孙向锦 / SunvoteEducation

/**
 <b>Ace custom scroller</b>. It is not as feature-rich as plugins such as NiceScroll but it's good enough for most cases.
*/
(function($ , undefined) {
	var Ace_Scroll = function(element , _settings) {
		var self = this;
		
		var attrib_values = ace.helper.getAttrSettings(element, $.fn.ace_scroll.defaults);
		var settings = $.extend({}, $.fn.ace_scroll.defaults, _settings, attrib_values);
	
		this.size = 0;
		this.lock = false;
		this.lock_anyway = false;
		
		this.$element = $(element);
		this.element = element;
		
		var vertical = true;

		var disabled = false;
		var active = false;
		var created = false;

		var $content_wrap = null, content_wrap = null;
		var $track = null, $bar = null, track = null, bar = null;
		var bar_style = null;
		
		var bar_size = 0, bar_pos = 0, bar_max_pos = 0, bar_size_2 = 0, move_bar = true;
		var reset_once = false;
		
		var styleClass = '';
		var trackFlip = false;//vertical on left or horizontal on top
		var trackSize = 0;

		var css_pos,
			css_size,
			max_css_size,
			client_size,
			scroll_direction,
			scroll_size;

		var ratio = 1;
		var inline_style = false;
		var mouse_track = false;
		var mouse_release_target = 'onmouseup' in window ? window : 'html';
		var dragEvent = settings.dragEvent || false;
		
		var trigger_scroll = _settings.scrollEvent || false;
		
		
		var detached = settings.detached || false;//when detached, hideOnIdle as well?
		var updatePos = settings.updatePos || false;//default is true
		
		var hideOnIdle = settings.hideOnIdle || false;
		var hideDelay = settings.hideDelay || 1500;
		var insideTrack = false;//used to hide scroll track when mouse is up and outside of track
		var observeContent = settings.observeContent || false;
		var prevContentSize = 0;
		
		var is_dirty = true;//to prevent consecutive 'reset' calls
		
		this.create = function(_settings) {
			if(created) return;
			//if(disabled) return;
			if(_settings) settings = $.extend({}, $.fn.ace_scroll.defaults, _settings);

			this.size = parseInt(this.$element.attr('data-size')) || settings.size || 200;
			vertical = !settings['horizontal'];

			css_pos = vertical ? 'top' : 'left';//'left' for horizontal
			css_size = vertical ? 'height' : 'width';//'width' for horizontal
			max_css_size = vertical ? 'maxHeight' : 'maxWidth';

			client_size = vertical ? 'clientHeight' : 'clientWidth';
			scroll_direction = vertical ? 'scrollTop' : 'scrollLeft';
			scroll_size = vertical ? 'scrollHeight' : 'scrollWidth';



			this.$element.addClass('ace-scroll');
			if(this.$element.css('position') == 'static') {
				inline_style = this.element.style.position;
				this.element.style.position = 'relative';
			} else inline_style = false;

			var scroll_bar = null;
			if(!detached) {
				this.$element.wrapInner('<div class="scroll-content" />');
				this.$element.prepend('<div class="scroll-track"><div class="scroll-bar"></div></div>');
			}
			else {
				scroll_bar = $('<div class="scroll-track scroll-detached"><div class="scroll-bar"></div></div>').appendTo('body');
			}


			$content_wrap = this.$element;
			if(!detached) $content_wrap = this.$element.find('.scroll-content').eq(0);
			
			if(!vertical) $content_wrap.wrapInner('<div />');
			
			content_wrap = $content_wrap.get(0);
			if(detached) {
				//set position for detached scrollbar
				$track = scroll_bar;
				setTrackPos();
			}
			else $track = this.$element.find('.scroll-track').eq(0);
			
			$bar = $track.find('.scroll-bar').eq(0);
			track = $track.get(0);
			bar = $bar.get(0);
			bar_style = bar.style;

			//add styling classes and horizontalness
			if(!vertical) $track.addClass('scroll-hz');
			if(settings.styleClass) {
				styleClass = settings.styleClass;
				$track.addClass(styleClass);
				trackFlip = !!styleClass.match(/scroll\-left|scroll\-top/);
			}
			
