(function ($, undefined) {

	/*
	 * Gallery object.
	 */
	$.Gallery = function (options, element) {

		this.$el = $(element);
		this._init(options);

	};

	$.Gallery.defaults = {
		current: 0,	// index of current item
		autoplay: false,// slideshow on / off
		interval: 4000  // time between transitions
	};

	$.Gallery.prototype = {
		_init: function (options) {

			this.options = $.extend(true, {}, $.Gallery.defaults, options);

			// support for 3d / 2d transforms and transitions
			this.support3d = Modernizr.csstransforms3d;
			this.support2d = Modernizr.csstransforms;
			this.supportTrans = Modernizr.csstransitions;

			this.$wrapper = this.$el.find('.dg-wrapper');

			this.$items = this.$wrapper.children();
			this.itemsCount = this.$items.length;

			this.$nav = this.$el.find('.nav');
			this.$navPrev = this.$nav.find('.dg-prev');
			this.$navNext = this.$nav.find('.dg-next');

			// minimum of 3 items
			if (this.itemsCount < 3) {

				this.$nav.remove();
				return false;

			}

			this.current = this.options.current;

			this.isAnim = false;

			this.$items.css({
				'opacity': 0,
				'visibility': 'hidden'
			});

			this._validate();

			this._layout();

			// load the events
			this._loadEvents();

			// slideshow
			if (this.options.autoplay) {

				this._startSlideshow();

			}

		},
		_validate: function () {

			if (this.options.current < 0 || this.options.current > this.itemsCount - 1) {

				this.current = 0;

			}

		},
		_layout: function () {

			// current, left and right items
			this._setItems();

			// current item is not changed
			// left and right one are rotated and translated
			var leftCSS, rightCSS, currentCSS;

			if (this.support3d && this.supportTrans) {

				leftCSS = {
					'-webkit-transform': 'translateX(-400px) translateZ(-380px) rotateY(38deg)',
					'-moz-transform': 'translateX(-400px) translateZ(-380px) rotateY(38deg)',
					'-o-transform': 'translateX(-400px) translateZ(-380px) rotateY(38deg)',
					'-ms-transform': 'translateX(-400px) translateZ(-380px) rotateY(38deg)',
					'transform': 'translateX(-400px) translateZ(-380px) rotateY(38deg)',
					'z-index': 1
				};

				rightCSS = {
					'-webkit-transform': 'translateX(400px) translateZ(-380px) rotateY(-38deg)',
					'-moz-transform': 'translateX(400px) translateZ(-380px) rotateY(-38deg)',
					'-o-transform': 'translateX(400px) translateZ(-380px) rotateY(-38deg)',
					'-ms-transform': 'translateX(400px) translateZ(-380px) rotateY(-38deg)',
					'transform': 'translateX(400px) translateZ(-380px) rotateY(-38deg)',
					'z-index': 1
				};

				leftCSS.opacity = 1;
				leftCSS.visibility = 'visible';
				rightCSS.opacity = 1;
				rightCSS.visibility = 'visible';

			}
			else if (this.support2d && this.supportTrans) {

				leftCSS = {
					'-webkit-transform': 'translate(-400px) scale(0.8)',
					'-moz-transform': 'translate(-400px) scale(0.8)',
					'-o-transform': 'translate(-400px) scale(0.8)',
					'-ms-transform': 'translate(-400px) scale(0.8)',
					'transform': 'translate(-400px) scale(0.8)',
					'z-index': 1

				};

				rightCSS = {
					'-webkit-transform': 'translate(400px) scale(0.8)',
					'-moz-transform': 'translate(400px) scale(0.8)',
					'-o-transform': 'translate(400px) scale(0.8)',
					'-ms-transform': 'translate(400px) scale(0.8)',
					'transform': 'translate(400px) scale(0.8)',
					'z-index': 1
				};

				currentCSS = {
					'z-index': 999
				};

				leftCSS.opacity = 1;
				leftCSS.visibility = 'visible';
				rightCSS.opacity = 1;
				rightCSS.visibility = 'visible';

			} else {
				leftCSS = {
					'left': '-250px',
					'height': "420px",
					'top': 20,
					'z-index': 1

