udacity_pause_youtube_frame_content.js

if(document.referrer.startsWith("https://classroom.udacity.com")){
	var safeGetYoutubePlayer = `

		if(window.YT === undefined){
			YT = {PlayerState : {
				BUFFERING : 3,
				CUED : 5,
				ENDED : 0,
				PAUSED : 2,
				PLAYING : 1,
				UNSTARTED : -1
			}}

		}

		var errMsg = null;
		var player = null;
		if(yt === null){
			errMsg = "UdacityPause error: yt is null, something went wrong."
		}else{
			/*
			var videoFrame = document.querySelector("div[class^=youtube-player] iframe");
			if(videoFrame === null){
				errMsg = "UdacityPause error: videoFrame is null, something went wrong."
			}else{
				//player = YT.get(videoFrame.id);
				if(player === null){
					errMsg = "UdacityPause error: failed to YT.get player.";
				}
			}
			*/
			/*
			player = yt.player.getPlayerByElement("player");
			if(player === null){
				errMsg = "UdacityPause error: yt.player.getPlayerByElement returned null, something went wrong."
			}
			*/
			if(!yt || !yt.player || !yt.player.utils || 
				!yt.player.utils.VideoTagPool.instance ||
				!yt.player.utils.VideoTagPool.instance.A ||
				!yt.player.utils.VideoTagPool.instance.A.length){
				errMsg = "Player not found";
			}else{
				player = yt.player.utils.VideoTagPool.instance.A[0];
			}
		}

		if(errMsg !== null){
			alert(errMsg);
			throw errMsg;
		}
	`

	// var startScript = `
	// 	${safeGetYoutubePlayer}
	// 	player.addEventListener("onStateChange", function(state){
	//     	if(state === 0){
	//     	// 	setTimeout(function(){
	//     	// 		var nextButton = document.querySelector("a[class^=_auto-advance-overlay--button]");
	//     	// 		if(nextButton){
	// 	    //     		nextButton.click();
	// 	    //     	}
	//     	// 	}, 1000);
	//     	// }
	    	
	// 	});
	// `;

	// runRemoteScript(startScript);

	chrome.runtime.onMessage.addListener(function(request, sender, sendResponse){
		if(request.action === "udacity_pause_pause"){
			var scriptContent = `
				${safeGetYoutubePlayer}
				if(player.paused){
					player.play();
				}else{
					player.pause();
				}


			`;
			runRemoteScript(scriptContent);
		}else if(request.action === "udacity_pause_forward"){
			seekUdacity(request.seekDuration);
		}else if(request.action === "udacity_pause_back"){
			seekUdacity(-request.seekDuration);
		}
	});	

	function seekUdacity(seconds){
		var scriptContent = `
			${safeGetYoutubePlayer}
			var time = player.currentTime;
			player.currentTime = time + ${seconds};
		`;
		runRemoteScript(scriptContent);
	}

	function runRemoteScript(scriptContent){
		var randomTagId = "_" + guidGenerator();
		var script = document.createElement('script');
		script.id = randomTagId;
		script.appendChild(document.createTextNode(scriptContent));
		(document.body || document.head || document.documentElement).appendChild(script);
		script.parentElement.removeChild(script);
	}


	function guidGenerator() {
	    var S4 = function() {
	       return (((1+Math.random())*0x10000)|0).toString(16).substring(1);
	    };
	    return (S4()+S4()+"-"+S4()+"-"+S4()+"-"+S4()+"-"+S4()+S4()+S4());
	}
}