'use client';

import { useState } from 'react';
import { createBrowserClient } from '@supabase/ssr'
import { useRouter } from 'next/navigation';

export default function LoginPage() {
    const [email, setEmail] = useState('');
    const [password, setPassword] = useState('');
    const [isSignUp, setIsSignUp] = useState(false);
    const [loading, setLoading] = useState(false);
    const router = useRouter();

    const supabase = createBrowserClient(
        process.env.NEXT_PUBLIC_SUPABASE_URL!,
        process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY!
    );

    const handleAuth = async (e: React.FormEvent) => {
        e.preventDefault();
        setLoading(true);

        if (isSignUp) {
            // Sign Up with Password
            const { data, error } = await supabase.auth.signUp({
                email,
                password,
                options: {
                    emailRedirectTo: `${window.location.origin}/auth/callback`,
                }
            });
            if (error) {
                alert('회원가입 실패: ' + error.message);
            } else if (data.user && data.user.identities && data.user.identities.length === 0) {
                alert('이미 가입된 이메일입니다. 로그인해주세요.');
            } else {
                alert('가입이 완료되었습니다! 이메일 인증이 필요할 수 있습니다. 로그인을 시도해주세요.');
                setIsSignUp(false); // Switch to login mode
            }
        } else {
            // Sign In with Password
            const { error } = await supabase.auth.signInWithPassword({
                email,
                password,
            });
            if (error) {
                alert('로그인 실패: ' + error.message);
            } else {
                router.push('/mypage');
                router.refresh();
            }
        }
        setLoading(false);
    };

    const handleSocialLogin = async (provider: 'google' | 'kakao') => {
        const { error } = await supabase.auth.signInWithOAuth({
            provider,
            options: {
                redirectTo: `${window.location.origin}/auth/callback`,
            },
        });
        if (error) alert('소셜 로그인 오류: ' + error.message);
    };

    return (
        <div className="min-h-screen bg-gradient-to-br from-indigo-50 to-purple-50 flex items-center justify-center p-4">
            <div className="bg-white rounded-2xl shadow-xl w-full max-w-md p-8">
                <div className="text-center mb-8">
                    <h1 className="text-3xl font-bold text-gray-900 mb-2">
                        {isSignUp ? '회원가입' : '로그인'}
                    </h1>
                    <p className="text-gray-500">사주 기록을 저장하고 언제든 다시 확인하세요</p>
                </div>

                <form onSubmit={handleAuth} className="space-y-4 mb-6">
                    <div>
                        <label htmlFor="email" className="block text-sm font-medium text-gray-700 mb-1">
                            이메일 주소
                        </label>
                        <input
                            id="email"
                            type="email"
                            placeholder="name@example.com"
                            className="w-full px-4 py-3 rounded-lg border border-gray-300 focus:ring-2 focus:ring-indigo-500 focus:border-indigo-500 outline-none transition"
                            value={email}
                            onChange={(e) => setEmail(e.target.value)}
                            required
                        />
                    </div>
                    <div>
                        <label htmlFor="password" className="block text-sm font-medium text-gray-700 mb-1">
                            비밀번호
                        </label>
                        <input
                            id="password"
                            type="password"
                            placeholder="••••••••"
                            className="w-full px-4 py-3 rounded-lg border border-gray-300 focus:ring-2 focus:ring-indigo-500 focus:border-indigo-500 outline-none transition"
                            value={password}
                            onChange={(e) => setPassword(e.target.value)}
                            required
                            minLength={6}
                        />
                    </div>
                    <button
                        type="submit"
                        disabled={loading}
                        className="w-full bg-indigo-600 hover:bg-indigo-700 text-white font-bold py-3 px-4 rounded-lg transition disabled:opacity-50"
                    >
                        {loading ? '처리 중...' : (isSignUp ? '회원가입' : '로그인')}
                    </button>
                </form>

                <div className="text-center mb-6">
                    <button
                        type="button"
                        className="text-sm text-indigo-600 hover:text-indigo-800 font-medium"
                        onClick={() => setIsSignUp(!isSignUp)}
                    >
                        {isSignUp ? '이미 계정이 있으신가요? 로그인' : '계정이 없으신가요? 회원가입'}
                    </button>
                </div>

                <div className="relative my-6">
                    <div className="absolute inset-0 flex items-center">
                        <div className="w-full border-t border-gray-200"></div>
                    </div>
                    <div className="relative flex justify-center text-sm">
                        <span className="px-2 bg-white text-gray-500">또는 소셜 로그인</span>
                    </div>
                </div>

                <div className="grid grid-cols-2 gap-3">
                    <button
                        onClick={() => handleSocialLogin('google')}
                        className="flex items-center justify-center px-4 py-2 border border-gray-300 rounded-lg hover:bg-gray-50 transition"
                    >
                        <span className="ml-2">Google</span>
                    </button>
                    <button
                        onClick={() => handleSocialLogin('kakao')}
                        className="flex items-center justify-center px-4 py-2 bg-[#FEE500] border border-[#FEE500] rounded-lg hover:bg-[#FDD835] transition"
                    >
                        <span className="ml-2 text-[#000000bd]">Kakao</span>
                    </button>
                </div>

                <div className="mt-6 p-4 bg-yellow-50 rounded-lg text-xs text-yellow-800 border border-yellow-200">
                    <h4 className="font-bold mb-1">⚠️ 회원가입 후 이메일 인증 필수!</h4>
                    <p className="mb-2">
                        Supabase는 기본적으로 이메일 인증을 요구합니다.
                        가입 후 받은 메일의 링크를 클릭해야 로그인이 가능합니다.
                    </p>
                    <p className="font-semibold text-gray-700">
                        (개발용 팁: Supabase 대시보드 &gt; Authentication &gt; Providers &gt; Email &gt; "Confirm email"를 끄면 인증 없이 바로 로그인 가능)
                    </p>
                </div>
            </div>
        </div>
    );
}