				};

				rightCSS = {
					'left': '250px',
					'height': "420px",
					'top': 20,
					'z-index': 1
				};

				currentCSS = {
					'left': '0',
					'height': "462px",
					'top': 0,
					'z-index': 999
				};

				leftCSS.opacity = 1;
				leftCSS.visibility = 'visible';
				rightCSS.opacity = 1;
				rightCSS.visibility = 'visible';
			}

			this.$leftItm.css(leftCSS || {});
			this.$rightItm.css(rightCSS || {});

			this.$currentItm.css(currentCSS || {}).css({
				'opacity': 1,
				'visibility': 'visible',
				'z-index': 999
			}).addClass('dg-center');

		},
		_setItems: function () {

			this.$items.removeClass('dg-center');

			this.$currentItm = this.$items.eq(this.current);
			this.$leftItm = (this.current === 0) ? this.$items.eq(this.itemsCount - 1) : this.$items.eq(this.current - 1);
			this.$rightItm = (this.current === this.itemsCount - 1) ? this.$items.eq(0) : this.$items.eq(this.current + 1);

			if (!this.support3d && this.support2d && this.supportTrans) {

				this.$items.css('z-index', 1);
				this.$currentItm.css('z-index', 999);

			}

			// next & previous items
			if (this.itemsCount > 3) {

				// next item
				this.$nextItm = (this.$rightItm.index() === this.itemsCount - 1) ? this.$items.eq(0) : this.$rightItm.next();
				this.$nextItm.css(this._getCoordinates('outright'));

				// previous item
				this.$prevItm = (this.$leftItm.index() === 0) ? this.$items.eq(this.itemsCount - 1) : this.$leftItm.prev();
				this.$prevItm.css(this._getCoordinates('outleft'));

			}

		},
		_loadEvents: function () {

			var _self = this;

			this.$navPrev.on('click.gallery', function (event) {

				if (_self.options.autoplay) {

					clearTimeout(_self.slideshow);
					_self.options.autoplay = false;

				}

				_self._navigate('prev');
				return false;

			});

			this.$navNext.on('click.gallery', function (event) {

				if (_self.options.autoplay) {

					clearTimeout(_self.slideshow);
					_self.options.autoplay = false;

				}

				_self._navigate('next');
				return false;

			});
			if (this.support2d && this.supportTrans) {
				this.$wrapper.on('webkitTransitionEnd.gallery transitionend.gallery OTransitionEnd.gallery', function (event) {

					_self.$currentItm.addClass('dg-center');
					_self.$items.removeClass('dg-transition');
					_self.isAnim = false;

				});
			} else {

				_self.$currentItm.addClass('dg-center');
				_self.$items.removeClass('dg-transition');
				_self.isAnim = false;
			}

