// Debounce utility
function debounce(func, wait) {
    let timeout;
    return function executedFunction(...args) {
        const later = () => {
            clearTimeout(timeout);
            func(...args);
        };
        clearTimeout(timeout);
        timeout = setTimeout(later, wait);
    };
}

// Active navigation highlighting
function initNavigation() {
    const sections = document.querySelectorAll('section[id]');
    const navLinks = document.querySelectorAll('.nav-link');
    
    if (!sections.length || !navLinks.length) return;
    
    const observer = new IntersectionObserver((entries) => {
        entries.forEach(entry => {
            if (entry.isIntersecting) {
                const id = entry.target.id;
                
                navLinks.forEach(link => {
                    link.classList.remove('active');
                    if (link.getAttribute('href') === `#${id}`) {
                        link.classList.add('active');
                    }
                });
            }
        });
    }, {
        rootMargin: '-30% 0px -70% 0px',
        threshold: 0
    });
    
    sections.forEach(section => observer.observe(section));
}

// Mobile menu toggle
function initMobileMenu() {
    const mobileMenuBtn = document.getElementById('mobile-menu-btn');
    const mobileMenu = document.getElementById('mobile-menu');
    const mobileMenuLinks = mobileMenu?.querySelectorAll('a');
    
    if (!mobileMenuBtn || !mobileMenu) return;
    
    mobileMenuBtn.addEventListener('click', () => {
        mobileMenu.classList.toggle('open');
    });
    
    // Close menu when link is clicked
    mobileMenuLinks?.forEach(link => {
        link.addEventListener('click', () => {
            mobileMenu.classList.remove('open');
        });
    });
    
    // Close menu on escape key
    document.addEventListener('keydown', (e) => {
        if (e.key === 'Escape') {
            mobileMenu.classList.remove('open');
        }
    });
}

// Animate stats counters
function animateStats() {
    const stats = document.querySelectorAll('[data-stat]');
    const observer = new IntersectionObserver((entries) => {
        entries.forEach(entry => {
            if (entry.isIntersecting) {
                const target = entry.target;
                const finalValue = parseInt(target.getAttribute('data-stat'));
                const duration = 1500;
                const startTime = performance.now();
                
                function updateCounter(currentTime) {
                    const elapsed = currentTime - startTime;
                    const progress = Math.min(elapsed / duration, 1);
                    const currentValue = Math.floor(progress * finalValue);
                    
                    target.textContent = currentValue.toLocaleString();
                    
                    if (progress < 1) {
                        requestAnimationFrame(updateCounter);
                    } else {
                        target.textContent = finalValue.toLocaleString();
                    }
                }
                
                requestAnimationFrame(updateCounter);
                observer.unobserve(target);
            }
        });
    }, { threshold: 0.5 });
    
    stats.forEach(stat => observer.observe(stat));
}

// Add fade-in animation to cards on scroll
function initScrollAnimations() {
    const cards = document.querySelectorAll('.glass-card, .spec-block, .node-card, .benefit-card, .use-case-card, .component-card, .network-card, .learning-card, .path-card, .final-card');
    
    const observer = new IntersectionObserver((entries) => {
        entries.forEach(entry => {
            if (entry.isIntersecting) {
                entry.target.classList.add('fade-in-up');
                observer.unobserve(entry.target);
            }
        });
    }, {
        threshold: 0.1,
        rootMargin: '0px 0px -50px 0px'
    });
    
    cards.forEach(card => observer.observe(card));
}

// Smooth scroll for navigation links
function initSmoothScroll() {
    const links = document.querySelectorAll('a[href^="#"]');
    
    links.forEach(link => {
        link.addEventListener('click', (e) => {
            e.preventDefault();
            const targetId = link.getAttribute('href');
            const targetElement = document.querySelector(targetId);
            
            if (targetElement) {
                const headerOffset = 80;
                const elementPosition = targetElement.offsetTop;
                const offsetPosition = elementPosition - headerOffset;
                
                window.scrollTo({
                    top: offsetPosition,
                    behavior: 'smooth'
                });
                
                // Update URL without jumping
                history.pushState(null, null, targetId);
            }
        });
    });
}

// Parallax effect for hero background
function initParallax() {
    const hero = document.getElementById('hero');
    if (!hero) return;
    
    window.addEventListener('scroll', debounce(() => {
        const scrolled = window.pageYOffset;
        const rate = scrolled * -0.5;
        
        hero.style.transform = `translateY(${rate}px)`;
    }, 10));
}

// Handle anchor links on page load
function handleAnchorLinks() {
    if (window.location.hash) {
        const element = document.querySelector(window.location.hash);
        if (element) {
            setTimeout(() => {
                const headerOffset = 80;
                const elementPosition = element.offsetTop;
                const offsetPosition = elementPosition - headerOffset;
                
                window.scrollTo({
                    top: offsetPosition,
                    behavior: 'smooth'
                });
            }, 100);
        }
    }
}

// Initialize all functionality
document.addEventListener('DOMContentLoaded', () => {
    initNavigation();
    initMobileMenu();
    initSmoothScroll();