'use client';

import { useState } from 'react';
import { useForm } from 'react-hook-form';
import { zodResolver } from '@hookform/resolvers/zod';
import { z } from 'zod';
import { publicApi } from '@/lib/services';
import { Button } from '@/components/ui/button';
import { Input } from '@/components/ui/input';
import { Label } from '@/components/ui/label';
import { Textarea } from '@/components/ui/textarea';

const ERROR_INPUT_CLASS = 'border-red-500 focus-visible:ring-red-500';

const schema = z.object({
  name: z
    .string()
    .trim()
    .min(1, '请输入姓名')
    .max(50, '姓名不能超过 50 个字'),
  phone: z
    .string()
    .trim()
    .min(1, '请输入手机号')
    .regex(/^1[3-9]\d{9}$/, '请输入正确的手机号（11 位）'),
  email: z
    .string()
    .trim()
    .max(254, '邮箱长度不能超过 254')
    .email('邮箱格式不正确')
    .optional()
    .or(z.literal('')),
  content: z
    .string()
    .trim()
    .min(5, '留言内容至少 5 个字')
    .max(2000, '留言内容不能超过 2000 个字'),
});

type FormData = z.infer<typeof schema>;

export function ContactForm() {
  const {
    register,
    handleSubmit,
    reset,
    formState: { errors, isSubmitting },
  } = useForm<FormData>({
    resolver: zodResolver(schema),
    mode: 'onTouched',
    reValidateMode: 'onChange',
    defaultValues: { name: '', phone: '', email: '', content: '' },
  });
  const [serverError, setServerError] = useState<string | null>(null);
  const [success, setSuccess] = useState(false);

  const onSubmit = async (data: FormData) => {
    setServerError(null);
    setSuccess(false);
    try {
      await publicApi.submitMessage({
        name: data.name,
        phone: data.phone,
        email: data.email || undefined,
        content: data.content,
      });
      setSuccess(true);
      reset();
    } catch (e) {
      setServerError((e as Error).message);
    }
  };

  return (
    <form
      onSubmit={(e) => {
        e.preventDefault();
        void handleSubmit(onSubmit)(e);
      }}
      className="space-y-4"
    >
      <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
        <Field label="姓名" error={errors.name?.message} required>
          <Input
            placeholder="请输入您的姓名"
            autoComplete="name"
            maxLength={50}
            className={errors.name ? ERROR_INPUT_CLASS : ''}
            {...register('name')}
          />
        </Field>
        <Field label="手机号" error={errors.phone?.message} required>
          <Input
            placeholder="请输入 11 位手机号"
            inputMode="numeric"
            autoComplete="tel"
            maxLength={11}
            className={errors.phone ? ERROR_INPUT_CLASS : ''}
            {...register('phone')}
          />
        </Field>
      </div>
      <Field label="邮箱（可选）" error={errors.email?.message}>
        <Input
          placeholder="example@company.com"
          inputMode="email"
          autoComplete="email"
          maxLength={254}
          className={errors.email ? ERROR_INPUT_CLASS : ''}
          {...register('email')}
        />
      </Field>
      <Field label="留言内容" error={errors.content?.message} required>
        <Textarea
          rows={5}
          placeholder="请简要描述您的需求（至少 5 个字）"
          maxLength={2000}
          className={errors.content ? ERROR_INPUT_CLASS : ''}
          {...register('content')}
        />
      </Field>

      {serverError && <p className="text-sm text-red-600">{serverError}</p>}
      {success && (
        <p className="text-sm text-green-600">
          ✓ 留言已提交，我们会尽快与您联系！
        </p>
      )}

      <Button type="submit" disabled={isSubmitting}>
        {isSubmitting ? '提交中…' : '提交留言'}
      </Button>
    </form>
  );
}

function Field({
  label,
  required,
  error,
  children,
}: {
  label: string;
  required?: boolean;
  error?: string;
  children: React.ReactNode;
}) {
  return (
    <div className="space-y-1.5">
      <Label>
        {label}
        {required && <span className="ml-1 text-red-500">*</span>}
      </Label>
      {children}
      {error && <p className="text-xs text-red-600">{error}</p>}
    </div>
  );
}