级管理员',
  admin: '管理员',
  moderator: '版主',
  user: '普通用户',
}

// 资源名称映射
const resourceNames: Record<string, string> = {
  users: '用户',
  posts: '帖子',
  comments: '评论',
  groups: '群组',
  messages: '消息',
  reports: '举报',
  settings: '设置',
  logs: '日志',
}

// 操作名称映射
const actionNames: Record<string, string> = {
  read: '读取',
  write: '写入',
  delete: '删除',
  manage: '管理',
}

// 预定义的权限矩阵结构
const permissionMatrix = {
  resources: ['users', 'posts', 'comments', 'groups', 'messages', 'reports', 'settings', 'logs'],
  actions: ['read', 'write', 'delete', 'manage'],
}

export default function Roles() {
  // 状态
  const [roles, setRoles] = useState<RoleInfo[]>([])
  const [loading, setLoading] = useState(true)
  const [selectedRole, setSelectedRole] = useState<string | null>(null)
  const [rolePermissions, setRolePermissions] = useState<Permission[]>([])
  const [permissionsLoading, setPermissionsLoading] = useState(false)
  const [saving, setSaving] = useState(false)

  // 加载角色列表
  const loadRoles = async () => {
    setLoading(true)
    try {
      const response = await rolesApi.getRoles()
      const data = response.data.data || []
      setRoles(data)
      if (data.length > 0 && !selectedRole) {
        setSelectedRole(data[0].name)
        loadRolePermissions(data[0].name)
      }
    } catch (error) {
      console.error('Failed to load roles:', error)
      setRoles([])
    } finally {
      setLoading(false)
    }
  }

  // 加载角色权限
  const loadRolePermissions = async (roleName: string) => {
    setPermissionsLoading(true)
    try {
      const response = await rolesApi.getRolePermissions(roleName)
      setRolePermissions(response.data.data || [])
    } catch (error) {
      console.error('Failed to load role permissions:', error)
      setRolePermissions([])
    } finally {
      setPermissionsLoading(false)
    }
  }

  // 初始加载
  useEffect(() => {
    loadRoles()
  }, [])

  // 选择角色时加载权限
  useEffect(() => {
    if (selectedRole) {
      loadRolePermissions(selectedRole)
    }
  }, [selectedRole])

  // 检查权限是否存在
  const hasPermission = (resource: string, action: string) => {
    return rolePermissions.some(
      (p) => p.resource === resource && p.action === action
    )
  }

  // 切换权限
  const togglePermission = async (resource: string, action: string) => {
    setSaving(true)
    try {
      const currentPermissions = [...rolePermissions]
      const hasIt = hasPermission(resource, action)
      
      let newPermissions: Permission[]
      if (hasIt) {
        newPermissions = currentPermissions.filter(
          (p) => !(p.resource === resource && p.action === action)
        )
      } else {
        newPermissions = [
          ...currentPermissions,
          { resource, action },
        ]
      }
      
      // 更新权限 - 发送 {resource, action} 格式的数组
      await rolesApi.updateRolePermissions(
        selectedRole!,
        newPermissions.map((p) => ({ resource: p.resource, action: p.action }))
      )
      
      setRolePermissions(newPermissions)
    } catch (error) {
      console.error('Failed to update permission:', error)
    } finally {
      setSaving(false)
    }
  }

  // 刷新
  const handleRefresh = () => {
    loadRoles()
    if (selectedRole) {
      loadRolePermissions(selectedRole)
    }
  }

  return (
    <div className="space-y-6">
      <div className="flex items-center justify-between">
        <div>
          <h1 className="text-3xl font-bold">角色管理</h1>
          <p className="text-muted-foreground">管理系统角色和权限</p>
        </div>
        <Button onClick={handleRefresh} disabled={loading}>
          {loading ? <Loader2 className="h-4 w-4 animate-spin" /> : <RefreshCw className="h-4 w-4" />}
          刷新
        </Button>
      </div>

      {/* 角色卡片 */}
      <div className="grid gap-4 md:grid-cols-2 lg:grid-cols-4">
        {loading ? (
          <Card className="col-span-full">
            <CardContent className="flex items-center justify-center py-8">
              <Loader2 className="h-8 w-8 animate-spin text-muted-foreground" />
            </CardContent>
          </Card>
        ) : roles.length === 0 ? (
          <Card className="col-span-full">
            <CardContent className="text-center py-8 text-muted-foreground">
              暂无角色数据
            </CardContent>
          </Card>
        ) : (
          roles.map((role) => {
            const colors = roleColors[role.name] || { bg: 'bg-gray-100', text: 'text-gray-700', border: 'border-gray-300' }
            const isSelected = selectedRole === role.name
            
