/**
 * A fork of EC.TouchScroll (c) Hy60koshk, CCRS
	args:
		Element: the HTML element the touchscroll is being applied to
		IsHorizontal (boolean, false) - горизонтальная ли прокрутка
		DrawArrows (boolean, false) - отображать ли стрелки
									может быть указан объект с полями up и down,
									в которых указываются классы соответствующих кнопок
		DrawScrollBar (boolean, false) - отображать ли скроллбар
		AllowArrowClick (boolean, true) - разрешать ли перемотку нажатием по стрелке
		InbarArrows (boolean, false) - помещены ли стрелки внутрь контейнера скролбара:
									к элементам стрелок и скроллбара будет добавлен класс InbarArrows,
									автоматически вычисляемая высота скроллбара будет уменьшена на высоту стрелок
		ArrowsForceDisplayNone (boolean, false) - если включено, то в граничных позициях скролла
											помимо класса inactive, отключаемая стрелка будет скрыта через .hide()
		OnReady (function) - выполняется по окончании построения скролла
								
	fields:
		SuspendTouchScrollCheck (boolean) - отключить ли проверки изменения размеров
	
	methods:
		TouchScrollCheck() - пересчитать размеры и при необходимости перестроить содержимое
		ScrollTo(Number | jQuery | HTMLElement) - прокрутить до нового оффсета или до конкретного элемента
**/

var isIE = window.document.documentMode !== undefined;
if (isIE) {
	HTMLElement.prototype.deferred = function(func, args) {
		_this = this
		setTimeout(function () {
			func.apply(_this, args)
		}, 3)
	}
}
else {
	HTMLElement.prototype.deferred = function(func, args) {
		_this = this
		requestAnimationFrame(function () {
			func.apply(_this, args)
		}, _this)
	}
}
function spawn(parent, tagName, classlist) {
	var newEl = parent.appendChild(document.createElement(tagName));
	if (classlist && classlist.length) {
		newEl.classList.add.apply(newEl.classList, classlist.split(' '))
	}
	return newEl;
}
HTMLElement.prototype.css = function(property) {
	return window.getComputedStyle(this)[property]
}
HTMLElement.prototype.hide = function() {
	if (!this._initialDisplay) {
		this._initialDisplay = this.css('display')
	}
	this.style.display = 'none'
}
HTMLElement.prototype.show = function() {
	if (!this._initialDisplay || this._initialDisplay == 'none') {
		this._initialDisplay = false
		this.style.display = 'block'
	}
	else {
		this.style.display = this._initialDisplay
	}
}

/*
if (!document.body.classList) {
	HTMLElement.prototype.addClass = function(class) {
		this.classList.add(class)
	}
}
else {
	HTMLElement.prototype.addClass = function(class) {
		this.classList.add(class)
	}
}
*/

var addTouchScroll = function(args) {
		var _self = this
		var _element$ = args.Element;
		var _isHorizontal = args.IsHorizontal ? true : false;
		var _MEASURE = _isHorizontal ? 'width' : 'height'
		//_element$.style[_isHorizontal ? 'overflowX' : 'overflowY'] = 'hidden'
		var _drawArrows = args.DrawArrows ? true : false;
		var _arrowUpClass = _arrowDownClass = null
		if (_drawArrows && (typeof args.DrawArrows == 'object')) {
			_arrowUpClass = args.DrawArrows.up
			_arrowDownClass = args.DrawArrows.down
		}
		var _drawScrollBar = args.DrawScrollBar ? true : false;
		var _drawArrowsInBar = args.InbarArrows ? true : false;
		var _arrowsForceDisplayNone = args.ArrowsForceDisplayNone ? true : false;
		var _allowArrowClick = args.AllowArrowClick === false ? false : true;
		var _onReady = []
		var _container$ = _element$.parentElement;
		_container$.classList.add(_isHorizontal ? 'horizontal' : 'vertical')
		var _startPosition = 0
		var _startY = 0
		var _totalScroll = 0
		var _arrows = {};
		var _lastFullHeight = 0;
		var _scrollBar = false
		var _elementBoxHeight = 0
		var _elementFullHeight = 0
		var _scrollBarRatio = 0
		var _scrollBarContainerHeight = 0
		var _scrollBarHeight = 0
		var _isReady = false

		if (typeof args.OnReady == 'function') {
			_onReady.push(args.OnReady)
		}
		
		_element$.SuspendTouchScrollCheck = true;
		
