document.addEventListener('DOMContentLoaded', () => {
    // DOM Elements
    const videoGrid = document.getElementById('videoGrid');
    const searchInput = document.getElementById('searchInput');
    const clearSearchBtn = document.getElementById('clearSearch');
    const videoModal = document.getElementById('videoModal');
    const videoPlayer = document.getElementById('videoPlayer');
    const modalVideoTitle = document.getElementById('modalVideoTitle');
    const closeModal = document.getElementById('closeModal');
    const loadingIndicator = document.getElementById('loadingIndicator');
    const errorMessage = document.getElementById('errorMessage');
    const retryBtn = document.getElementById('retryBtn');
    const gridViewBtn = document.getElementById('gridViewBtn');
    const listViewBtn = document.getElementById('listViewBtn');
    const pagination = document.getElementById('pagination');
    const visibleCount = document.getElementById('visibleCount');
    const totalCount = document.getElementById('totalCount');
    // *** NEW: Player Loading Elements ***
    const playerLoadingIndicator = document.getElementById('playerLoadingIndicator');
    const playerLoadPercent = document.getElementById('playerLoadPercent');

    // State
    let videos = [];
    let filteredVideos = [];
    let currentPage = 1;
    let videosPerPage = 12;
    let currentPlayer = null;
    let viewMode = 'grid';
    let lastTapTime = 0;
    let lastDoubleTapX = 0;
    let doubleTapThreshold = 10; // px tolerance for tap position

    // Initialize the app
    init();

    function init() {
        fetchVideoData();
        setupEventListeners();
    }

    // Fetch video data from JSON
    async function fetchVideoData() {
        try {
            loadingIndicator.style.display = 'flex';
            errorMessage.style.display = 'none';
            videoGrid.innerHTML = '';

            const response = await fetch('database.json');
            if (!response.ok) {
                throw new Error(`Failed to load database.json: ${response.status}`);
            }

            const data = await response.json();

            // Check if data has the expected structure
            if (!data.videos || !Array.isArray(data.videos)) {
                throw new Error('Invalid database format: missing "videos" array');
            }

            // Filter out invalid entries
            videos = data.videos.filter(video => {
                if (!video.title || !video.url) {
                    console.warn('Invalid video entry:', video);
                    return false;
                }
                return true;
            });

            filteredVideos = [...videos];
            updateVideoCount();
            renderPagination();
            renderVideos();

            showToast('Videos loaded successfully!', 'success');
        } catch (error) {
            console.error('Error loading videos:', error);
            loadingIndicator.style.display = 'none';
            errorMessage.style.display = 'flex';
        }
    }

    // Set up event listeners
    function setupEventListeners() {
        // Search functionality
        searchInput.addEventListener('input', handleSearch);
        clearSearchBtn.addEventListener('click', clearSearch);

        // Modal controls
        closeModal.addEventListener('click', closeVideoModal);

        // Retry button
        retryBtn.addEventListener('click', fetchVideoData);

        // View toggle
        gridViewBtn.addEventListener('click', () => setViewMode('grid'));
        listViewBtn.addEventListener('click', () => setViewMode('list'));

        // Handle clicks outside the modal to close it
        window.addEventListener('click', (e) => {
            if (e.target === videoModal) {
                closeVideoModal();
            }
        });

        // Keyboard controls for modal
        window.addEventListener('keydown', (e) => {
            if (videoModal.style.display === 'block') {
                if (e.key === 'Escape') {
                    closeVideoModal();
                }
            }
        });
    }

    // Handle search input
    function handleSearch() {
        const searchTerm = searchInput.value.toLowerCase().trim();
        clearSearchBtn.style.display = searchTerm ? 'block' : 'none';

        if (searchTerm === '') {
            filteredVideos = [...videos];
        } else {
            filteredVideos = videos.filter(video =>
                video.title.toLowerCase().includes(searchTerm)
            );
        }

        currentPage = 1;
        updateVideoCount();
        renderPagination();
        renderVideos();
    }

    // Clear search
    function clearSearch() {
        searchInput.value = '';
        clearSearchBtn.style.display = 'none';
        filteredVideos = [...videos];
        currentPage = 1;
        updateVideoCount();
        renderPagination();
        renderVideos();
    }

