var presentation = ["<word>warning<\/word>","<word>toxic<\/word>","<word>ash<\/word>","<word>air<\/word>","<word>eruption<\/word>","<phrase>Sometimes a volcano roars to life with little or no <strong data-readahead=\"warning\" class=\"presentation_word\">warning<\/strong>. That's what happened in late September when Japan's Mount Ontake belched <strong data-readahead=\"toxic\" class=\"presentation_word\">toxic<\/strong> fumes and <strong data-readahead=\"ash\" class=\"presentation_word\">ash<\/strong> into the <strong data-readahead=\"air\" class=\"presentation_word\">air<\/strong>, killing dozens of hikers. Other volcanoes, like Iceland's Bardarbunga, give some <strong data-readahead=\"warning\">warning<\/strong> of an impending <strong data-readahead=\"eruption\" class=\"presentation_word\">eruption<\/strong>.<\/phrase>","<word>Sensors<\/word>","<word>rumblings<\/word>","<word>warning<\/word>","<word>eruption<\/word>","<word>ash<\/word>","<word>Iceland's 30 active volcanoes<\/word>","<phrase>Scientists began getting clues that Bardarbunga was stirring to life weeks before it erupted this August: <strong data-readahead=\"Sensors\" class=\"presentation_word\">Sensors<\/strong> had detected <strong data-readahead=\"rumblings\" class=\"presentation_word\">rumblings<\/strong> in Earth's crust nearby. Despite the <strong data-readahead=\"warning\" class=\"presentation_word\">warning<\/strong>, no one knew if the recent <strong data-readahead=\"eruption\" class=\"presentation_word\">eruption<\/strong> would become dangerous. Back in 2010, <strong data-readahead=\"ash\" class=\"presentation_word\">ash<\/strong> from a volcano in Iceland grounded thousands of airplanes-stranding millions of passengers. Since then, scientists have begun closely monitoring <strong data-readahead=\"Iceland's 30 active volcanoes\" class=\"presentation_word\">Iceland's 30 active volcanoes<\/strong>.<\/phrase>","<word>predict<\/word>","<word>eruption<\/word>","<word>FutureVolc<\/word>","<word>warning<\/word>","<phrase>So far, there's no reliable way to <strong data-readahead=\"predict\" class=\"presentation_word\">predict<\/strong> when or where on Earth the next big <strong data-readahead=\"eruption\" class=\"presentation_word\">eruption<\/strong> will occur. Scientists from a project called <strong data-readahead=\"FutureVolc\" class=\"presentation_word\">FutureVolc<\/strong>, which is monitoring Iceland's volcanoes, want to change that. \"We hope to develop better <strong data-readahead=\"warning\" class=\"presentation_word\">warning<\/strong> systems all over the world,\" says earth scientist Aoife Braiden.<\/phrase>","<word>structure<\/word>","<word>geology<\/word>","<word>complex<\/word>","<word>Mid-Atlantic Ridge<\/word>","<word>two tectonic plates<\/word>","<word>Magma<\/word>","<word>lava<\/word>","<phrase>WHAT LURKS BENEATH\nIceland's explosiveness results from the <strong data-readahead=\"structure\" class=\"presentation_word\">structure<\/strong> of the earth beneath it. \"The <strong data-readahead=\"geology\" class=\"presentation_word\">geology<\/strong> in Iceland is quite <strong data-readahead=\"complex\" class=\"presentation_word\">complex<\/strong>,\" says Braiden. The island nation sits on the <strong data-readahead=\"Mid-Atlantic Ridge\" class=\"presentation_word\">Mid-Atlantic Ridge<\/strong>, a border between <strong data-readahead=\"two tectonic plates\" class=\"presentation_word\">two tectonic plates<\/strong> that are gradually sliding away from each other. <strong data-readahead=\"Magma\" class=\"presentation_word\">Magma<\/strong>, or liquid rock, pushes through the cracks between them and oozes to the surface as <strong data-readahead=\"lava\" class=\"presentation_word\">lava<\/strong>.<\/phrase>","<word>Mid-Atlantic Ridge<\/word>","<word>Ocean<\/word>","<word>lava<\/word>","<word>seafloor<\/word>","<phrase>Most of the <strong data-readahead=\"Mid-Atlantic Ridge\" class=\"presentation_word\">Mid-Atlantic Ridge<\/strong> runs along the bottom of the Atlantic <strong data-readahead=\"Ocean\" class=\"presentation_word\">Ocean<\/strong>. <strong data-readahead=\"lava\" class=\"presentation_word\">lava<\/strong> that emerges there hardens into new <strong data-readahead=\"seafloor\" class=\"presentation_word\">seafloor<\/strong>. But where the ridge cuts across Iceland, <strong data-readahead=\"lava\">lava<\/strong> erupts from volcanoes on land.