import { useEffect, useState, useCallback } from 'react'
import { toast } from 'sonner'
import { Users, Search, MessageSquare, Clock, KeyRound, Ban, CheckCircle, Loader2 } from 'lucide-react'
import { PageLayout } from '@/components/common/PageLayout'
import { EmptyState } from '@/components/common/EmptyState'
import { LoadingState } from '@/components/common/LoadingState'
import { ErrorState } from '@/components/common/ErrorState'
import { Card, CardContent } from '@/components/ui/card'
import { Badge } from '@/components/ui/badge'
import { Button } from '@/components/ui/button'
import { Input } from '@/components/ui/input'
import { Label } from '@/components/ui/label'
import {
  Dialog, DialogContent, DialogHeader, DialogTitle, DialogDescription, DialogFooter,
} from '@/components/ui/dialog'
import { api } from '@/lib/api'
import { cn } from '@/lib/utils'

/** 用户列表项(含统计) */
interface AdminUser {
  id: number
  phone: string
  name: string
  status: string
  created_at: string
  message_count: number
  last_active: string | null
  last_scene: string | null
}

/** 场景中文映射 */
const SCENE_LABELS: Record<string, string> = {
  legal: '法务参谋',
  decision: '经营决策',
  life: '生活助理',
  emotion: '情绪中心',
}

/** 格式化时间 */
function formatTime(dt: string | null): string {
  if (!dt) return '从未使用'
  return new Date(dt).toLocaleString('zh-CN', {
    month: '2-digit', day: '2-digit', hour: '2-digit', minute: '2-digit',
  })
}

export function AdminUsers() {
  const [users, setUsers] = useState<AdminUser[]>([])
  const [loading, setLoading] = useState(true)
  const [error, setError] = useState<string | null>(null)
  const [search, setSearch] = useState('')
  const [searching, setSearching] = useState(false)

  // 重置密码弹窗
  const [resetTarget, setResetTarget] = useState<AdminUser | null>(null)
  const [newPassword, setNewPassword] = useState('')
  const [resetting, setResetting] = useState(false)

  // 状态切换弹窗
  const [statusTarget, setStatusTarget] = useState<AdminUser | null>(null)
  const [statusUpdating, setStatusUpdating] = useState(false)

  const load = useCallback(async (q?: string) => {
    setLoading(true)
    setError(null)
    try {
      const res = await api.adminListUsers(q)
      setUsers(res.results as AdminUser[])
    } catch (e) {
      setError(e instanceof Error ? e.message : '加载失败')
    } finally {
      setLoading(false)
      setSearching(false)
    }
  }, [])

  useEffect(() => { load() }, [load])

  /** 搜索(防抖) */
  useEffect(() => {
    if (search === undefined) return
    const timer = setTimeout(() => {
      if (search !== '') {
        setSearching(true)
        load(search)
      } else {
        load()
      }
    }, 400)
    return () => clearTimeout(timer)
  }, [search]) // eslint-disable-line react-hooks/exhaustive-deps

  /** 确认重置密码 */
  const handleResetPassword = async () => {
    if (!resetTarget || !newPassword.trim()) return
    if (newPassword.length < 6) {
      toast.error('密码至少 6 位')
      return
    }
    setResetting(true)
    try {
      await api.adminResetPassword(resetTarget.id, newPassword)
      toast.success(`已重置 ${resetTarget.name || resetTarget.phone} 的密码`)
      setResetTarget(null)
      setNewPassword('')
      load(search || undefined)
    } catch (e) {
      toast.error(e instanceof Error ? e.message : '重置失败')
    } finally {
      setResetting(false)
    }
  }

  /** 确认激活/停用 */
  const handleToggleStatus = async () => {
    if (!statusTarget) return
    const newStatus = statusTarget.status === 'active' ? 'inactive' : 'active'
    setStatusUpdating(true)
    try {
      await api.adminUpdateUserStatus(statusTarget.id, newStatus)
      toast.success(`已${newStatus === 'active' ? '激活' : '停用'} ${statusTarget.name || statusTarget.phone}`)
      setStatusTarget(null)
      load(search || undefined)
    } catch (e) {
      toast.error(e instanceof Error ? e.message : '操作失败')
    } finally {
      setStatusUpdating(false)
    }
  }

