// ==UserScript==
// @name         Douyin Video Downloader
// @namespace    https://git.ponywave.de/Akamaru/Userscripts
// @version      1.0
// @description  Extrahiert und lädt MP4-Videos von Douyin herunter
// @author       Akamaru
// @match        https://www.douyin.com/
// @match        https://www.douyin.com/?*
// @match        https://www.douyin.com/follow
// @match        https://www.douyin.com/user/*
// @match        https://www.douyin.com/video/*
// @icon         https://www.google.com/s2/favicons?domain=douyin.com&sz=32
// @grant        none
// @updateURL    https://git.ponywave.de/Akamaru/Userscripts/raw/branch/master/douyin-video-downloader.user.js
// @downloadURL  https://git.ponywave.de/Akamaru/Userscripts/raw/branch/master/douyin-video-downloader.user.js
// ==/UserScript==

(function() {
    'use strict';

    // Styles
    const style = document.createElement('style');
    style.textContent = `
        /* Detail page button styles */
        #douyin-download-btn.detail-mode {
            display: flex;
            flex-direction: column;
            align-items: center;
            cursor: pointer;
            transition: transform 0.2s;
        }

        #douyin-download-btn.detail-mode:hover {
            transform: scale(1.1);
        }

        #douyin-download-btn.detail-mode .icon-wrapper {
            width: 48px;
            height: 48px;
            display: flex;
            align-items: center;
            justify-content: center;
            background: rgba(255, 255, 255, 0.1);
            border-radius: 50%;
            margin-bottom: 4px;
        }

        #douyin-download-btn.detail-mode svg {
            width: 24px;
            height: 24px;
            color: white;
        }

        /* Feed page button styles */
        #douyin-download-btn.feed-mode {
            display: flex;
            flex-direction: column;
            align-items: center;
            cursor: pointer;
            transition: transform 0.2s;
            padding: 8px 0;
        }

        #douyin-download-btn.feed-mode:hover {
            transform: scale(1.05);
        }

        #douyin-download-btn.feed-mode .icon-wrapper {
            width: 40px;
            height: 40px;
            display: flex;
            align-items: center;
            justify-content: center;
            background: rgba(255, 255, 255, 0.15);
            border-radius: 50%;
            margin-bottom: 6px;
            transition: background 0.2s;
        }

        #douyin-download-btn.feed-mode:hover .icon-wrapper {
            background: rgba(255, 255, 255, 0.25);
        }

        #douyin-download-btn.feed-mode svg {
            width: 20px;
            height: 20px;
            color: white;
        }

        #douyin-modal-overlay {
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background: rgba(0, 0, 0, 0.75);
            z-index: 10000;
            display: flex;
            align-items: center;
            justify-content: center;
            backdrop-filter: blur(4px);
        }

        #douyin-modal {
            background: #1f1f1f;
            color: white;
            padding: 24px;
            border-radius: 16px;
            max-width: 600px;
            width: 90%;
            max-height: 80vh;
            overflow-y: auto;
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            box-shadow: 0 8px 32px rgba(0, 0, 0, 0.5);
            position: relative;
        }

        #douyin-modal h3 {
            margin: 0 0 20px 0;
            font-size: 20px;
            font-weight: 700;
            display: flex;
            align-items: center;
            gap: 10px;
        }

        .modal-close-btn {
            position: absolute;
            top: 16px;
            right: 16px;
            background: transparent;
            border: none;
            color: #999;
            font-size: 28px;
            cursor: pointer;
            padding: 4px 8px;
            line-height: 1;
            transition: color 0.2s;
        }

        .modal-close-btn:hover {
            color: #ff4444;
        }

        .video-url-item {
            margin: 12px 0;
            padding: 16px;
            background: rgba(255, 255, 255, 0.08);
            border-radius: 10px;
            border: 1px solid rgba(255, 255, 255, 0.1);
        }

        .video-url-item strong {
            display: block;
            margin-bottom: 10px;
            font-size: 14px;
            color: #fe2c55;
        }

