Discord Image Downloader

Adds a download button to images and GIFs in Discord.
换行
// ==UserScript==
// @name         Discord Image Downloader
// @namespace    http://tampermonkey.net/
// @version      1.06
// @description  Adds a download button to images and GIFs in Discord.
// @author       Yukiteru
// @match        https://discord.com/*
// @icon         https://www.google.com/s2/favicons?sz=64&domain=discord.com
// @grant        GM_download
// @grant        GM_log
// @run-at       document-idle
// @license      MIT
// ==/UserScript==

(function() {
    'use strict';

    GM_log('Discord Universal Image Downloader script started.');

    // --- Configuration ---
    const MESSAGE_LI_SELECTOR = 'li[id^="chat-messages-"]';
    const MESSAGE_ACCESSORIES_SELECTOR = 'div[id^="message-accessories-"]';

    // Selectors for different types of media containers within accessories
    const MOSAIC_ITEM_SELECTOR = 'div[class^="mosaicItem"]';             // Grid items (attachments, some embeds)
    const SPOILER_CONTENT_SELECTOR = 'div[class^="spoilerContent"]';     // Spoiler overlay (often inside mosaicItem)
    const INLINE_MEDIA_EMBED_SELECTOR = 'div[class^="inlineMediaEmbed"]';// Simple inline embeds (like the new example)
    // Combined selector for any top-level distinct media block
    const ANY_MEDIA_BLOCK_SELECTOR = `${MOSAIC_ITEM_SELECTOR}, ${INLINE_MEDIA_EMBED_SELECTOR}`;

    // Selectors for elements *within* a media block
    const IMAGE_WRAPPER_SELECTOR = 'div[class^="imageWrapper"]';         // Actual image container (consistent across types)
    const ORIGINAL_LINK_SELECTOR = 'a[class^="originalLink"]';          // Link with source URL (consistent)
    const HOVER_BUTTON_GROUP_SELECTOR = 'div[class^="hoverButtonGroup"]';// Target container for buttons (may need creation)
    // const IMAGE_CONTENT_SELECTOR = 'div[class^="imageContent"]';      // Common parent, less specific now

    // Markers
    const IMAGE_PROCESSED_MARKER = 'data-dl-img-processed';
    const SPOILER_LISTENER_MARKER = 'data-dl-spoiler-listener-added';
    const DOWNLOAD_BUTTON_CLASS = 'discord-native-dl-button';

    // Native Button Styling
    const NATIVE_ANCHOR_CLASSES_PREFIXES = ['anchor_', 'anchorUnderlineOnHover_', 'hoverButton_'];
    const DOWNLOAD_SVG_HTML = `
        <svg class="downloadHoverButtonIcon__6c706" aria-hidden="true" role="img" xmlns="http://www.w3.org/2000/svg" width="24" height="24" fill="none" viewBox="0 0 24 24">
            <path fill="currentColor" d="M12 2a1 1 0 0 1 1 1v10.59l3.3-3.3a1 1 0 1 1 1.4 1.42l-5 5a1 1 0 0 1-1.4 0l-5-5a1 1 0 1 1 1.4-1.42l3.3 3.3V3a1 1 0 0 1 1-1ZM3 20a1 1 0 1 0 0 2h18a1 1 0 1 0 0-2H3Z" class=""></path>
        </svg>`;

    // --- Dynamic Class Name Cache ---
    const classCache = {};

    function findActualClassName(scope, prefix) {
        if (classCache[prefix]) return classCache[prefix];
        const searchScope = scope || document.body;
        try {
            const element = searchScope.querySelector(`[class^="${prefix}"]`);
            if (element) {
                const classList = element.classList;
                for (let i = 0; i < classList.length; i++) {
                    if (classList[i].startsWith(prefix)) {
                        classCache[prefix] = classList[i];
                        return classList[i];
                    }
                }
            }
        } catch (e) { GM_log(`Error finding class with prefix ${prefix}: ${e}`); }
        return null;
    }

    function generateFilename(originalUrl, imageWrapper) {
        let dateStamp = '0000-00-00';
        let messageId = 'unknownMsgId';
        let fileIndexStr = '';

        const messageLi = imageWrapper.closest(MESSAGE_LI_SELECTOR);
        if (messageLi) {
            // Get date from message timestamp
            const timeElement = messageLi.querySelector('time[datetime]');
            if (timeElement && timeElement.dateTime) {
                try {
                    const messageDate = new Date(timeElement.dateTime);
                    if (!isNaN(messageDate.getTime())) {
                        const year = messageDate.getFullYear();
                        const month = String(messageDate.getMonth() + 1).padStart(2, '0');
                        const day = String(messageDate.getDate()).padStart(2, '0');
                        dateStamp = `${year}-${month}-${day}`;
                    } else { GM_log(`Filename Date: Failed parse: ${timeElement.dateTime}`); }
                } catch (e) { GM_log(`Filename Date: Error parsing: ${e}`); }
            } else { GM_log(`Filename Date: No time[datetime] found in msg ${messageLi.id}`); }

