// DOM Content Loaded
document.addEventListener('DOMContentLoaded', function() {
    // Mobile Navigation Toggle
    const hamburger = document.querySelector('.hamburger');
    const navMenu = document.querySelector('.nav-menu');

    hamburger.addEventListener('click', function() {
        hamburger.classList.toggle('active');
        navMenu.classList.toggle('active');
    });

    // Close mobile menu when clicking on a link
    document.querySelectorAll('.nav-link').forEach(link => {
        link.addEventListener('click', () => {
            hamburger.classList.remove('active');
            navMenu.classList.remove('active');
        });
    });

    // Smooth scrolling for navigation links
    document.querySelectorAll('a[href^="#"]').forEach(anchor => {
        anchor.addEventListener('click', function (e) {
            e.preventDefault();
            const target = document.querySelector(this.getAttribute('href'));
            if (target) {
                const offsetTop = target.offsetTop - 70; // Account for fixed navbar
                window.scrollTo({
                    top: offsetTop,
                    behavior: 'smooth'
                });
            }
        });
    });

    // Navbar background on scroll
    const navbar = document.querySelector('.navbar');
    window.addEventListener('scroll', function() {
        if (window.scrollY > 50) {
            navbar.style.background = 'rgba(255, 255, 255, 0.98)';
            navbar.style.boxShadow = '0 2px 20px rgba(0, 0, 0, 0.1)';
        } else {
            navbar.style.background = 'rgba(255, 255, 255, 0.95)';
            navbar.style.boxShadow = 'none';
        }
    });

    // Animated counter for hero stats
    function animateCounter(element, target, duration = 2000) {
        let start = 0;
        const increment = target / (duration / 16);
        
        function updateCounter() {
            start += increment;
            if (start < target) {
                element.textContent = Math.floor(start);
                requestAnimationFrame(updateCounter);
            } else {
                element.textContent = target;
            }
        }
        
        updateCounter();
    }

    // Intersection Observer for animations
    const observerOptions = {
        threshold: 0.1,
        rootMargin: '0px 0px -50px 0px'
    };

    const observer = new IntersectionObserver(function(entries) {
        entries.forEach(entry => {
            if (entry.isIntersecting) {
                entry.target.classList.add('fade-in-up');
                
                // Animate counters when hero section is visible
                if (entry.target.classList.contains('hero-stats')) {
                    const counters = entry.target.querySelectorAll('.stat-number');
                    counters.forEach(counter => {
                        const target = parseInt(counter.getAttribute('data-target'));
                        animateCounter(counter, target);
                    });
                }
                
                observer.unobserve(entry.target);
            }
        });
    }, observerOptions);

    // Observe elements for animation
    const animatedElements = document.querySelectorAll('.contribution-item, .finding-item, .resource-item, .hero-stats, .example-container, .categories-visual');
    animatedElements.forEach(el => observer.observe(el));

    // Active navigation link highlighting
    const sections = document.querySelectorAll('section[id]');
    const navLinks = document.querySelectorAll('.nav-link');

    function highlightNavigation() {
        let current = '';
        sections.forEach(section => {
            const sectionTop = section.offsetTop - 100;
            const sectionHeight = section.clientHeight;
            if (window.scrollY >= sectionTop && window.scrollY < sectionTop + sectionHeight) {
                current = section.getAttribute('id');
            }
        });

        navLinks.forEach(link => {
            link.classList.remove('active');
            if (link.getAttribute('href') === `#${current}`) {
                link.classList.add('active');
            }
        });
    }

    window.addEventListener('scroll', highlightNavigation);

    // Parallax effect for hero section
    const hero = document.querySelector('.hero');
    window.addEventListener('scroll', function() {
        const scrolled = window.pageYOffset;
        const rate = scrolled * -0.5;
        if (hero) {
            hero.style.transform = `translateY(${rate}px)`;
        }
    });

    // Copy citation to clipboard
    const citationBox = document.querySelector('.citation-box');
    if (citationBox) {
        citationBox.addEventListener('click', function() {
            const text = this.textContent;
            navigator.clipboard.writeText(text).then(function() {
                // Show feedback
                const feedback = document.createElement('div');
                feedback.textContent = 'Citation copied to clipboard!';
                feedback.style.cssText = `
                    position: fixed;
                    top: 20px;
                    right: 20px;
                    background: #10b981;
                    color: white;
                    padding: 1rem 2rem;
                    border-radius: 10px;
                    z-index: 10000;
                    animation: slideInRight 0.3s ease;
                `;
                document.body.appendChild(feedback);
                
                setTimeout(() => {
                    feedback.remove();
                }, 3000);
            });
        });
    }

