/*
 * jQuery Scrolltastic plugin 1.1
 *
 * Copyright (c) 2010 Stephen Coley, DK New Media
 *
 * Licensed under MIT
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * http://www.opensource.org/licenses/mit-license.php
 *
 */


(function($){
	$.fn.scrolltastic = function(options) {
		var anchors;
		var timer;
		var mouseWheelActive;
		var defaults = {
			up: null,
			down: null,
			duration: "auto",
			autohide: false
		};
		var options = $.extend(defaults, options);

		var elem = this;

		var content = $(elem);
		var wrapper = content.parent();
		if(wrapper.css("position") == "static") {
			wrapper.css("position", "relative");
		}
		var wrapperHeight = wrapper.height();
		var contentHeight = content.height();

		content.children(":last-child").each(function(){
			if($(this).css("margin-top") != "") {
				var margin = $(this).css("margin-top");
				var marginArr = margin.split("p");
				contentHeight = contentHeight + parseInt(marginArr[0]);
			}
		});

		if((options.up != null && options.down == null) || (options.up == null && options.down != null)) {
			alert('Scrolltastic: If you\'re going to assign anchors, you MUST asign both "up" and "down" anchors. Not just one of them.');
		} else if(options.up != null && options.down != null) {

			$.each(["mousedown", "touchstart"], function(j, event) {

				options.up.bind(event, function() {
					upMouseDown();
					return false;
				});

				options.down.bind(event, function() {
					downMouseDown();
					return false;
				});

			});

			$.each([options.up, options.down], function(i, button) {
				$.each(["mouseup", "touchend"], function(j, event) {
					button.bind(event, function() {
						mouseUp();
					});
				});
			});

			$(options.down).click(function(){
				return false;
			});

			$(options.up).click(function(){
				return false;
			});

			anchors = true;
		} else {
			anchors = false;
		}

		content.mousewheel(function(event, delta, deltaX, deltaY) {
			if(mouseWheelActive == null) {
				$.clear(timer);
				if(delta > 0) {
					upMouseDown(content);
				} else {
					downMouseDown(content);
				}
				$.timeout(mouseUp, 100);
				mouseWheelActive = true;
			}
			return false;
		});

		function upMouseDown() {
			if(options.duration == "auto") {
				var dis = $(content).position().top * -1;
				var dur = dis * 3;
			}
			$(content).stop().animate({
				top: "0px"
			}, dur, "linear");
		}

		function downMouseDown() {
			if(options.duration == "auto") {
				var dis = ($(content).position().top + contentHeight) - wrapperHeight;
				var dur = dis * 3;
			}
			$(content).stop().animate({
				top: (contentHeight - wrapperHeight) * -1
			}, dur, "linear");
		}

		function mouseUp() {
			content.stop();
			var top = $(content).position().top;
			if(anchors) {
				if(top * -1 == contentHeight - wrapperHeight && options.autohide == true) {
					options.down.hide();
				} else {
					options.down.show();
				}
				if(top == 0 && options.autohide == true) {
					options.up.hide();
				} else {
					options.up.show();
				}
			}
			mouseWheelActive = null;
		}

	};
})(jQuery);