import { useState, useEffect } from 'react'
import { Card, CardContent } from '@/components/ui/card'
import { Input } from '@/components/ui/input'
import { Button } from '@/components/ui/button'
import { Label } from '@/components/ui/label'
import {
  Table,
  TableBody,
  TableCell,
  TableHead,
  TableHeader,
  TableRow,
} from '@/components/ui/table'
import { Badge } from '@/components/ui/badge'
import {
  Dialog,
  DialogContent,
  DialogHeader,
  DialogTitle,
  DialogFooter,
} from '@/components/ui/dialog'
import { ShieldCheck, Plus, Edit3, Trash2, X, Save, RefreshCw } from 'lucide-react'
import { get, post, put, del } from '@/api/client'
import { Pagination } from '@/components/ui/Pagination'
import { useDebounce } from '@/hooks/useDebounce'

interface AdminUser {
  id: number
  username: string
  role: string
  name: string
  status: string
  createdAt: string
  updatedAt?: string
}

interface ListRes {
  success?: boolean
  records?: AdminUser[]
  total?: number
  page?: number
  pageSize?: number
  totalPages?: number
  error?: string
}

function confirmDangerousDelete(entity: string): boolean {
  if (!confirm(`确定删除该${entity}？此操作不可恢复。`)) return false
  const verifyText = window.prompt(`请输入「删除」以确认删除${entity}`)
  return verifyText === '删除'
}

export function AdminUsersPage() {
  const [records, setRecords] = useState<AdminUser[]>([])
  const [total, setTotal] = useState(0)
  const [page, setPage] = useState(1)
  const [pageSize] = useState(10)
  const [totalPages, setTotalPages] = useState(0)
  const [searchTerm, setSearchTerm] = useState('')
  const debouncedSearch = useDebounce(searchTerm, 300)
  const [loading, setLoading] = useState(true)
  const [error, setError] = useState<string | null>(null)
  const [showModal, setShowModal] = useState(false)
  const [editingUser, setEditingUser] = useState<AdminUser | null>(null)
  const [formUsername, setFormUsername] = useState('')
  const [formPassword, setFormPassword] = useState('')
  const [formName, setFormName] = useState('')
  const [formRole, setFormRole] = useState<'super_admin' | 'admin'>('admin')
  const [formStatus, setFormStatus] = useState<'active' | 'disabled'>('active')
  const [saving, setSaving] = useState(false)

  async function loadList() {
    setLoading(true)
    setError(null)
    try {
      const params = new URLSearchParams({
        page: String(page),
        pageSize: String(pageSize),
      })
      if (debouncedSearch.trim()) params.set('search', debouncedSearch.trim())
      const data = await get<ListRes>(`/api/admin/users?${params}`)
      if (data?.success) {
        setRecords((data as ListRes).records || [])
        setTotal((data as ListRes).total ?? 0)
        setTotalPages((data as ListRes).totalPages ?? 0)
      } else {
        setError((data as ListRes).error || '加载失败')
      }
    } catch (e: unknown) {
      const err = e as { status?: number; data?: { error?: string } }
      setError(err.status === 403 ? '无权限访问' : err?.data?.error || '加载失败')
      setRecords([])
    } finally {
      setLoading(false)
    }
  }

  useEffect(() => {
    loadList()
  }, [page, pageSize, debouncedSearch])

  const handleAdd = () => {
    setEditingUser(null)
    setFormUsername('')
    setFormPassword('')
    setFormName('')
    setFormRole('admin')
    setFormStatus('active')
    setShowModal(true)
  }

  const handleEdit = (u: AdminUser) => {
    setEditingUser(u)
    setFormUsername(u.username)
    setFormPassword('')
    setFormName(u.name || '')
    setFormRole((u.role === 'super_admin' ? 'super_admin' : 'admin') as 'super_admin' | 'admin')
    setFormStatus((u.status === 'disabled' ? 'disabled' : 'active') as 'active' | 'disabled')
    setShowModal(true)
  }