        .video-url-link {
            display: block;
            color: #4CAF50;
            text-decoration: none;
            word-break: break-all;
            font-size: 12px;
            margin: 8px 0;
            padding: 8px;
            background: rgba(0, 0, 0, 0.3);
            border-radius: 6px;
        }

        .video-url-link:hover {
            background: rgba(0, 0, 0, 0.5);
        }

        .button-group {
            display: flex;
            gap: 8px;
            margin-top: 10px;
        }

        .copy-btn, .download-btn {
            flex: 1;
            padding: 10px 16px;
            border: none;
            border-radius: 6px;
            cursor: pointer;
            font-size: 13px;
            font-weight: 600;
            transition: all 0.2s;
        }

        .copy-btn {
            background: #2196F3;
            color: white;
        }

        .copy-btn:hover {
            background: #1976D2;
        }

        .download-btn {
            background: #4CAF50;
            color: white;
        }

        .download-btn:hover {
            background: #45a049;
        }

        .no-video {
            text-align: center;
            color: #ff9800;
            font-size: 14px;
            padding: 20px;
        }
    `;
    document.head.appendChild(style);

    let cachedUrls = [];
    let feedVideoUrls = new Map(); // Map video ID -> URL for feed videos

    // Store the latest video URL for feed
    let latestFeedVideoUrl = null;
    let latestFeedVideoTime = 0;

    // Intercept fetch to capture video URLs in feed mode
    const originalFetch = window.fetch;
    window.fetch = function(...args) {
        const url = typeof args[0] === 'string' ? args[0] : args[0]?.url;

        // Check if this is a video request
        if (url && (url.includes('douyinvod.com') || url.includes('zjcdn.com')) && url.includes('video')) {
            // Extract video ID from URL (__vid parameter)
            try {
                const urlObj = new URL(url);
                const videoId = urlObj.searchParams.get('__vid');

                // Clean URL (remove hash and fragment)
                const cleanUrl = url.split('#')[0];

                if (videoId) {
                    feedVideoUrls.set(videoId, cleanUrl);
                    console.log('[Douyin Downloader] Cached video URL for ID:', videoId);
                }

                // Also store as latest video (fallback for videos without __vid)
                latestFeedVideoUrl = cleanUrl;
                latestFeedVideoTime = Date.now();
                console.log('[Douyin Downloader] Cached latest video URL');
            } catch (e) {
                // Ignore URL parse errors
            }
        }

        return originalFetch.apply(this, args);
    };

    // Detect page type
    function getPageType() {
        const path = window.location.pathname;
        const urlParams = new URLSearchParams(window.location.search);
        const hasModalId = urlParams.has('modal_id');

        if (path.startsWith('/video/')) {
            return 'detail';
        }

        // User page - treat as feed (modal will open on video click)
        if (path.startsWith('/user/')) {
            return 'user';
        }

        // Feed pages: /, /?*, /follow
        if (path === '/' || path === '/follow') {
            return 'feed';
        }

        return 'unknown';
    }

    // Extract video URLs
    function extractVideoURLs() {
        const pageType = getPageType();

        if (pageType === 'feed' || pageType === 'user') {
            // In feed mode: get URL from intercepted fetch cache
            let videoId = null;

            // Check if it's a user modal (has modal_id in URL)
            const urlParams = new URLSearchParams(window.location.search);
            const modalId = urlParams.get('modal_id');

            if (modalId) {
                // User modal: use modal_id from URL
                videoId = modalId;
            } else {
                // Regular feed: use data-e2e-vid from active video
                const activeVideo = document.querySelector('[data-e2e="feed-active-video"]');
                if (!activeVideo) return [];
                videoId = activeVideo.getAttribute('data-e2e-vid');
            }

            // Try to get cached URL by video ID
            if (videoId) {
                const cachedUrl = feedVideoUrls.get(videoId);
                if (cachedUrl) {
                    return [cachedUrl];
                }
            }

            // Fallback 1: Use latest intercepted video URL (for videos without __vid)
            // Only use if it's recent (within last 10 seconds)
            if (latestFeedVideoUrl && (Date.now() - latestFeedVideoTime) < 10000) {
                console.log('[Douyin Downloader] Using latest video URL as fallback');
                return [latestFeedVideoUrl];
            }

