// ==UserScript==
// @name        Maximizer For YouTube™
// @description Maximizes the YouTube player to fill the entire browser viewport when in theater mode, plus a few other enhancements.
// @license     MIT
// @author      Rotem Dan <rotemdan@gmail.com>
// @match       https://www.youtube.com/*
// @version     0.2.4
// @run-at      document-start
// @grant       none
// @namespace   https://github.com/rotemdan
// @homepageURL https://github.com/rotemdan/MaximizerForYouTube
// @require     https://cdn.jsdelivr.net/npm/js-cookie@2/src/js.cookie.min.js
// @require     https://code.jquery.com/jquery-3.3.1.slim.min.js
// @downloadURL none
// ==/UserScript==

////////////////////////////////////////////////////////////////////////////////////////////////////////
// Utility definitions
////////////////////////////////////////////////////////////////////////////////////////////////////////

const debugModeEnabled = true;
function log(...args) {
	if (debugModeEnabled) {
		console.log("[MaximizerForYoutube]", ...args)
	}
}

// Try to emulate setImmediate() like execution:
function setImmediate(func) {
	const channel = new MessageChannel();
	channel.port1.onmessage = () => func();
	channel.port2.postMessage("");
}

////////////////////////////////////////////////////////////////////////////////////////////////////////
// Core script modification functions
////////////////////////////////////////////////////////////////////////////////////////////////////////

// Install or uninstall full-size player page stylesheet if needed
function installOrUninstallPlayerModIfNeeded() {
	if (inWatchPage() && theaterModeEnabled()) {
		if ($("#MaximizerForYouTube_PlayerMod").length == 0) {
			const styleSheet = `
					<style id='MaximizerForYouTube_PlayerMod' type='text/css'>
						ytd-page-manager { margin-top: 0px !important; }

						#masthead-container { visibility: hidden; opacity: 0; transition: opacity 0.2s ease-in-out; }

						#player-wide-container, #player-full-bleed-container { height: 100vh !important; min-height: 0vh !important; max-height: 100vh !important; }

						:focus { outline: 0; }

						#movie_player { -webkit-user-select: none; -moz-user-select: none; -ms-user-select: none; user-select: none; }

						/*
						body {
							scrollbar-width: 10px;
							scrollbar-color: #000000;
						}
						*/

						body::-webkit-scrollbar {
							width: 10px;
							background-color: #000000;
						}

						body::-webkit-scrollbar-track {
							border-radius: 10px;
							background: rgba(0,0,0,0.1);
							border: 1px solid #383838;
						}

						body::-webkit-scrollbar-thumb {
							border-radius: 10px;
							background: linear-gradient(left, #fff, #e4e4e4);
							border: 1px solid #5b5b5b;
						}

						body::-webkit-scrollbar-thumb:hover {
							background: #fff;
						}
					</style>`;

			$("head").append(styleSheet);

			log("Player mod installed");
		}

		if (pageScrolledToTop())
			hideTopBar();
	} else {
		if ($("#MaximizerForYouTube_PlayerMod").length > 0) {
			$("#MaximizerForYouTube_PlayerMod").remove();
			showTopBar();

			log("Player mod uninstalled");
		}
	}
}

// Automatically shows/hides the top bar based on different properties of the view.
function installTopBarAutohide() {
	function onPageScroll() {
		if (!inWatchPage())
			return;

		if (pageScrolledToTop() && theaterModeEnabled())
			hideTopBar();
		else
			showTopBar();
	}

	function onKeyDown(e) {
		if (!inWatchPage() || !theaterModeEnabled())
			return;

		if (e.which === 27) { // Handle escape key
			log("esc");

			if (pageScrolledToTop()) {
				if (topBarIsVisible()) {
					hideTopBar();
					e.stopPropagation();
				} else {
					showTopBar();

					setTimeout(() => $("input#search").focus(), 50);
				}
			}
		}
	}

	function installEscHandlerToSearchInput() {
		let inputElement = $("input#search");

		if (inputElement.length > 0) {
			inputElement.on("keydown", onKeyDown);
			//inputElement[0].addEventListener("keydown", onKeyDown, true);
			log("Esc handler installed on search input");
		} else {
			setTimeout(() => installEscHandlerToSearchInput(), 50);
		}
	}

	installEscHandlerToSearchInput();
	$(document).on("keydown", onKeyDown);
	$(document).on("scroll", onPageScroll);
}

