Youtube download button

Adds a download button

您需要先安裝使用者腳本管理器擴展,如 TampermonkeyGreasemonkeyViolentmonkey 之後才能安裝該腳本。

You will need to install an extension such as Tampermonkey to install this script.

您需要先安裝使用者腳本管理器擴充功能,如 TampermonkeyViolentmonkey 後才能安裝該腳本。

您需要先安裝使用者腳本管理器擴充功能,如 TampermonkeyUserscripts 後才能安裝該腳本。

你需要先安裝一款使用者腳本管理器擴展,比如 Tampermonkey,才能安裝此腳本

您需要先安裝使用者腳本管理器擴充功能後才能安裝該腳本。

(我已經安裝了使用者腳本管理器,讓我安裝!)

你需要先安裝一款使用者樣式管理器擴展,比如 Stylus,才能安裝此樣式

你需要先安裝一款使用者樣式管理器擴展,比如 Stylus,才能安裝此樣式

你需要先安裝一款使用者樣式管理器擴展,比如 Stylus,才能安裝此樣式

你需要先安裝一款使用者樣式管理器擴展後才能安裝此樣式

你需要先安裝一款使用者樣式管理器擴展後才能安裝此樣式

你需要先安裝一款使用者樣式管理器擴展後才能安裝此樣式

(我已經安裝了使用者樣式管理器,讓我安裝!)

// ==UserScript==
// @name        Youtube download button
// @namespace   Violentmonkey Scripts
// @match       https://www.youtube.com/watch
// @include     https://*.youtube.com/*
// @grant       GM_addStyle
// @run-at      document-start
// @version     3.0
// @author      Nojyto
// @license     MIT
// @description Adds a download button
// ==/UserScript==

(function() {
    const TEXT_BUTTON = "Download";
    const SVG_NAMESPACE = "http://www.w3.org/2000/svg";
    const ICON_SVG_PATH_DATA = "M17 18v1H6v-1h11zm-.5-6.6-.7-.7-3.8 3.7V4h-1v10.4l-3.8-3.8-.7.7 5 5 5-4.9z";

    const DOWNLOAD_API = "https://www.y2mate.com/download-youtube/";
    const BUTTON_ID = "ytDownloadButton";
    const TARGET_CONTAINER_SELECTOR = "div#owner";

    let lastUrl = null;
    let currentVideoId = null;
    let buttonObserver = null;

    GM_addStyle(`
        #${BUTTON_ID} {
            background-color: var(--yt-spec-additive-background);
            color: var(--yt-spec-text-primary);
            margin: 0px 4px;
            border-radius: 18px;
            width: 120px;
            height: 36px;
            line-height: 37px;
            text-align: center;
            font-style: normal;
            font-size: 14px;
            font-family: Roboto, Noto, sans-serif;
            font-weight: 500;
            text-decoration: none;
            display: flex;
            align-items: center;
            justify-content: center;
            cursor: pointer;
            transition: background-color 0.2s;
            white-space: nowrap;
            min-width: fit-content;
            padding: 0 10px;
        }
        #${BUTTON_ID}:hover {
            background-color: var(--yt-spec-mono-tonal-hover);
            color: var(--yt-spec-text-primary);
        }
        #${BUTTON_ID} .yt-download-icon-container {
            height: 84%;
            margin-left: -8px;
            fill: currentcolor;
            display: flex;
            align-items: center;
            justify-content: center;
        }
        #${BUTTON_ID} > span {
            margin-left: 4px;
        }
        #owner {
            display: flex;
            align-items: center;
            flex-wrap: wrap;
        }
    `);

    function waitForElement(selector) {
        // console.log(`[Youtube Download] Waiting for element: ${selector}`);
        return new Promise((resolve) => {
            const element = document.querySelector(selector);
            if (element) {
                // console.log(`[Youtube Download] Element found immediately:`, element);
                return resolve(element);
            }
            const observer = new MutationObserver((mutationsList, obs) => {
                const foundElement = document.querySelector(selector);
                if (foundElement) {
                    obs.disconnect();
                    // console.log(`[Youtube Download] Element found via MutationObserver:`, foundElement);
                    resolve(foundElement);
                }
            });
            observer.observe(document.documentElement, { childList: true, subtree: true });
        });
    }

    function getVideoId(url) {
        try {
            const urlObj = new URL(url);
            const urlParams = new URLSearchParams(urlObj.search);
            return urlParams.get('v');
        } catch (e) {
            console.error("[Youtube Download] Error parsing URL to get video ID:", e);
            return null;
        }
    }