            // Fallback 2: try to find from video element (though it's usually a blob)
            const videoContainer = modalId ?
                document.querySelector('[class*="modal-video-container"]') :
                document.querySelector('[data-e2e="feed-active-video"]');

            if (videoContainer) {
                const video = videoContainer.querySelector('video');
                if (video && video.currentSrc && !video.currentSrc.startsWith('blob:')) {
                    return [video.currentSrc];
                }
            }

            return [];
        } else {
            // In detail mode: get from source elements
            const videoSources = document.querySelectorAll('video source');
            const urls = [];

            videoSources.forEach(source => {
                const src = source.src;
                if (src && (src.includes('v3-dy-o.zjcdn.com') || src.includes('.douyinvod.com'))) {
                    urls.push(src);
                }
            });

            return [...new Set(urls)];
        }
    }

    // Add download button for detail page
    function addDownloadButtonDetail() {
        // Check if button already exists
        if (document.getElementById('douyin-download-btn')) {
            return;
        }

        // Find the interaction buttons container
        const buttonContainer = document.querySelector('[data-e2e="detail-video-info"] .bm6Yr1Fm .fN2jqmuV');

        if (!buttonContainer) {
            return;
        }

        // Create download button wrapper
        const downloadWrapper = document.createElement('div');
        downloadWrapper.className = 'fcEX2ARL';
        downloadWrapper.style.cssText = 'margin-top: 12px;';

        const downloadBtn = document.createElement('div');
        downloadBtn.id = 'douyin-download-btn';
        downloadBtn.className = 'detail-mode';
        downloadBtn.setAttribute('tabindex', '0');
        downloadBtn.innerHTML = `
            <div class="icon-wrapper">
                <svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
                    <path d="M21 15v4a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2v-4M7 10l5 5 5-5M12 15V3"/>
                </svg>
            </div>
        `;

        downloadWrapper.appendChild(downloadBtn);
        downloadBtn.addEventListener('click', showModal);

        // Insert button after the share button
        buttonContainer.appendChild(downloadWrapper);
    }

    // Add download button for feed page
    function addDownloadButtonFeed() {
        // Check if button already exists
        if (document.getElementById('douyin-download-btn')) {
            return;
        }

        // Determine container: user modal or feed
        const urlParams = new URLSearchParams(window.location.search);
        const modalId = urlParams.get('modal_id');

        let videoContainer;
        if (modalId) {
            // User modal: find button container in modal
            videoContainer = document.querySelector('[class*="modal-video-container"]');
        } else {
            // Regular feed: find active video
            videoContainer = document.querySelector('[data-e2e="feed-active-video"]');
        }

        if (!videoContainer) {
            return;
        }

        // Find the button container
        const buttonContainer = videoContainer.querySelector('.WU6dkKao');
        if (!buttonContainer) {
            return;
        }

        // Create download button wrapper (matching feed button structure)
        const downloadWrapper = document.createElement('div');
        downloadWrapper.className = 'JPLz9DCE';

        const downloadBtn = document.createElement('div');
        downloadBtn.id = 'douyin-download-btn';
        downloadBtn.className = 'feed-mode';
        downloadBtn.setAttribute('tabindex', '0');
        downloadBtn.innerHTML = `
            <div class="icon-wrapper">
                <svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
                    <path d="M21 15v4a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2v-4M7 10l5 5 5-5M12 15V3"/>
                </svg>
            </div>
        `;

        downloadWrapper.appendChild(downloadBtn);
        downloadBtn.addEventListener('click', showModal);

        // Try to insert after share button (feed pages)
        const shareButton = buttonContainer.querySelector('[data-e2e="video-player-share"]');
        if (shareButton) {
            const shareWrapper = shareButton.closest('.JPLz9DCE');
            if (shareWrapper && shareWrapper.parentElement) {
                shareWrapper.parentElement.insertBefore(downloadWrapper, shareWrapper.nextSibling);
                return;
            }
        }