  const handleSave = async () => {
    if (!formUsername.trim()) {
      setError('用户名不能为空')
      return
    }
    if (!editingUser && !formPassword) {
      setError('新建时密码必填，至少 6 位')
      return
    }
    if (formPassword && formPassword.length < 6) {
      setError('密码至少 6 位')
      return
    }
    setError(null)
    setSaving(true)
    try {
      if (editingUser) {
        const data = await put<{ success?: boolean; error?: string }>('/api/admin/users', {
          id: editingUser.id,
          password: formPassword || undefined,
          name: formName.trim(),
          role: formRole,
          status: formStatus,
        })
        if (data?.success) {
          setShowModal(false)
          loadList()
        } else {
          setError(data?.error || '保存失败')
        }
      } else {
        const data = await post<{ success?: boolean; error?: string }>('/api/admin/users', {
          username: formUsername.trim(),
          password: formPassword,
          name: formName.trim(),
          role: formRole,
        })
        if (data?.success) {
          setShowModal(false)
          loadList()
        } else {
          setError(data?.error || '保存失败')
        }
      }
    } catch (e: unknown) {
      const err = e as { data?: { error?: string } }
      setError(err?.data?.error || '保存失败')
    } finally {
      setSaving(false)
    }
  }

  const handleDelete = async (id: number) => {
    if (!confirmDangerousDelete('管理员')) {
      setError('已取消删除')
      return
    }
    try {
      const data = await del<{ success?: boolean; error?: string }>(`/api/admin/users?id=${id}`)
      if (data?.success) loadList()
      else setError(data?.error || '删除失败')
    } catch (e: unknown) {
      const err = e as { data?: { error?: string } }
      setError(err?.data?.error || '删除失败')
    }
  }

  const formatDate = (s: string) => {
    if (!s) return '-'
    try {
      const d = new Date(s)
      return isNaN(d.getTime()) ? s : d.toLocaleString('zh-CN')
    } catch {
      return s
    }
  }

  return (
    <div className="p-8 w-full">
      <div className="flex justify-between items-center mb-6">
        <div>
          <h2 className="text-2xl font-bold text-white flex items-center gap-2">
            <ShieldCheck className="w-5 h-5 text-[#38bdac]" />
            管理员用户
          </h2>
          <p className="text-gray-400 mt-1">后台登录账号管理，仅超级管理员可操作</p>
        </div>
        <div className="flex items-center gap-2">
          <Input
            placeholder="搜索用户名/昵称"
            value={searchTerm}
            onChange={(e) => setSearchTerm(e.target.value)}
            className="w-48 bg-[#0f2137] border-gray-700 text-white placeholder:text-gray-500"
          />
          <Button
            variant="outline"
            size="sm"
            onClick={loadList}
            disabled={loading}
            className="border-gray-600 text-gray-300"
          >
            <RefreshCw className={`w-4 h-4 ${loading ? 'animate-spin' : ''}`} />
          </Button>
          <Button onClick={handleAdd} className="bg-[#38bdac] hover:bg-[#2da396] text-white">
            <Plus className="w-4 h-4 mr-2" />
            新增管理员
          </Button>
        </div>
      </div>

      {error && (
        <div className="mb-4 p-3 rounded-lg bg-red-500/10 border border-red-500/20 text-red-400 text-sm flex justify-between items-center">
          <span>{error}</span>
          <button type="button" onClick={() => setError(null)} className="text-red-400 hover:text-red-300">
            ×
          </button>
        </div>
      )}

      <Card className="bg-[#0f2137] border-gray-700/50">
        <CardContent className="p-0">
          {loading ? (
            <div className="py-12 text-center text-gray-400">加载中...</div>
          ) : (
            <>
              <Table>
                <TableHeader>
                  <TableRow className="bg-[#0a1628] border-gray-700">
                    <TableHead className="text-gray-400">ID</TableHead>
                    <TableHead className="text-gray-400">用户名</TableHead>
                    <TableHead className="text-gray-400">昵称</TableHead>
                    <TableHead className="text-gray-400">角色</TableHead>
                    <TableHead className="text-gray-400">状态</TableHead>
                    <TableHead className="text-gray-400">创建时间</TableHead>
                    <TableHead className="text-right text-gray-400">操作</TableHead>
                  </TableRow>
                </TableHeader>
                <TableBody>
                  {records.map((u) => (
                    <TableRow key={u.id} className="border-gray-700/50">
                      <TableCell className="text-gray-300">{u.id}</TableCell>
                      <TableCell className="text-white font-medium">{u.username}</TableCell>
                      <TableCell className="text-gray-400">{u.name || '-'}</TableCell>
                      <TableCell>
                        <Badge
                          variant="outline"
                          className={
                            u.role === 'super_admin'
                              ? 'border-amber-500/50 text-amber-400'
                              : 'border-gray-600 text-gray-400'
                          }
                        >
                          {u.role === 'super_admin' ? '超级管理员' : '管理员'}
                        </Badge>
                      </TableCell>
                      <TableCell>
                        <Badge
                          variant="outline"
                          className={
                            u.status === 'active'
                              ? 'border-[#38bdac]/50 text-[#38bdac]'
                              : 'border-gray-500 text-gray-500'
                          }
                        >
                          {u.status === 'active' ? '正常' : '已禁用'}
                        </Badge>
                      </TableCell>
                      <TableCell className="text-gray-500 text-sm">{formatDate(u.createdAt)}</TableCell>
                      <TableCell className="text-right">
                        <Button
                          variant="ghost"
                          size="sm"
                          onClick={() => handleEdit(u)}
                          className="text-gray-400 hover:text-[#38bdac]"
                        >
                          <Edit3 className="w-4 h-4" />
                        </Button>
                        <Button
                          variant="ghost"
                          size="sm"
                          onClick={() => handleDelete(u.id)}
                          className="text-gray-400 hover:text-red-400"
                        >
                          <Trash2 className="w-4 h-4" />
                        </Button>
                      </TableCell>
                    </TableRow>
                  ))}
                  {records.length === 0 && !loading && (
                    <TableRow>
                      <TableCell colSpan={7} className="text-center py-12 text-gray-500">
                        {error === '无权限访问' ? '仅超级管理员可查看' : '暂无管理员'}
                      </TableCell>
                    </TableRow>
                  )}
                </TableBody>
              </Table>
              {totalPages > 1 && (
                <div className="p-4 border-t border-gray-700/50">
                  <Pagination
                    page={page}
                    pageSize={pageSize}
                    total={total}
                    totalPages={totalPages}
                    onPageChange={setPage}
                  />
                </div>
              )}
            </>
          )}
        </CardContent>
      </Card>

