// Authentication JavaScript

// API Configuration
const API_BASE_URL = '/api';

// DOM Elements
let currentForm = 'login';

// Initialize page
document.addEventListener('DOMContentLoaded', function() {
    initializeAuth();
    setupPasswordStrength();
    setupFormValidation();
});

function initializeAuth() {
    // Set initial form state
    showLogin();
}

function showLogin() {
    hideAllForms();
    document.getElementById('loginForm').style.display = 'block';
    setActiveNavButton('loginNavBtn');
    currentForm = 'login';
}

function showRegister() {
    hideAllForms();
    document.getElementById('registerForm').style.display = 'block';
    setActiveNavButton('registerNavBtn');
    currentForm = 'register';
}

function showForgotPassword() {
    hideAllForms();
    document.getElementById('forgotPasswordForm').style.display = 'block';
    clearActiveNavButtons();
    currentForm = 'forgot';
}

function hideAllForms() {
    const forms = ['loginForm', 'registerForm', 'forgotPasswordForm'];
    forms.forEach(formId => {
        document.getElementById(formId).style.display = 'none';
    });
}

function setActiveNavButton(activeId) {
    clearActiveNavButtons();
    document.getElementById(activeId).classList.add('active');
}

function clearActiveNavButtons() {
    document.querySelectorAll('.nav-btn').forEach(btn => {
        btn.classList.remove('active');
    });
}

// Password visibility toggle
function togglePassword(inputId) {
    const input = document.getElementById(inputId);
    const button = input.parentElement.querySelector('.password-toggle i');
    
    if (input.type === 'password') {
        input.type = 'text';
        button.classList.remove('fa-eye');
        button.classList.add('fa-eye-slash');
    } else {
        input.type = 'password';
        button.classList.remove('fa-eye-slash');
        button.classList.add('fa-eye');
    }
}

// Password strength checker
function setupPasswordStrength() {
    const passwordInput = document.getElementById('registerPassword');
    const strengthBar = document.querySelector('.strength-fill');
    const strengthText = document.querySelector('.strength-text');
    
    if (passwordInput) {
        passwordInput.addEventListener('input', function() {
            const password = this.value;
            const strength = calculatePasswordStrength(password);
            updatePasswordStrength(strength, strengthBar, strengthText);
        });
    }
}

function calculatePasswordStrength(password) {
    let score = 0;
    let feedback = [];
    
    // Length check
    if (password.length >= 8) score += 20;
    else feedback.push('At least 8 characters');
    
    // Uppercase check
    if (/[A-Z]/.test(password)) score += 20;
    else feedback.push('One uppercase letter');
    
    // Lowercase check
    if (/[a-z]/.test(password)) score += 20;
    else feedback.push('One lowercase letter');
    
    // Number check
    if (/\d/.test(password)) score += 20;
    else feedback.push('One number');
    
    // Special character check
    if (/[!@#$%^&*(),.?":{}|<>]/.test(password)) score += 20;
    else feedback.push('One special character');
    
    return { score, feedback };
}

function updatePasswordStrength(strength, strengthBar, strengthText) {
    const { score, feedback } = strength;
    
    strengthBar.style.width = score + '%';
    
    if (score < 40) {
        strengthBar.style.background = '#e74c3c';
        strengthText.textContent = 'Weak password';
        strengthText.style.color = '#e74c3c';
    } else if (score < 80) {
        strengthBar.style.background = '#f39c12';
        strengthText.textContent = 'Medium password';
        strengthText.style.color = '#f39c12';
    } else {
        strengthBar.style.background = '#27ae60';
        strengthText.textContent = 'Strong password';
        strengthText.style.color = '#27ae60';
    }
    
    if (feedback.length > 0 && score < 100) {
        strengthText.textContent += ' - Missing: ' + feedback.join(', ');
    }
}

// Form validation
function setupFormValidation() {
    // Real-time validation for username
    const usernameInput = document.getElementById('registerUsername');
    if (usernameInput) {
        usernameInput.addEventListener('input', validateUsername);
        usernameInput.addEventListener('blur', validateUsername);
    }
    
    // Real-time validation for email
    const emailInputs = document.querySelectorAll('input[type="email"]');
    emailInputs.forEach(input => {
        input.addEventListener('input', validateEmail);
        input.addEventListener('blur', validateEmail);
    });
    