        // Fallback: Insert before "more" button (user modals)
        const moreButton = buttonContainer.querySelector('[data-e2e="video-play-more"]');
        if (moreButton) {
            const moreWrapper = moreButton.closest('.JPLz9DCE') || moreButton.parentElement;
            if (moreWrapper && moreWrapper.parentElement) {
                moreWrapper.parentElement.insertBefore(downloadWrapper, moreWrapper);
                return;
            }
        }

        // Last fallback: Append to container
        buttonContainer.appendChild(downloadWrapper);
    }

    // Main function to add download button based on page type
    function addDownloadButton() {
        const pageType = getPageType();

        if (pageType === 'detail') {
            addDownloadButtonDetail();
        } else if (pageType === 'feed' || pageType === 'user') {
            addDownloadButtonFeed();
        }
    }

    // Remove download button (used when video changes in feed)
    function removeDownloadButton() {
        const btn = document.getElementById('douyin-download-btn');
        if (btn) {
            const wrapper = btn.closest('.JPLz9DCE, .fcEX2ARL');
            if (wrapper) {
                wrapper.remove();
            } else {
                btn.remove();
            }
        }
    }

    // Show modal with download links
    function showModal() {
        // Update URLs when opening modal
        cachedUrls = extractVideoURLs();

        // Remove old modal if exists
        const oldModal = document.getElementById('douyin-modal-overlay');
        if (oldModal) {
            oldModal.remove();
        }

        // Create modal overlay
        const overlay = document.createElement('div');
        overlay.id = 'douyin-modal-overlay';

        // Create modal
        const modal = document.createElement('div');
        modal.id = 'douyin-modal';

        modal.innerHTML = `
            <button class="modal-close-btn" title="Schließen">×</button>
            <h3>📥 Video herunterladen</h3>
            <div id="modal-video-list"></div>
        `;

        overlay.appendChild(modal);
        document.body.appendChild(overlay);

        // Populate video list
        updateModalContent();

        // Close modal on overlay click
        overlay.addEventListener('click', (e) => {
            if (e.target === overlay) {
                overlay.remove();
            }
        });

        // Close modal on close button click
        modal.querySelector('.modal-close-btn').addEventListener('click', () => {
            overlay.remove();
        });

        // Close on ESC key
        const handleEsc = (e) => {
            if (e.key === 'Escape') {
                overlay.remove();
                document.removeEventListener('keydown', handleEsc);
            }
        };
        document.addEventListener('keydown', handleEsc);
    }

    // Format duration from seconds to MM:SS
    function formatDuration(seconds) {
        if (!seconds || isNaN(seconds)) return 'N/A';
        const mins = Math.floor(seconds / 60);
        const secs = Math.floor(seconds % 60);
        return `${mins}:${secs.toString().padStart(2, '0')}`;
    }

    // Get video info
    function getVideoInfo() {
        const video = document.querySelector('video');
        if (!video) return { duration: 'N/A', resolution: 'N/A' };

        return {
            duration: formatDuration(video.duration),
            resolution: `${video.videoWidth}x${video.videoHeight}`
        };
    }

    // Update modal content with video URLs
    function updateModalContent() {
        const listContainer = document.getElementById('modal-video-list');
        if (!listContainer) return;

        if (cachedUrls.length === 0) {
            listContainer.innerHTML = '<p class="no-video">Kein Video gefunden. Bitte warte, bis das Video geladen ist.</p>';
            return;
        }

        const videoInfo = getVideoInfo();

        listContainer.innerHTML = cachedUrls.map((url, index) => `
            <div class="video-url-item">
                <strong>Video ${index + 1} <span style="color: #999; font-weight: normal; font-size: 12px;">(${videoInfo.resolution} • ${videoInfo.duration})</span></strong>
                <a href="${url}" target="_blank" class="video-url-link">${url}</a>
                <div class="button-group">
                    <button class="copy-btn" data-url="${url}">URL kopieren</button>
                    <button class="download-btn" data-url="${url}">Herunterladen</button>
                </div>
            </div>
        `).join('');

