// ==UserScript==
// @name         更好的视频倍速|Better video speed
// @namespace    http://tampermonkey.net/
// @version      1.5.9
// @description  为YouTube等默认需要长按鼠标加速的视频网站增加长按方向键加速|Add keyboard long‑press speed boost for video sites like YouTube that normally require holding the mouse button to accelerate.
// @license      MIT
// @author       zmabin
// @include      http://*/*
// @include      https://*/*
// @exclude      *://*.bilibili.com/*
// @downloadURL https://update.greasyfork.icu/scripts/575987/%E6%9B%B4%E5%A5%BD%E7%9A%84%E8%A7%86%E9%A2%91%E5%80%8D%E9%80%9F%7CBetter%20video%20speed.user.js
// @updateURL https://update.greasyfork.icu/scripts/575987/%E6%9B%B4%E5%A5%BD%E7%9A%84%E8%A7%86%E9%A2%91%E5%80%8D%E9%80%9F%7CBetter%20video%20speed.meta.js
// ==/UserScript==

(function () {
  "use strict";

  let keydownListener = null;
  let keyupListener = null;
  let titleObserver = null;        // 监听标题变化
  let videoElementObserver = null; // 等待视频出现
  let videoChangeObserver = null;  // 监听当前视频被移除
  let speedIndicator = null;
  let currentVideo = null;
  let indicatorParentOriginalPosition = null;
  let initPromise = null;
  let ytNavigateListener = null;
  let activeObservers = new WeakSet(); // 追踪观察器便于清理

  // ---------- 清理所有监听和界面 ----------
  function fullCleanup() {
    // 键盘事件
    if (keydownListener) {
      document.removeEventListener("keydown", keydownListener, true);
      keydownListener = null;
    }
    if (keyupListener) {
      document.removeEventListener("keyup", keyupListener, true);
      keyupListener = null;
    }

    // 所有观察器
    [titleObserver, videoElementObserver, videoChangeObserver].forEach(obs => {
      if (obs) {
        obs.disconnect();
        activeObservers.delete(obs);
      }
    });
    titleObserver = null;
    videoElementObserver = null;
    videoChangeObserver = null;

    removeSpeedIndicator();

    if (window.__videoSpeedStyleEl) {
      window.__videoSpeedStyleEl.remove();
      delete window.__videoSpeedStyleEl;
    }
  }

  // ---------- 倍速指示器 ----------
  function showSpeedIndicator(rate, video) {
    removeSpeedIndicator();
    currentVideo = video;

    const parent = video.parentNode;
    if (!parent) return;

    const computedStyle = window.getComputedStyle(parent);
    if (computedStyle.position === "static") {
      indicatorParentOriginalPosition = "static";
      parent.style.position = "relative";
    } else {
      indicatorParentOriginalPosition = null;
    }

    if (!document.getElementById("video-speed-anim-style")) {
      const styleEl = document.createElement("style");
      styleEl.id = "video-speed-anim-style";
      styleEl.textContent = `
        @keyframes breathe {
          0%, 100% { opacity: 0.2; }
          50% { opacity: 1; }
        }
        .video-speed-indicator .triangle {
          display: inline-block;
          font-size: 10px;
          color: #fff;
          margin-right: 0;
          animation: breathe 1.2s ease-in-out infinite;
        }
        .video-speed-indicator .triangle:nth-child(1) { animation-delay: 0s; }
        .video-speed-indicator .triangle:nth-child(2) { animation-delay: 0.15s; }
        .video-speed-indicator .triangle:nth-child(3) { animation-delay: 0.3s; }
      `;
      document.head.appendChild(styleEl);
      window.__videoSpeedStyleEl = styleEl;
    }

    speedIndicator = document.createElement("div");
    speedIndicator.className = "video-speed-indicator";
    Object.assign(speedIndicator.style, {
      position: "absolute",
      left: "50%",
      transform: "translateX(-50%)",
      background: "rgba(0,0,0,0.75)",
      color: "#fff",
      padding: "4px 16px",
      borderRadius: "4px",
      zIndex: "2147483647",
      pointerEvents: "none",
      display: "flex",
      alignItems: "center",
      gap: "2px",
      whiteSpace: "nowrap",
      fontFamily: "Arial, sans-serif",
      border: "none"
    });

    for (let i = 0; i < 3; i++) {
      const tri = document.createElement("span");
      tri.className = "triangle";
      tri.textContent = "▶";
      speedIndicator.appendChild(tri);
    }

    const text = document.createElement("span");
    text.className = "speed-text";
    text.textContent = `${rate.toFixed(1)}x 倍速播放中`;
    text.style.fontSize = "14px";
    text.style.fontWeight = "500";
    speedIndicator.appendChild(text);