    // Password confirmation validation
    const confirmPasswordInput = document.getElementById('confirmPassword');
    if (confirmPasswordInput) {
        confirmPasswordInput.addEventListener('input', validatePasswordConfirmation);
        confirmPasswordInput.addEventListener('blur', validatePasswordConfirmation);
    }
}

function validateUsername() {
    const input = document.getElementById('registerUsername');
    const value = input.value.trim();
    const inputGroup = input.parentElement;
    
    clearValidationState(inputGroup);
    
    if (value.length === 0) return;
    
    if (value.length < 3 || value.length > 80) {
        setValidationState(inputGroup, 'error', 'Username must be 3-80 characters');
        return false;
    }
    
    if (!/^[a-zA-Z0-9_-]+$/.test(value)) {
        setValidationState(inputGroup, 'error', 'Only letters, numbers, hyphens, and underscores allowed');
        return false;
    }
    
    setValidationState(inputGroup, 'success');
    return true;
}

function validateEmail() {
    const input = this;
    const value = input.value.trim();
    const inputGroup = input.parentElement;
    
    clearValidationState(inputGroup);
    
    if (value.length === 0) return;
    
    const emailRegex = /^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/;
    
    if (!emailRegex.test(value)) {
        setValidationState(inputGroup, 'error', 'Please enter a valid email address');
        return false;
    }
    
    setValidationState(inputGroup, 'success');
    return true;
}

function validatePasswordConfirmation() {
    const passwordInput = document.getElementById('registerPassword');
    const confirmInput = document.getElementById('confirmPassword');
    const inputGroup = confirmInput.parentElement;
    
    clearValidationState(inputGroup);
    
    if (confirmInput.value.length === 0) return;
    
    if (passwordInput.value !== confirmInput.value) {
        setValidationState(inputGroup, 'error', 'Passwords do not match');
        return false;
    }
    
    setValidationState(inputGroup, 'success');
    return true;
}

function setValidationState(inputGroup, state, message = '') {
    inputGroup.classList.remove('error', 'success');
    inputGroup.classList.add(state);
    
    // Remove existing error message
    const existingError = inputGroup.parentElement.querySelector('.error-message');
    if (existingError) {
        existingError.remove();
    }
    
    // Add error message if provided
    if (message && state === 'error') {
        const errorDiv = document.createElement('div');
        errorDiv.className = 'error-message';
        errorDiv.innerHTML = `<i class="fas fa-exclamation-circle"></i> ${message}`;
        inputGroup.parentElement.appendChild(errorDiv);
    }
}

function clearValidationState(inputGroup) {
    inputGroup.classList.remove('error', 'success');
    const existingError = inputGroup.parentElement.querySelector('.error-message');
    if (existingError) {
        existingError.remove();
    }
}

// Form submission handlers
async function handleLogin(event) {
    event.preventDefault();
    
    const form = event.target;
    const formData = new FormData(form);
    const loginData = {
        login: formData.get('login'),
        password: formData.get('password')
    };
    
    const button = document.getElementById('loginBtn');
    setButtonLoading(button, true);
    
    try {
        const response = await fetch(`${API_BASE_URL}/login`, {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
            },
            body: JSON.stringify(loginData)
        });
        
        const result = await response.json();
        
        if (response.ok) {
            // Store tokens
            localStorage.setItem('auth_token', result.auth_token);
            localStorage.setItem('refresh_token', result.refresh_token);
            localStorage.setItem('user_data', JSON.stringify(result.user));
            
            showAlert('success', 'Login successful! Redirecting to dashboard...');
            
            // Redirect to dashboard
            setTimeout(() => {
                window.location.href = '/dashboard.html';
            }, 1500);
            
        } else {
            showAlert('error', result.error || 'Login failed');
        }
        
    } catch (error) {
        console.error('Login error:', error);
        showAlert('error', 'Network error. Please try again.');
    } finally {
        setButtonLoading(button, false);
    }
}

async function handleRegister(event) {
    event.preventDefault();
    
    const form = event.target;
    const formData = new FormData(form);
    
    // Validate form
    if (!validateRegistrationForm(form)) {
        showAlert('error', 'Please fix the errors in the form');
        return;
    }
    
    const registerData = {
        username: formData.get('username'),
        email: formData.get('email'),
        password: formData.get('password'),
        subscription_type: formData.get('subscriptionType')
    };
    
    const button = document.getElementById('registerBtn');
    setButtonLoading(button, true);
    
    try {
        const response = await fetch(`${API_BASE_URL}/register`, {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
            },
            body: JSON.stringify(registerData)
        });
        
        const result = await response.json();
        
        if (response.ok) {
            // Store tokens
            localStorage.setItem('auth_token', result.auth_token);
            localStorage.setItem('refresh_token', result.refresh_token);
            localStorage.setItem('user_data', JSON.stringify(result.user));
            
            showAlert('success', 'Account created successfully! Redirecting to dashboard...');
            
            // Redirect to dashboard
            setTimeout(() => {
                window.location.href = '/dashboard.html';
            }, 1500);
            
        } else {
            showAlert('error', result.error || 'Registration failed');
        }
        