    // Update video count display
    function updateVideoCount() {
        const start = (currentPage - 1) * videosPerPage;
        const end = Math.min(start + videosPerPage, filteredVideos.length);
        const count = Math.min(videosPerPage, filteredVideos.length - start);

        visibleCount.textContent = count > 0 ? end - start : 0;
        totalCount.textContent = filteredVideos.length;
    }

    // Set view mode (grid or list)
    function setViewMode(mode) {
        viewMode = mode;

        // Update active button
        gridViewBtn.classList.toggle('active', mode === 'grid');
        listViewBtn.classList.toggle('active', mode === 'list');

        // Update grid class
        videoGrid.classList.toggle('list-view', mode === 'list');

        // Re-render to apply changes
        renderVideos();
    }

    // Render videos in grid
    function renderVideos() {
        loadingIndicator.style.display = 'none';
        videoGrid.innerHTML = '';

        if (filteredVideos.length === 0) {
            videoGrid.innerHTML = `
                <div class="error-container" style="grid-column: 1 / -1;">
                    <i class="fas fa-search"></i>
                    <p>No videos found matching your search.</p>
                </div>
            `;
            updateVideoCount(); // Ensure count shows 0 of 0
            return;
        }

        // Calculate pagination
        const start = (currentPage - 1) * videosPerPage;
        const end = Math.min(start + videosPerPage, filteredVideos.length);
        const currentPageVideos = filteredVideos.slice(start, end);
        updateVideoCount(); // Update count based on current page

        // Create video cards
        currentPageVideos.forEach((video, index) => {
            const videoCard = document.createElement('div');
            videoCard.className = `video-card ${viewMode === 'list' ? 'list-view' : ''}`;

            // Determine if URL is from Hugging Face
            const isHuggingFaceUrl = video.url.includes('huggingface.co');

            // For HF URLs, append download=true if not already present
            let videoUrl = video.url;
            if (isHuggingFaceUrl && !videoUrl.includes('download=true')) {
                videoUrl = videoUrl.includes('?') ?
                    `${videoUrl}&download=true` :
                    `${videoUrl}?download=true`;
            }

            videoCard.innerHTML = `
                <div class="video-thumbnail">
                    <div class="thumbnail-placeholder">
                        <i class="fas fa-film fa-2x"></i>
                    </div>
                    <div class="play-icon">
                        <i class="fas fa-play fa-lg"></i>
                    </div>
                </div>
                <div class="video-info">
                    <h3 class="video-title">${video.title}</h3>
                </div>
            `;

            videoCard.addEventListener('click', () => {
                playVideo(video);
            });

            videoGrid.appendChild(videoCard);
        });
    }

    // Render pagination controls
    function renderPagination() {
        pagination.innerHTML = '';

        if (filteredVideos.length <= videosPerPage) {
            return; // No pagination needed
        }

        const totalPages = Math.ceil(filteredVideos.length / videosPerPage);

        // Previous button
        const prevBtn = document.createElement('button');
        prevBtn.className = `page-btn ${currentPage === 1 ? 'disabled' : ''}`;
        prevBtn.innerHTML = '<i class="fas fa-chevron-left"></i>';
        prevBtn.disabled = currentPage === 1;
        prevBtn.addEventListener('click', () => {
            if (currentPage > 1) {
                goToPage(currentPage - 1);
            }
        });
        pagination.appendChild(prevBtn);

        // Page numbers with ellipsis
        const renderPageButton = (pageNum) => {
            const pageBtn = document.createElement('button');
            pageBtn.className = `page-btn ${currentPage === pageNum ? 'active' : ''}`;
            pageBtn.textContent = pageNum;
            pageBtn.addEventListener('click', () => goToPage(pageNum));
            pagination.appendChild(pageBtn);
        };

        // Determine visible page range
        const delta = 1; // Reduced delta for smaller screens / cleaner look
        const range = [];
        const rangeWithDots = [];
        let l;

        range.push(1); // Always show first page

        // Calculate boundaries for center range
        let left = currentPage - delta;
        let right = currentPage + delta;

        if (left <= 1) left = 2;
        if (right >= totalPages) right = totalPages - 1;

