// DOM Elements
const loginForm = document.getElementById('loginForm');
const emailInput = document.getElementById('email');
const passwordInput = document.getElementById('password');
const passwordToggle = document.getElementById('passwordToggle');
const loginButton = document.getElementById('loginButton');
const toast = document.getElementById('toast');

// Error message elements
const emailError = document.getElementById('emailError');
const passwordError = document.getElementById('passwordError');
const generalError = document.getElementById('generalError');

// API Configuration
const API_BASE_URL = '/api/v1';
const LOGIN_ENDPOINT = `${API_BASE_URL}/auth/login`;

// Password visibility toggle
passwordToggle.addEventListener('click', () => {
    const type = passwordInput.getAttribute('type') === 'password' ? 'text' : 'password';
    passwordInput.setAttribute('type', type);

    const icon = passwordToggle.querySelector('.toggle-icon');
    icon.textContent = type === 'password' ? '👁️' : '🙈';
});

// Form validation functions
const validateEmail = (email) => {
    return true;
    const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
    return emailRegex.test(email);
};

const validatePassword = (password) => {
    return password.length >= 6;
};

const showError = (element, message) => {
    element.textContent = message;
    element.style.display = 'block';
};

const hideError = (element) => {
    element.textContent = '';
    element.style.display = 'none';
};

const clearAllErrors = () => {
    hideError(emailError);
    hideError(passwordError);
    generalError.classList.remove('show');

    emailInput.classList.remove('error');
    passwordInput.classList.remove('error');
};

// Real-time validation
emailInput.addEventListener('blur', () => {
    const email = emailInput.value.trim();
    if (email && !validateEmail(email)) {
        showError(emailError, 'Please enter a valid email address');
        emailInput.classList.add('error');
    } else {
        hideError(emailError);
        emailInput.classList.remove('error');
    }
});

passwordInput.addEventListener('blur', () => {
    const password = passwordInput.value;
    if (password && !validatePassword(password)) {
        showError(passwordError, 'Password must be at least 6 characters long');
        passwordInput.classList.add('error');
    } else {
        hideError(passwordError);
        passwordInput.classList.remove('error');
    }
});

// Clear errors on input
emailInput.addEventListener('input', () => {
    if (emailInput.classList.contains('error')) {
        hideError(emailError);
        emailInput.classList.remove('error');
    }
});

passwordInput.addEventListener('input', () => {
    if (passwordInput.classList.contains('error')) {
        hideError(passwordError);
        passwordInput.classList.remove('error');
    }
});

// Show toast notification
const showToast = (message, type = 'success') => {
    const toastContent = toast.querySelector('.toast-content');
    const toastIcon = toast.querySelector('.toast-icon');
    const toastMessage = toast.querySelector('.toast-message');

    // Set icon and color based on type
    if (type === 'success') {
        toastIcon.textContent = '✓';
        toast.style.background = 'var(--success)';
    } else if (type === 'error') {
        toastIcon.textContent = '✕';
        toast.style.background = 'var(--error)';
    }

    toastMessage.textContent = message;
    toast.classList.add('show');

    setTimeout(() => {
        toast.classList.remove('show');
    }, 4000);
};

// Set loading state
const setLoadingState = (loading) => {
    if (loading) {
        loginButton.classList.add('loading');
        loginButton.disabled = true;
    } else {
        loginButton.classList.remove('loading');
        loginButton.disabled = false;
    }
};

// Make login API request
const makeLoginRequest = async (credentials) => {
    try {
        const response = await fetch(LOGIN_ENDPOINT, {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
                'Accept': 'application/json',
            },
            body: JSON.stringify(credentials)
        });

        const data = await response.json();

        if (!response.ok) {
            throw new Error(data.message || `HTTP error! status: ${response.status}`);
        }

        return data;
    } catch (error) {
        // Handle network errors or API errors
        if (error.name === 'TypeError' && error.message.includes('fetch')) {
            throw new Error('Network error. Please check your connection and try again.');
        }
        throw error;
    }
};

// Handle successful login
const handleLoginSuccess = (data) => {
    // Store authentication data
    if (data.token) {
        localStorage.setItem('taskflow_token', data.token);
    }

    if (data.refreshToken) {
        localStorage.setItem('taskflow_refresh_token', data.refreshToken);
    }

    if (data.user) {
        localStorage.setItem('taskflow_user', JSON.stringify(data.user));
    }

    // Show success message
    showToast('Login successful! Redirecting to dashboard...', 'success');

    // Redirect to dashboard after a short delay
    setTimeout(() => {
        window.location.href = 'index.html'; // or wherever the dashboard is located
    }, 2000);
};