            // Get Message ID
            if (messageLi.id) {
                 const idParts = messageLi.id.split('-');
                 if (idParts.length > 0) messageId = idParts[idParts.length - 1];
            }

            // Calculate Index - UPDATED to count diverse media blocks
            const accessoriesContainer = messageLi.querySelector(MESSAGE_ACCESSORIES_SELECTOR);
            if (accessoriesContainer) {
                // --- FIX: Count all distinct top-level media blocks ---
                const allMediaBlocks = accessoriesContainer.querySelectorAll(ANY_MEDIA_BLOCK_SELECTOR);
                const totalCount = allMediaBlocks.length;
                // GM_log(`Filename Index: Found ${totalCount} media blocks in msg ${messageId}`);

                if (totalCount > 1) {
                    // --- FIX: Find the current media block (mosaic or inline embed) ---
                    const currentBlock = imageWrapper.closest(ANY_MEDIA_BLOCK_SELECTOR);
                    if (currentBlock) {
                        const index = Array.from(allMediaBlocks).indexOf(currentBlock) + 1;
                        if (index > 0) {
                            fileIndexStr = `_${index}`;
                            // GM_log(`Filename Index: Assigned index ${index} for msg ${messageId}`);
                        } else { GM_log(`Filename Index: Could not find current block in allMediaBlocks list for msg ${messageId}.`); }
                    } else { GM_log(`Filename Index: Could not find parent media block for imageWrapper in msg ${messageId}`); }
                }
            } else { GM_log(`Filename Index: Could not find accessories container in msg ${messageId}`); }

        } else { GM_log(`Filename: Could not find parent message LI.`); }


        let extension = 'dat'; // Default fallback
        try {
            const url = new URL(originalUrl);
            const pathname = url.pathname;

            // 1. Try extracting from the path
            const lastDotIndex = pathname.lastIndexOf('.');
            const lastSlashIndex = pathname.lastIndexOf('/'); // Ensure dot is in the filename part
            if (lastDotIndex > lastSlashIndex) {
                const extFromPath = pathname.substring(lastDotIndex + 1);
                // Basic validation: check if it looks like a typical extension (alphanumeric, reasonable length)
                if (/^[a-z0-9]{2,5}$/i.test(extFromPath)) {
                    extension = extFromPath.toLowerCase();
                    // GM_log(`Extracted extension from path: ${extension}`); // Debug log
                }
            }

            // 2. If path didn't yield a valid extension, try 'format' query parameter
            if (extension === 'dat') { // Only check format if path failed
                const formatParam = url.searchParams.get('format');
                if (formatParam && /^[a-z0-9]{2,5}$/i.test(formatParam)) {
                    extension = formatParam.toLowerCase();
                    // GM_log(`Extracted extension from format param: ${extension}`); // Debug log
                }
            }

        } catch (e) {
             GM_log(`Error parsing URL for extension: ${originalUrl}. Error: ${e}`);
             // Keep the default 'dat' on error
        }

        return `${dateStamp}_${messageId}${fileIndexStr}.${extension}`;
    }

    /**
     * Finds or creates the container where the download button should be placed.
     * Works for mosaic items, spoilers, and inline embeds.
     * @param {Element} imageWrapper - The image wrapper element.
     * @returns {Element|null} The container element (usually hoverButtonGroup) or null if creation fails.
     */
    function findButtonTargetContainer(imageWrapper) {
        // --- FIX: Find the parent media block (mosaic, inline embed, or spoiler) ---
        // For spoilers, we actually want the container *inside* the spoiler if possible,
        // or the spoiler itself as the fallback parent for the hover group.
        const parentSpoiler = imageWrapper.closest(SPOILER_CONTENT_SELECTOR);
        const parentMediaBlock = parentSpoiler || imageWrapper.closest(ANY_MEDIA_BLOCK_SELECTOR); // Prefer spoiler if present

        if (!parentMediaBlock) {
            GM_log('findButtonTargetContainer: Could not find parent media block (mosaic, embed, or spoiler).');
            return null;
        }
        // GM_log('findButtonTargetContainer: Found parent block:', parentMediaBlock);

        // 1. Try to find an EXISTING hoverButtonGroup within the parent block
        // Need to search carefully, could be direct child or deeper (e.g., inside imageContainer for inline)
        const existingGroup = parentMediaBlock.querySelector(HOVER_BUTTON_GROUP_SELECTOR);
        if (existingGroup) {
            // GM_log('findButtonTargetContainer: Found existing hoverButtonGroup.');
            return existingGroup;
        }