    async function addOrUpdateDownloadButton() {
        // console.log("[Youtube Download] addOrUpdateDownloadButton called.");
        const currentUrl = window.location.href;

        if (!currentUrl.includes("watch?v=")) {
            // console.log("[Youtube Download] Not a YouTube watch page. Skipping.");
            return;
        }

        const targetContainer = await waitForElement(TARGET_CONTAINER_SELECTOR);
        if (!targetContainer) {
            console.warn("[Youtube Download] Target container element not found after waiting. Cannot add download button.");
            return;
        }
        // console.log(`[Youtube Download] Found target container:`, targetContainer);

        let downloadLink = document.getElementById(BUTTON_ID);
        let videoIdForCurrentUrl = getVideoId(currentUrl);

        if (!videoIdForCurrentUrl) {
            console.warn("[Youtube Download] Could not get video ID for current URL:", currentUrl);
            return;
        }

        if (!downloadLink || downloadLink.parentNode !== targetContainer) {
            // console.log("[Youtube Download] Button missing or detached. Creating/re-creating download button.");
            if (downloadLink && downloadLink.parentNode) {
                downloadLink.parentNode.removeChild(downloadLink);
                // console.log("[Youtube Download] Removed detached old button instance.");
            }

            downloadLink = document.createElement('a');
            downloadLink.id = BUTTON_ID;
            downloadLink.target = "_blank";
            downloadLink.rel = "noopener noreferrer";

            const iconWrapper = document.createElement('div');
            iconWrapper.className = 'yt-download-icon-container';
            const svgElement = document.createElementNS(SVG_NAMESPACE, "svg");
            svgElement.setAttribute("height", "24");
            svgElement.setAttribute("viewBox", "0 0 24 24");
            svgElement.setAttribute("width", "24");
            svgElement.setAttribute("focusable", "false");
            svgElement.style.pointerEvents = "none";
            svgElement.style.display = "inherit";
            svgElement.style.width = "100%";
            svgElement.style.height = "100%";
            const pathElement = document.createElementNS(SVG_NAMESPACE, "path");
            pathElement.setAttribute("d", ICON_SVG_PATH_DATA);
            svgElement.appendChild(pathElement);
            iconWrapper.appendChild(svgElement);
            downloadLink.appendChild(iconWrapper);

            const textSpan = document.createElement('span');
            textSpan.textContent = TEXT_BUTTON;
            downloadLink.appendChild(textSpan);

            targetContainer.appendChild(downloadLink);
            // console.log("[Youtube Download] Download button created and inserted into container.");

            setupButtonObserver(targetContainer);
        } else {
            // console.log("[Youtube Download] Button exists and is in place.");
            if (!buttonObserver || buttonObserver.observedElement !== targetContainer) {
                setupButtonObserver(targetContainer);
            }
        }

        if (currentUrl !== lastUrl || !lastUrl || !downloadLink.href.includes(videoIdForCurrentUrl)) {
             lastUrl = currentUrl;
             currentVideoId = videoIdForCurrentUrl;
             downloadLink.href = DOWNLOAD_API + currentVideoId;
            //  console.log(`[Youtube Download] Button href updated to: ${downloadLink.href}`);
        } else {
            //  console.log("[Youtube Download] URL unchanged, button already updated. No action needed for href.");
        }
    }

    function setupButtonObserver(parentEl) {
        if (buttonObserver) {
            buttonObserver.disconnect();
            // console.log("[Youtube Download] Existing button observer disconnected.");
        }

        buttonObserver = new MutationObserver((mutationsList) => {
            let downloadLink = document.getElementById(BUTTON_ID);
            if (!downloadLink) {
                // console.log("[Youtube Download] Download button detected as removed. Attempting to re-add.");
                if (buttonObserver) {
                    buttonObserver.disconnect();
                    buttonObserver = null;
                }
                setTimeout(() => addOrUpdateDownloadButton(), 500);
            }
        });

        buttonObserver.observedElement = parentEl;
        buttonObserver.observe(parentEl, { childList: true, subtree: false });
        // console.log("[Youtube Download] Button observer set up on:", parentEl);
    }

    if (document.readyState === 'loading') {
        // console.log("[Youtube Download] DOM still loading, adding DOMContentLoaded listener.");
        document.addEventListener('DOMContentLoaded', addOrUpdateDownloadButton);
    } else {
        // console.log("[Youtube Download] DOM already loaded, running addOrUpdateDownloadButton immediately.");
        addOrUpdateDownloadButton();
    }
    window.addEventListener("yt-navigate-finish", addOrUpdateDownloadButton, true);
    // console.log("[Youtube Download] Script initialized. Listening for navigation events.");
})();