import { useNavigate, useLocation } from 'react-router-dom';
import { useState, useEffect } from 'react';
import { FaGoogle, FaMicrosoft, FaEnvelopeOpenText } from 'react-icons/fa';

import { useAuth, useMsalAuth, useGoogleAuth } from '../hooks/useAuthentication';
import { generateAndStoreCSRFToken } from '../utils/csrfUtils';
import { PENDING_INVITATION_KEY } from './InvitePage';

import styles from './Login.module.css';


function Login() {
  const navigate = useNavigate();
  const location = useLocation();
  const [username, setUsername] = useState('');
  const [password, setPassword] = useState('');
  const [usernameFocused, setUsernameFocused] = useState(false);
  const [passwordFocused, setPasswordFocused] = useState(false);
  const { login, error: loginError, isLoading: isLoginLoading } = useAuth();
  const { loginWithMsal, error: msalError, isLoading: isMsalLoading } = useMsalAuth();
  const { loginWithGoogle, error: googleError, isLoading: isGoogleLoading } = useGoogleAuth();
  
  // Check for pending invitation
  const pendingInvitationToken = localStorage.getItem(PENDING_INVITATION_KEY);
  const hasPendingInvitation = !!pendingInvitationToken;
  
  // Get the page the user was trying to visit
  const from = location.state?.from?.pathname || "/";
  
  // Set page title and generate CSRF token
  useEffect(() => {
    document.title = "PowerOn AI Platform - Login";
    
    // Generate CSRF token for new security implementation
    generateAndStoreCSRFToken();
  }, []);

  // Check for autofilled inputs
  useEffect(() => {
    const checkAutofill = () => {
      const usernameInput = document.querySelector('input[type="text"]') as HTMLInputElement;
      const passwordInput = document.querySelector('input[type="password"]') as HTMLInputElement;
      
      if (usernameInput && usernameInput.value) {
        setUsername(usernameInput.value);
      }
      if (passwordInput && passwordInput.value) {
        setPassword(passwordInput.value);
      }
    };

    // Check immediately and after a short delay
    checkAutofill();
    const timer = setTimeout(checkAutofill, 100);

    return () => clearTimeout(timer);
  }, []);

  // Handle redirect after successful login
  const handleSuccessfulLogin = () => {
    // If there's a pending invitation, redirect to accept it
    if (pendingInvitationToken) {
      navigate(`/invite/${pendingInvitationToken}`, { replace: true });
    } else {
      navigate(from, { replace: true });
    }
  };
  
  const handleMsalLogin = async () => {
    try {
      console.log("Attempting MSAL login...");
      const response = await loginWithMsal();
      console.log("MSAL login successful:", response);
      handleSuccessfulLogin();
    } catch (error) {
      console.error("MSAL login failed:", error);
    }
  };

  const handleGoogleLogin = async () => {
    try {
      console.log("Attempting Google login...");
      const response = await loginWithGoogle();
      console.log("Google login successful:", response);
      handleSuccessfulLogin();
    } catch (error) {
      console.error("Google login failed:", error);
    }
  };

  const handleCredentialLogin = async (e?: React.MouseEvent) => {
    e?.preventDefault(); // Prevent default form submission
    try {
      console.log("Attempting login with:", username);
      await login(username, password);
      console.log("Login successful");
      handleSuccessfulLogin();
    } catch (error) {
      console.error("Login failed:", error);
      // Stay on login page to show error message
      // The error will be displayed via the loginError state from useAuth hook
    }
  };

  return (
    <div className={styles.container}>
      <div className={styles.mainContent}>
        <div className={styles.logo}>
          <div className={styles.logoText}>
            <span className={styles.logoPower}>Power</span>
            <span className={styles.logoOn}>On</span>
          </div>
        </div>
        <div className={styles.loginSection}>
          <div className={styles.loginBox}>
            <div className={styles.loginForm}>
              {/* Pending invitation notice */}
              {hasPendingInvitation && (
                <div className={styles.invitationNotice}>
                  <FaEnvelopeOpenText className={styles.invitationIcon} />
                  <span>Sie haben eine ausstehende Einladung. Bitte melden Sie sich an, um diese anzunehmen.</span>
                </div>
              )}
              
              {(loginError || msalError || googleError) && (
                <div className={styles.error}>{loginError || msalError || googleError}</div>
              )}
              <div className={styles.floatingLabelInput}>
                <input
                  type="text"
                  placeholder=" "
                  value={username}
                  onChange={(e) => setUsername(e.target.value)}
                  onFocus={() => setUsernameFocused(true)}
                  onBlur={() => setUsernameFocused(false)}
                  onKeyDown={(e) => {
                    if (e.key === 'Enter') {
                      e.preventDefault();
                      handleCredentialLogin();
                    }
                  }}
                  className={`${styles.input} ${usernameFocused || username ? styles.focused : ''}`}
                />
                <label className={usernameFocused || username ? styles.focusedLabel : styles.label}>Benutzername</label>
              </div>
              <div className={styles.floatingLabelInput}>
                <input
                  type="password"
                  placeholder=" "
                  value={password}
                  onChange={(e) => setPassword(e.target.value)}
                  onFocus={() => setPasswordFocused(true)}
                  onBlur={() => setPasswordFocused(false)}
                  onKeyDown={(e) => {
                    if (e.key === 'Enter') {
                      e.preventDefault();
                      handleCredentialLogin();
                    }
                  }}
                  className={`${styles.input} ${passwordFocused || password ? styles.focused : ''}`}
                />
                <label className={passwordFocused || password ? styles.focusedLabel : styles.label}>Passwort</label>
              </div>
              <div className={styles.disclaimer}>
                <p>
                  Mit der Anmeldung stimmen Sie unseren Datenschutzbestimmungen zur KI-Nutzung zu.
                </p>
              </div>
              <button 
                className={`${styles.button} ${styles.loginButton}`}
                onClick={handleCredentialLogin}
                disabled={isLoginLoading}
              >
                {isLoginLoading ? "wird geladen..." : "Anmelden"}
              </button>

              <div className={styles.passwordResetLink}>
                <button 
                  className={styles.textButton}
                  onClick={() => navigate("/password-reset-request")}
                >
                  Passwort vergessen?
                </button>
              </div>

              <div className={styles.divider}>
                <span>oder</span>
              </div>

              <button 
                className={`${styles.button} ${styles.microsoftButton}`}
                onClick={handleMsalLogin}
                disabled={isMsalLoading}
              >
                <div className={styles.buttonContent}>
                  <FaMicrosoft />
                  {isMsalLoading ? "Signing in..." : "Mit Microsoft anmelden"}
                </div>
              </button>

              <button 
                className={`${styles.button} ${styles.googleButton}`}
                onClick={handleGoogleLogin}
                disabled={isGoogleLoading}
              >
                <div className={styles.buttonContent}>
                  <FaGoogle />
                  {isGoogleLoading ? "Signing in..." : "Mit Google anmelden"}
                </div>
              </button>

              <div className={styles.registerLink}>
                <span>Du hast noch keinen Konto?</span>
                <button 
                  className={styles.textButton}
                  onClick={() => navigate("/register", { state: location.state })}
                >
                  Registrieren
                </button>
              </div>
            </div>
          </div>
        </div>
      </div>
    </div>
  );
}

export default Login;
