import { useState } from 'react';
import { useRouter } from 'next/router';
import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card';
import { Input } from '@/components/ui/input';
import { Button } from '@/components/ui/button';
import { Label } from '@/components/ui/label';

export default function Register() {
  const router = useRouter();
  const [formData, setFormData] = useState({
    username: '',
    password: '',
    name: '',
  });
  const [error, setError] = useState('');
  const [isLoading, setIsLoading] = useState(false);

  const handleSubmit = async (e: React.FormEvent) => {
    e.preventDefault();
    setError('');
    setIsLoading(true);

    try {
      const response = await fetch('/api/auth/register', {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
        },
        body: JSON.stringify(formData),
      });

      const data = await response.json();

      if (!response.ok) {
        throw new Error(data.message || 'ユーザー登録に失敗しました');
      }

      // 登録成功後、ログインページへリダイレクト
      router.push('/login?registered=true');
    } catch (error) {
      setError(error.message);
    } finally {
      setIsLoading(false);
    }
  };

  return (
    <div className="min-h-screen flex items-center justify-center bg-slate-50">
      <Card className="w-full max-w-md">
        <CardHeader>
          <CardTitle className="text-center">ユーザー登録</CardTitle>
        </CardHeader>
        <CardContent>
          <form onSubmit={handleSubmit} className="space-y-4">
            {error && (
              <div className="p-3 text-sm text-red-600 bg-red-50 rounded-md">
                {error}
              </div>
            )}
            
            <div className="space-y-2">
              <Label htmlFor="username">ユーザーID</Label>
              <Input
                id="username"
                type="text"
                value={formData.username}
                onChange={(e) => setFormData({ ...formData, username: e.target.value })}
                required
              />
            </div>

            <div className="space-y-2">
              <Label htmlFor="name">名前</Label>
              <Input
                id="name"
                type="text"
                value={formData.name}
                onChange={(e) => setFormData({ ...formData, name: e.target.value })}
                required
              />
            </div>

            <div className="space-y-2">
              <Label htmlFor="password">パスワード</Label>
              <Input
                id="password"
                type="password"
                value={formData.password}
                onChange={(e) => setFormData({ ...formData, password: e.target.value })}
                required
              />
            </div>

            <Button type="submit" className="w-full" disabled={isLoading}>
              {isLoading ? '登録中...' : 'アカウントを作成'}
            </Button>

            <div className="text-center text-sm text-gray-600">
              <a href="/login" className="hover:underline">
                既にアカウントをお持ちの方はこちら
              </a>
            </div>
          </form>
        </CardContent>
      </Card>
    </div>
  );
}