			//calculate size of track!
			if(trackSize == 0) {
				$track.show();
				getTrackSize();
			}
			
			$track.hide();
			

			//if(!touchDrag) {
			$track.on('mousedown', mouse_down_track);
			$bar.on('mousedown', mouse_down_bar);
			//}

			$content_wrap.on('scroll', function() {
				if(move_bar) {
					bar_pos = parseInt(Math.round(this[scroll_direction] * ratio));
					bar_style[css_pos] = bar_pos + 'px';
				}
				move_bar = false;
				if(trigger_scroll) this.$element.trigger('scroll', [content_wrap]);
			})


			if(settings.mouseWheel) {
				this.lock = settings.mouseWheelLock;
				this.lock_anyway = settings.lockAnyway;

				//mousewheel library available?
				this.$element.on(!!$.event.special.mousewheel ? 'mousewheel.ace_scroll' : 'mousewheel.ace_scroll DOMMouseScroll.ace_scroll', function(event) {
					if(disabled) return;
					checkContentChanges(true);

					if(!active) return !self.lock_anyway;

					if(mouse_track) {
						mouse_track = false;
						$('html').off('.ace_scroll')
						$(mouse_release_target).off('.ace_scroll');
						if(dragEvent) self.$element.trigger('drag.end');
					}
					

					event.deltaY = event.deltaY || 0;
					var delta = (event.deltaY > 0 || event.originalEvent.detail < 0 || event.originalEvent.wheelDelta > 0) ? 1 : -1
					var scrollEnd = false//have we reached the end of scrolling?
					
					var clientSize = content_wrap[client_size], scrollAmount = content_wrap[scroll_direction];
					if( !self.lock ) {
						if(delta == -1)	scrollEnd = (content_wrap[scroll_size] <= scrollAmount + clientSize);
						else scrollEnd = (scrollAmount == 0);
					}

					self.move_bar(true);

					//var step = parseInt( Math.min(Math.max(parseInt(clientSize / 8) , 80) , self.size) ) + 1;
					var step = parseInt(clientSize / 8);
					if(step < 80) step = 80;
					if(step > self.size) step = self.size;
					step += 1;
					
					content_wrap[scroll_direction] = scrollAmount - (delta * step);


					return scrollEnd && !self.lock_anyway;
				})
			}
			
			
			//swipe not available yet
			var touchDrag = ace.vars['touch'] && 'ace_drag' in $.event.special && settings.touchDrag //&& !settings.touchSwipe;
			//add drag event for touch devices to scroll
			if(touchDrag/** || ($.fn.swipe && settings.touchSwipe)*/) {
				var dir = '', event_name = touchDrag ? 'ace_drag' : 'swipe';
				this.$element.on(event_name + '.ace_scroll', function(event) {
					if(disabled) {
						event.retval.cancel = true;
						return;
					}
					checkContentChanges(true);
					
					if(!active) {
						event.retval.cancel = this.lock_anyway;
						return;
					}

					dir = event.direction;
					if( (vertical && (dir == 'up' || dir == 'down'))
						||
						(!vertical && (dir == 'left' || dir == 'right'))
					   )
					{
						var distance = vertical ? event.dy : event.dx;

						if(distance != 0) {
							if(Math.abs(distance) > 20 && touchDrag) distance = distance * 2;

							self.move_bar(true);
							content_wrap[scroll_direction] = content_wrap[scroll_direction] + distance;
						}
					}
					
				})
			}
			
			
			/////////////////////////////////
			
			if(hideOnIdle) {
				$track.addClass('idle-hide');
			}
			if(observeContent) {
				$track.on('mouseenter.ace_scroll', function() {
					insideTrack = true;
					checkContentChanges(false);
				}).on('mouseleave.ace_scroll', function() {
					insideTrack = false;
					if(mouse_track == false) hideScrollbars();
				});
			}


