import { useEffect, useState } from 'react';
import { useNavigate } from 'react-router-dom';
import {
  getAuthConfig,
  loginWithAd,
  startMicrosoftLogin,
  storeAuthSession,
} from '../services/authService';
import { isAuthenticated } from '../services/sessionService';

function decodeAuthPayload(payload) {
  const base64 = payload.replace(/-/g, '+').replace(/_/g, '/');
  const paddedBase64 = base64.padEnd(base64.length + ((4 - (base64.length % 4)) % 4), '=');

  return JSON.parse(atob(paddedBase64));
}

export function useLogin() {
  const navigate = useNavigate();
  const [isSubmitting, setIsSubmitting] = useState(false);
  const [error, setError] = useState('');
  const [providers, setProviders] = useState({ ldap: true, microsoft: false });

  useEffect(() => {
    if (!window.location.hash.includes('auth=') && isAuthenticated()) {
      navigate('/home', { replace: true });
      return;
    }

    getAuthConfig()
      .then((config) => setProviders(config.providers || { ldap: true, microsoft: false }))
      .catch(() => setProviders({ ldap: true, microsoft: false }));
  }, [navigate]);

  useEffect(() => {
    const hashParams = new URLSearchParams(window.location.hash.replace(/^#/, ''));
    const authPayload = hashParams.get('auth');

    if (authPayload) {
      try {
        storeAuthSession(decodeAuthPayload(authPayload));
        window.history.replaceState({}, document.title, window.location.pathname);
        navigate('/home', { replace: true });
        return;
      } catch {
        window.history.replaceState({}, document.title, window.location.pathname);
        setError('Nao foi possivel concluir o login Microsoft.');
      }
    }

    if (window.location.search.includes('token=') || window.location.search.includes('user=')) {
      window.history.replaceState({}, document.title, window.location.pathname);
      setError('Fluxo de login expirado. Tente novamente.');
    }
  }, [navigate]);

  async function login(credentials) {
    setIsSubmitting(true);
    setError('');

    try {
      const authResult = await loginWithAd(credentials);
      storeAuthSession(authResult);
      navigate('/home');
    } catch (loginError) {
      setError(loginError.message || 'Falha ao autenticar.');
    } finally {
      setIsSubmitting(false);
    }
  }

  return {
    isSubmitting,
    error,
    providers,
    login,
    startMicrosoftLogin,
  };
}