// Main JavaScript functions for Kayal Aqua Management System
document.addEventListener('DOMContentLoaded', function() {
    
    // Initialize the app
    initializeApp();
    
    // Auto-hide alerts after 5 seconds
    setTimeout(hideAlerts, 5000);
    
    // Add loading states to forms
    setupFormLoading();
    
    // Setup mobile menu if exists
    setupMobileMenu();
}

// Global error handler
window.addEventListener('error', function(e) {
    console.error('JavaScript error:', e.error);
    // Could implement error reporting here
});

// Global unhandled promise rejection handler
window.addEventListener('unhandledrejection', function(e) {
    console.error('Unhandled promise rejection:', e.reason);
    // Could implement error reporting here
    e.preventDefault();
}););

// Initialize application
function initializeApp() {
    // Set active navigation item
    setActiveNavigation();
    
    // Setup form validations
    setupFormValidations();
    
    // Setup confirmation dialogs
    setupConfirmations();
    
    // Handle anchor scrolling for edit forms
    handleEditFormScrolling();
}

// Set active navigation item based on current page
function setActiveNavigation() {
    const currentPage = window.location.pathname.split('/').pop() || 'index.php';
    const navItems = document.querySelectorAll('.nav-item');
    
    navItems.forEach(item => {
        const href = item.getAttribute('href');
        if (href === currentPage || (currentPage === '' && href === 'index.php')) {
            item.classList.add('active');
        } else {
            item.classList.remove('active');
        }
    });
}

// Auto-hide alert messages
function hideAlerts() {
    const alerts = document.querySelectorAll('.alert');
    alerts.forEach(alert => {
        alert.style.transition = 'opacity 0.5s ease-out';
        alert.style.opacity = '0';
        setTimeout(() => {
            if (alert.parentNode) {
                alert.parentNode.removeChild(alert);
            }
        }, 500);
    });
}

// Show alert message
function showAlert(message, type = 'success') {
    const alertDiv = document.createElement('div');
    alertDiv.className = `alert alert-${type}`;
    alertDiv.textContent = message;
    
    const mainContent = document.querySelector('.main-content');
    if (mainContent) {
        mainContent.insertBefore(alertDiv, mainContent.firstChild);
    }
    
    // Auto-hide after 5 seconds
    setTimeout(() => {
        hideAlert(alertDiv);
    }, 5000);
}

// Hide specific alert
function hideAlert(alertElement) {
    alertElement.style.transition = 'opacity 0.5s ease-out';
    alertElement.style.opacity = '0';
    setTimeout(() => {
        if (alertElement.parentNode) {
            alertElement.parentNode.removeChild(alertElement);
        }
    }, 500);
}

// Setup form loading states
function setupFormLoading() {
    const forms = document.querySelectorAll('form');
    
    forms.forEach(form => {
        form.addEventListener('submit', function(e) {
            const submitBtn = form.querySelector('button[type="submit"], input[type="submit"]');
            if (submitBtn) {
                const originalText = submitBtn.textContent || submitBtn.value;
                submitBtn.disabled = true;
                
                if (submitBtn.tagName === 'BUTTON') {
                    submitBtn.innerHTML = '<span class="loading"></span> ' + originalText;
                } else {
                    submitBtn.value = 'Processing...';
                }
                
                // Re-enable after 10 seconds as fallback
                setTimeout(() => {
                    submitBtn.disabled = false;
                    if (submitBtn.tagName === 'BUTTON') {
                        submitBtn.textContent = originalText;
                    } else {
                        submitBtn.value = originalText;
                    }
                }, 10000);
            }
        });
    });
}

// Setup form validations
function setupFormValidations() {
    // Phone number validation
    const phoneInputs = document.querySelectorAll('input[name="phone"]');
    phoneInputs.forEach(input => {
        input.addEventListener('input', function() {
            this.value = this.value.replace(/[^0-9+\-\s]/g, '');
        });
        
        input.addEventListener('blur', function() {
            if (this.value && !isValidPhone(this.value)) {
                showAlert('Please enter a valid phone number', 'error');
                this.focus();
            }
        });
    });
    
    // Username validation
    const usernameInputs = document.querySelectorAll('input[name="username"]');
    usernameInputs.forEach(input => {
        input.addEventListener('input', function() {
            this.value = this.value.replace(/[^a-zA-Z0-9_]/g, '').toLowerCase();
        });
    });
    
    // Password strength indicator
    const passwordInputs = document.querySelectorAll('input[name="password"]');
    passwordInputs.forEach(input => {
        input.addEventListener('input', function() {
            checkPasswordStrength(this);
        });
    });
}

// Validate phone number
function isValidPhone(phone) {
    const phoneRegex = /^[\+]?[0-9\-\s]{10,15}$/;
    return phoneRegex.test(phone.replace(/\s/g, ''));
}