			
			//some mobile browsers don't have mouseenter
			this.$element.on('mouseenter.ace_scroll touchstart.ace_scroll', function(e) {
				//if(ace.vars['old_ie']) return;//IE8 has a problem triggering event two times and strangely wrong values for this.size especially in fullscreen widget!
				
				is_dirty = true;
				if(observeContent) checkContentChanges(true);
				else if(settings.hoverReset) self.reset(true);
				
				$track.addClass('scroll-hover');
			}).on('mouseleave.ace_scroll touchend.ace_scroll', function() {
				$track.removeClass('scroll-hover');
			});
			//

			if(!vertical) $content_wrap.children(0).css(css_size, this.size);//the extra wrapper
			$content_wrap.css(max_css_size , this.size);
			
			disabled = false;
			created = true;
		}
		this.is_active = function() {
			return active;
		}
		this.is_enabled = function() {
			return !disabled;
		}
		this.move_bar = function($move) {
			move_bar = $move;
		}
		
		this.get_track = function() {
			return track;
		}

		this.reset = function(innert_call) {
			if(disabled) return;// this;
			if(!created) this.create();
			/////////////////////
			var size = this.size;
			
			if(innert_call && !is_dirty) {
				return;
			}
			is_dirty = false;

			if(detached) {
				var border_size = parseInt(Math.round( (parseInt($content_wrap.css('border-top-width')) + parseInt($content_wrap.css('border-bottom-width'))) / 2.5 ));//(2.5 from trial?!)
				size -= border_size;//only if detached
			}
	
			var content_size   = vertical ? content_wrap[scroll_size] : size;
			if( (vertical && content_size == 0) || (!vertical && this.element.scrollWidth == 0) ) {
				//element is hidden
				//this.$element.addClass('scroll-hidden');
				$track.removeClass('scroll-active')
				return;// this;
			}

			var available_space = vertical ? size : content_wrap.clientWidth;

			if(!vertical) $content_wrap.children(0).css(css_size, size);//the extra wrapper
			$content_wrap.css(max_css_size , this.size);
			

			if(content_size > available_space) {
				active = true;
				$track.css(css_size, available_space).show();

				ratio = parseFloat((available_space / content_size).toFixed(5))
				
				bar_size = parseInt(Math.round(available_space * ratio));
				bar_size_2 = parseInt(Math.round(bar_size / 2));

				bar_max_pos = available_space - bar_size;
				bar_pos = parseInt(Math.round(content_wrap[scroll_direction] * ratio));

				bar_style[css_size] = bar_size + 'px';
				bar_style[css_pos] = bar_pos + 'px';
				
				$track.addClass('scroll-active');
				
				if(trackSize == 0) {
					getTrackSize();
				}

				if(!reset_once) {
					//this.$element.removeClass('scroll-hidden');
					if(settings.reset) {
						//reset scrollbar to zero position at first							
						content_wrap[scroll_direction] = 0;
						bar_style[css_pos] = 0;
					}
					reset_once = true;
				}
				
				if(detached) setTrackPos();
			} else {
				active = false;
				$track.hide();
				$track.removeClass('scroll-active');
				$content_wrap.css(max_css_size , '');
			}

			return;// this;
		}
		this.disable = function() {
			content_wrap[scroll_direction] = 0;
			bar_style[css_pos] = 0;

			disabled = true;
			active = false;
			$track.hide();
			
			this.$element.addClass('scroll-disabled');
			
			$track.removeClass('scroll-active');
			$content_wrap.css(max_css_size , '');
		}
		this.enable = function() {
			disabled = false;
			this.$element.removeClass('scroll-disabled');
		}
		this.destroy = function() {
			active = false;
			disabled = false;
			created = false;
			
			this.$element.removeClass('ace-scroll scroll-disabled scroll-active');
			this.$element.off('.ace_scroll')

			if(!detached) {
				if(!vertical) {
					//remove the extra wrapping div
					$content_wrap.find('> div').children().unwrap();
				}
				$content_wrap.children().unwrap();
				$content_wrap.remove();
			}
			
