/**
 * HoverScroll jQuery Plugin
 *
 * Make an unordered list scrollable by hovering the mouse over it
 *
 * @author RasCarlito <carl.ogren@gmail.com>
 * @version 0.2.2
 * @revision 14
 *
 * 
 *
 * FREE BEER LICENSE VERSION 1.02
 *
 * The free beer license is a license to give free software to you and free
 * beer (in)to the author(s).
 * 
 *
 * Released: 27-06-2009 6:00pm
 *
 * Changelog
 * ----------------------------------------------------
 * 0.2.2	Bug fixes
 *      	- Backward compatibility with jQuery 1.1.x
 *      	- Added test file to the archive
 *      	- Bug fix: The right arrow appeared when it wasn't necessary (thanks to <admin at unix dot am)
 * 
 * 0.2.1	Bug fixes
 *      	- Backward compatibility with jQuery 1.2.x (thanks to Andy Mull for compatibility with jQuery >= 1.2.4)
 *      	- Added information to the debug log
 * 
 * 0.2.0	Added some new features
 *      	- Direction indicator arrows
 *      	- Permanent override of default parameters
 * 
 * 0.1.1	Minor bug fix
 *      	- Hover zones did not cover the complete container
 *
 *      	note: The css file has not changed therefore it is still versioned 0.1.0
 *
 * 0.1.0	First release of the plugin. Supports:
 *      	- Horizontal and vertical lists
 *      	- Width and height control
 *      	- Debug log (doesn't show useful information for the moment)
 */
 
(function($) {

/**
 * @method hoverscroll
 * @param	params {Object}  Parameter list
 * 	params = {
 * 		vertical {Boolean},	// Vertical list or not ?
 * 		width {Integer},	// Width of list container
 * 		height {Integer},	// Height of list container
 *  	arrows {Boolean},	// Show direction indicators or not
 *  	arrowsOpacity {Float},	// Arrows maximum opacity
 * 		debug {Boolean}		// Debug output in firebug console
 * 	};
 */
$.fn.hoverscroll = function(params) {
	if (!params) { params = {}; }
	
	// Extend default parameters
	// note: empty object to prevent params object from overriding default params object
	params = $.extend({}, $.fn.hoverscroll.params, params);
	
	// Loop through all the elements
	this.each(function() {
		var $this = $(this);
		
		if (params.debug) {
			$.log('[HoverScroll] Trying to create hoverscroll on element ' + this.tagName + '#' + this.id);
		}
		
		// wrap ul list with a div.listcontainer
		$this.wrap('<div class="listcontainer"></div>');
		
		$this.addClass('list');
		//.addClass('ui-helper-clearfix');
		
		// store handle to listcontainer
		var listctnr = $this.parent();
		
		// wrap listcontainer with a div.hoverscroll
		listctnr.wrap('<div class="ui-widget-content hoverscroll"></div>');
		//listctnr.wrap('<div class="hoverscroll"></div>');
		
		// store hoverscroll container
		var ctnr = listctnr.parent();
		
		// Add arrow containers
		if (params.arrows) {
			if (!params.vertical) {
				listctnr.append('<div class="arrow left"></div>').append('<div class="arrow right"></div>')
				//.append('<div class="hoverZoneLeft"></div>').append('<div class="hoverZoneRight"></div>');
			}
			else {
				listctnr.append('<div class="arrow top"></div>').append('<div class="arrow bottom"></div>')
				//.append('<div class="hoverZoneTop"></div>').append('<div class="hoverZoneBottom"></div>');
			}
		}
		
		// Apply parameters width and height
		ctnr.width(params.width).height(params.height);
		listctnr.width(params.width).height(params.height);
		
		var size = 0;
		
		if (!params.vertical) {
			ctnr.addClass('horizontal');
			
			// Determine content width
			$this.children().each(function() {
				$(this).addClass('item');
				
				if ($(this).outerWidth) {
					size += $(this).outerWidth(true);
				}
				else {
					// jQuery < 1.2.x backward compatibility patch
					size += $(this).width() + parseInt($(this).css('padding-left')) + parseInt($(this).css('padding-right'))
						+ parseInt($(this).css('margin-left')) + parseInt($(this).css('margin-right'));
				}
			});
			// Apply computed width to listcontainer
			$this.width(size);
			
			if (params.debug) {
				$.log('[HoverScroll] Computed content width : ' + size + 'px');
			}
			