            return (
              <Card
                key={role.name}
                className={`cursor-pointer transition-all hover:shadow-md ${
                  isSelected ? `ring-2 ring-primary ${colors.border}` : ''
                }`}
                onClick={() => setSelectedRole(role.name)}
              >
                <CardHeader className="pb-2">
                  <div className="flex items-center justify-between">
                    <CardTitle className={`text-lg ${colors.text}`}>
                      {roleNameMap[role.name] || role.display_name || role.name}
                    </CardTitle>
                    {isSelected && (
                      <Check className="h-5 w-5 text-primary" />
                    )}
                  </div>
                  <CardDescription className="line-clamp-2">
                    {role.description || '暂无描述'}
                  </CardDescription>
                </CardHeader>
                <CardContent>
                  <div className="flex items-center justify-between text-sm">
                    <div className="flex items-center gap-1 text-muted-foreground">
                      <Users className="h-4 w-4" />
                      <span>{role.priority} 优先级</span>
                    </div>
                  </div>
                </CardContent>
              </Card>
            )
          })
        )}
      </div>

      {/* 权限矩阵 */}
      {selectedRole && (
        <Card>
          <CardHeader>
            <div className="flex items-center justify-between">
              <div>
                <CardTitle>
                  权限矩阵 - {roleNameMap[selectedRole] || selectedRole}
                </CardTitle>
                <CardDescription>
                  管理角色的各项权限，点击复选框切换权限状态
                </CardDescription>
              </div>
              {saving && (
                <Badge variant="outline" className="text-orange-500">
                  <Loader2 className="h-3 w-3 animate-spin mr-1" />
                  保存中...
                </Badge>
              )}
            </div>
          </CardHeader>
          <CardContent>
            {permissionsLoading ? (
              <div className="flex items-center justify-center py-8">
                <Loader2 className="h-8 w-8 animate-spin text-muted-foreground" />
              </div>
            ) : (
              <div className="overflow-x-auto">
                <Table>
                  <TableHeader>
                    <TableRow>
                      <TableHead className="w-[120px] font-semibold">资源</TableHead>
                      {permissionMatrix.actions.map((action) => (
                        <TableHead key={action} className="text-center font-semibold">
                          {actionNames[action] || action}
                        </TableHead>
                      ))}
                    </TableRow>
                  </TableHeader>
                  <TableBody>
                    {permissionMatrix.resources.map((resource) => (
                      <TableRow key={resource}>
                        <TableCell className="font-medium">
                          {resourceNames[resource] || resource}
                        </TableCell>
                        {permissionMatrix.actions.map((action) => {
                          const has = hasPermission(resource, action)
                          return (
                            <TableCell key={`${resource}-${action}`} className="text-center">
                              <div className="flex justify-center">
                                <Checkbox
                                  checked={has}
                                  onCheckedChange={() => togglePermission(resource, action)}
                                  disabled={saving || selectedRole === 'super_admin'}
                                  className="data-[state=checked]:bg-primary"
                                />
                              </div>
                            </TableCell>
                          )
                        })}
                      </TableRow>
                    ))}
                  </TableBody>
                </Table>
              </div>
            )}
            
            {selectedRole === 'super_admin' && (
              <p className="text-sm text-muted-foreground mt-4 text-center">
                超级管理员拥有所有权限，无法修改
              </p>
            )}
          </CardContent>
        </Card>
      )}

      {/* 角色说明 */}
      <Card>
        <CardHeader>
          <CardTitle>角色说明</CardTitle>
          <CardDescription>各角色的权限范围说明</CardDescription>
        </CardHeader>
        <CardContent>
          <div className="space-y-4">
            <div className="flex items-start gap-3">
              <Badge className={`${roleColors.super_admin?.bg} ${roleColors.super_admin?.text}`}>
                超级管理员
              </Badge>
              <p className="text-sm text-muted-foreground">
                拥有系统所有权限，可以管理其他管理员、系统设置等核心功能
              </p>
            </div>
            <div className="flex items-start gap-3">
              <Badge className={`${roleColors.admin?.bg} ${roleColors.admin?.text}`}>
                管理员
              </Badge>
              <p className="text-sm text-muted-foreground">
                可以管理用户、帖子、评论、群组等内容，处理用户举报
              </p>
            </div>
            <div className="flex items-start gap-3">
              <Badge className={`${roleColors.moderator?.bg} ${roleColors.moderator?.text}`}>
                版主
              </Badge>
              <p className="text-sm text-muted-foreground">
                负责审核和管理帖子、评论等内容，处理违规内容
              </p>
            </div>
            <div className="flex items-start gap-3">
              <Badge className={`${roleColors.user?.bg} ${roleColors.user?.text}`}>
                普通用户
              </Badge>
              <p className="text-sm text-muted-foreground">
                基本用户权限，可以发帖、评论、加入群组等
              </p>
            </div>
          </div>
        </CardContent>
      </Card>
    </div>
  )
}