		_element$.OnReady = function(func) {
			if (typeof func == 'function') {
				if (!_isReady) {
					_onReady.push(func)
				} else {
					func()
				}
			}
		}
		_element$.TouchScrollCheck = function() {
			_checkFitting()
		}
		_element$.GetScroll = function() {
			return _isHorizontal ? _element$.scrollLeft : _element$.scrollTop
		}
		_element$.ScrollTo = function(element$) {
			_element$.OnReady(function() {
				if (typeof element$ == 'number') {
					_setScrollTop(element$)
					return
				}
				else if (!(element$ instanceof HTMLElement)) {
					return
				}
				var top = 0, child = element$
				parent = child.parentElement
				do {
					top += _isHorizontal ? child.offsetTop : child.offsetLeft
					var parentPosition = parent.style.position
					var wentUp = false
					while ((parentPosition != 'absolute') && (parentPosition != 'relative') && containerHasntYetHit()) {
						child = child.parentElement
						parent = child.parentElement
						parentPosition = parent.style.position
						wentUp = true
					}
					if (!wentUp) {
						child = child.parentElement
						parent = child.parentElement
					}
				} while (containerHasntYetHit());

				_setScrollTop(top)

				function containerHasntYetHit() {
					return (parent != _element$) && (child != _element$)
				}
			})
		}
		
		var _doesFit = true;

		_element$.deferred(function() {
			_checkFitting()
			_element$.SuspendTouchScrollCheck = false
			_isReady = true
			
			_element$.deferred(function() {
				for (var i = 0; i < _onReady.length; i++) {
					_onReady[i]()
				}
			});
		});

		if (IE9) {
			spawn(_container$, 'div', 'article-scrollbar-hider')
		}

		if (_drawArrows) {
			_arrows.up$ = spawn(_container$, 'div', 'touchScrollArrowUp inactive unused')
			_arrows.down$ = spawn(_container$, 'div', 'touchScrollArrowDown inactive unused')
			if (_arrowUpClass) {
				_arrows.up$.classList.add(_arrowUpClass)
			}
			if (_arrowDownClass) {
				_arrows.down$.classList.add(_arrowDownClass)
			}
			if (_drawArrowsInBar) {
				_arrows.up$.classList.add('InbarArrows')
				_arrows.down$.classList.add('InbarArrows')
			}
			if (_arrowsForceDisplayNone) {
				_arrows.up$.hide()
				_arrows.down$.hide()
			}
			
			if (_allowArrowClick) {
				_arrows.down$.addEventListener('click', function (event) {
					var scrollTop = _element$.GetScroll()
					var skiph = _elementBoxHeight * 0.67;
					if (scrollTop + skiph + _elementBoxHeight >= _elementFullHeight) {
						skiph = _elementFullHeight - scrollTop;
					}
					_setScrollTop(scrollTop + skiph)
				});
				_arrows.up$.addEventListener('click', function (event) {
					var scrollTop = _element$.GetScroll()
					var skiph = (_isHorizontal ? _element$.offsetWidth : _element$.offsetHeight) * 0.67;
					if (scrollTop - skiph <= 0) {
						skiph = scrollTop
					}
					_setScrollTop(scrollTop - skiph)
				});
			}
		}
		if (_drawScrollBar) {
			_scrollBar = {
				position: 0
				, clickPos: 0
			}
			_scrollBar.bar$ = spawn(_container$, 'div', 'touchScrollBar')
			_scrollBar.line$ = spawn(_scrollBar.bar$, 'div', 'touchScrollBarLine')
			_scrollBar.handle$ = spawn(_scrollBar.bar$, 'div', 'touchScrollBarHandle')
			_scrollBar.handleDisplay$ = spawn(_scrollBar.handle$, 'div', 'touchScrollBarHandleDisplay')
			if (_drawArrowsInBar) {
				_scrollBar.bar$.classList.add('InbarArrows')
			}
			
			_scrollBar.bar$.hide()