			// Retrieve container width instead of using the given params.width to include padding
			if (ctnr.outerWidth) {
				size = ctnr.outerWidth();
			}
			else {
				// jQuery < 1.2.x backward compatibility patch
				size = ctnr.width() + parseInt(ctnr.css('padding-left')) + parseInt(ctnr.css('padding-right'))
					+ parseInt(ctnr.css('margin-left')) + parseInt(ctnr.css('margin-right'));
			}
			
			if (params.debug) {
				$.log('[HoverScroll] Computed container width : ' + size + 'px');
			}
		}
		else {
			ctnr.addClass('vertical');
			
			// Determine content height
			$this.children().each(function() {
				$(this).addClass('item')
				
				if ($(this).outerHeight) {
					size += $(this).outerHeight(true);
				}
				else {
					// jQuery < 1.2.x backward compatibility patch
					size += $(this).height() + parseInt($(this).css('padding-top')) + parseInt($(this).css('padding-bottom'))
						+ parseInt($(this).css('margin-bottom')) + parseInt($(this).css('margin-bottom'));
				}
			});
			// Apply computed height to listcontainer
			$this.height(size);
			
			if (params.debug) {
				$.log('[HoverScroll] Computed content height : ' + size + 'px');
			}
			
			// Retrieve container height instead of using the given params.height to include padding
			if (ctnr.outerHeight) {
				size = ctnr.outerHeight();
			}
			else {
				// jQuery < 1.2.x backward compatibility patch
				size = ctnr.height() + parseInt(ctnr.css('padding-top')) + parseInt(ctnr.css('padding-bottom'))
					+ parseInt(ctnr.css('margin-top')) + parseInt(ctnr.css('margin-bottom'));
			}
			
			if (params.debug) {
				$.log('[HoverScroll] Computed container height : ' + size + 'px');
			}
		}
		
		// Define hover zones on container
		var zone = {
			1: { action: 'move', from: 0, to: 0.06 * size, direction: -1 , speed: 16 },
			2: { action: 'move', from: 0.06 * size, to: 0.15 * size, direction: -1 , speed: 8 },
			3: { action: 'move', from: 0.15 * size, to: 0.25 * size, direction: -1 , speed: 4 },
			4: { action: 'move', from: 0.25 * size, to: 0.4 * size, direction: -1 , speed: 2 },
			5: { action: 'stop', from: 0.4 * size, to: 0.6 * size },
			6: { action: 'move', from: 0.6 * size, to: 0.75 * size, direction: 1 , speed: 2 },
			7: { action: 'move', from: 0.75 * size, to: 0.85 * size, direction: 1 , speed: 4 },
			8: { action: 'move', from: 0.85 * size, to: 0.94 * size, direction: 1 , speed: 8 },
			9: { action: 'move', from: 0.94 * size, to: size, direction: 1 , speed: 16 }
		}
		
		// Store default state values in container
		ctnr[0].isChanging = false;
		ctnr[0].direction  = 0;
		ctnr[0].speed      = 1;
		
		
		/**
		 * Check mouse position relative to hoverscroll container
		 * and trigger actions according to the zone table
		 *
		 * @param x {Integer} Mouse X event position
		 * @param y {Integer} Mouse Y event position
		 */
		function checkMouse(x, y) {
			x = x - ctnr.offset().left;
			y = y - ctnr.offset().top;
			
			var pos;
			if (!params.vertical) { pos = x; }
			else { pos = y; }
			
			for (i in zone) {
				if (pos >= zone[i].from && pos < zone[i].to) {
					if (zone[i].action == 'move') { startMoving(zone[i].direction, zone[i].speed); }
					else { stopMoving(); }
				}
			}
		}
		