        // 2. If no existing group, CREATE one
        const newGroup = document.createElement('div');
        newGroup.classList.add('custom-dl-hover-group'); // Custom marker

        // Try to append it next to where other buttons might be, or as a direct child.
        // For inline embeds, inside the 'imageContainer__' seems appropriate if it exists.
        let appendTarget = parentMediaBlock; // Default target
        const imageContainer = imageWrapper.closest('div[class^="imageContainer"]');
        if (imageContainer && parentMediaBlock.contains(imageContainer)) {
             // If an imageContainer exists within our block, append the group there.
             // This handles the inline embed case better.
             appendTarget = imageContainer;
             // GM_log('findButtonTargetContainer: Appending new group to imageContainer.');
        } else {
            // GM_log('findButtonTargetContainer: Appending new group directly to parentMediaBlock.');
        }

        appendTarget.appendChild(newGroup);
        // GM_log('findButtonTargetContainer: Created and appended new hover group.');

        return newGroup;
    }

    /**
     * Extract correct image/video url from the anchor element.
     * @param {Element} linkElement - The image anchor element.
     */
    function getImageUrl(linkElement) {
      const href = linkElement.href;
      const dataSafeSrc = linkElement.getAttribute('data-safe-src');

      try {
        const pathname = new URL(href).pathname;
        const ext = pathname.slice((pathname.lastIndexOf(".") - 1 >>> 0) + 2);
        return ext ? href : dataSafeSrc;
      } catch(e) {
        return dataSafeSrc;
      }
    }


    /**
     * Attempts to add a download button to a given imageWrapper. Checks markers and existing buttons.
     * @param {Element} imageWrapper - The image wrapper element.
     * @param {boolean} forceCheck - If true, bypasses the IMAGE_PROCESSED_MARKER check (used after spoiler click).
     */
    function addDownloadButton(imageWrapper, forceCheck = false) {
        if (!imageWrapper || (!forceCheck && imageWrapper.hasAttribute(IMAGE_PROCESSED_MARKER))) {
            return;
        }
        imageWrapper.setAttribute(IMAGE_PROCESSED_MARKER, 'true');

        const originalLinkElement = imageWrapper.querySelector(ORIGINAL_LINK_SELECTOR);
        if (!originalLinkElement || !originalLinkElement.href) {
            return;
        }

        const imageUrl = getImageUrl(originalLinkElement);
        const targetContainer = findButtonTargetContainer(imageWrapper); // Should now find/create container

        if (!targetContainer) {
            // Log updated message
            GM_log(`AddButton: Failed to find or create a suitable hover buttons container for image: ${imageUrl}`);
            return; // Cannot proceed without a container
        }

        // Check if OUR button already exists in the found/created container
        if (targetContainer.querySelector(`.${DOWNLOAD_BUTTON_CLASS}`)) {
            // GM_log('AddButton: Download button already exists in target container.');
            return;
        }

        const filename = generateFilename(imageUrl, imageWrapper);
        // GM_log(`AddButton: Preparing button for ${filename} in`, targetContainer);

        const downloadButton = document.createElement('a');
        downloadButton.href = imageUrl;
        downloadButton.target = "_blank";
        downloadButton.rel = "noreferrer noopener";
        downloadButton.setAttribute('role', 'button');
        downloadButton.setAttribute('aria-label', 'Download Image');
        downloadButton.title = `Download ${filename}`;
        downloadButton.tabIndex = 0;

        NATIVE_ANCHOR_CLASSES_PREFIXES.forEach(prefix => {
            const actualClass = findActualClassName(document.body, prefix);
            if (actualClass) downloadButton.classList.add(actualClass);
        });

        downloadButton.classList.add(DOWNLOAD_BUTTON_CLASS);
        downloadButton.innerHTML = DOWNLOAD_SVG_HTML;

        downloadButton.addEventListener('click', (event) => {
            event.preventDefault();
            event.stopPropagation();
            GM_log(`Attempting GM_download: ${imageUrl} as ${filename}`);
            try {
                GM_download({ url: imageUrl, name: filename, onerror: (err) => GM_log(`Download error: ${JSON.stringify(err)}`) });
            } catch (e) { GM_log(`Error initiating GM_download: ${e}`); }
        });

        targetContainer.appendChild(downloadButton);
        GM_log(`AddButton: Added button for ${filename}`);
    }