			_scrollBar.handle$.addEventListener('mousedown', function (event) {
				_startY = _isHorizontal ? event.clientX : event.clientY
				_startPosition = _element$.GetScroll()
				_clickBreaker$.show()
				_scrollBar.bar$.classList.add('scrolling')
				document.addEventListener('mousemove', _scrollBarMouseMoveEvent)
				document.addEventListener('mouseup', _scrollBarMouseUpEvent)
			});
			_scrollBar.bar$.addEventListener('click', function (event) {
				if (event.target != _scrollBar.handle$) {
					var offset = _isHorizontal ? (event.clientX - _scrollBar.bar$.offsetLeft)
												: (event.clientY - _scrollBar.bar$.offsetTop)
					var center = _elementFullHeight * (offset / _scrollBarContainerHeight)
					var newScrollTop = center - _elementBoxHeight / 2
					
					_setScrollTop(newScrollTop)
				}
			})
		}

		function recalculateSizes() {
			_elementBoxHeight = _isHorizontal ? _element$.offsetWidth : _element$.offsetHeight
			var ebhDec = _elementBoxHeight % 1
			if (ebhDec > 0) {
				_elementBoxHeight -= ebhDec
				if (ebhDec > 0.25) {
					_elementBoxHeight++
				}
			}
			; _isHorizontal ? _recalculateFullWidth() : _recalculateFullHeight()
		}
		
		function _recalculateFullHeight() {
			_elementFullHeight = _element$.scrollHeight;
		}
		
		function _recalculateFullWidth() {
			_elementFullHeight = _element$.scrollWidth;
		}
		
		function _checkFitting() {
			recalculateSizes()
			var doesFit = _elementBoxHeight >= _elementFullHeight;
			 
			if (_drawArrowsInBar && _drawArrows) {
				var arrowUpHeight = _arrows.up$.css(_MEASURE)
				var arrowDownHeight = _arrows.down$.css(_MEASURE) // arrows may be of different size (tfw tho)
				arrowUpHeight = arrowUpHeight.substring(0, arrowUpHeight.length - 2)
				arrowDownHeight = arrowDownHeight.substring(0, arrowDownHeight.length - 2)
				_scrollBarContainerHeight = _elementBoxHeight - arrowUpHeight - arrowDownHeight
			} else {
				_scrollBarContainerHeight = _elementBoxHeight
			}
			if (doesFit != _doesFit) {
				_doesFit = doesFit
				if (_doesFit) {
					_element$.classList.remove('scroll')
					if (_drawArrows) {
						_arrows.down$.classList.add('unused')
						_arrows.up$.classList.add('unused')
						if (_arrowsForceDisplayNone) {
							_arrows.down$.hide()
							_arrows.up$.hide()
						}
					}
					if (_drawScrollBar) {
						_scrollBar.bar$.hide()
					}
					_unbindHandlers()
				}
				else {
					_element$.classList.add('scroll')
					if (_drawArrows) {
						if (_arrowsForceDisplayNone) {
							_arrows.down$.show()
						}
						_arrows.down$.classList.remove('unused')
						_arrows.up$.classList.remove('unused')
						_arrows.down$.classList.remove('inactive');
					}
					if (_drawScrollBar) {
						_scrollBar.bar$.style[_MEASURE] = _scrollBarContainerHeight + 'px'
						_scrollBar.bar$.show()
					}
					_bindHandlers()
					
					_element$.deferred(function() {
						recalculateSizes()
						if (_drawScrollBar && !_doesFit) {
							_scrollBarRatio = _scrollBarContainerHeight / _elementFullHeight
							_scrollBarHeight = _elementBoxHeight * _scrollBarRatio
							_scrollBar.handle$.style[_MEASURE] = _scrollBarHeight + 'px'
						}
					});
				}
			}
			else if (_drawScrollBar && !_doesFit) {
				_scrollBarRatio = _scrollBarContainerHeight / _elementFullHeight
				_scrollBarHeight = _elementBoxHeight * _scrollBarRatio
				_scrollBar.handle$.style[_MEASURE] = _scrollBarHeight + 'px'
				_scrollBar.bar$.style[_MEASURE] = _scrollBarContainerHeight + 'px'
			}
		}
		