        // Add copy button functionality
        listContainer.querySelectorAll('.copy-btn').forEach(btn => {
            btn.addEventListener('click', function() {
                const url = this.getAttribute('data-url');
                navigator.clipboard.writeText(url).then(() => {
                    const originalText = this.textContent;
                    this.textContent = '✓ Kopiert!';
                    this.style.background = '#45a049';
                    setTimeout(() => {
                        this.textContent = originalText;
                        this.style.background = '';
                    }, 2000);
                });
            });
        });

        // Add download button functionality
        listContainer.querySelectorAll('.download-btn').forEach(btn => {
            btn.addEventListener('click', async function() {
                const url = this.getAttribute('data-url');
                const originalText = this.textContent;

                try {
                    this.textContent = 'Lädt...';
                    this.disabled = true;

                    // Get video title from page
                    const titleElement = document.querySelector('[data-e2e="detail-video-info"] h1');
                    let videoTitle = 'douyin-video';

                    if (titleElement) {
                        // Extract text and remove hashtags
                        videoTitle = titleElement.textContent
                            .replace(/#[^\s#]+/g, '') // Remove hashtags
                            .trim()
                            .replace(/[/\\?%*:|"<>]/g, '-') // Replace invalid filename chars
                            .substring(0, 100); // Limit length
                    }

                    // Fetch video as blob
                    const response = await fetch(url);
                    const blob = await response.blob();

                    // Create download
                    const blobUrl = URL.createObjectURL(blob);
                    const a = document.createElement('a');
                    a.href = blobUrl;
                    a.download = `${videoTitle}.mp4`;
                    document.body.appendChild(a);
                    a.click();
                    document.body.removeChild(a);

                    // Cleanup
                    setTimeout(() => URL.revokeObjectURL(blobUrl), 100);

                    this.textContent = '✓ Download gestartet!';
                    setTimeout(() => {
                        this.textContent = originalText;
                        this.disabled = false;
                    }, 2000);
                } catch (error) {
                    console.error('Download error:', error);
                    this.textContent = '✗ Fehler';
                    setTimeout(() => {
                        this.textContent = originalText;
                        this.disabled = false;
                    }, 2000);
                }
            });
        });
    }

    // Initialize for detail page
    function initDetail() {
        // Try to add button immediately
        setTimeout(addDownloadButton, 1000);

        // Debounced function to add button and update URLs
        let debounceTimer;
        const debouncedCheck = () => {
            clearTimeout(debounceTimer);
            debounceTimer = setTimeout(() => {
                addDownloadButton();
                cachedUrls = extractVideoURLs();
            }, 1000);
        };

        // Watch for DOM changes to add button when video info loads
        const observer = new MutationObserver(debouncedCheck);

        const videoContainer = document.querySelector('#pagelet-worklist') || document.body;
        observer.observe(videoContainer, {
            childList: true,
            subtree: true
        });

        // Periodic check as fallback
        setInterval(() => {
            addDownloadButton();
            cachedUrls = extractVideoURLs();
        }, 10000);
    }

    // Initialize for feed page
    function initFeed() {
        // Try to add button multiple times (for modals that load slowly)
        const tryAddButton = () => {
            addDownloadButton();
            if (!document.getElementById('douyin-download-btn')) {
                // Button not added yet, retry
                setTimeout(tryAddButton, 500);
            }
        };
        setTimeout(tryAddButton, 500);

        // Watch for video changes in feed
        let currentVideoId = null;
        let currentUrl = window.location.href;

        const checkActiveVideo = () => {
            // Check if URL changed (for user modals)
            if (window.location.href !== currentUrl) {
                currentUrl = window.location.href;
                removeDownloadButton();
                setTimeout(() => {
                    addDownloadButton();
                    cachedUrls = extractVideoURLs();
                }, 500);
                return;
            }

            // Check for feed video changes
            const activeVideo = document.querySelector('[data-e2e="feed-active-video"]');
            if (!activeVideo) return;

            const newVideoId = activeVideo.getAttribute('data-e2e-vid');