        // Add pages around current page
        for (let i = left; i <= right; i++) {
            if (i > 1 && i < totalPages) { // Avoid duplicates if delta overlaps 1 or totalPages
                 range.push(i);
            }
        }

        if (totalPages > 1) { // Always show last page if different from first
             range.push(totalPages);
        }
        range.sort((a,b) => a - b); // Ensure order

        // Add ellipsis logic
        for (let i of range) {
            if (l) {
                if (i - l === 2) {
                    rangeWithDots.push(l + 1); // Add missing page
                } else if (i - l > 1) {
                    rangeWithDots.push('...'); // Add ellipsis
                }
            }
            rangeWithDots.push(i);
            l = i;
        }

        // Render the determined buttons/ellipsis
        rangeWithDots.forEach(item => {
            if (item === '...') {
                const ellipsis = document.createElement('span');
                ellipsis.className = 'page-btn disabled';
                ellipsis.textContent = '...';
                pagination.appendChild(ellipsis);
            } else {
                renderPageButton(item);
            }
        });

        // Next button
        const nextBtn = document.createElement('button');
        nextBtn.className = `page-btn ${currentPage === totalPages ? 'disabled' : ''}`;
        nextBtn.innerHTML = '<i class="fas fa-chevron-right"></i>';
        nextBtn.disabled = currentPage === totalPages;
        nextBtn.addEventListener('click', () => {
            if (currentPage < totalPages) {
                goToPage(currentPage + 1);
            }
        });
        pagination.appendChild(nextBtn);
    }

    // Navigate to a specific page
    function goToPage(pageNum) {
        currentPage = pageNum;
        renderPagination(); // Re-render pagination to update active state/ellipsis
        renderVideos(); // Re-render videos for the new page
        updateVideoCount(); // Update counts *after* rendering new page

        // Scroll to top of video grid
        // Use a slight delay if needed for smooth scroll to work reliably after render
        setTimeout(() => {
             const controlsBar = document.querySelector('.controls-bar');
             if (controlsBar) {
                 controlsBar.scrollIntoView({ behavior: 'smooth', block: 'start' });
             } else {
                 videoGrid.scrollIntoView({ behavior: 'smooth', block: 'start' });
             }
        }, 50);
    }

    // Play video in modal
    function playVideo(video) {
        // Clean up any existing player *before* setting up the new one
        cleanupPlayer();

        console.log("Setting up new video:", video.title);

        // Update modal title
        modalVideoTitle.textContent = video.title;

        // Determine if URL is from Hugging Face
        const isHuggingFaceUrl = video.url.includes('huggingface.co');

        // For HF URLs, append download=true if not already present
        let videoUrl = video.url;
        if (isHuggingFaceUrl && !videoUrl.includes('download=true')) {
            videoUrl = videoUrl.includes('?') ?
                `${videoUrl}&download=true` :
                `${videoUrl}?download=true`;
        }

        // Set up video player source
        videoPlayer.src = videoUrl;

        // Initialize Plyr
        try {
             currentPlayer = new Plyr(videoPlayer, {
                 controls: [
                    'play-large', 'play', 'progress', 'current-time', 'mute',
                    'volume', 'captions', 'settings', 'pip', 'airplay', 'fullscreen'
                 ],
                 keyboard: { focused: true, global: false },
                 tooltips: { controls: true, seek: true },
                 captions: { active: true, language: 'auto', update: true }
             });
             console.log("Plyr initialized.");
        } catch (error) {
             console.error("Error initializing Plyr:", error);
             showToast('Failed to initialize video player.', 'error');
             closeVideoModal(); // Close modal if Plyr fails
             return;
        }