		function _doScrollBarScroll(clientY) {
			var scrollTop = _startPosition + (clientY - _startY) / _scrollBarRatio;
			_setScrollTop(scrollTop)
		}

		function _doTouchScroll(clientY) {
			var scrollTop = _startPosition - clientY + _startY
			_totalScroll = _totalScroll + (clientY - _startY)
			if (_totalScroll > 6 || _totalScroll < -6) {
				_clickBreaker$.show()
			}
			_setScrollTop(scrollTop)
		}
		
		function _setScrollTop(scrollTop) {
			if (_isHorizontal) {
				_element$.scrollLeft = scrollTop
			} else {
				_element$.scrollTop = scrollTop
			}
			if (!_doesFit && _drawArrows) {
				if (scrollTop > 0) {
					_arrows.up$.classList.remove('inactive')
					if (_arrowsForceDisplayNone) {
						_arrows.up$.show()
					}
				} else {
					_arrows.up$.classList.add('inactive')
					if (_arrowsForceDisplayNone) {
						_arrows.up$.hide()
					}
				}
				if (_elementBoxHeight < (_elementFullHeight - scrollTop)) {
					_arrows.down$.classList.remove('inactive')
					if (_arrowsForceDisplayNone) {
						_arrows.down$.show()
					}
				}  else {
					_arrows.down$.classList.add('inactive')
					if (_arrowsForceDisplayNone) {
						_arrows.down$.hide()
					}
				}
			}
			if (_drawScrollBar) {
				var scrollBarScrollTop = _scrollBarRatio * scrollTop
				if (scrollBarScrollTop > _scrollBarContainerHeight - _scrollBarHeight) {
					scrollBarScrollTop = _scrollBarContainerHeight - _scrollBarHeight
				} else if (scrollTop < 0 ) {
					scrollBarScrollTop = 0
				}
				_scrollBar.handle$.style[_isHorizontal ? 'marginLeft' : 'marginTop'] = scrollBarScrollTop + 'px'
			}
		}
		
		function _mouseMoveEvent(event) {
			_doTouchScroll(_isHorizontal ? event.clientX : event.clientY)
		}
		function _mouseUpEvent(event) {
			_clickBreaker$.hide()
			document.removeEventListener('mousemove', _mouseMoveEvent)
			document.removeEventListener('mouseup', _mouseUpEvent)
		}
		function _scrollBarMouseMoveEvent(event) {
			_doScrollBarScroll(_isHorizontal ? event.clientX : event.clientY)
		}
		function _scrollBarMouseUpEvent(event) {
			_clickBreaker$.hide()
			_scrollBar.bar$.classList.remove('scrolling')

			document.removeEventListener('mousemove', _scrollBarMouseMoveEvent);
			document.removeEventListener('mouseup', _scrollBarMouseUpEvent);
		}
		function _mouseDownEvent(event) {
			_totalScroll = 0
			if (_isHorizontal) {
				_startPosition = _element$.scrollLeft
				_startY = event.clientX
			} else {
				_startPosition = _element$.scrollTop
				_startY = event.clientY
			}
			document.addEventListener('mousemove', _mouseMoveEvent);
			document.addEventListener('mouseup', _mouseUpEvent);
			return false;
		}
		function _scrollEvent(event) {
			_setScrollTop(_element$.GetScroll());
		}
		function _bindHandlers() {
			_element$.addEventListener('scroll', _scrollEvent);
		}
		function _unbindHandlers() {
			_element$.removeEventListener('scroll', _scrollEvent);
		}
		if (args.Mutable) {
			var onDomChange = function () {
				if (!_element$.SuspendTouchScrollCheck) {
					_element$.SuspendTouchScrollCheck = true;
					_element$.deferred(function() {
						_checkFitting()
						_element$.SuspendTouchScrollCheck = false
					});
				}
			}
			if (window.MutationObserver) {
				(new MutationObserver(onDomChange)).observe(_element$, { childList: true })
			}
			else {
				_element$.addEventListener("DOMNodeInserted", onDomChange)
				_element$.addEventListener("DOMNodeRemoved", onDomChange)
			}
		}
		
		return _element$;
	}