			$track.remove();
			
			if(inline_style !== false) this.element.style.position = inline_style;
			
			if(idleTimer != null) {
				clearTimeout(idleTimer);
				idleTimer = null;
			}
		}
		this.modify = function(_settings) {
			if(_settings) settings = $.extend({}, settings, _settings);
			
			this.destroy();
			this.create();
			is_dirty = true;
			this.reset(true);
		}
		this.update = function(_settings) {
			if(_settings) settings = $.extend({}, settings, _settings);
		
			this.size = _settings.size || this.size;
			
			this.lock = _settings.mouseWheelLock || this.lock;
			this.lock_anyway = _settings.lockAnyway || this.lock_anyway;
			
			if(_settings.styleClass != undefined) {
				if(styleClass) $track.removeClass(styleClass);
				styleClass = _settings.styleClass;
				if(styleClass) $track.addClass(styleClass);
				trackFlip = !!styleClass.match(/scroll\-left|scroll\-top/);
			}
		}
		
		this.start = function() {
			content_wrap[scroll_direction] = 0;
		}
		this.end = function() {
			content_wrap[scroll_direction] = content_wrap[scroll_size];
		}
		
		this.hide = function() {
			$track.hide();
		}
		this.show = function() {
			$track.show();
		}

		
		this.update_scroll = function() {
			move_bar = false;
			bar_style[css_pos] = bar_pos + 'px';
			content_wrap[scroll_direction] = parseInt(Math.round(bar_pos / ratio));
		}

		function mouse_down_track(e) {
			e.preventDefault();
			e.stopPropagation();
				
			var track_offset = $track.offset();
			var track_pos = track_offset[css_pos];//top for vertical, left for horizontal
			var mouse_pos = vertical ? e.pageY : e.pageX;
			
			if(mouse_pos > track_pos + bar_pos) {
				bar_pos = mouse_pos - track_pos - bar_size + bar_size_2;
				if(bar_pos > bar_max_pos) {						
					bar_pos = bar_max_pos;
				}
			}
			else {
				bar_pos = mouse_pos - track_pos - bar_size_2;
				if(bar_pos < 0) bar_pos = 0;
			}

			self.update_scroll()
		}

		var mouse_pos1 = -1, mouse_pos2 = -1;
		function mouse_down_bar(e) {
			e.preventDefault();
			e.stopPropagation();

			if(vertical) {
				mouse_pos2 = mouse_pos1 = e.pageY;
			} else {
				mouse_pos2 = mouse_pos1 = e.pageX;
			}

			mouse_track = true;
			$('html').off('mousemove.ace_scroll').on('mousemove.ace_scroll', mouse_move_bar)
			$(mouse_release_target).off('mouseup.ace_scroll').on('mouseup.ace_scroll', mouse_up_bar);
			
			$track.addClass('active');
			if(dragEvent) self.$element.trigger('drag.start');
		}
		function mouse_move_bar(e) {
			e.preventDefault();
			e.stopPropagation();

			if(vertical) {
				mouse_pos2 = e.pageY;
			} else {
				mouse_pos2 = e.pageX;
			}
			

			if(mouse_pos2 - mouse_pos1 + bar_pos > bar_max_pos) {
				mouse_pos2 = mouse_pos1 + bar_max_pos - bar_pos;
			} else if(mouse_pos2 - mouse_pos1 + bar_pos < 0) {
				mouse_pos2 = mouse_pos1 - bar_pos;
			}
			bar_pos = bar_pos + (mouse_pos2 - mouse_pos1);

			mouse_pos1 = mouse_pos2;

			if(bar_pos < 0) {
				bar_pos = 0;
			}
			else if(bar_pos > bar_max_pos) {
				bar_pos = bar_max_pos;
			}
			
			self.update_scroll()
		}
		function mouse_up_bar(e) {
			e.preventDefault();
			e.stopPropagation();
			
			mouse_track = false;
			$('html').off('.ace_scroll')
			$(mouse_release_target).off('.ace_scroll');