<\/phrase>","<word>hot spot<\/word>","<word>Magma<\/word>","<word>volcanically active regions<\/word>","<phrase>Additionally, Iceland is situated on a <strong data-readahead=\"hot spot\" class=\"presentation_word\">hot spot<\/strong>, an area where heat wells up from deep within the planet. That heat melts rock into <strong data-readahead=\"Magma\" class=\"presentation_word\">Magma<\/strong>, making the country one of the most <strong data-readahead=\"volcanically active regions\" class=\"presentation_word\">volcanically active regions<\/strong> in the world. That makes Iceland an ideal place to study volcanoes.<\/phrase>","<word>warning<\/word>","<word>hard to<\/word>","<word>measure<\/word>","<word>New tools<\/word>","<phrase>GATHERING CLUES\nMost volcanoes give <strong data-readahead=\"warning\" class=\"presentation_word\">warning<\/strong> signs before they erupt. But these signs have been <strong data-readahead=\"hard to\" class=\"presentation_word\">hard to<\/strong> <strong data-readahead=\"measure\" class=\"presentation_word\">measure<\/strong> since it's dangerous to work near a volcano. <strong data-readahead=\"New tools\" class=\"presentation_word\">New tools<\/strong> are helping scientists study volcanoes remotely.<\/phrase>","<word>FutureVolc<\/word>","<word>Sensors<\/word>","<word>detect gases<\/word>","<word>Magma<\/word>","<word>rocks<\/word>","<word>eruption<\/word>","<word>measure vibrations<\/word>","<phrase><strong data-readahead=\"FutureVolc\" class=\"presentation_word\">FutureVolc<\/strong> is looking for signs of activity using high-tech <strong data-readahead=\"Sensors\" class=\"presentation_word\">Sensors<\/strong> that they've placed near volcanoes all over Iceland. <strong data-readahead=\"Sensors\">Sensors<\/strong> near cracks in Earth's crust can <strong data-readahead=\"detect gases\" class=\"presentation_word\">detect gases<\/strong> that could indicate the movement of <strong data-readahead=\"Magma\" class=\"presentation_word\">Magma<\/strong> beneath the surface. <strong data-readahead=\"Sensors\">Sensors<\/strong> on <strong data-readahead=\"rocks\" class=\"presentation_word\">rocks<\/strong> can detect the crust rising before an <strong data-readahead=\"eruption\" class=\"presentation_word\">eruption<\/strong>. Others can <strong data-readahead=\"measure vibrations\" class=\"presentation_word\">measure vibrations<\/strong> that pulse through the crust during earthquakes. \"Earthquakes within a volcano are often the first sign that it's coming alive,\" says Braiden.<\/phrase>","<word>Data<\/word>","<word>network<\/word>","<word>Sensors<\/word>","<word>erupt next<\/word>","<phrase><strong data-readahead=\"Data\" class=\"presentation_word\">Data<\/strong> from the <strong data-readahead=\"network\" class=\"presentation_word\">network<\/strong> of <strong data-readahead=\"Sensors\" class=\"presentation_word\">Sensors<\/strong> may someday help scientists figure out which volcano could <strong data-readahead=\"erupt next\" class=\"presentation_word\">erupt next<\/strong>.<\/phrase>","<word>SAFETY<\/word>","<word>predict<\/word>","<word>FutureVolc<\/word>","<word>how ash spreads<\/word>","<word>eruption<\/word>","<phrase>FOR <strong data-readahead=\"SAFETY\" class=\"presentation_word\">SAFETY<\/strong>'S SAKE\nStill, scientists may never be able to <strong data-readahead=\"predict\" class=\"presentation_word\">predict<\/strong> exactly when a volcano will erupt, says Braiden. That's why <strong data-readahead=\"FutureVolc\" class=\"presentation_word\">FutureVolc<\/strong> is also studying <strong data-readahead=\"how ash spreads\" class=\"presentation_word\">how ash spreads<\/strong> during an <strong data-readahead=\"eruption\" class=\"presentation_word\">eruption<\/strong>.<\/phrase>","<word>humans and animals<\/word>","<word>ash<\/word>","<word>damage their lungs<\/word>","<word>pollute<\/word>","<phrase>\"If <strong data-readahead=\"humans and animals\" class=\"presentation_word\">humans and animals<\/strong> breathe in the <strong data-readahead=\"ash\" class=\"presentation_word\">ash<\/strong>, it can <strong data-readahead=\"damage their lungs\" class=\"presentation_word\">damage their lungs<\/strong>,\" says Braiden. <strong data-readahead=\"ash\">ash<\/strong> also can <strong data-readahead=\"pollute\" class=\"presentation_word\">pollute<\/strong> lakes and rivers. The more information scientists can gather on volcanoes now, the better everyone can prepare for the next big boom.<\/phrase>"];
	var currentPosition = 0;
	var totalPositions = 0;
	var timePerWord = 1500;
	var timePerPhraseWord = 120
	var readAheadPlayerTimer;
	var autoPlay = true;
	var setMinimized = false;

