'use client';

import { useState } from 'react';
import { useRouter } from 'next/navigation';
import { Lock, Send, Loader2 } from 'lucide-react';

export default function LoginPage() {
  const [step, setStep] = useState<'initial' | 'verify'>('initial');
  const [code, setCode] = useState('');
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState('');
  const router = useRouter();

  const sendCode = async () => {
    setLoading(true);
    setError('');
    try {
      const res = await fetch('/api/auth/send', { method: 'POST' });
      const data = await res.json();
      if (!res.ok) throw new Error(data.error || 'Failed to send code');
      setStep('verify');
    } catch (err: any) {
      setError(err.message);
    } finally {
      setLoading(false);
    }
  };

  const verifyCode = async () => {
    setLoading(true);
    setError('');
    try {
      const res = await fetch('/api/auth/verify', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ code })
      });
      const data = await res.json();
      if (!res.ok) throw new Error(data.error || 'Invalid code');
      
      // Redirect
      router.push('/');
      router.refresh(); 
    } catch (err: any) {
      setError(err.message);
    } finally {
      setLoading(false);
    }
  };

  return (
    <div className="flex min-h-screen items-center justify-center bg-gray-900 text-white p-4">
      <div className="w-full max-w-md bg-gray-800 rounded-lg shadow-xl p-8 border border-gray-700">
        <div className="flex flex-col items-center mb-8">
          <div className="bg-blue-600 p-3 rounded-full mb-4">
            <Lock className="w-8 h-8 text-white" />
          </div>
          <h1 className="text-2xl font-bold">Secure Access</h1>
          <p className="text-gray-400 mt-2 text-center">
            Finanzas Personales
          </p>
        </div>

        {error && (
          <div className="bg-red-900/50 border border-red-500 text-red-200 p-3 rounded mb-4 text-sm">
            {error}
          </div>
        )}

        {step === 'initial' ? (
          <div className="space-y-4">
            <p className="text-gray-300 text-center text-sm">
              Click below to receive a login code via Telegram.
            </p>
            <button
              onClick={sendCode}
              disabled={loading}
              className="w-full bg-blue-600 hover:bg-blue-500 text-white font-semibold py-3 px-4 rounded-lg transition flex items-center justify-center gap-2 disabled:opacity-50"
            >
              {loading ? <Loader2 className="animate-spin" /> : <Send size={20} />}
              Send Code to Telegram
            </button>
          </div>
        ) : (
          <div className="space-y-4">
            <p className="text-gray-300 text-center text-sm">
              Enter the 6-digit code sent to your Telegram.
            </p>
            <input
              type="text"
              value={code}
              onChange={(e) => setCode(e.target.value)}
              placeholder="123456"
              className="w-full bg-gray-700 border border-gray-600 rounded-lg px-4 py-3 text-center text-2xl tracking-widest focus:outline-none focus:ring-2 focus:ring-blue-500"
              maxLength={6}
            />
            <button
              onClick={verifyCode}
              disabled={loading || code.length < 4}
              className="w-full bg-green-600 hover:bg-green-500 text-white font-semibold py-3 px-4 rounded-lg transition flex items-center justify-center gap-2 disabled:opacity-50"
            >
              {loading ? <Loader2 className="animate-spin" /> : 'Verify & Login'}
            </button>
            <button 
              onClick={() => setStep('initial')}
              className="w-full text-gray-400 hover:text-white text-sm"
            >
              Cancel
            </button>
          </div>
        )}
      </div>
    </div>
  );
}