function Slider() { }

Slider.container = null;
Slider.containerUl = null
Slider.position = 0;

Slider.btnUp = null;
Slider.btnDown = null;

Slider.init = function() {

	var container = $("#podcast");
	var containerUl = $("ul", container); 
		
	var btnUp = $('<button id="podcast-up">up</button>');
	var btnDown = $('<button id="podcast-down">down</button>');

	btnUp.addClass('up');
	btnUp.addClass('inactive');
	
	btnDown.addClass('down');

	btnDown.bind('click', function() {

			if (Slider.position >= containerUl.height() * 2) {
				return;
			}

			Slider.position += 200;

			if (Slider.position >= containerUl.height() * 2) {
				Slider.position = containerUl.height() * 2;
			}

			Slider.checkActivation();
			
			containerUl
				.animate({ scrollTop: Slider.position }, "slow");
	
	});
	btnUp.bind('click', function() {

		// If it's already at the top, don't scroll up
		if (Slider.position <= 0) {
			return;
		}

		Slider.position -= 200;

		if (Slider.position < 0) {
			Slider.position = 0;
		}

		Slider.checkActivation();

		containerUl
			.animate({ scrollTop: Slider.position }, "slow");

	});

	Slider.btnUp = btnUp;
	Slider.btnDown = btnDown;
	Slider.containerUl = containerUl;
	
	container.prepend(btnUp);
	container.append(btnDown);

}

Slider.checkActivation = function() {

	if (Slider.position >= Slider.containerUl.height() * 2) {
		Slider.btnDown.addClass('inactive');
	}
	else {
		Slider.btnUp.removeClass('inactive');
		Slider.btnDown.removeClass('inactive');
	}

	if (Slider.position <= 0) {
		Slider.btnUp.addClass('inactive');		
	}
	else {
		Slider.btnUp.removeClass('inactive');
	}	
	
}

$(document).ready(function() {

	Slider.init();

});