	var wordSpeedOptions = {'Slower':2000,'Moderate':1200,'Fast':800};
	var phraseSpeedOptions = {'Slower':280,'Moderate':200,'Fast':80};
	var defaultWordSpeedOption = 'Moderate';
	var defaultPhraseSpeedOption = 'Moderate';
	var logToLTI = false;

	$(window).load(function(){
		totalPositions = presentation.length;
		if (totalPositions > 0){
			$('body').prepend('<div id="read_ahead_player_back"></div>');
			$('body').prepend('<div id="read_ahead_player"></div>');
			$('#read_ahead_player').prepend('<div id="read_ahead_player_field" class="read_ahead_word_section"></div>');
			initializeReadAheadControls();
			initializeReadAheadSlider();
			initializeReadAheadSpeedOptions();
			currentReadAheadControls();
			resumeReadAheadPlayback();
		}
	});

	$(document).keyup(function(e){
		switch(e.which) {
			case 37: 
				pauseReadAheadPresentation();
				priorReadAheadPresentationItem();
				break;
			case 39:
				pauseReadAheadPresentation();
				nextReadAheadPresentationItem();
				break;
			default:
				break;
		}

	});

	function initializeReadAheadControls(){
		var s = '';
		s += '<a href="javascript:void(0)" onclick="read_ahead_switch_min_max(true);" id="read_ahead_player_max_min" class="player-icons" aria-label="minimize/maximize player">';
		s += '<span class="fa-stack fa-lg " aria-hidden><i class="fa fa-circle fa-stack-2x"></i><i class="fa fa-minus fa-stack-1x fa-inverse"></i></span>';
		s += '</a>';
		s += '<div id="read_ahead_controls">';
		s += '<a href="javascript:void(0)" onclick="priorReadAheadPresentationItem()" id="read_ahead_player_previous_word" class="player-icons" aria-label="previous keyword">';
		s += '<span class="fa-stack fa-lg " aria-hidden><i class="fa fa-circle fa-stack-2x"></i><i class="fa fa-backward fa-stack-1x fa-inverse"></i></span>';
		s += '</a>';
		s += '<a href="javascript:void(0)" onclick="pauseReadAheadPresentation()" id="read_ahead_player_pause_play" class="player-icons" aria-label="play/pause">';
		s += '<span class="fa-stack fa-lg " aria-hidden><i class="fa fa-circle fa-stack-2x"></i><i class="fa fa-pause fa-stack-1x fa-inverse"></i></span>';
		s += '</a>';
		s += '<a href="javascript:void(0)" onclick="nextReadAheadPresentationItem()" id="read_ahead_player_next_word" class="player-icons" aria-label="next keyword">';
		s += '<span class="fa-stack fa-lg " aria-hidden><i class="fa fa-circle fa-stack-2x"></i><i class="fa fa-forward fa-stack-1x fa-inverse"></i></span>';
		s += '</a>';
		s += '</div>';
		$('#read_ahead_player').append(s);
	}

