'use client';

import { useEffect, useState } from 'react';
import { useForm } from 'react-hook-form';
import { zodResolver } from '@hookform/resolvers/zod';
import * as z from 'zod';
import { Card, CardContent } from '@/components/ui/card';
import { Button } from '@/components/ui/button';
import { Input } from '@/components/ui/input';
import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from '@/components/ui/select';
import { Form, FormControl, FormField, FormItem, FormLabel, FormMessage } from '@/components/ui/form';
import { Dialog, DialogContent, DialogHeader, DialogTitle, DialogTrigger } from '@/components/ui/dialog';
import { Table, TableBody, TableCell, TableHead, TableHeader, TableRow } from '@/components/ui/table';
import { Switch } from '@/components/ui/switch';
import { useUser } from '@/components/user-context';
import { DIRECTION_LABELS } from '@/lib/constants';
import type { Metric } from '@/types/database';
import { toast } from 'sonner';
import { Plus, Pencil, Trash2, Gauge, Loader2, TrendingUp, TrendingDown } from 'lucide-react';
import { getErrorMessage } from '@/lib/error-utils';
import {
  AlertDialog,
  AlertDialogAction,
  AlertDialogCancel,
  AlertDialogContent,
  AlertDialogDescription,
  AlertDialogFooter,
  AlertDialogHeader,
  AlertDialogTitle,
} from '@/components/ui/alert-dialog';
import { fetchApi } from '@/lib/api-client';

const metricSchema = z.object({
  name: z.string().min(1, '名称不能为空'),
  unit: z.string().min(1, '单位不能为空'),
  direction: z.enum(['increase', 'decrease']),
  category: z.string().optional(),
});

type MetricFormValues = z.infer<typeof metricSchema>;

export default function AdminMetricsPage() {
  const { currentUser } = useUser();
  const [metrics, setMetrics] = useState<Metric[]>([]);
  const [isLoading, setIsLoading] = useState(true);
  const [isDialogOpen, setIsDialogOpen] = useState(false);
  const [editingMetric, setEditingMetric] = useState<Metric | null>(null);
  const [isSubmitting, setIsSubmitting] = useState(false);
  const [deleteMetricId, setDeleteMetricId] = useState<string | null>(null);
  const [isDeleteOpen, setIsDeleteOpen] = useState(false);
  const [isDeleting, setIsDeleting] = useState(false);

  const form = useForm<MetricFormValues>({
    resolver: zodResolver(metricSchema),
    defaultValues: {
      name: '',
      unit: '',
      direction: 'increase',
      category: '',
    },
  });

  const fetchMetrics = async () => {
    try {
      const res = await fetchApi('/api/metrics');
      if (res.ok) {
        const data = await res.json();
        setMetrics(data);
      }
    } catch (error) {
      console.error('Failed to fetch metrics:', error);
    } finally {
      setIsLoading(false);
    }
  };

  useEffect(() => {
    fetchMetrics();
  }, []);

  const onSubmit = async (values: MetricFormValues) => {
    setIsSubmitting(true);
    try {
      const url = editingMetric ? `/api/metrics/${editingMetric.id}` : '/api/metrics';
      const method = editingMetric ? 'PATCH' : 'POST';

      const res = await fetchApi(url, {
        method,
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify(values),
      });

      if (!res.ok) {
        const data = await res.json();
        throw new Error(data.error || '操作失败');
      }

      toast.success(editingMetric ? '指标已更新' : '指标已创建');
      setIsDialogOpen(false);
      setEditingMetric(null);
      form.reset();
      fetchMetrics();
    } catch (error) {
      toast.error(getErrorMessage(error));
    } finally {
      setIsSubmitting(false);
    }
  };

  const handleEdit = (metric: Metric) => {
    setEditingMetric(metric);
    form.reset({
      name: metric.name,
      unit: metric.unit,
      direction: metric.direction,
      category: metric.category || '',
    });
    setIsDialogOpen(true);
  };