    parent.appendChild(speedIndicator);

    const videoHeight = video.offsetHeight || video.clientHeight || 0;
    const topOffset = Math.max(videoHeight * 0.04, 8);
    speedIndicator.style.top = topOffset + "px";
  }

  function updateSpeedIndicator(rate) {
    const textEl = speedIndicator?.querySelector(".speed-text");
    if (textEl) textEl.textContent = `${rate.toFixed(1)}x 倍速播放中`;
  }

  function removeSpeedIndicator() {
    if (speedIndicator) {
      if (indicatorParentOriginalPosition === "static" && speedIndicator.parentNode) {
        speedIndicator.parentNode.style.position = "";
      }
      speedIndicator.remove();
      speedIndicator = null;
      indicatorParentOriginalPosition = null;
    }
  }

  // ---------- 等待有效视频元素（纯观察，无轮询）----------
  function waitForVideoElement() {
    return new Promise((resolve) => {
      let observer = null;
      let currentTarget = null;

      function cleanObserver() {
        if (observer) {
          observer.disconnect();
          activeObservers.delete(observer);
          observer = null;
        }
      }

      function foundVideo(video) {
        cleanObserver();
        resolve(video);
      }

      function handleVideo(video) {
        if (!video || video === currentTarget) return;
        currentTarget = video;

        if (video.readyState >= 1) {
          foundVideo(video);
        } else {
          // 等待元数据加载
          const onMeta = () => {
            video.removeEventListener('loadedmetadata', onMeta);
            if (document.contains(video)) {
              foundVideo(video);
            } else {
              // 视频节点被移除了，重新搜索
              currentTarget = null;
              startObserving();
            }
          };
          video.addEventListener('loadedmetadata', onMeta, { once: true });

          // 若 30 秒仍未加载元数据，放弃并重新搜索
          const timeout = setTimeout(() => {
            video.removeEventListener('loadedmetadata', onMeta);
            currentTarget = null;
            startObserving();
          }, 30000);
          // 清理函数
          const originalClean = cleanObserver;
          cleanObserver = () => {
            clearTimeout(timeout);
            originalClean();
          };
        }
      }

      function checkAndObserve() {
        const video = document.querySelector("video");
        if (video) {
          handleVideo(video);
          return true;
        }
        return false;
      }

      function startObserving() {
        cleanObserver();
        if (checkAndObserve()) return;

        // 使用 MutationObserver 等待视频出现（不再用 setInterval）
        observer = new MutationObserver(() => {
          if (checkAndObserve()) {
            cleanObserver();
          }
        });
        // 确保 body 已存在
        const target = document.body || document.documentElement;
        if (target) {
          observer.observe(target, { childList: true, subtree: true });
          activeObservers.add(observer);
        } else {
          document.addEventListener('DOMContentLoaded', () => {
            observer.observe(document.body, { childList: true, subtree: true });
            activeObservers.add(observer);
            checkAndObserve(); // 再次检查
          }, { once: true });
        }
      }

      startObserving();
    });
  }

  // ---------- 判断是否在输入框内 ----------
  function isInInputElement(event) {
    const target = event.target;
    if (target.isContentEditable) return true;
    const tag = target.tagName;
    if (tag === "INPUT" || tag === "TEXTAREA" || tag === "SELECT") return true;
    // 常见代码编辑器
    const cls = target.className || "";
    if (/editor|ace_editor|monaco-editor|CodeMirror/i.test(cls)) return true;
    return false;
  }

  // ---------- 核心初始化 ----------
  async function setupForVideo(video) {
    // 绑定键盘控制
    const KEY = "ArrowRight";
    const ADD_KEY = "NumpadAdd";
    const SUB_KEY = "NumpadSubtract";
    const RESET_KEY = "KeyP";

    let targetRate = 3;
    const MAX_RATE = 16;
    const MIN_RATE = 0.5;
    let keyDownTime = 0;
    let originalRate = video.playbackRate;
    let isSpeedUp = false;

    // 观察当前视频是否被移除或替换
    if (video.parentElement) {
      videoChangeObserver = new MutationObserver((mutations) => {
        const videoChanged = mutations.some(mutation => {
          return Array.from(mutation.removedNodes).some(node => node.nodeName === "VIDEO") ||
                 Array.from(mutation.addedNodes).some(node => node.nodeName === "VIDEO");
        });
        if (videoChanged) {
          console.log("视频元素变化，重新初始化");
          fullCleanup();
          initScript();
        }
      });
      videoChangeObserver.observe(video.parentElement, { childList: true, subtree: true });
      activeObservers.add(videoChangeObserver);
    }

