유튜브 영상 회전기 (단축키 전용).js

// ==UserScript==
// @name         범용 영상 회전기 (단축키 전용)
// @version      1.7
// @description  단축키(Ctrl+Shift+Alt+R)로 모든 웹사이트의 HTML5 영상을 90도씩 순차적으로 회전시킵니다.
// @author       Gemini
// @match        *://*/*
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    const VideoRotator = (function() {
        const config = {
            ROTATION_STEPS: 4,
            ROTATION_ANGLE_DEGREES: 90,
            SHORTCUT_KEY: 'KeyR',
            VIDEO_SELECTORS: ['video:hover', 'video:not([paused])', 'video'],
            INPUT_TAGS: ['INPUT', 'TEXTAREA'],
        };

        const state = new WeakMap();

        const findTargetVideo = () => {
            for (const selector of config.VIDEO_SELECTORS) {
                const videoElement = document.querySelector(selector);
                if (videoElement) return videoElement;
            }
            return null;
        };

        const isInputActive = (target) => {
            return target.isContentEditable || config.INPUT_TAGS.includes(target.tagName);
        };

        const getNextRotation = (video) => {
            const currentRotation = state.get(video)?.rotation ?? 0;
            return (currentRotation + 1) % config.ROTATION_STEPS;
        };

        const calculateTransformStyle = (rotation, video) => {
            if (rotation === 0) return '';
            const angle = rotation * config.ROTATION_ANGLE_DEGREES;
            const transforms = [`rotate(${angle}deg)`];
            const { clientWidth, clientHeight } = video;

            if (rotation % 2 !== 0 && clientWidth > 0 && clientHeight > 0) {
                const scale = Math.min(clientWidth / clientHeight, clientHeight / clientWidth);
                transforms.push(`scale(${scale})`);
            }
            return transforms.join(' ');
        };

        const applyRotation = (video) => {
            const newRotation = getNextRotation(video);
            const transformStyle = calculateTransformStyle(newRotation, video);

            video.style.transform = transformStyle;
            video.style.willChange = transformStyle ? 'transform' : '';

            if (newRotation === 0) {
                state.delete(video);
            } else {
                state.set(video, { rotation: newRotation });
            }
        };

        const handleKeyDown = (event) => {
            const isShortcut = event.ctrlKey && event.shiftKey && event.altKey && event.code === config.SHORTCUT_KEY;
            if (!isShortcut || isInputActive(event.target)) return;

            event.preventDefault();
            const targetVideo = findTargetVideo();
            if (targetVideo) {
                applyRotation(targetVideo);
            }
        };

        const init = () => {
            document.addEventListener('keydown', handleKeyDown, true);
        };

        return {
            init,
        };
    })();

    VideoRotator.init();

})();