	function initializeReadAheadSlider(){
		var s = '';
		s += '<div class="read_ahead_slider" id="readAheadSlider">';
		s += '<div class="read_ahead_slider_bar" id="readAheadSliderBar"></div>';
		s += '</div>';
		$('#read_ahead_controls').prepend(s);
		updateReadAheadSliderPosition();
	}

	function initializeReadAheadSpeedOptions(){
		var s = '<div id="read_ahead_player_options">';
		s += '<div class="slider_control" id="slider_control_word_speed">';
		s += ' Word Speed<br/>';
		s += '<div class="slider_bar">';
		optionCount = 0;
		for (index in wordSpeedOptions) { optionCount++; }
		optionWidth = 100 / optionCount;
		for (index in wordSpeedOptions) {
			var option = wordSpeedOptions[index];
			if (index == defaultWordSpeedOption) {
				s += '<a href="javascript:void(0)" id="slider_control_word_speed_'+option+'" onclick="updateReadAheadWordSpeed('+option+',this)" style="width:'+optionWidth+'%;" title="'+index+'" data-speed="'+option+'" class="current_speed" aria-label="'+index+'"></a>';
				updateReadAheadWordSpeed(option);
			} else {
				s += '<a href="javascript:void(0)" id="slider_control_word_speed_'+option+'" onclick="updateReadAheadWordSpeed('+option+',this)" style="width:'+optionWidth+'%;" title="'+index+'" data-speed="'+option+'" aria-label="'+index+'"></a>';
			}
		}
		s += '</div>';
		s += '</div>';
		s += '<div class="slider_control" id="slider_control_phrase_speed">';
		s += ' Phrase Speed<br/>';
		s += '<div class="slider_bar">';
		optionCount = 0;
		for (index in phraseSpeedOptions) { optionCount++; }
		optionWidth = 100 / optionCount;
		for (index in phraseSpeedOptions) {
			var option = phraseSpeedOptions[index];
			if (index == defaultWordSpeedOption) {
				s += '<a href="javascript:void(0)" id="slider_control_phrase_speed_'+option+'" onclick="updateReadAheadPhraseSpeed('+option+',this)" style="width:'+optionWidth+'%;" title="'+index+'" data-speed="'+option+'" class="current_speed" aria-label="'+index+'"></a>';
				updateReadAheadPhraseSpeed(option);
			} else {
				s += '<a href="javascript:void(0)" id="slider_control_phrase_speed_'+option+'" onclick="updateReadAheadPhraseSpeed('+option+',this)" style="width:'+optionWidth+'%;" title="'+index+'" data-speed="'+option+'" aria-label="'+index+'"></a>';
			}
		}
		s += '</div>';
		s += '</div>';
		s += '</div>';
		$('#read_ahead_controls').append(s);
	}

	function updateReadAheadWordSpeed(microseconds,sender) {
		microseconds = microseconds != undefined && microseconds > 0 ? microseconds : 0;
		if (microseconds > 0) { timePerWord = microseconds; }
		if (sender!=undefined) { 
			$('#slider_control_word_speed').find('a').removeClass('current_speed');
			$(sender).addClass('current_speed');
		}
		logReadAheadPlayerAction('updateReadAheadWordSpeed','Presentation',microseconds);
	}

	function updateReadAheadPhraseSpeed(microseconds,sender) {
		microseconds = microseconds != undefined && microseconds > 0 ? microseconds : 0;
		if (microseconds > 0 ) { timePerPhraseWord = microseconds; }
		if (sender!=undefined) { 
			$('#slider_control_phrase_speed').find('a').removeClass('current_speed');
			$(sender).addClass('current_speed');
		}
		logReadAheadPlayerAction('updateReadAheadPhraseSpeed','Presentation',microseconds);
	}