		
		/**
		 * Sets the opacity of the left|top and right|bottom
		 * arrows according to the scroll position.
		 */
		function setArrowOpacity() {
			if (!params.arrows) { return; }
			
			var maxScroll;
			var scroll;
			
			if (!params.vertical) {
				maxScroll = listctnr[0].scrollWidth - listctnr.width();
				scroll = listctnr[0].scrollLeft;
			}
			else {
				maxScroll = listctnr[0].scrollHeight - listctnr.height();
				scroll = listctnr[0].scrollTop;
			}
			
			var opacity = (scroll / maxScroll);
			var limit = params.arrowsOpacity;
			
			if (isNaN(opacity)) { opacity = 0; }
			
			// Check if the arrows are needed
			// Thanks to <admin at unix dot am> for fixing the bug that displayed the right arrow when it was not needed
			var done = false;
			if (opacity <= 0) { $('div.arrow.left, div.arrow.top', ctnr).hide(); done = true; }
			if (opacity >= limit || maxScroll <= 0) { $('div.arrow.right, div.arrow.bottom', ctnr).hide(); done = true; }
			
			if (!done) {
				$('div.arrow.left, div.arrow.top', ctnr).show().css('opacity', (opacity > limit ? limit : opacity));
				$('div.arrow.right, div.arrow.bottom', ctnr).show().css('opacity', (1 - opacity > limit ? limit : 1 - opacity));
			}
		}
		
		
		/**
		 * Start scrolling the list with a given speed and direction
		 *
		 * @param direction {Integer}	Direction of the displacement, either -1|1
		 * @param speed {Integer}		Speed of the displacement (20 being very fast)
		 */
		function startMoving(direction, speed) {
			if (ctnr[0].direction != direction) {
				if (params.debug) {
					$.log('[HoverScroll] Starting to move. direction: ' + direction + ', speed: ' + speed);
				}
				
				stopMoving();
				ctnr[0].direction  = direction;
				ctnr[0].isChanging = true;
				move();
			}
			if (ctnr[0].speed != speed) {
				if (params.debug) {
					$.log('[HoverScroll] Changed speed: ' + speed);
				}
				
				ctnr[0].speed = speed;
			}
		}
		
		/**
		 * Stop scrolling the list
		 */
		function stopMoving() {
			if (ctnr[0].isChanging) {
				if (params.debug) {
					$.log('[HoverScroll] Stoped moving');
				}
				
				ctnr[0].isChanging = false;
				ctnr[0].direction  = 0;
				ctnr[0].speed      = 1;
				clearTimeout(ctnr[0].timer);
			}
		}
		
		/**
		 * Move the list one step in the given direction and speed
		 */
		function move() {
			if (ctnr[0].isChanging == false) { return; }
			
			setArrowOpacity();
			
			var scrollSide;
			if (!params.vertical) { scrollSide = 'scrollLeft'; }
			else { scrollSide = 'scrollTop'; }
			
			listctnr[0][scrollSide] += ctnr[0].direction * ctnr[0].speed;
			ctnr[0].timer = setTimeout(function() { move(); }, 50);
		}
		
		// Bind actions to the hoverscroll container
		ctnr
		// Bind checkMouse to the mousemove
		.mousemove(function(e) { checkMouse(e.pageX, e.pageY); })
		// Bind stopMoving to the mouseleave
		// jQuery 1.2.x backward compatibility, thanks to Andy Mull!
		// replaced .mouseleave(...) with .bind('mouseleave', ...)
		.bind('mouseleave', function() { stopMoving(); });
		
		if (params.arrows) {
			// Initialise arrow opacity
			setArrowOpacity();
		}
		else {
			// Hide arrows
			$('.arrowleft, .arrowright, .arrowtop, .arrowbottom', ctnr).hide();
		}
	});
	
	return this;
};


// Backward compatibility with jQuery 1.1.x
if (!$.fn.offset) {
	$.fn.offset = function() {
		this.left = this.top = 0;
		
		if (this[0] && this[0].offsetParent) {
			var obj = this[0];
			do {
				this.left += obj.offsetLeft;
				this.top += obj.offsetTop;
			} while (obj = obj.offsetParent);
		}
		
		return this;
	}
}



/**
 * HoverScroll default parameters
 */
$.fn.hoverscroll.params = {
	vertical:	true,
	width:		550,
	height:		300,
	arrows:		true,
	arrowsOpacity:	0.7,
	debug:		false
};



/**
 * log to firebug console if exists
 */
$.log = function(msg) {
	if (console && console.log) {
		console.log(msg);
	}
};


})(jQuery);