    /**
     * Attaches a click listener to a spoiler element if it hasn't been done yet.
     * The listener reveals the image and then calls addDownloadButton.
     * @param {Element} spoilerElement - The spoiler content element.
     */
    function handleSpoiler(spoilerElement) {
        if (!spoilerElement || spoilerElement.hasAttribute(SPOILER_LISTENER_MARKER)) {
            return;
        }
        const imageWrapperInside = spoilerElement.querySelector(IMAGE_WRAPPER_SELECTOR);
        if (!imageWrapperInside) {
            spoilerElement.setAttribute(SPOILER_LISTENER_MARKER, 'true'); // Mark anyway
            return;
        }
        spoilerElement.setAttribute(SPOILER_LISTENER_MARKER, 'true');
        spoilerElement.addEventListener('click', () => {
            setTimeout(() => {
                const revealedImageWrapper = spoilerElement.querySelector(IMAGE_WRAPPER_SELECTOR);
                if (revealedImageWrapper) {
                    addDownloadButton(revealedImageWrapper, true); // Force check after reveal
                } else { GM_log("HandleSpoiler: Could not find revealed image wrapper post-click."); }
            }, 200);
        }, { once: true });
    }

    /**
     * Processes a node to find image wrappers or spoilers containing images.
     * Handles regular images, spoiled images, and inline embeds.
     * @param {Node} node - The node to process.
     */
    function processNode(node) {
        if (node.nodeType === Node.ELEMENT_NODE) {
            // Find all image wrappers within this node that haven't been processed
            const imageWrappers = node.querySelectorAll(`${IMAGE_WRAPPER_SELECTOR}:not([${IMAGE_PROCESSED_MARKER}])`);
            imageWrappers.forEach(wrapper => {
                // If it's inside a spoiler, let the spoiler handler deal with it upon click
                 if (wrapper.closest(SPOILER_CONTENT_SELECTOR)) {
                     wrapper.setAttribute(IMAGE_PROCESSED_MARKER, 'true'); // Mark now, handle later
                 } else {
                     // Process directly (regular image or inline embed) with slight delay
                     setTimeout(() => addDownloadButton(wrapper), 150);
                 }
            });
            // Also check if the node itself is a non-spoiled wrapper
            if (node.matches(IMAGE_WRAPPER_SELECTOR) && !node.hasAttribute(IMAGE_PROCESSED_MARKER) && !node.closest(SPOILER_CONTENT_SELECTOR)) {
                setTimeout(() => addDownloadButton(node), 150);
            }

            // Find spoiler elements containing images that need listeners
            const spoilerElements = node.querySelectorAll(`${SPOILER_CONTENT_SELECTOR}:not([${SPOILER_LISTENER_MARKER}]):has(${IMAGE_WRAPPER_SELECTOR})`);
             spoilerElements.forEach(spoiler => {
                 setTimeout(() => handleSpoiler(spoiler), 150);
             });
             // Also check if the node itself is a spoiler needing handling
             if (node.matches(`${SPOILER_CONTENT_SELECTOR}:has(${IMAGE_WRAPPER_SELECTOR})`) && !node.hasAttribute(SPOILER_LISTENER_MARKER)) {
                  setTimeout(() => handleSpoiler(node), 150);
             }
        }
    }

    // --- Observer ---
    const observer = new MutationObserver((mutationsList) => {
        NATIVE_ANCHOR_CLASSES_PREFIXES.forEach(prefix => findActualClassName(document.body, prefix)); // Ensure classes cached

        for (const mutation of mutationsList) {
            if (mutation.type === 'childList') {
                mutation.addedNodes.forEach(processNode);
            }
        }
    });

    // --- Initialization ---
    function initialize() {
         GM_log("Initializing Universal Downloader...");
         GM_log("Fetching initial dynamic class names...");
         NATIVE_ANCHOR_CLASSES_PREFIXES.forEach(prefix => findActualClassName(document.body, prefix));

        GM_log("Starting MutationObserver.");
        observer.observe(document.body, { childList: true, subtree: true });

        GM_log("Performing initial scan...");
        // Scan for non-spoiled images/embeds
        document.querySelectorAll(`${IMAGE_WRAPPER_SELECTOR}:not([${IMAGE_PROCESSED_MARKER}])`).forEach(wrapper => {
            if (!wrapper.closest(SPOILER_CONTENT_SELECTOR)) {
                addDownloadButton(wrapper);
            } else {
                 wrapper.setAttribute(IMAGE_PROCESSED_MARKER, 'true'); // Mark spoiled ones
            }
        });
        // Scan for spoilers needing listeners
        document.querySelectorAll(`${SPOILER_CONTENT_SELECTOR}:not([${SPOILER_LISTENER_MARKER}]):has(${IMAGE_WRAPPER_SELECTOR})`).forEach(handleSpoiler);
    }

    setTimeout(initialize, 2000);

})();
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