  /** 统计概览 */
  const totalUsers = users.length
  const activeUsers = users.filter(u => u.status === 'active' && u.message_count > 0).length
  const inactiveUsers = users.filter(u => u.status === 'inactive').length
  const totalMessages = users.reduce((sum, u) => sum + u.message_count, 0)

  return (
    <PageLayout
      title="用户管理"
      description="平台注册用户列表,含对话统计、活跃度和账号管理"
      actions={
        <div className="relative">
          <Search className="absolute left-2.5 top-1/2 h-3.5 w-3.5 -translate-y-1/2 text-muted-foreground" />
          <Input
            value={search}
            onChange={(e) => setSearch(e.target.value)}
            placeholder="搜索手机号或昵称..."
            className="h-8 w-48 pl-8 text-xs"
          />
        </div>
      }
    >
      {/* 统计概览 */}
      <div className="mb-4 grid grid-cols-4 gap-3">
        <Card>
          <CardContent className="p-3">
            <p className="text-xs text-muted-foreground">总用户数</p>
            <p className="mt-1 text-xl font-semibold">{totalUsers}</p>
          </CardContent>
        </Card>
        <Card>
          <CardContent className="p-3">
            <p className="text-xs text-muted-foreground">活跃用户</p>
            <p className="mt-1 text-xl font-semibold text-emerald-600">{activeUsers}</p>
          </CardContent>
        </Card>
        <Card>
          <CardContent className="p-3">
            <p className="text-xs text-muted-foreground">已停用</p>
            <p className="mt-1 text-xl font-semibold text-rose-600">{inactiveUsers}</p>
          </CardContent>
        </Card>
        <Card>
          <CardContent className="p-3">
            <p className="text-xs text-muted-foreground">总对话数</p>
            <p className="mt-1 text-xl font-semibold">{totalMessages}</p>
          </CardContent>
        </Card>
      </div>

      {loading ? (
        <LoadingState label={searching ? '搜索中...' : '加载用户...'} />
      ) : error ? (
        <ErrorState message={error} onRetry={() => load(search || undefined)} />
      ) : users.length === 0 ? (
        <EmptyState
          title={search ? '未找到匹配用户' : '暂无用户'}
          description={search ? '尝试其他关键词' : '注册用户将显示在这里'}
          icon={<Users className="h-8 w-8" />}
        />
      ) : (
        <div className="space-y-2">
          {users.map((u) => (
            <Card key={u.id} className={u.status === 'inactive' ? 'opacity-60' : ''}>
              <CardContent className="p-4">
                <div className="flex items-center gap-3">
                  {/* 头像占位 */}
                  <div className={cn(
                    'flex h-10 w-10 shrink-0 items-center justify-center rounded-full text-sm font-medium',
                    u.status === 'inactive'
                      ? 'bg-muted text-muted-foreground'
                      : u.message_count > 0
                        ? 'bg-primary/10 text-primary'
                        : 'bg-muted text-muted-foreground',
                  )}>
                    {(u.name || u.phone.slice(-2)).slice(0, 2)}
                  </div>
                  <div className="min-w-0 flex-1">
                    <div className="flex items-center gap-2">
                      <p className="truncate text-sm font-medium">{u.name || '未设置昵称'}</p>
                      <span className="truncate text-xs text-muted-foreground">{u.phone}</span>
                    </div>
                    <div className="mt-1 flex flex-wrap items-center gap-3 text-xs text-muted-foreground">
                      <span className="flex items-center gap-1">
                        <MessageSquare className="h-3 w-3" />
                        {u.message_count} 条对话
                      </span>
                      <span className="flex items-center gap-1">
                        <Clock className="h-3 w-3" />
                        {formatTime(u.last_active)}
                      </span>
                      {u.last_scene && (
                        <Badge variant="secondary" className="text-[10px]">
                          {SCENE_LABELS[u.last_scene] || u.last_scene}
                        </Badge>
                      )}
                      <span>注册:{formatTime(u.created_at)}</span>
                    </div>
                  </div>
                  {/* 状态 Badge */}
                  <Badge
                    variant={u.status === 'active' ? 'default' : 'destructive'}
                    className="shrink-0 text-xs"
                  >
                    {u.status === 'active' ? '正常' : '已停用'}
                  </Badge>
                </div>
                {/* 操作按钮 */}
                <div className="mt-3 flex flex-wrap gap-2 border-t pt-3">
                  <Button
                    size="sm"
                    variant="outline"
                    onClick={() => { setResetTarget(u); setNewPassword('') }}
                  >
                    <KeyRound className="h-3.5 w-3.5" /> 重置密码
                  </Button>
                  {u.status === 'active' ? (
                    <Button
                      size="sm"
                      variant="outline"
                      className="text-rose-600 hover:bg-rose-50"
                      onClick={() => setStatusTarget(u)}
                    >
                      <Ban className="h-3.5 w-3.5" /> 停用账号
                    </Button>
                  ) : (
                    <Button
                      size="sm"
                      variant="outline"
                      className="text-emerald-600 hover:bg-emerald-50"
                      onClick={() => setStatusTarget(u)}
                    >
                      <CheckCircle className="h-3.5 w-3.5" /> 激活账号
                    </Button>
                  )}
                </div>
              </CardContent>
            </Card>
          ))}
        </div>
      )}