// Continuously auto-focus the player keyboard input when some conditions are met.
function installPlayerInputAutoFocus() {
	function autoFocusIfNeeded() {
		if (inWatchPage() && !topBarIsVisible()) {
			getVideoContainer().focus();
		}

		setTimeout(autoFocusIfNeeded, 20);
	}

	autoFocusIfNeeded();
}

function installPlayerKeyboardShortcutExtensions() {
	// Install keyboard shortcut extensions
	function onKeyDown(e) {
		if (!inWatchPage())
			return;

		if (getVideoContainer().is(":focus")) {
			if (e.ctrlKey) {
				if (e.which === 37) { // Handle ctl + left key
					var previousButton = $("a.ytp-prev-button")[0];
					if (previousButton)
						previousButton.click();
				}
				else if (e.which === 39) { // Handle ctl + right key
					var nextButton = $("a.ytp-next-button")[0]
					if (nextButton)
						nextButton.click();
				}
			}
		}
	}

	$(document).on("keydown", onKeyDown);
}

// Expands video description
function ensureExpandedVideoDescription() {
	setInterval(() => {
		$("ytd-expander.description, ytd-expander.ytd-video-secondary-info-renderer").removeAttr("collapsed")
	}, 50);
}

// Expands video description
function ensureModdedTheaterModeButton() {
	setInterval(() => {
		const playerModeButton = $("button.ytp-size-button");

		if (playerModeButton.length === 0 || playerModeButton.hasClass("MaximizerForYouTube_PlayerMod_Modded"))
			return;

		playerModeButton.on("click", () => {
			setTimeout(() => {
				installOrUninstallPlayerModIfNeeded();

				const resizeEvent = new Event('resize');
				window.dispatchEvent(resizeEvent);
			}, 0)
		})

		playerModeButton.addClass("MaximizerForYouTube_PlayerMod_Modded");
	}, 50);
}

function ensurePlayerIsAlwaysPaused() {
	setInterval(() => {
		const player = getVideoPlayer().get(0);
		if (player) {
			player.pause();
		}
	}, 1000);
}

function hideSPFLoadingBar() {
	$("head").append("<style>#progress, yt-page-navigation-progress {display: none !important}</style>");
}

// Pauses playing videos in other tabs when a video play event is detected (works in both watch and channel page videos)
function ensurePlayerAutoPause() {
	const videoPlayer = getVideoPlayer();

	if (videoPlayer.length > 0 &&
		!videoPlayer.hasClass("MaximizerForYouTube_Modded_Autopause") &&
		!inHomePage() &&
		!inFeedPage() &&
		!inSearchPage()) {
		// Generate a random script instance ID
		const instanceID = Math.random().toString();

		function onVideoPlay() {
			log("onVideoPlay")
			localStorage["MaximizerForYouTube_PlayingInstanceID"] = instanceID;

			function pauseWhenAnotherPlayerStartsPlaying() {
				if (localStorage["MaximizerForYouTube_PlayingInstanceID"] !== instanceID)
					videoPlayer[0].pause();
				else
					setTimeout(pauseWhenAnotherPlayerStartsPlaying, 20);
			}

			pauseWhenAnotherPlayerStartsPlaying();
		}

		// If video isn't paused on startup, fire the handler immediately
		if (!videoPlayer[0].paused)
			onVideoPlay();