    // 键盘按下
    keydownListener = (e) => {
      if (isInInputElement(e)) return;

      if (e.code === KEY) {
        e.preventDefault();
        e.stopImmediatePropagation();

        if (!keyDownTime) keyDownTime = Date.now();
        if (!isSpeedUp && Date.now() - keyDownTime > 300) {
          isSpeedUp = true;
          originalRate = video.playbackRate;
          video.playbackRate = targetRate;
          showSpeedIndicator(targetRate, video);
        }
        return;
      }

      if (e.code === ADD_KEY) {
        e.preventDefault();
        e.stopImmediatePropagation();
        if (targetRate < MAX_RATE) {
          targetRate += 0.5;
          if (isSpeedUp) {
            video.playbackRate = targetRate;
            updateSpeedIndicator(targetRate);
          }
        }
        return;
      }

      if (e.code === SUB_KEY) {
        e.preventDefault();
        e.stopImmediatePropagation();
        if (targetRate > MIN_RATE) {
          targetRate -= 0.5;
          if (isSpeedUp) {
            video.playbackRate = targetRate;
            updateSpeedIndicator(targetRate);
          }
        }
        return;
      }

      if (e.code === RESET_KEY) {
        e.preventDefault();
        e.stopImmediatePropagation();
        targetRate = 3;
        if (isSpeedUp) {
          video.playbackRate = targetRate;
          updateSpeedIndicator(targetRate);
        }
      }
    };

    // 键盘松开
    keyupListener = (e) => {
      if (isInInputElement(e)) return;

      if (e.code === KEY) {
        e.preventDefault();
        e.stopImmediatePropagation();

        const pressDuration = Date.now() - keyDownTime;
        if (pressDuration < 300) {
          video.currentTime += 5; // 短按快进5秒
        }
        if (isSpeedUp) {
          video.playbackRate = originalRate;
          removeSpeedIndicator();
          isSpeedUp = false;
        }
        keyDownTime = 0;
      }
    };

    document.addEventListener("keydown", keydownListener, true);
    document.addEventListener("keyup", keyupListener, true);
  }

  async function initScript() {
    fullCleanup();
    try {
      const video = await waitForVideoElement();
      console.log("找到视频元素：", video);
      await setupForVideo(video);
    } catch (err) {
      console.error("初始化失败:", err);
    }
  }

  // ---------- 监听 URL / 页面变化 ----------
  function enableTitleWatcher() {
    const titleEl = document.querySelector("title");
    if (!titleEl) return;

    // 通过监听<title>的文本内容变化判断页面切换（轻量级）
    titleObserver = new MutationObserver(() => {
      // 简单比较 URL 是否真的变了（防止 title 其他属性变化导致误触发）
      const newHref = location.href;
      if (newHref !== titleObserver._lastHref) {
        titleObserver._lastHref = newHref;
        console.log("title 变化，可能跳转了页面");
        fullCleanup();
        initScript();
      }
    });
    titleObserver.observe(titleEl, { characterData: true, childList: true, subtree: true });
    titleObserver._lastHref = location.href;
    activeObservers.add(titleObserver);
  }

  function watchPageChanges() {
    // 1. 劫持 history 方法（pushState / replaceState）
    const origPush = history.pushState;
    const origReplace = history.replaceState;
    history.pushState = function () {
      origPush.apply(this, arguments);
      onPotentialNavigate();
    };
    history.replaceState = function () {
      origReplace.apply(this, arguments);
      onPotentialNavigate();
    };
    window.addEventListener("popstate", onPotentialNavigate);

    // 2. 对 YouTube 特殊事件
    if (location.hostname.includes("youtube.com")) {
      ytNavigateListener = () => {
        console.log("YouTube 导航事件触发");
        fullCleanup();
        initScript();
      };
      document.addEventListener("yt-navigate-finish", ytNavigateListener);
    }

    // 3. 标题变化作为通用 SPA 检测
    enableTitleWatcher();

    function onPotentialNavigate() {
      // 轻微延迟，确保 DOM 更新完成
      setTimeout(() => {
        if (location.href !== (titleObserver?._lastHref || "")) {
          if (titleObserver) titleObserver._lastHref = location.href;
          fullCleanup();
          initScript();
        }
      }, 100);
    }
  }

  // ---------- 启动入口 ----------
  function start() {
    if (document.body) {
      initScript();
      watchPageChanges();
    } else {
      document.addEventListener("DOMContentLoaded", () => {
        initScript();
        watchPageChanges();
      }, { once: true });
    }
  }

  start();
})();