      <Dialog open={showModal} onOpenChange={setShowModal}>
        <DialogContent className="bg-[#0f2137] border-gray-700 text-white max-w-sm">
          <DialogHeader>
            <DialogTitle className="text-white">
              {editingUser ? '编辑管理员' : '新增管理员'}
            </DialogTitle>
          </DialogHeader>
          <div className="space-y-4 py-4">
            <div className="space-y-2">
              <Label className="text-gray-300">用户名</Label>
              <Input
                className="bg-[#0a1628] border-gray-700 text-white"
                placeholder="登录用户名"
                value={formUsername}
                onChange={(e) => setFormUsername(e.target.value)}
                disabled={!!editingUser}
              />
              {editingUser && (
                <p className="text-xs text-gray-500">用户名不可修改</p>
              )}
            </div>
            <div className="space-y-2">
              <Label className="text-gray-300">{editingUser ? '新密码（留空不改）' : '密码'}</Label>
              <Input
                type="password"
                className="bg-[#0a1628] border-gray-700 text-white"
                placeholder={editingUser ? '留空表示不修改' : '至少 6 位'}
                value={formPassword}
                onChange={(e) => setFormPassword(e.target.value)}
              />
            </div>
            <div className="space-y-2">
              <Label className="text-gray-300">昵称</Label>
              <Input
                className="bg-[#0a1628] border-gray-700 text-white"
                placeholder="显示名称"
                value={formName}
                onChange={(e) => setFormName(e.target.value)}
              />
            </div>
            <div className="space-y-2">
              <Label className="text-gray-300">角色</Label>
              <select
                value={formRole}
                onChange={(e) => setFormRole(e.target.value as 'super_admin' | 'admin')}
                className="w-full h-10 px-3 rounded-md bg-[#0a1628] border border-gray-700 text-white"
              >
                <option value="admin">管理员</option>
                <option value="super_admin">超级管理员</option>
              </select>
            </div>
            {editingUser && (
              <div className="space-y-2">
                <Label className="text-gray-300">状态</Label>
                <select
                  value={formStatus}
                  onChange={(e) => setFormStatus(e.target.value as 'active' | 'disabled')}
                  className="w-full h-10 px-3 rounded-md bg-[#0a1628] border border-gray-700 text-white"
                >
                  <option value="active">正常</option>
                  <option value="disabled">禁用</option>
                </select>
              </div>
            )}
          </div>
          <DialogFooter>
            <Button
              variant="outline"
              onClick={() => setShowModal(false)}
              className="border-gray-600 text-gray-300"
            >
              <X className="w-4 h-4 mr-2" />
              取消
            </Button>
            <Button
              onClick={handleSave}
              disabled={saving}
              className="bg-[#38bdac] hover:bg-[#2da396] text-white"
            >
              <Save className="w-4 h-4 mr-2" />
              {saving ? '保存中...' : '保存'}
            </Button>
          </DialogFooter>
        </DialogContent>
      </Dialog>
    </div>
  )
}