  const handleToggleActive = async (metric: Metric) => {
    try {
      const res = await fetchApi(`/api/metrics/${metric.id}`, {
        method: 'PATCH',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ is_active: !metric.is_active }),
      });

      if (!res.ok) throw new Error('操作失败');

      toast.success(metric.is_active ? '已停用' : '已启用');
      fetchMetrics();
    } catch (error) {
      toast.error(getErrorMessage(error));
    }
  };

  const requestDelete = (metricId: string) => {
    setDeleteMetricId(metricId);
    setIsDeleteOpen(true);
  };

  const confirmDelete = async () => {
    if (!deleteMetricId) return;
    setIsDeleting(true);
    try {
      const res = await fetchApi(`/api/metrics/${deleteMetricId}`, { method: 'DELETE' });
      if (!res.ok) throw new Error('删除失败');

      toast.success('指标已删除');
      fetchMetrics();
    } catch (error) {
      toast.error(getErrorMessage(error));
    } finally {
      setIsDeleting(false);
      setIsDeleteOpen(false);
      setDeleteMetricId(null);
    }
  };

  const handleDialogClose = () => {
    setIsDialogOpen(false);
    setEditingMetric(null);
    form.reset();
  };

  if (currentUser?.role !== 'owner') {
    return (
      <div className="max-w-4xl mx-auto px-4 py-8 text-center">
        <p className="text-muted-foreground">仅老板可访问此页面</p>
      </div>
    );
  }

  if (isLoading) {
    return (
      <div className="max-w-4xl mx-auto px-4 py-8">
        <div className="animate-pulse space-y-6">
          <div className="h-8 bg-slate-200 rounded w-32" />
          <div className="h-64 bg-slate-200 rounded-lg" />
        </div>
      </div>
    );
  }

  const categories = Array.from(new Set(metrics.map(m => m.category).filter(Boolean)));

  return (
    <div className="max-w-4xl mx-auto px-4 py-8">
      <div className="flex items-center justify-between mb-8">
        <div>
          <h1 className="text-2xl font-bold text-slate-800 flex items-center gap-2">
            <Gauge className="h-6 w-6 text-teal-600" />
            指标库管理
          </h1>
          <p className="text-muted-foreground mt-1">管理可复用的 KR 指标</p>
        </div>

        <Dialog open={isDialogOpen} onOpenChange={setIsDialogOpen}>
          <DialogTrigger asChild>
            <Button className="bg-teal-600 hover:bg-teal-700">
              <Plus className="h-4 w-4 mr-2" />
              新建指标
            </Button>
          </DialogTrigger>
          <DialogContent>
            <DialogHeader>
              <DialogTitle>{editingMetric ? '编辑指标' : '新建指标'}</DialogTitle>
            </DialogHeader>
            <Form {...form}>
              <form onSubmit={form.handleSubmit(onSubmit)} className="space-y-4">
                <FormField
                  control={form.control}
                  name="name"
                  render={({ field }) => (
                    <FormItem>
                      <FormLabel>指标名称 *</FormLabel>
                      <FormControl>
                        <Input placeholder="如：页面加载时间" {...field} />
                      </FormControl>
                      <FormMessage />
                    </FormItem>
                  )}
                />

                <FormField
                  control={form.control}
                  name="unit"
                  render={({ field }) => (
                    <FormItem>
                      <FormLabel>单位 *</FormLabel>
                      <FormControl>
                        <Input placeholder="如：秒、个、%" {...field} />
                      </FormControl>
                      <FormMessage />
                    </FormItem>
                  )}
                />

                <FormField
                  control={form.control}
                  name="direction"
                  render={({ field }) => (
                    <FormItem>
                      <FormLabel>方向</FormLabel>
                      <Select onValueChange={field.onChange} defaultValue={field.value}>
                        <FormControl>
                          <SelectTrigger>
                            <SelectValue />
                          </SelectTrigger>
                        </FormControl>
                        <SelectContent>
                          {Object.entries(DIRECTION_LABELS).map(([key, label]) => (
                            <SelectItem key={key} value={key}>
                              {label}
                            </SelectItem>
                          ))}
                        </SelectContent>
                      </Select>
                      <FormMessage />
                    </FormItem>
                  )}
                />