        // --- Buffering Event Listeners ---
        const handleVideoWaiting = () => {
            console.log("Video waiting (buffering)...");
            playerLoadPercent.textContent = 'Buffering...'; // Update text during wait
            playerLoadingIndicator.style.display = 'flex';
        };

        const handleVideoPlaying = () => {
            console.log("Video playing.");
            playerLoadingIndicator.style.display = 'none';
        };

        const handleVideoProgress = () => {
            if (!videoPlayer.duration || !isFinite(videoPlayer.duration)) {
                playerLoadPercent.textContent = 'Loading...'; // Or 'Live' if applicable
                return; // Avoid NaN if duration isn't loaded or is infinite
            }

            try {
                 let bufferedEnd = 0;
                 if (videoPlayer.buffered.length > 0) {
                     // Get the end time of the last buffered time range
                     bufferedEnd = videoPlayer.buffered.end(videoPlayer.buffered.length - 1);
                 }

                 const loadPercent = Math.round((bufferedEnd / videoPlayer.duration) * 100);
                 // Only update if indicator is visible (or always, depending on preference)
                 // if (playerLoadingIndicator.style.display === 'flex') {
                    playerLoadPercent.textContent = `Loading ${loadPercent}%`;
                 // }
                 // console.log(`Buffered: ${bufferedEnd.toFixed(2)}s / ${videoPlayer.duration.toFixed(2)}s (${loadPercent}%)`);
            } catch (e) {
                 console.warn("Error calculating buffer progress:", e);
                 playerLoadPercent.textContent = 'Loading...';
            }
        };

        // Store handlers on the element for easy removal later
        videoPlayer._eventListeners = {
            waiting: handleVideoWaiting,
            playing: handleVideoPlaying,
            progress: handleVideoProgress
        };

        videoPlayer.addEventListener('waiting', videoPlayer._eventListeners.waiting);
        videoPlayer.addEventListener('playing', videoPlayer._eventListeners.playing);
        videoPlayer.addEventListener('progress', videoPlayer._eventListeners.progress);

        // Also hide indicator initially if player emits 'canplay' or ready early on
        // Use Plyr's 'ready' event as it's more reliable after initialization
        if (currentPlayer) {
             currentPlayer.once('ready', () => {
                 console.log("Plyr ready event fired.");
                 // Duration might be available here, trigger initial progress update
                 handleVideoProgress();
                 // If it's not already playing and not buffering, hide loader
                 if (!videoPlayer.paused && videoPlayer.readyState >= 3) { // HAVE_FUTURE_DATA or more
                      playerLoadingIndicator.style.display = 'none';
                 }
             });
            // Handle cases where video fails to load within Plyr
            currentPlayer.once('error', (event) => {
                console.error("Plyr error event:", event.detail.plyr.source);
                showToast('Error loading video source.', 'error');
                playerLoadingIndicator.style.display = 'none'; // Hide indicator on error
            });
        }


        // Reset loading text for the new video
        playerLoadPercent.textContent = 'Loading 0%';

        // Set up double-tap controls for mobile
        setupDoubleTapControls();

        // Show modal
        videoModal.style.display = 'block';
        document.body.style.overflow = 'hidden'; // Prevent scrolling while modal is open

        // Attempt to Play the video (with error handling)
        try {
            // Show loading indicator immediately before play attempt
            playerLoadingIndicator.style.display = 'flex';
            playerLoadPercent.textContent = 'Loading 0%'; // Reset text

            const playPromise = currentPlayer.play();

            if (playPromise !== undefined) {
                playPromise.then(_ => {
                    console.log("Autoplay successful or initiated.");
                    // 'playing' event will hide the indicator
                }).catch(error => {
                    console.warn('Autoplay prevented:', error);
                    // Autoplay was prevented. User needs to click play.
                    // The indicator is already shown. 'playing' event will hide it when user clicks.
                     showToast('Click play to start video', 'info');
                    // Ensure indicator hides if playing starts manually after prevention
                    currentPlayer.once('playing', handleVideoPlaying);
                });
            }
        } catch (error) {
            console.error('Error initiating video play:', error);
            showToast('Error playing video. Please try again.', 'error');
            playerLoadingIndicator.style.display = 'none'; // Hide indicator on critical error
        }
    }

    // Set up double-tap controls for mobile
    function setupDoubleTapControls() {
        const playerElement = videoPlayer.closest('.plyr'); // Target the Plyr container

        if (!playerElement) {
             console.warn("Could not find Plyr container for double-tap setup.");
             return;
        }

        const handleTap = (e) => {
            if (!currentPlayer) return; // Don't do anything if player isn't active

            const now = Date.now();
            // Use clientX from the touch event
            const tapX = e.touches && e.touches.length > 0 ? e.touches[0].clientX : e.clientX;