			$track.removeClass('active');
			if(dragEvent) self.$element.trigger('drag.end');
			
			if(active && hideOnIdle && !insideTrack) hideScrollbars();
		}
		
		
		var idleTimer = null;
		var prevCheckTime = 0;
		function checkContentChanges(hideSoon) {
			//check if content size has been modified since last time?
			//and with at least 1s delay
			var newCheck = +new Date();
			if(observeContent && newCheck - prevCheckTime > 1000) {
				var newSize = content_wrap[scroll_size];
				if(prevContentSize != newSize) {
					prevContentSize = newSize;
					is_dirty = true;
					self.reset(true);
				}
				prevCheckTime = newCheck;
			}
			
			//show scrollbars when not idle anymore i.e. triggered by mousewheel, dragging, etc
			if(active && hideOnIdle) {
				if(idleTimer != null) {
					clearTimeout(idleTimer);
					idleTimer = null;
				}
				$track.addClass('not-idle');
			
				if(!insideTrack && hideSoon == true) {
					//hideSoon is false when mouse enters track
					hideScrollbars();
				}
			}
		}

		function hideScrollbars() {
			if(idleTimer != null) {
				clearTimeout(idleTimer);
				idleTimer = null;
			}
			idleTimer = setTimeout(function() {
				idleTimer = null;
				$track.removeClass('not-idle');
			} , hideDelay);
		}
		
		//for detached scrollbars
		function getTrackSize() {
			$track.css('visibility', 'hidden').addClass('scroll-hover');
			if(vertical) trackSize = parseInt($track.outerWidth()) || 0;
			 else trackSize = parseInt($track.outerHeight()) || 0;
			$track.css('visibility', '').removeClass('scroll-hover');
		}
		this.track_size = function() {
			if(trackSize == 0) getTrackSize();
			return trackSize;
		}
		
		//for detached scrollbars
		function setTrackPos() {
			if(updatePos === false) return;
		
			var off = $content_wrap.offset();//because we want it relative to parent not document
			var left = off.left;
			var top = off.top;

			if(vertical) {
				if(!trackFlip) {
					left += ($content_wrap.outerWidth() - trackSize)
				}
			}
			else {
				if(!trackFlip) {
					top += ($content_wrap.outerHeight() - trackSize)
				}
			}
			
			if(updatePos === true) $track.css({top: parseInt(top), left: parseInt(left)});
			else if(updatePos === 'left') $track.css('left', parseInt(left));
			else if(updatePos === 'top') $track.css('top', parseInt(top));
		}
		


		this.create();
		is_dirty = true;
		this.reset(true);
		prevContentSize = content_wrap[scroll_size];

		return this;
	}

	
	$.fn.ace_scroll = function (option,value) {
		var retval;

		var $set = this.each(function () {
			var $this = $(this);
			var data = $this.data('ace_scroll');
			var options = typeof option === 'object' && option;

			if (!data) $this.data('ace_scroll', (data = new Ace_Scroll(this, options)));
			 //else if(typeof options == 'object') data['modify'](options);
			if (typeof option === 'string') retval = data[option](value);
		});

		return (retval === undefined) ? $set : retval;
	};


	$.fn.ace_scroll.defaults = {
		'size' : 200,
		'horizontal': false,
		'mouseWheel': true,
		'mouseWheelLock': false,
		'lockAnyway': false,
		'styleClass' : false,
		
		'observeContent': false,
		'hideOnIdle': false,
		'hideDelay': 1500,
		
		'hoverReset': true //reset scrollbar sizes on mouse hover because of possible sizing changes
		,
		'reset': false //true= set scrollTop = 0
		,
		'dragEvent': false
		,
		'touchDrag': true
		,
		'touchSwipe': false
		,
		'scrollEvent': false //trigger scroll event

		,
		'detached': false
		,
		'updatePos': true
		/**
		,		
		'track' : true,
		'show' : false,
		'dark': false,
		'alwaysVisible': false,
		'margin': false,
		'thin': false,
		'position': 'right'
		*/
     }

	/**
	$(document).on('ace.settings.ace_scroll', function(e, name) {
		if(name == 'sidebar_collapsed') $('.ace-scroll').scroller('reset');
	});
	$(window).on('resize.ace_scroll', function() {
		$('.ace-scroll').scroller('reset');
	});
	*/

})(window.jQuery);