// Check password strength
function checkPasswordStrength(passwordInput) {
    const password = passwordInput.value;
    const strengthIndicator = document.getElementById('password-strength');
    
    if (!strengthIndicator) return;
    
    let strength = 0;
    let message = '';
    let color = '';
    
    if (password.length >= 8) strength++;
    if (/[a-z]/.test(password)) strength++;
    if (/[A-Z]/.test(password)) strength++;
    if (/[0-9]/.test(password)) strength++;
    if (/[^A-Za-z0-9]/.test(password)) strength++;
    
    switch (strength) {
        case 0:
        case 1:
            message = 'Very Weak';
            color = '#f44336';
            break;
        case 2:
            message = 'Weak';
            color = '#ff9800';
            break;
        case 3:
            message = 'Fair';
            color = '#ffeb3b';
            break;
        case 4:
            message = 'Good';
            color = '#4caf50';
            break;
        case 5:
            message = 'Strong';
            color = '#2e7d32';
            break;
    }
    
    strengthIndicator.textContent = message;
    strengthIndicator.style.color = color;
}

// Setup confirmation dialogs
function setupConfirmations() {
    const deleteButtons = document.querySelectorAll('.btn-danger, [data-confirm]');
    
    deleteButtons.forEach(button => {
        button.addEventListener('click', function(e) {
            const message = this.dataset.confirm || 'Are you sure you want to perform this action?';
            if (!confirm(message)) {
                e.preventDefault();
                return false;
            }
        });
    });
}

// Setup mobile menu (if needed for future mobile navigation)
function setupMobileMenu() {
    const mobileMenuToggle = document.querySelector('.mobile-menu-toggle');
    const navMenu = document.querySelector('.nav-menu');
    
    if (mobileMenuToggle && navMenu) {
        mobileMenuToggle.addEventListener('click', function() {
            navMenu.classList.toggle('show');
        });
    }
}

// Utility function to format currency
function formatCurrency(amount) {
    return '₹' + parseFloat(amount).toLocaleString('en-IN', {
        minimumFractionDigits: 2,
        maximumFractionDigits: 2
    });
}

// Utility function to format date
function formatDate(dateString) {
    const date = new Date(dateString);
    return date.toLocaleDateString('en-IN', {
        year: 'numeric',
        month: 'short',
        day: 'numeric'
    });
}

// Utility function to validate email
function isValidEmail(email) {
    const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
    return emailRegex.test(email);
}

// Utility function to show loading state
function showLoading(element) {
    element.disabled = true;
    element.innerHTML = '<span class="loading"></span> ' + element.textContent;
}

// Utility function to hide loading state
function hideLoading(element, originalText) {
    element.disabled = false;
    element.textContent = originalText;
}

// Function to handle AJAX requests
function makeRequest(url, method = 'GET', data = null) {
    return new Promise((resolve, reject) => {
        const xhr = new XMLHttpRequest();
        xhr.open(method, url, true);
        
        if (method === 'POST') {
            xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
        }
        
        xhr.onreadystatechange = function() {
            if (xhr.readyState === 4) {
                if (xhr.status === 200) {
                    try {
                        const response = JSON.parse(xhr.responseText);
                        resolve(response);
                    } catch (e) {
                        resolve(xhr.responseText);
                    }
                } else {
                    reject(new Error('Request failed: ' + xhr.status));
                }
            }
        };
        
        xhr.send(data);
    });
}

// Global error handler
window.addEventListener('error', function(e) {
    console.error('JavaScript error:', e.error);
    // Could implement error reporting here
});

// Handle anchor scrolling for edit forms in settings page
function handleEditFormScrolling() {
    // Check if we're on settings page and have edit parameters
    const currentPage = window.location.pathname.split('/').pop();
    const urlParams = new URLSearchParams(window.location.search);
    
    if (currentPage === 'settings.php' || currentPage === '') {
        let targetSection = null;
        
        // Determine which section to scroll to based on URL parameters
        if (urlParams.has('edit_unit')) {
            targetSection = 'units-section';
        } else if (urlParams.has('edit_category')) {
            targetSection = 'categories-section';
        } else if (urlParams.has('edit_subcategory')) {
            targetSection = 'subcategories-section';
        } else if (urlParams.has('edit_ps')) {
            targetSection = 'products-section';
        }
        
        // Also check for hash in URL
        if (window.location.hash) {
            const hashSection = window.location.hash.substring(1);
            if (document.getElementById(hashSection)) {
                targetSection = hashSection;
            }
        }
        
        // Scroll to the target section if found
        if (targetSection) {
            setTimeout(() => {
                const element = document.getElementById(targetSection);
                if (element) {
                    element.scrollIntoView({
                        behavior: 'smooth',
                        block: 'start'
                    });
                    
                    // Add a subtle highlight effect
                    element.style.transition = 'background-color 0.3s ease';
                    element.style.backgroundColor = 'rgba(255, 215, 0, 0.1)';
                    setTimeout(() => {
                        element.style.backgroundColor = '';
                    }, 2000);
                }
            }, 100);
        }
    }
}