    // Add hover effects to performance table rows
    const tableRows = document.querySelectorAll('.performance-table tbody tr');
    tableRows.forEach(row => {
        row.addEventListener('mouseenter', function() {
            this.style.backgroundColor = 'rgba(37, 99, 235, 0.05)';
            this.style.transform = 'scale(1.02)';
            this.style.transition = 'all 0.3s ease';
        });
        
        row.addEventListener('mouseleave', function() {
            if (!this.classList.contains('top-performer')) {
                this.style.backgroundColor = '';
            }
            this.style.transform = 'scale(1)';
        });
    });

  /* Ensure images are visible and properly loaded */
    const images = document.querySelectorAll('img[src]');
    images.forEach(img => {
        img.style.opacity = '1';
        img.style.transition = 'opacity 0.3s ease';
        
        // Ensure image is loaded
        if (!img.complete) {
            img.onload = function() {
                this.style.opacity = '1';
            };
        }
    });
    // Add scroll progress indicator
    const progressBar = document.createElement('div');
    progressBar.style.cssText = `
        position: fixed;
        top: 0;
        left: 0;
        width: 0%;
        height: 3px;
        background: linear-gradient(90deg, #667eea, #764ba2);
        z-index: 10000;
        transition: width 0.1s ease;
    `;
    document.body.appendChild(progressBar);

    window.addEventListener('scroll', function() {
        const scrollTop = window.pageYOffset;
        const docHeight = document.body.scrollHeight - window.innerHeight;
        const scrollPercent = (scrollTop / docHeight) * 100;
        progressBar.style.width = scrollPercent + '%';
    });

    // Add smooth fade-in effect to hero title instead of typing
    const heroTitle = document.querySelector('.hero-title');
    if (heroTitle) {
        heroTitle.style.opacity = '0';
        heroTitle.style.transform = 'translateY(30px)';
        heroTitle.style.transition = 'opacity 1s ease, transform 1s ease';
        
        setTimeout(() => {
            heroTitle.style.opacity = '1';
            heroTitle.style.transform = 'translateY(0)';
        }, 300);
    }

    // Add floating animation to contribution items
    const contributionItems = document.querySelectorAll('.contribution-item');
    contributionItems.forEach((item, index) => {
        item.style.animationDelay = `${index * 0.1}s`;
        item.classList.add('float-animation');
    });

    // Add CSS for floating animation
    const style = document.createElement('style');
    style.textContent = `
        @keyframes float {
            0%, 100% { transform: translateY(0px); }
            50% { transform: translateY(-10px); }
        }
        
        .float-animation {
            animation: float 3s ease-in-out infinite;
        }
        
        @keyframes slideInRight {
            from { transform: translateX(100%); opacity: 0; }
            to { transform: translateX(0); opacity: 1; }
        }
        
        .nav-link.active {
            color: var(--primary-color);
        }
        
        .nav-link.active::after {
            width: 100%;
        }
    `;
    document.head.appendChild(style);

    // Add click effects to buttons
    const buttons = document.querySelectorAll('.btn, .resource-link');
    buttons.forEach(button => {
        button.addEventListener('click', function(e) {
            const ripple = document.createElement('span');
            const rect = this.getBoundingClientRect();
            const size = Math.max(rect.width, rect.height);
            const x = e.clientX - rect.left - size / 2;
            const y = e.clientY - rect.top - size / 2;
            
            ripple.style.cssText = `
                position: absolute;
                width: ${size}px;
                height: ${size}px;
                left: ${x}px;
                top: ${y}px;
                background: rgba(255, 255, 255, 0.3);
                border-radius: 50%;
                transform: scale(0);
                animation: ripple 0.6s linear;
                pointer-events: none;
            `;
            
            this.style.position = 'relative';
            this.style.overflow = 'hidden';
            this.appendChild(ripple);
            
            setTimeout(() => {
                ripple.remove();
            }, 600);
        });
    });

    // Add ripple animation CSS
    const rippleStyle = document.createElement('style');
    rippleStyle.textContent = `
        @keyframes ripple {
            to {
                transform: scale(4);
                opacity: 0;
            }
        }
    `;
    document.head.appendChild(rippleStyle);

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

    // Apply debouncing to scroll events
    const debouncedScrollHandler = debounce(() => {
        highlightNavigation();
    }, 10);

    window.addEventListener('scroll', debouncedScrollHandler);

    console.log('BIS Reasoning 1.0 website loaded successfully!');
});