            // Get bounding box relative to viewport
            const rect = playerElement.getBoundingClientRect();
            const playerWidth = rect.width;
            const tapPositionRelative = (tapX - rect.left) / playerWidth; // 0 to 1 position within player bounds

            // Check tap time and proximity
            if (now - lastTapTime < 300 && Math.abs(tapX - lastDoubleTapX) < doubleTapThreshold * (window.devicePixelRatio || 1)) {
                // Double tap detected
                e.preventDefault(); // Prevent zoom or other default actions

                // Ensure feedback is relative to the correct container
                const feedbackContainer = playerElement.querySelector('.plyr__video-wrapper') || playerElement;

                if (tapPositionRelative < 0.33) { // Use thirds for clearer zones
                    // Double tap on left side - rewind
                    currentPlayer.rewind(10);
                    showControlFeedback(feedbackContainer, 'left', 'Rewind 10s');
                } else if (tapPositionRelative > 0.66) {
                    // Double tap on right side - forward
                    currentPlayer.forward(10);
                    showControlFeedback(feedbackContainer, 'right', 'Forward 10s');
                } else {
                    // Double tap in center - play/pause
                     if (currentPlayer.playing) {
                         currentPlayer.pause();
                     } else {
                         currentPlayer.play();
                     }
                    // Optional: show play/pause feedback
                    // showControlFeedback(feedbackContainer, 'center', currentPlayer.playing ? 'Pause' : 'Play');
                }
                 lastTapTime = 0; // Reset time after double tap to prevent triple tap issues
                 lastDoubleTapX = 0;
            } else {
                // Single tap
                 lastTapTime = now;
                 lastDoubleTapX = tapX;
            }
        };

        // Add touch event listener - use touchstart for mobile responsiveness
        playerElement.addEventListener('touchstart', handleTap, { passive: false }); // Need passive: false to call preventDefault

        // Store for cleanup
        playerElement.handleTapFunc = handleTap;
    }

    // Visual feedback for touch controls
    function showControlFeedback(container, position, text) {
        // Remove any existing feedback first
        const existingFeedback = container.querySelector('.tap-feedback');
        if(existingFeedback) existingFeedback.remove();

        // Create a feedback element
        const feedback = document.createElement('div');
        feedback.className = `tap-feedback ${position}`;
        feedback.innerHTML = `
            <div class="feedback-icon">
                <i class="fas fa-${position === 'left' ? 'backward' : position === 'right' ? 'forward' : (currentPlayer && currentPlayer.playing ? 'pause' : 'play')} fa-lg"></i>
            </div>
            <div class="feedback-text">${text}</div>
        `;

        // Basic inline styles (better to define in CSS)
        feedback.style.position = 'absolute';
        feedback.style.top = '50%';
        feedback.style.transform = 'translateY(-50%) scale(0.8)'; // Start smaller
        feedback.style.color = 'white';
        feedback.style.backgroundColor = 'rgba(0, 0, 0, 0.6)';
        feedback.style.padding = '10px 15px';
        feedback.style.borderRadius = '8px'; // Less prominent than circle
        feedback.style.display = 'flex';
        feedback.style.flexDirection = 'column';
        feedback.style.alignItems = 'center';
        feedback.style.zIndex = '20'; // Ensure visibility over video/some controls
        feedback.style.opacity = '0';
        feedback.style.transition = 'opacity 0.5s ease-in-out, transform 0.5s ease-in-out';
        feedback.style.pointerEvents = 'none'; // Don't interfere with clicks


        if (position === 'left') {
            feedback.style.left = '15%';
            feedback.style.transform = 'translate(-50%, -50%) scale(0.8)';
        } else if (position === 'right') {
            feedback.style.right = '15%';
             feedback.style.transform = 'translate(50%, -50%) scale(0.8)'; // Correct transform for right
        } else { // Center (Play/Pause)
             feedback.style.left = '50%';
             feedback.style.transform = 'translate(-50%, -50%) scale(0.8)';
        }