      {/* 重置密码弹窗 */}
      <Dialog open={!!resetTarget} onOpenChange={(o) => !o && setResetTarget(null)}>
        <DialogContent className="max-w-sm">
          <DialogHeader>
            <DialogTitle>重置密码</DialogTitle>
            <DialogDescription>
              为用户「{resetTarget?.name || resetTarget?.phone}」设置新密码,用户需用新密码登录。
            </DialogDescription>
          </DialogHeader>
          <div className="space-y-2">
            <Label htmlFor="new-password">新密码(至少 6 位)</Label>
            <Input
              id="new-password"
              type="password"
              value={newPassword}
              onChange={(e) => setNewPassword(e.target.value)}
              placeholder="输入新密码..."
            />
          </div>
          <DialogFooter>
            <Button variant="outline" onClick={() => setResetTarget(null)}>取消</Button>
            <Button onClick={handleResetPassword} disabled={resetting || newPassword.length < 6}>
              {resetting ? <Loader2 className="h-3.5 w-3.5 animate-spin" /> : <KeyRound className="h-3.5 w-3.5" />}
              确认重置
            </Button>
          </DialogFooter>
        </DialogContent>
      </Dialog>

      {/* 激活/停用确认弹窗 */}
      <Dialog open={!!statusTarget} onOpenChange={(o) => !o && setStatusTarget(null)}>
        <DialogContent className="max-w-sm">
          <DialogHeader>
            <DialogTitle>
              {statusTarget?.status === 'active' ? '停用账号' : '激活账号'}
            </DialogTitle>
            <DialogDescription>
              {statusTarget?.status === 'active'
                ? `确认停用用户「${statusTarget?.name || statusTarget?.phone}」?停用后该用户将无法登录。`
                : `确认激活用户「${statusTarget?.name || statusTarget?.phone}」?激活后该用户可正常登录。`
              }
            </DialogDescription>
          </DialogHeader>
          <DialogFooter>
            <Button variant="outline" onClick={() => setStatusTarget(null)}>再想想</Button>
            <Button
              variant={statusTarget?.status === 'active' ? 'destructive' : 'default'}
              onClick={handleToggleStatus}
              disabled={statusUpdating}
            >
              {statusUpdating ? <Loader2 className="h-3.5 w-3.5 animate-spin" /> : null}
              确认{statusTarget?.status === 'active' ? '停用' : '激活'}
            </Button>
          </DialogFooter>
        </DialogContent>
      </Dialog>
    </PageLayout>
  )
}