/**
 * Swipe Navigation for Echo
 * Swipe left/right to navigate between pages
 */
(function() {
    const pages = ['index.html', 'notes.html', 'files.html'];
    
    // Get current page index
    function getCurrentIndex() {
        const path = window.location.pathname;
        let filename = path.split('/').pop() || 'index.html';
        // Handle /echo/ without filename
        if (filename === '' || filename === 'echo') filename = 'index.html';
        const idx = pages.indexOf(filename);
        return idx >= 0 ? idx : 0;
    }
    
    // Navigate to page
    function navigateTo(index) {
        if (index >= 0 && index < pages.length) {
            window.location.href = pages[index];
        }
    }
    
    // Swipe detection
    let touchStartX = 0;
    let touchStartY = 0;
    let touchEndX = 0;
    let touchEndY = 0;
    
    const minSwipeDistance = 80;
    const maxVerticalDistance = 100;
    
    document.addEventListener('touchstart', function(e) {
        touchStartX = e.changedTouches[0].screenX;
        touchStartY = e.changedTouches[0].screenY;
    }, { passive: true });
    
    document.addEventListener('touchend', function(e) {
        touchEndX = e.changedTouches[0].screenX;
        touchEndY = e.changedTouches[0].screenY;
        handleSwipe();
    }, { passive: true });
    
    function handleSwipe() {
        const deltaX = touchEndX - touchStartX;
        const deltaY = Math.abs(touchEndY - touchStartY);
        
        // Ignore if vertical swipe or too short
        if (deltaY > maxVerticalDistance) return;
        if (Math.abs(deltaX) < minSwipeDistance) return;
        
        const currentIndex = getCurrentIndex();
        
        if (deltaX > 0) {
            // Swipe right → previous page
            navigateTo(currentIndex - 1);
        } else {
            // Swipe left → next page
            navigateTo(currentIndex + 1);
        }
    }
    
    // Visual indicator (optional dots)
    function createIndicator() {
        const indicator = document.createElement('div');
        indicator.className = 'swipe-indicator';
        indicator.innerHTML = pages.map((_, i) => 
            `<span class="swipe-dot ${i === getCurrentIndex() ? 'active' : ''}"></span>`
        ).join('');
        document.body.appendChild(indicator);
    }
    
    // Add indicator styles
    const style = document.createElement('style');
    style.textContent = `
        .swipe-indicator {
            position: fixed;
            bottom: 24px;
            left: 50%;
            transform: translateX(-50%);
            display: flex;
            gap: 10px;
            z-index: 9999;
            padding: 10px 16px;
            background: rgba(50, 50, 60, 0.9);
            border: 1px solid rgba(255, 255, 255, 0.2);
            border-radius: 24px;
            backdrop-filter: blur(8px);
        }
        .swipe-dot {
            width: 10px;
            height: 10px;
            border-radius: 50%;
            background: rgba(255, 255, 255, 0.3);
            border: 1px solid rgba(255, 255, 255, 0.5);
            transition: all 0.2s;
        }
        .swipe-dot.active {
            background: #3b82f6;
            border-color: #3b82f6;
            transform: scale(1.3);
            box-shadow: 0 0 8px rgba(59, 130, 246, 0.6);
        }
        @media (min-width: 769px) {
            .swipe-indicator { display: none; }
        }
    `;
    document.head.appendChild(style);
    
    // Init after DOM ready
    function init() {
        if ('ontouchstart' in window || navigator.maxTouchPoints > 0) {
            createIndicator();
        }
    }
    
    if (document.readyState === 'loading') {
        document.addEventListener('DOMContentLoaded', init);
    } else {
        init();
    }
})();