		// Add event handler for the "play" event.
		videoPlayer.on("play", onVideoPlay);

		// Mark the player as modded to ensure the autopause mod isn't installed again
		videoPlayer.addClass("MaximizerForYouTube_Modded_Autopause");
	}

	setTimeout(ensurePlayerAutoPause, 50);
}

////////////////////////////////////////////////////////////////////////////////////////////////////////
// Utility functions
////////////////////////////////////////////////////////////////////////////////////////////////////////

// Get the video player element
function getVideoContainer() {
	// Note: the channel page has another hidden video except the main one (if it exists). The hidden video doesn't have an "src" attribute.
	return $("div.html5-video-player");
}

// Get the video player element
function getVideoPlayer() {
	// Note: the channel page has another hidden video except the main one (if it exists). The hidden video doesn't have an "src" attribute.
	return $('.html5-main-video').filter(function (index) { return $(this).attr("src") !== undefined });
}

// Get the top bar element
function getTopBar() {
	return $("#masthead-container");
}

function showTopBar() {
	getTopBar().css("visibility", "visible");
	getTopBar().css("opacity", "1");
}

function hideTopBar() {
	getTopBar().css("opacity", "0");
	getTopBar().css("visibility", "hidden");
}

function pageScrolledToTop() {
	return $(document).scrollTop() === 0;
}

function scrollPageToTopIfNeeded() {
	setTimeout(() => {
		if (inWatchPage() && $(document).scrollTop() > 0) {
			log("Scrolling page to top");
			$(document).scrollTop(0);
		}
	}, 20);
}

function topBarIsVisible() {
	return getTopBar().css("visibility") === "visible";
}

function inWatchPage() {
	return location.href.indexOf("https://www.youtube.com/watch?") === 0;
}

function inSearchPage() {
	return location.href.indexOf("https://www.youtube.com/results?") === 0;
}

function inFeedPage() {
	return location.href.indexOf("https://www.youtube.com/feed") === 0;
}

function inHomePage() {
	return location.href == "https://www.youtube.com";
}

function theaterModeEnabled() {
	return Cookies.get("wide") === "1";
}

////////////////////////////////////////////////////////////////////////////////////////////////////////
// Event handlers
////////////////////////////////////////////////////////////////////////////////////////////////////////

let installInterval;

function onDocumentStart() {
	log("onDocumentStart")
	log("Script loaded, theater mode enabled:", theaterModeEnabled());

	//installOrUninstallPlayerModIfNeeded();

	installInterval = setInterval(() => {
		installOrUninstallPlayerModIfNeeded();
		//log("Trying to install mod")
	}, 1);
}

function onDocumentEnd() {
	log("onDocumentEnd");

	clearInterval(installInterval)
	installOrUninstallPlayerModIfNeeded();

	//ensurePlayerIsAlwaysPaused();

	hideSPFLoadingBar();
	installTopBarAutohide();
	installPlayerInputAutoFocus();
	installPlayerKeyboardShortcutExtensions();
	//ensureExpandedVideoDescription();
}

function onWindowLoad() {
	log("onWindowLoad");

	ensureModdedTheaterModeButton();
	ensurePlayerAutoPause();
}

function onNavigation() {
	log("onNavigation, new location:", location.href);

	//scrollPageToTopIfNeeded();
	installOrUninstallPlayerModIfNeeded();
}

////////////////////////////////////////////////////////////////////////////////////////////////////////
// Install event handlers and start script
////////////////////////////////////////////////////////////////////////////////////////////////////////

function startScript() {
	document.addEventListener('DOMContentLoaded', onDocumentEnd, false);
	$(window).on("load", onWindowLoad);
	$(window).on("yt-navigate-start", () => { log("yt-navigate-start"), onNavigation() });
	$(window).on("popstate", () => { log("popstate"); onNavigation() });

	onDocumentStart();
}

if (window.self === window.top) {
	startScript();
}