// ==UserScript==
// @name         YouTube Screenshot Helper
// @name:zh-TW   YouTube 截圖助手
// @name:zh-CN   YouTube 截图助手
// @namespace    https://www.tampermonkey.net/
// @version      1.5
// @description  YouTube Screenshot Tool – supports hotkey capture, burst mode, customizable hotkeys, burst interval settings, and menu language switch between Chinese and English.
// @description:zh-TW YouTube截圖工具，支援快捷鍵截圖、連拍模式、自定義快捷鍵、連拍間隔、中英菜單切換
// @description:zh-CN YouTube截图工具，支援快捷键截图、连拍模式、自定义快捷键、连拍间隔、中英菜单切换
// @author       ChatGPT
// @match        https://www.youtube.com/*
// @grant        GM_registerMenuCommand
// @grant        GM_getValue
// @grant        GM_setValue
// @license MIT
// @downloadURL none
// ==/UserScript==

(function () {
    'use strict';

    // 預設參數
    const CONFIG = {
        defaultHotkey: 's',
        defaultInterval: 1000,
        minInterval: 100,
        defaultLang: 'EN',
    };

    // 取得設定值
    let screenshotKey = GM_getValue('screenshotKey', CONFIG.defaultHotkey);
    let interval = Math.max(parseInt(GM_getValue('captureInterval', CONFIG.defaultInterval)), CONFIG.minInterval);
    let lang = GM_getValue('lang', CONFIG.defaultLang);

    // 多語系
    const I18N = {
        EN: {
            langToggle: 'LANG EN',
            setHotkey: `Set Screenshot Key (Now: ${screenshotKey.toUpperCase()})`,
            setInterval: `Set Burst Interval (Now: ${interval}ms)`,
            promptKey: 'Enter new hotkey (a-z):',
            promptInterval: `Enter new interval (min ${CONFIG.minInterval}ms):`,
        },
        ZH: {
            langToggle: '語言 中文',
            setHotkey: `設定截圖快捷鍵（目前：${screenshotKey.toUpperCase()}）`,
            setInterval: `設定連拍間隔（目前：${interval}ms）`,
            promptKey: '請輸入新的快捷鍵（單一字母）:',
            promptInterval: `請輸入新的連拍間隔（單位ms，最低 ${CONFIG.minInterval}ms）：`,
        },
    };
    const t = I18N[lang];

    // 狀態變數
    let keyDown = false;
    let intervalId = null;

    // 取得影片元素
    const getVideoElement = () => document.querySelector('video');

    // 格式化時間
    const formatTime = (seconds) => {
        const h = String(Math.floor(seconds / 3600)).padStart(2, '0');
        const m = String(Math.floor((seconds % 3600) / 60)).padStart(2, '0');
        const s = String(Math.floor(seconds % 60)).padStart(2, '0');
        const ms = String(Math.floor((seconds % 1) * 1000)).padStart(3, '0');
        return `${h}_${m}_${s}_${ms}`;
    };

    // 取得影片ID
    const getVideoID = () => {
        const match = window.location.href.match(/[?&]v=([^&]+)/);
        return match ? match[1] : 'unknown';
    };

    // 取得影片標題（多重嘗試，兼容新版YouTube）
    const getVideoTitle = () => {
        let title =
            document.querySelector('h1.ytd-watch-metadata')?.textContent ||
            document.querySelector('h1.title')?.innerText ||
            document.querySelector('h1')?.innerText ||
            document.querySelector('meta[name="title"]')?.getAttribute('content') ||
            document.title ||
            'unknown';
        // 移除檔名不允許的字元
        return title.replace(/[\\/:*?"<>|]/g, '').trim();
    };

    // 截圖主程式
    function takeScreenshot() {
        const video = getVideoElement();
        if (!video) return;

        const canvas = document.createElement('canvas');
        canvas.width = video.videoWidth;
        canvas.height = video.videoHeight;
        canvas.getContext('2d').drawImage(video, 0, 0, canvas.width, canvas.height);

        const link = document.createElement('a');
        const timestamp = formatTime(video.currentTime);
        const title = getVideoTitle();
        const id = getVideoID();
        const resolution = `${canvas.width}x${canvas.height}`;
        // 命名規則：時間_影片標題_影片ID_解析度.png
        link.download = `${timestamp}_${title}_${id}_${resolution}.png`;
        link.href = canvas.toDataURL('image/png');
        link.click();
    }

    // 快捷鍵事件
    document.addEventListener('keydown', (e) => {
        if (
            e.key.toLowerCase() === screenshotKey &&
            !keyDown &&
            !['INPUT', 'TEXTAREA'].includes(e.target.tagName)
        ) {
            keyDown = true;
            takeScreenshot();
            intervalId = setInterval(takeScreenshot, interval);
        }
    });

    document.addEventListener('keyup', (e) => {
        if (e.key.toLowerCase() === screenshotKey) {
            keyDown = false;
            clearInterval(intervalId);
        }
    });

    // 油猴選單
    GM_registerMenuCommand(t.setHotkey, () => {
        const input = prompt(t.promptKey, screenshotKey);
        if (input && /^[a-zA-Z]$/.test(input)) {
            GM_setValue('screenshotKey', input.toLowerCase());
            location.reload();
        }
    });

    GM_registerMenuCommand(t.setInterval, () => {
        const input = parseInt(prompt(t.promptInterval, interval));
        if (!isNaN(input) && input >= CONFIG.minInterval) {
            GM_setValue('captureInterval', input);
            location.reload();
        }
    });

    GM_registerMenuCommand(t.langToggle, () => {
        GM_setValue('lang', lang === 'EN' ? 'ZH' : 'EN');
        location.reload();
    });
})();