	function updateReadAheadSliderPosition(){
		var currentSliderBarWidth = 100 - (100 / totalPositions * (currentPosition + 1));
		$('#readAheadSliderBar').css('width',currentSliderBarWidth+'%');
	}

	function currentReadAheadControls(){
		$('#read_ahead_player_pause_play').show();
		if (currentPosition < totalPositions - 1)	{
			$('#read_ahead_player_next_word').removeClass('disabled');
		} else {
			$('#read_ahead_player_next_word').addClass('disabled');
		}
		if (currentPosition > 0) {
			$('#read_ahead_player_previous_word').removeClass('disabled');
		} else {
			$('#read_ahead_player_previous_word').addClass('disabled');
		}
	}

	function restartReadAheadPresentation(){
		currentPosition = 0;
		logReadAheadPlayerAction('restartReadAheadPresentation','Presentation','');
		resumeReadAheadPlayback();
	}

	function resumeReadAheadPlayback(){
		$('.fa-repeat').removeClass('fa-repeat').addClass('fa-play');
		$('#read_ahead_player_pause_play').each(function(){
			$(this).find('.fa-play').removeClass('fa-play').addClass('fa-pause');
			$(this).off('click');
			$(this).attr('onclick','pauseReadAheadPresentation()');
		});
		logReadAheadPlayerAction('resumeReadAheadPlayback','Presentation','');
		playReadAheadPresentation();
	}

	function pauseReadAheadPresentation(){
		$('#read_ahead_player_pause_play').each(function(){
			$(this).find('.fa-pause').removeClass('fa-pause').addClass('fa-play');
			$(this).off('click');
			$(this).attr('onclick','resumeReadAheadPlayback()');
		});
		logReadAheadPlayerAction('pauseReadAheadPresentation','Presentation','');
		read_ahead_pause();
	}

	function endReadAheadPresentation(){
		$('.fa-play').removeClass('fa-play').addClass('fa-repeat');
		$('.fa-pause').removeClass('fa-pause').addClass('fa-repeat');
		$('#read_ahead_player_pause_play').each(function(){
			$(this).off('click');
			$(this).attr('onclick','restartReadAheadPresentation()');
		});
		logReadAheadPlayerAction('endReadAheadPresentation','Presentation','');
		logLTIEndPresentation();
	}

	function playReadAheadPresentation(){
		autoPlay=true;
		currentPosition--;
		logReadAheadPlayerAction('playReadAheadPresentation','Presentation','');
		nextReadAheadPresentationItem(); 
	}

	function startReadAheadStepper(timeDisplayWord){
		clearInterval(readAheadPlayerTimer);
		readAheadPlayerTimer = setTimeout(function() { read_ahead_step(); },timeDisplayWord);
	}

	function stopReadAheadStepper(){
		clearInterval(readAheadPlayerTimer);
	}

	function read_ahead_step(){
		if (autoPlay) {
			nextReadAheadPresentationItem();
		}
	}

	function read_ahead_pause(){
		autoPlay=false;
		stopReadAheadStepper();
	}

	function showReadAheadPresentationItem(index){
		currentPosition = index;
		currentPresentationItem = presentation[currentPosition] != undefined ? presentation[currentPosition].trim() : "";
		if (currentPresentationItem != "") {
			currentItemWordCount = presentation[currentPosition].replace("\n","").split(" ").length;
			if (currentPresentationItem.startsWith("<word>")){
				startReadAheadStepper(currentItemWordCount*timePerWord);
				$('#read_ahead_player_field').html('<div class="read_ahead_word" style="display:block;">'+currentPresentationItem+'</div>');
				logReadAheadPlayerAction('showReadAheadPresentationItem','Word',currentPresentationItem);
		
			} else {
				startReadAheadStepper(currentItemWordCount*timePerPhraseWord);
				$('#read_ahead_player_field').html('<div class="read_ahead_text_box" style="display:block;"><div class="read_ahead_text">'+currentPresentationItem.replace("\n","<br />")+'</div></div>');
				logReadAheadPlayerAction('showReadAheadPresentationItem','Phrase','');
		