        // Add to the specified container (e.g., plyr__video-wrapper)
        container.appendChild(feedback);


        // Animate in, then out
        requestAnimationFrame(() => {
            feedback.style.opacity = '1';
            feedback.style.transform = feedback.style.transform.replace('scale(0.8)', 'scale(1)'); // Grow to full size
             setTimeout(() => {
                 feedback.style.opacity = '0';
                 feedback.style.transform = feedback.style.transform.replace('scale(1)', 'scale(0.8)'); // Shrink out
                 setTimeout(() => {
                     feedback.remove();
                 }, 500); // Match transition duration
             }, 600); // Duration visible
        });
    }


    // Close video modal and clean up player
    function closeVideoModal() {
        // Clean up player first
        cleanupPlayer();

        // Hide modal
        videoModal.style.display = 'none';
        document.body.style.overflow = ''; // Restore scrolling
    }

    // *** UPDATED: Clean up video player ***
    function cleanupPlayer() {
        console.log("Cleaning up player...");

        const playerElement = videoPlayer.closest('.plyr'); // Get Plyr wrapper

        // Remove buffering event listeners first
        if (videoPlayer._eventListeners) {
            console.log("Removing video event listeners...");
            videoPlayer.removeEventListener('waiting', videoPlayer._eventListeners.waiting);
            videoPlayer.removeEventListener('playing', videoPlayer._eventListeners.playing);
            videoPlayer.removeEventListener('progress', videoPlayer._eventListeners.progress);
            delete videoPlayer._eventListeners; // Clear the stored listeners
            // Hide player loading indicator just in case
            if (playerLoadingIndicator) {
                playerLoadingIndicator.style.display = 'none';
            }
        }

        // Remove touch event listeners from the player container
        if (playerElement && playerElement.handleTapFunc) {
            console.log("Removing touch listener...");
            playerElement.removeEventListener('touchstart', playerElement.handleTapFunc);
            delete playerElement.handleTapFunc;
        }

        // Destroy Plyr instance if it exists
        if (currentPlayer) {
            try {
                console.log("Destroying Plyr instance...");
                // Pause Plyr first (best practice)
                currentPlayer.pause();
                // Destroy Plyr instance
                currentPlayer.destroy();
                 console.log("Plyr instance destroyed.");
            } catch (e) {
                console.warn('Error destroying Plyr instance:', e);
            } finally {
                 currentPlayer = null; // Ensure reference is cleared even if destroy fails
            }
        }

        // Reset the native video element thoroughly
        console.log("Resetting native video element...");
        videoPlayer.pause(); // Ensure native element is paused
        videoPlayer.removeAttribute('src'); // Remove the source attribute
        // Clear any child <source> elements if they were added dynamically
        while (videoPlayer.firstChild) {
            videoPlayer.removeChild(videoPlayer.firstChild);
        }
        videoPlayer.src = ''; // Explicitly set src to empty string
        videoPlayer.load(); // Crucial: Resets the media element to its initial state
        console.log("Native video element reset.");


        // Ensure modal is ready for next video by clearing title etc. (optional but good practice)
        modalVideoTitle.textContent = 'Video Title'; // Reset title placeholder

        // Clear any existing feedback elements (double-tap indicators)
        const feedbacks = document.querySelectorAll('.tap-feedback');
        feedbacks.forEach(el => el.remove());

         console.log("Player cleanup complete.");
    }

    // Show toast message
    function showToast(message, type = 'info') {
        const toastContainer = document.getElementById('toastContainer');

        const toast = document.createElement('div');
        toast.className = `toast ${type}`;
        toast.textContent = message;

        toastContainer.appendChild(toast);

        // Trigger animation/transition
        requestAnimationFrame(() => {
             toast.style.opacity = 1;
             toast.style.transform = 'translateY(0)';
        });


        // Remove toast after duration
        setTimeout(() => {
             toast.style.opacity = 0;
             toast.style.transform = 'translateY(20px)';
             // Remove from DOM after transition
             toast.addEventListener('transitionend', () => toast.remove());
             // Fallback removal if transitionend doesn't fire
             setTimeout(() => toast.remove(), 500);
        }, 3000); // Keep toast visible for 3 seconds
    }
});