"use client";
import { useState, Suspense } from 'react';
import { useSearchParams, useRouter } from 'next/navigation';

function LoginForm() {
  const searchParams = useSearchParams();
  const alertParam = searchParams.get('alert');
  const router = useRouter();
  const [isLogin, setIsLogin] = useState(true);
  const [email, setEmail] = useState('');
  const [password, setPassword] = useState('');
  const [name, setName] = useState('');
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState(alertParam === 'login_required' ? 'Anda harus masuk (login) terlebih dahulu untuk menyimpan data belajar.' : '');

  const handleSubmit = async (e: React.FormEvent) => {
    e.preventDefault();
    setLoading(true);
    setError('');
    
    const endpoint = isLogin ? '/api/auth/login' : '/api/auth/register';
    const body = isLogin ? { email, password } : { email, password, name };

    try {
      const res = await fetch(endpoint, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify(body)
      });
      
      const data = await res.json();
      
      if (res.ok) {
        // Force hard redirect to reload session state
        window.location.href = '/dashboard';
      } else {
        setError(data.error || "Gagal masuk. Periksa kembali data Anda.");
      }
    } catch (err) {
      setError("Terjadi kesalahan jaringan.");
    } finally {
      setLoading(false);
    }
  };

  return (
      <div className="w-full max-w-md bg-white rounded-2xl shadow-xl border border-gray-100 p-8 sm:p-10">
        <div className="text-center mb-8">
          <h1 className="text-3xl font-extrabold text-gray-900 mb-3 tracking-tight">
            {isLogin ? "Masuk ke Akun" : "Daftar Akun Baru"}
          </h1>
          <p className="text-gray-500 font-medium text-sm">
            Simpan progres belajar Anda dengan aman dan akses dari mana saja.
          </p>
        </div>
        
        {error && (
          <div className="bg-red-50 border-l-4 border-red-500 p-3 mb-6 rounded text-sm text-red-700">
            {error}
          </div>
        )}

        <form onSubmit={handleSubmit} className="space-y-5">
          {!isLogin && (
            <div>
              <label htmlFor="name" className="block text-sm font-semibold text-gray-700 mb-1">
                Nama Lengkap
              </label>
              <input 
                id="name"
                type="text" 
                required={!isLogin}
                value={name}
                onChange={(e) => setName(e.target.value)}
                placeholder="John Doe"
                className="w-full px-4 py-3 rounded-xl border border-gray-300 focus:ring-2 focus:ring-blue-500 focus:border-blue-500 transition-all text-gray-900 shadow-sm bg-gray-50 focus:bg-white"
              />
            </div>
          )}

          <div>
            <label htmlFor="email" className="block text-sm font-semibold text-gray-700 mb-1">
              Alamat Email
            </label>
            <input 
              id="email"
              type="email" 
              required
              value={email}
              onChange={(e) => setEmail(e.target.value)}
              placeholder="nama@email.com"
              className="w-full px-4 py-3 rounded-xl border border-gray-300 focus:ring-2 focus:ring-blue-500 focus:border-blue-500 transition-all text-gray-900 shadow-sm bg-gray-50 focus:bg-white"
            />
          </div>

          <div>
            <label htmlFor="password" className="block text-sm font-semibold text-gray-700 mb-1">
              Kata Sandi
            </label>
            <input 
              id="password"
              type="password" 
              required
              value={password}
              onChange={(e) => setPassword(e.target.value)}
              placeholder="••••••••"
              className="w-full px-4 py-3 rounded-xl border border-gray-300 focus:ring-2 focus:ring-blue-500 focus:border-blue-500 transition-all text-gray-900 shadow-sm bg-gray-50 focus:bg-white"
            />
          </div>

          <button 
            type="submit" 
            disabled={loading} 
            className="w-full flex justify-center items-center py-3.5 px-4 rounded-xl shadow-md text-base font-bold text-white bg-blue-600 hover:bg-blue-700 focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-blue-500 transition-all transform hover:-translate-y-1 disabled:bg-blue-300 disabled:cursor-not-allowed disabled:transform-none mt-4"
          >
            {loading ? (
              <>
                <svg className="animate-spin -ml-1 mr-3 h-5 w-5 text-white" xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24">
                  <circle className="opacity-25" cx="12" cy="12" r="10" stroke="currentColor" strokeWidth="4"></circle>
                  <path className="opacity-75" fill="currentColor" d="M4 12a8 8 0 018-8V0C5.373 0 0 5.373 0 12h4zm2 5.291A7.962 7.962 0 014 12H0c0 3.042 1.135 5.824 3 7.938l3-2.647z"></path>
                </svg>
                Memproses...
              </>
            ) : (isLogin ? "Masuk Sekarang" : "Daftar Sekarang")}
          </button>
        </form>
        
        <div className="mt-8 text-center text-sm font-medium text-gray-600">
          {isLogin ? (
            <>
              Belum punya akun?{' '}
              <button onClick={() => setIsLogin(false)} className="text-blue-600 hover:text-blue-800 font-bold hover:underline transition-all">
                Daftar Gratis
              </button>
            </>
          ) : (
            <>
              Sudah punya akun?{' '}
              <button onClick={() => setIsLogin(true)} className="text-blue-600 hover:text-blue-800 font-bold hover:underline transition-all">
                Masuk di sini
              </button>
            </>
          )}
        </div>
      </div>
  );
}

export default function LoginPage() {
  return (
    <main className="min-h-[85vh] flex items-center justify-center bg-gray-50 px-6 py-12">
      <Suspense fallback={<div className="text-gray-500">Memuat...</div>}>
        <LoginForm />
      </Suspense>
    </main>
  );
}