'use client';

import { useState, useEffect } from 'react';
import { useRouter } from 'next/navigation';
import Link from 'next/link';
import { useForm } from 'react-hook-form';
import { zodResolver } from '@hookform/resolvers/zod';
import * as z from 'zod';
import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card';
import { Button } from '@/components/ui/button';
import { Input } from '@/components/ui/input';
import { Textarea } from '@/components/ui/textarea';
import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from '@/components/ui/select';
import { Form, FormControl, FormField, FormItem, FormLabel, FormMessage } from '@/components/ui/form';
import { Checkbox } from '@/components/ui/checkbox';
import { useUser } from '@/components/user-context';
import { toast } from 'sonner';
import type { User } from '@/types/database';
import { ArrowLeft, Loader2 } from 'lucide-react';
import { getErrorMessage } from '@/lib/error-utils';

const formSchema = z.object({
  name: z.string().min(1, '项目名称不能为空'),
  description: z.string().optional(),
  project_type: z.string().optional(),
  pm_id: z.string().optional(),
  member_ids: z.array(z.string()).optional(),
});

type FormValues = z.infer<typeof formSchema>;

export default function NewProjectPage() {
  const router = useRouter();
  const { currentUser, users } = useUser();
  const [isSubmitting, setIsSubmitting] = useState(false);

  const form = useForm<FormValues>({
    resolver: zodResolver(formSchema),
    defaultValues: {
      name: '',
      description: '',
      project_type: '',
      pm_id: '',
      member_ids: [],
    },
  });

  const onSubmit = async (values: FormValues) => {
    setIsSubmitting(true);
    try {
      const res = await fetch('/api/projects', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({
          ...values,
          owner_id: currentUser?.id,
        }),
      });

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

      const project = await res.json();
      toast.success('项目创建成功');
      router.push(`/projects/${project.id}`);
    } catch (error) {
      toast.error(getErrorMessage(error));
    } finally {
      setIsSubmitting(false);
    }
  };

  const pmCandidates = users.filter(u => u.role === 'owner' || u.role === 'pm');
  const memberCandidates = users;

  return (
    <div className="max-w-2xl mx-auto px-4 py-8">
      <Link
        href="/projects"
        className="inline-flex items-center text-sm text-muted-foreground hover:text-slate-800 mb-6"
      >
        <ArrowLeft className="h-4 w-4 mr-1" />
        返回项目列表
      </Link>

      <Card>
        <CardHeader>
          <CardTitle>新建项目</CardTitle>
        </CardHeader>
        <CardContent>
          <Form {...form}>
            <form onSubmit={form.handleSubmit(onSubmit)} className="space-y-6">
              <FormField
                control={form.control}
                name="name"
                render={({ field }) => (
                  <FormItem>
                    <FormLabel>项目名称 *</FormLabel>
                    <FormControl>
                      <Input placeholder="输入项目名称" {...field} />
                    </FormControl>
                    <FormMessage />
                  </FormItem>
                )}
              />

              <FormField
                control={form.control}
                name="description"
                render={({ field }) => (
                  <FormItem>
                    <FormLabel>项目描述</FormLabel>
                    <FormControl>
                      <Textarea placeholder="输入项目描述" rows={3} {...field} />
                    </FormControl>
                    <FormMessage />
                  </FormItem>
                )}
              />

              <FormField
                control={form.control}
                name="project_type"
                render={({ field }) => (
                  <FormItem>
                    <FormLabel>项目类型</FormLabel>
                    <FormControl>
                      <Input placeholder="如：产品研发、市场营销" {...field} />
                    </FormControl>
                    <FormMessage />
                  </FormItem>
                )}
              />

              <FormField
                control={form.control}
                name="pm_id"
                render={({ field }) => (
                  <FormItem>
                    <FormLabel>项目经理</FormLabel>
                    <Select onValueChange={field.onChange} defaultValue={field.value}>
                      <FormControl>
                        <SelectTrigger>
                          <SelectValue placeholder="选择项目经理" />
                        </SelectTrigger>
                      </FormControl>
                      <SelectContent>
                        {pmCandidates.map(user => (
                          <SelectItem key={user.id} value={user.id}>
                            {user.name}
                          </SelectItem>
                        ))}
                      </SelectContent>
                    </Select>
                    <FormMessage />
                  </FormItem>
                )}
              />

              <FormField
                control={form.control}
                name="member_ids"
                render={() => (
                  <FormItem>
                    <FormLabel>项目成员</FormLabel>
                    <div className="space-y-2">
                      {memberCandidates.map(user => (
                        <FormField
                          key={user.id}
                          control={form.control}
                          name="member_ids"
                          render={({ field }) => (
                            <FormItem className="flex items-center space-x-2 space-y-0">
                              <FormControl>
                                <Checkbox
                                  checked={field.value?.includes(user.id)}
                                  onCheckedChange={(checked) => {
                                    const current = field.value || [];
                                    if (checked) {
                                      field.onChange([...current, user.id]);
                                    } else {
                                      field.onChange(current.filter(id => id !== user.id));
                                    }
                                  }}
                                />
                              </FormControl>
                              <span className="text-sm">{user.name}</span>
                            </FormItem>
                          )}
                        />
                      ))}
                    </div>
                    <FormMessage />
                  </FormItem>
                )}
              />

              <div className="flex gap-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" />}
                  创建项目
                </Button>
                <Button type="button" variant="outline" onClick={() => router.back()}>
                  取消
                </Button>
              </div>
            </form>
          </Form>
        </CardContent>
      </Card>
    </div>
  );
}