    } catch (error) {
        console.error('Registration error:', error);
        showAlert('error', 'Network error. Please try again.');
    } finally {
        setButtonLoading(button, false);
    }
}

async function handleForgotPassword(event) {
    event.preventDefault();
    
    const form = event.target;
    const formData = new FormData(form);
    const email = formData.get('email');
    
    const button = document.getElementById('forgotPasswordBtn');
    setButtonLoading(button, true);
    
    try {
        const response = await fetch(`${API_BASE_URL}/forgot-password`, {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
            },
            body: JSON.stringify({ email })
        });
        
        const result = await response.json();
        
        if (response.ok) {
            showAlert('success', 'Password reset instructions sent to your email');
            
            // Show reset token for development (remove in production)
            if (result.reset_token) {
                showAlert('info', `Development: Reset token is ${result.reset_token}`);
            }
            
            // Switch back to login form
            setTimeout(() => {
                showLogin();
            }, 3000);
            
        } else {
            showAlert('error', result.error || 'Failed to send reset instructions');
        }
        
    } catch (error) {
        console.error('Forgot password error:', error);
        showAlert('error', 'Network error. Please try again.');
    } finally {
        setButtonLoading(button, false);
    }
}

function validateRegistrationForm(form) {
    let isValid = true;
    
    // Validate username
    const usernameInput = form.querySelector('#registerUsername');
    if (!validateUsername.call(usernameInput)) {
        isValid = false;
    }
    
    // Validate email
    const emailInput = form.querySelector('#registerEmail');
    if (!validateEmail.call(emailInput)) {
        isValid = false;
    }
    
    // Validate password strength
    const passwordInput = form.querySelector('#registerPassword');
    const strength = calculatePasswordStrength(passwordInput.value);
    if (strength.score < 80) {
        const inputGroup = passwordInput.parentElement;
        setValidationState(inputGroup, 'error', 'Password is too weak');
        isValid = false;
    }
    
    // Validate password confirmation
    if (!validatePasswordConfirmation()) {
        isValid = false;
    }
    
    // Validate terms agreement
    const termsCheckbox = form.querySelector('#agreeTerms');
    if (!termsCheckbox.checked) {
        showAlert('error', 'You must agree to the Terms of Service and Privacy Policy');
        isValid = false;
    }
    
    return isValid;
}

// Utility functions
function setButtonLoading(button, loading) {
    const btnText = button.querySelector('.btn-text');
    const btnLoader = button.querySelector('.btn-loader');
    
    if (loading) {
        button.classList.add('loading');
        button.disabled = true;
        btnText.style.opacity = '0';
        btnLoader.style.display = 'block';
    } else {
        button.classList.remove('loading');
        button.disabled = false;
        btnText.style.opacity = '1';
        btnLoader.style.display = 'none';
    }
}

function showAlert(type, message, duration = 5000) {
    const alertContainer = document.getElementById('alertContainer');
    
    const alert = document.createElement('div');
    alert.className = `alert ${type}`;
    
    const icon = getAlertIcon(type);
    
    alert.innerHTML = `
        <i class="${icon}"></i>
        <span>${message}</span>
        <button class="alert-close" onclick="closeAlert(this)">
            <i class="fas fa-times"></i>
        </button>
    `;
    
    alertContainer.appendChild(alert);
    
    // Auto-remove alert after duration
    setTimeout(() => {
        if (alert.parentElement) {
            closeAlert(alert.querySelector('.alert-close'));
        }
    }, duration);
}

function getAlertIcon(type) {
    const icons = {
        success: 'fas fa-check-circle',
        error: 'fas fa-exclamation-circle',
        warning: 'fas fa-exclamation-triangle',
        info: 'fas fa-info-circle'
    };
    return icons[type] || icons.info;
}

function closeAlert(button) {
    const alert = button.parentElement;
    alert.style.animation = 'slideOutRight 0.3s ease-out forwards';
    setTimeout(() => {
        if (alert.parentElement) {
            alert.parentElement.removeChild(alert);
        }
    }, 300);
}

async function verifyTokenAndRedirect(token) {
    try {
        const response = await fetch(`${API_BASE_URL}/profile`, {
            headers: {
                'Authorization': `Bearer ${token}`
            }
        });
        
        if (response.ok) {
            // Token is valid, redirect to dashboard
            window.location.href = '/dashboard.html';
        } else {
            // Token is invalid, remove from storage
            localStorage.removeItem('auth_token');
            localStorage.removeItem('refresh_token');
            localStorage.removeItem('user_data');
        }
    } catch (error) {
        console.error('Token verification error:', error);
        // Remove invalid tokens
        localStorage.removeItem('auth_token');
        localStorage.removeItem('refresh_token');
        localStorage.removeItem('user_data');
    }
}

// Add CSS animation for slide out
const style = document.createElement('style');
style.textContent = `
    @keyframes slideOutRight {
        from {
            opacity: 1;
            transform: translateX(0);
        }
        to {
            opacity: 0;
            transform: translateX(100%);
        }
    }
`;
document.head.appendChild(style);