            // Video changed, re-add button
            if (newVideoId && newVideoId !== currentVideoId) {
                currentVideoId = newVideoId;
                removeDownloadButton();
                setTimeout(() => {
                    addDownloadButton();
                    cachedUrls = extractVideoURLs();
                }, 500);
            }
        };

        // Debounced check
        let debounceTimer;
        const debouncedCheck = () => {
            clearTimeout(debounceTimer);
            debounceTimer = setTimeout(checkActiveVideo, 300);
        };

        // Observe feed container for video changes (only on actual feed pages)
        const feedObserver = new MutationObserver(debouncedCheck);

        const observeFeed = () => {
            const feedContainer = document.querySelector('#slidelist');
            if (feedContainer) {
                feedObserver.observe(feedContainer, {
                    attributes: true,
                    attributeFilter: ['data-e2e'],
                    subtree: true
                });
                return true;
            }
            return false;
        };

        // Try to observe feed, but don't retry if we're on a user page with modal
        const urlParams = new URLSearchParams(window.location.search);
        if (!urlParams.has('modal_id')) {
            // Only retry if not on user modal
            const tryObserve = () => {
                if (!observeFeed()) {
                    setTimeout(tryObserve, 500);
                }
            };
            tryObserve();
        }

        // Watch for URL changes (for user modals)
        setInterval(() => {
            if (window.location.href !== currentUrl) {
                checkActiveVideo();
            }
        }, 1000);

        // Periodic check as fallback
        setInterval(() => {
            checkActiveVideo();
        }, 5000);
    }

    // Initialize for user page (watches for modal_id changes)
    function initUser() {
        let currentModalId = new URLSearchParams(window.location.search).get('modal_id');
        let lastUrl = window.location.href;
        let modalObserver = null;

        // Watch for button container to appear and add button
        const observeForButtonContainer = () => {
            // Cleanup previous observer
            if (modalObserver) {
                modalObserver.disconnect();
                modalObserver = null;
            }

            const tryAddButton = () => {
                addDownloadButton();
                if (document.getElementById('douyin-download-btn')) {
                    // Button added successfully, stop observing
                    if (modalObserver) {
                        modalObserver.disconnect();
                        modalObserver = null;
                    }
                    return true;
                }
                return false;
            };

            // Try immediately
            if (tryAddButton()) return;

            // Observe DOM for button container to appear
            modalObserver = new MutationObserver(() => {
                tryAddButton();
            });

            modalObserver.observe(document.body, {
                childList: true,
                subtree: true
            });

            // Fallback: retry a few times with increasing delays
            let retryCount = 0;
            const maxRetries = 10;
            const retryWithDelay = () => {
                if (retryCount >= maxRetries) return;
                if (document.getElementById('douyin-download-btn')) return;

                retryCount++;
                addDownloadButton();

                if (!document.getElementById('douyin-download-btn')) {
                    setTimeout(retryWithDelay, 500);
                }
            };
            setTimeout(retryWithDelay, 500);
        };

        // Initial button add if modal is already open
        if (currentModalId) {
            setTimeout(observeForButtonContainer, 500);
        }

        // Watch for URL/modal changes
        const checkModalChange = () => {
            const newUrl = window.location.href;
            if (newUrl === lastUrl) return;

            lastUrl = newUrl;
            const newModalId = new URLSearchParams(window.location.search).get('modal_id');

            if (newModalId !== currentModalId) {
                currentModalId = newModalId;
                removeDownloadButton();

                if (newModalId) {
                    // Modal opened or changed - wait for DOM to stabilize then add button
                    setTimeout(observeForButtonContainer, 300);
                }
            }
        };

        // Check for URL changes frequently (modal navigation)
        setInterval(checkModalChange, 300);
    }

    // Main init function
    function init() {
        const pageType = getPageType();

        if (pageType === 'detail') {
            initDetail();
        } else if (pageType === 'feed') {
            initFeed();
        } else if (pageType === 'user') {
            initUser();
        }
    }

    // Wait for page to load
    if (document.readyState === 'loading') {
        document.addEventListener('DOMContentLoaded', init);
    } else {
        init();
    }
})();