                <FormField
                  control={form.control}
                  name="category"
                  render={({ field }) => (
                    <FormItem>
                      <FormLabel>分类</FormLabel>
                      <FormControl>
                        <Input placeholder="如：技术性能、业务" {...field} />
                      </FormControl>
                      <FormMessage />
                    </FormItem>
                  )}
                />

                <div className="flex gap-2 pt-4">
                  <Button type="submit" disabled={isSubmitting} className="bg-teal-600 hover:bg-teal-700">
                    {isSubmitting && <Loader2 className="h-4 w-4 mr-2 animate-spin" />}
                    {editingMetric ? '保存' : '创建'}
                  </Button>
                  <Button type="button" variant="outline" onClick={handleDialogClose}>
                    取消
                  </Button>
                </div>
              </form>
            </Form>
          </DialogContent>
        </Dialog>
      </div>

      <Card>
        <CardContent className="p-0">
          <Table>
            <TableHeader>
              <TableRow>
                <TableHead>指标名称</TableHead>
                <TableHead>单位</TableHead>
                <TableHead>方向</TableHead>
                <TableHead>分类</TableHead>
                <TableHead>状态</TableHead>
                <TableHead className="text-right">操作</TableHead>
              </TableRow>
            </TableHeader>
            <TableBody>
              {metrics.map(metric => (
                <TableRow key={metric.id} className={!metric.is_active ? 'opacity-50' : ''}>
                  <TableCell className="font-medium">{metric.name}</TableCell>
                  <TableCell>{metric.unit}</TableCell>
                  <TableCell>
                    <div className="flex items-center gap-1">
                      {metric.direction === 'increase' ? (
                        <TrendingUp className="h-4 w-4 text-emerald-500" />
                      ) : (
                        <TrendingDown className="h-4 w-4 text-rose-500" />
                      )}
                      {DIRECTION_LABELS[metric.direction]}
                    </div>
                  </TableCell>
                  <TableCell className="text-muted-foreground">
                    {metric.category || '-'}
                  </TableCell>
                  <TableCell>
                    <Switch
                      checked={metric.is_active}
                      onCheckedChange={() => handleToggleActive(metric)}
                    />
                  </TableCell>
                  <TableCell className="text-right">
                    <Button variant="ghost" size="sm" onClick={() => handleEdit(metric)}>
                      <Pencil className="h-4 w-4" />
                    </Button>
                    <Button variant="ghost" size="sm" onClick={() => requestDelete(metric.id)}>
                      <Trash2 className="h-4 w-4 text-rose-500" />
                    </Button>
                  </TableCell>
                </TableRow>
              ))}

              {metrics.length === 0 && (
                <TableRow>
                  <TableCell colSpan={6} className="text-center py-8 text-muted-foreground">
                    暂无指标
                  </TableCell>
                </TableRow>
              )}
            </TableBody>
          </Table>
        </CardContent>
      </Card>

      <AlertDialog open={isDeleteOpen} onOpenChange={setIsDeleteOpen}>
        <AlertDialogContent>
          <AlertDialogHeader>
            <AlertDialogTitle>确认删除指标？</AlertDialogTitle>
            <AlertDialogDescription>
              删除后无法恢复。
            </AlertDialogDescription>
          </AlertDialogHeader>
          <AlertDialogFooter>
            <AlertDialogCancel disabled={isDeleting}>取消</AlertDialogCancel>
            <AlertDialogAction
              className="bg-rose-600 hover:bg-rose-700"
              onClick={confirmDelete}
              disabled={isDeleting}
            >
              {isDeleting ? '删除中...' : '确认删除'}
            </AlertDialogAction>
          </AlertDialogFooter>
        </AlertDialogContent>
      </AlertDialog>
    </div>
  );
}