			}
		} else {
			if (currentPosition < totalPositions) {
				nextReadAheadPresentationItem();
			} else {
				endReadAheadPresentation();
				read_ahead_minimize();
			}
		}
		currentReadAheadControls();
		updateReadAheadSliderPosition();
		saveReadAheadPosition();
	}

	function priorReadAheadPresentationItem(){
		stopReadAheadStepper();
		logReadAheadPlayerAction('priorReadAheadPresentationItem','Controls','');
		showReadAheadPresentationItem(currentPosition-1);
	}


	function nextReadAheadPresentationItem(){
		stopReadAheadStepper();
		logReadAheadPlayerAction('nextReadAheadPresentationItem','Controls','');
		showReadAheadPresentationItem(currentPosition+1);
	}

	function read_ahead_playAgain(){
		currentWordIndex = 0;
		logReadAheadPlayerAction('read_ahead_playAgain','Controls','');
		playReadAheadPresentation();
	}


	function read_ahead_minimize(){
		setMinimized = true;
		logReadAheadPlayerAction('read_ahead_minimize','Controls','');
		read_ahead_switch_min_max();
	}

	function read_ahead_maximize(){
		setMinimized = false;
		logReadAheadPlayerAction('read_ahead_maximize','Controls','');
		read_ahead_switch_min_max();
	}

	function read_ahead_switch_min_max(forceSwitch){
		forceSwitch = forceSwitch != undefined ? forceSwitch : false;
		if (forceSwitch) { setMinimized = !setMinimized; }

		if (setMinimized) {
			$('#read_ahead_player_back').fadeOut();
			$('#read_ahead_player').addClass('minimize');
			$('.player-icons .fa-stack').removeClass('fa-lg').addClass('fa-sm');
			$('.player-icons .fa-minus').removeClass('fa-minus').addClass('fa-expand');
			logReadAheadPlayerAction('read_ahead_switch_min_max','Min','');
			//$('#read_ahead_player_max_min').each(function(){
			//	$(this).off('click');
			//	$(this).attr('onclick','read_ahead_maximize()');
			//});
		} else {
			$('#read_ahead_player_back').fadeIn();
			$('#read_ahead_player').removeClass('minimize');
			$('.player-icons .fa-stack').removeClass('fa-sm').addClass('fa-lg');
			$('.player-icons .fa-expand').removeClass('fa-expand').addClass('fa-minus');
			logReadAheadPlayerAction('read_ahead_switch_min_max','Max','');
			//$('#read_ahead_player_max_min').each(function(){
			//	$(this).off('click');
			//	$(this).attr('onclick','read_ahead_minimize()');
			//});
		}

	}

	function saveReadAheadPosition(){
		$.ajax({
			type:'POST',
			url:'/ajax/save_user_presentation_position.php',
			data: { 'id':93,
					'position': currentPosition
				}
		})
		.done(function(results){
		})
		.fail(function( jqXHR, textStatus ) {
			alert( "Request failed: " + textStatus );
		});

	}

	function logLTIEndPresentation(action) {
		if (!logToLTI) {
			return;
		}

		$.ajax({
			type:'POST',
			url:'/lti/presentationEnded.php',
			data: { 'documentId':93,
					'userId':0,
				}
		})
	}

	function logReadAheadPlayerAction(action,area,details){
		var d = new Date();
		var t = d.getTime();
		action = action != undefined ? action.trim() : 'UNKNOWN';
		area = area != undefined ? area.trim() : '';
		details = details != undefined ? details : '';

		// If we are about to show a new word, increase the number of keywords
		// reinforced so we can log that for the Dashboard page.
		if (area == 'Word') {
			window.keywordCount++;
		}

		$.ajax({
			type:'POST',
			url:'/logging/logPlayerAction.php',
			data: { 'documentId':93,
					'userId':0,
					'playerAction':action,
					'playerArea':area,
					'details':details,
					'timestamp': t
				}
		})
		.done(function(results){
		})
		.fail(function( jqXHR, textStatus ) {
			alert( "Request failed: " + textStatus );
		});

	}