// Handle login error
const handleLoginError = (error) => {
    console.error('Login error:', error);

    let errorMessage = 'An unexpected error occurred. Please try again.';

    if (error.message.includes('Invalid credentials') || 
        error.message.includes('Unauthorized') ||
        error.message.includes('401')) {
        errorMessage = 'Invalid email or password. Please check your credentials and try again.';
    } else if (error.message.includes('Network error')) {
        errorMessage = error.message;
    } else if (error.message.includes('Too many attempts')) {
        errorMessage = 'Too many login attempts. Please try again later.';
    }

    generalError.textContent = errorMessage;
    generalError.classList.add('show');
    showToast(errorMessage, 'error');
};

// Form submission handler
loginForm.addEventListener('submit', async (e) => {
    e.preventDefault();

    // Clear previous errors
    clearAllErrors();

    // Get form data
    const email = emailInput.value.trim();
    const password = passwordInput.value;
    const rememberMe = document.getElementById('rememberMe').checked;

    // Validate inputs
    let hasErrors = false;

    if (!email) {
        showError(emailError, 'Email is required');
        emailInput.classList.add('error');
        hasErrors = true;
    } else if (!validateEmail(email)) {
        showError(emailError, 'Please enter a valid email address');
        emailInput.classList.add('error');
        hasErrors = true;
    }

    if (!password) {
        showError(passwordError, 'Password is required');
        passwordInput.classList.add('error');
        hasErrors = true;
    } else if (!validatePassword(password)) {
        showError(passwordError, 'Password must be at least 6 characters long');
        passwordInput.classList.add('error');
        hasErrors = true;
    }

    if (hasErrors) {
        return;
    }

    // Set loading state
    setLoadingState(true);

    try {
        // Prepare request payload
        const credentials = {
            email,
            password,
            rememberMe
        };

        // Make API request
        const response = await makeLoginRequest(credentials);

        // Handle success
        handleLoginSuccess(response);

    } catch (error) {
        // Handle error
        handleLoginError(error);
    } finally {
        // Remove loading state
        setLoadingState(false);
    }
});

// Social login handlers
document.querySelector('.btn-google').addEventListener('click', () => {
    // In a real application, this would initiate OAuth flow
    showToast('Google login would be initiated here', 'success');

    // Simulate OAuth redirect
    setTimeout(() => {
        window.location.href = `${API_BASE_URL}/auth/google?redirect_uri=${encodeURIComponent(window.location.origin + '/dashboard')}`;
    }, 1000);
});

document.querySelector('.btn-microsoft').addEventListener('click', () => {
    // In a real application, this would initiate OAuth flow
    showToast('Microsoft login would be initiated here', 'success');

    // Simulate OAuth redirect
    setTimeout(() => {
        window.location.href = `${API_BASE_URL}/auth/microsoft?redirect_uri=${encodeURIComponent(window.location.origin + '/dashboard')}`;
    }, 1000);
});

// Forgot password handler
document.querySelector('.forgot-password').addEventListener('click', (e) => {
    e.preventDefault();

    const email = emailInput.value.trim();
    if (email && validateEmail(email)) {
        showToast(`Password reset link sent to ${email}`, 'success');
    } else {
        showToast('Please enter a valid email address first', 'error');
        emailInput.focus();
    }
});

// Sign up link handler
document.querySelector('a[href="#signup"]').addEventListener('click', (e) => {
    e.preventDefault();
    window.location.href = 'signup.html'; // Redirect to signup page
});

// Check if user is already logged in
window.addEventListener('load', () => {
    const token = localStorage.getItem('taskflow_token');
    if (token) {
        // Verify token is still valid (in a real app, you'd make an API call)
        showToast('You are already logged in. Redirecting...', 'success');
        setTimeout(() => {
            window.location.href = 'index.html';
        }, 2000);
    }
});

// Demo credentials helper (for development/demo purposes)
const addDemoCredentials = () => {
    const demoButton = document.createElement('button');
    demoButton.type = 'button';
    demoButton.className = 'btn btn-secondary btn-full';
    demoButton.textContent = 'Use Demo Credentials';
    demoButton.style.marginTop = '1rem';
    demoButton.style.fontSize = '0.875rem';

    demoButton.addEventListener('click', () => {
        emailInput.value = 'demo@taskflow.com';
        passwordInput.value = 'demo123';
        showToast('Demo credentials filled. Click Sign In to continue.', 'success');
    });

    // Add after the social login section
    const socialLogin = document.querySelector('.social-login');
    socialLogin.appendChild(demoButton);
};

// Add demo credentials in development
if (window.location.hostname === 'localhost' || window.location.hostname === '127.0.0.1') {
    addDemoCredentials();
}