var timerInterval = 4500, timer;

function stopToPlay() {
	if(timer !== undefined) {
		clearInterval(timer);
	}
}

function createTimer() {
	if(timer !== undefined) {
		clearInterval(timer);
	}

	timer = setInterval(function() { byTickOrByClickHandler(null) }, timerInterval);
}

function byTickOrByClickHandler(manualFrameChange) {
	var	csRef = $('#content-slider').attr('class'), classOfNextFrame;

	if(!manualFrameChange) {
		if(csRef === 'video') {
			classOfNextFrame = 'educator';
		}
		else if(csRef === 'educator') {
			classOfNextFrame = 'librarian';
		}
		else if(csRef === 'librarian') {
			classOfNextFrame = 'parent';
		}
		else if(csRef === 'parent') {
			classOfNextFrame = 'video';
		}
	} else {
		classOfNextFrame = manualFrameChange;
		createTimer();
	}

	if(csRef !== manualFrameChange) {
		$('#content-slider').attr('class', classOfNextFrame);
	}
}

function navigationClickHandler(event) {
	var $target = $(event.target), longName;

	if ($target.is("li")) {
		switch($target.attr('class')) {
			case "edu":
				longName = "educator";
				break;
			case "lib":
				longName = "librarian";
				break;
			case "par":
				longName = "parent";
				break;
			case "vid":
				longName = "video";
				break;
		}
	}

	byTickOrByClickHandler(longName);
}

$(document).ready(function() {
	$('#switch-btns').click(navigationClickHandler);
	$('#player').click(stopToPlay);

	createTimer();
});