// Custom JavaScript for IT Learning Notes

// Wait for the DOM to be fully loaded
document.addEventListener('DOMContentLoaded', function() {
    // Improve anchor link scrolling behavior
    document.querySelectorAll('a[href^="#"]').forEach(anchor => {
        anchor.addEventListener('click', function(e) {
            e.preventDefault();
            const targetId = this.getAttribute('href');
            
            // Only process internal page links
            if (targetId.startsWith('#')) {
                const targetElement = document.querySelector(targetId);
                
                if (targetElement) {
                    // Smooth scroll to the target
                    window.scrollTo({
                        top: targetElement.offsetTop - 60, // Account for header/navigation
                        behavior: 'smooth'
                    });
                    
                    // Update URL without reloading the page
                    history.pushState(null, null, targetId);
                }
            }
        });
    });
    
    // Add "Back to Top" links if they don't exist in the content
    const sections = document.querySelectorAll('h2');
    sections.forEach(section => {
        // Check if there's already a back-to-top link after this section
        const nextElement = section.nextElementSibling;
        const hasBackToTop = false;
        
        // Find the end of this section (next h2 or end of document)
        let currentElement = section.nextElementSibling;
        while (currentElement && currentElement.tagName !== 'H2') {
            if (currentElement.tagName === 'A' && 
                currentElement.getAttribute('href') && 
                currentElement.getAttribute('href').includes('top')) {
                hasBackToTop = true;
                break;
            }
            currentElement = currentElement.nextElementSibling;
        }
        
        // Add back-to-top link if needed
        if (!hasBackToTop && currentElement && currentElement.tagName === 'H2') {
            const backToTop = document.createElement('a');
            backToTop.href = '#';
            backToTop.textContent = 'Back to Top';
            backToTop.className = 'back-to-top';
            backToTop.style.display = 'block';
            backToTop.style.marginBottom = '2em';
            
            // Insert before the next heading
            section.parentNode.insertBefore(backToTop, currentElement);
        }
    });
    
    // Fix for any dynamically loaded content
    setTimeout(function() {
        // Force redraw of content area
        const content = document.querySelector('.content');
        if (content) {
            content.style.display = 'none';
            content.offsetHeight; // Force reflow
            content.style.display = 'block';
        }
        
        // Scroll to anchor if present in URL
        if (window.location.hash) {
            const element = document.getElementById(window.location.hash.substring(1));
            if (element) {
                element.scrollIntoView({behavior: 'smooth'});
            }
        }
    }, 100);
});

// Create a table of contents if it doesn't exist
function generateTableOfContents() {
    // Only run if we don't have a TOC div already
    if (!document.querySelector('.toc')) {
        const headings = document.querySelectorAll('h2');
        if (headings.length > 2) { // Only if we have a reasonable number of headings
            const toc = document.createElement('div');
            toc.className = 'toc';
            
            const tocTitle = document.createElement('h2');
            tocTitle.textContent = 'Table of Contents';
            toc.appendChild(tocTitle);
            
            const tocList = document.createElement('ul');
            
            headings.forEach(heading => {
                if (!heading.textContent.toLowerCase().includes('table of contents')) {
                    const listItem = document.createElement('li');
                    const link = document.createElement('a');
                    
                    // Create an id for the heading if it doesn't have one
                    if (!heading.id) {
                        heading.id = heading.textContent.toLowerCase()
                            .replace(/[^\w]+/g, '-');
                    }
                    
                    link.href = '#' + heading.id;
                    link.textContent = heading.textContent;
                    
                    listItem.appendChild(link);
                    tocList.appendChild(listItem);
                }
            });
            
            toc.appendChild(tocList);
            
            // Insert after the first heading (title)
            const title = document.querySelector('h1');
            if (title && title.nextElementSibling) {
                title.parentNode.insertBefore(toc, title.nextElementSibling.nextElementSibling);
            }
        }
    }
}

// Run when the page loads
window.addEventListener('load', function() {
    // Generate TOC if needed
    generateTableOfContents();
    
    // Enable all sections that might have been hidden
    document.querySelectorAll('.content-hidden')
        .forEach(el => el.classList.remove('content-hidden'));
});

// Monitor for any dynamically added elements and ensure they're visible
const observer = new MutationObserver(function(mutations) {
    mutations.forEach(function(mutation) {
        if (mutation.addedNodes && mutation.addedNodes.length > 0) {
            for (let i = 0; i < mutation.addedNodes.length; i++) {
                const node = mutation.addedNodes[i];
                if (node.nodeType === 1) { // Element node
                    if (node.classList && (
                        node.classList.contains('section') || 
                        node.classList.contains('content') ||
                        node.classList.contains('content-hidden')
                    )) {
                        node.style.display = 'block';
                        node.style.visibility = 'visible';
                        node.style.opacity = '1';
                        node.classList.remove('content-hidden');
                    }
                }
            }
        }
    });
});

// Start observing the document body for changes
observer.observe(document.body, {
    childList: true,
    subtree: true
});