		},
		_getCoordinates: function (position) {

			if (this.support3d && this.supportTrans) {

				switch (position) {
					case 'outleft':
						return {
							'-webkit-transform': 'translateX(-400px) translateZ(-300px) rotateY(38deg)',
							'-moz-transform': 'translateX(-400px) translateZ(-300px) rotateY(38deg)',
							'-o-transform': 'translateX(-400px) translateZ(-300px) rotateY(38deg)',
							'-ms-transform': 'translateX(-400px) translateZ(-300px) rotateY(38deg)',
							'transform': 'translateX(-400px) translateZ(-300px) rotateY(38deg)',
							'opacity': 0,
							'visibility': 'hidden',
							'z-index': 1
						};
						break;
					case 'outright':
						return {
							'-webkit-transform': 'translateX(400px) translateZ(-300px) rotateY(-38deg)',
							'-moz-transform': 'translateX(400px) translateZ(-300px) rotateY(-38deg)',
							'-o-transform': 'translateX(400px) translateZ(-300px) rotateY(-38deg)',
							'-ms-transform': 'translateX(400px) translateZ(-300px) rotateY(-38deg)',
							'transform': 'translateX(400px) translateZ(-300px) rotateY(-38deg)',
							'opacity': 0,
							'visibility': 'hidden',
							'z-index': 1
						};
						break;
					case 'left':
						return {
							'-webkit-transform': 'translateX(-400px) translateZ(-380px) rotateY(38deg)',
							'-moz-transform': 'translateX(-400px) translateZ(-380px) rotateY(38deg)',
							'-o-transform': 'translateX(-400px) translateZ(-380px) rotateY(38deg)',
							'-ms-transform': 'translateX(-400px) translateZ(-380px) rotateY(38deg)',
							'transform': 'translateX(-400px) translateZ(-380px) rotateY(38deg)',
							'opacity': 1,
							'visibility': 'visible',
							'z-index': 1
						};
						break;
					case 'right':
						return {
							'-webkit-transform': 'translateX(400px) translateZ(-380px) rotateY(-38deg)',
							'-moz-transform': 'translateX(400px) translateZ(-380px) rotateY(-38deg)',
							'-o-transform': 'translateX(400px) translateZ(-380px) rotateY(-38deg)',
							'-ms-transform': 'translateX(400px) translateZ(-380px) rotateY(-38deg)',
							'transform': 'translateX(400px) translateZ(-380px) rotateY(-38deg)',
							'opacity': 1,
							'visibility': 'visible',
							'z-index': 1
						};
						break;
					case 'center':
						return {
							'-webkit-transform': 'translateX(0px) translateZ(0px) rotateY(0deg)',
							'-moz-transform': 'translateX(0px) translateZ(0px) rotateY(0deg)',
							'-o-transform': 'translateX(0px) translateZ(0px) rotateY(0deg)',
							'-ms-transform': 'translateX(0px) translateZ(0px) rotateY(0deg)',
							'transform': 'translateX(0px) translateZ(0px) rotateY(0deg)',
							'opacity': 1,
							'visibility': 'visible',
							'z-index': 999
						};
						break;
				};

			}
			else if (this.support2d && this.supportTrans) {

				switch (position) {
					case 'outleft':
						return {
							'-webkit-transform': 'translate(-400px) scale(0.7)',
							'-moz-transform': 'translate(-400px) scale(0.7)',
							'-o-transform': 'translate(-400px) scale(0.7)',
							'-ms-transform': 'translate(-400px) scale(0.7)',
							'transform': 'translate(-400px) scale(0.7)',
							'opacity': 0,
							'visibility': 'hidden'
						};
						break;
					case 'outright':
						return {
							'-webkit-transform': 'translate(400px) scale(0.7)',
							'-moz-transform': 'translate(400px) scale(0.7)',
							'-o-transform': 'translate(400px) scale(0.7)',
							'-ms-transform': 'translate(400px) scale(0.7)',
							'transform': 'translate(400px) scale(0.7)',
							'opacity': 0,
							'visibility': 'hidden'
						};
						break;
					case 'left':
						return {
							'-webkit-transform': 'translate(-400px) scale(0.8)',
							'-moz-transform': 'translate(-400px) scale(0.8)',
							'-o-transform': 'translate(-400px) scale(0.8)',
							'-ms-transform': 'translate(-400px) scale(0.8)',
							'transform': 'translate(-400px) scale(0.8)',
							'opacity': 1,
							'visibility': 'visible'
						};
						break;
					case 'right':
						return {
							'-webkit-transform': 'translate(400px) scale(0.8)',
							'-moz-transform': 'translate(400px) scale(0.8)',
							'-o-transform': 'translate(400px) scale(0.8)',
							'-ms-transform': 'translate(400px) scale(0.8)',
							'transform': 'translate(400px) scale(0.8)',
							'opacity': 1,
							'visibility': 'visible'
						};
						break;
					case 'center':
						return {
							'-webkit-transform': 'translate(0px) scale(1)',
							'-moz-transform': 'translate(0px) scale(1)',
							'-o-transform': 'translate(0px) scale(1)',
							'-ms-transform': 'translate(0px) scale(1)',
							'transform': 'translate(0px) scale(1)',
							'opacity': 1,
							'visibility': 'visible',
							'z-index': 999
						};
						break;
				};

			}
			else {
				switch (position) {
					case 'outleft':
						return {
							'left': '0',
							'opacity': 0,
							'visibility': 'hidden',
							'height': "420px",
							'top': 20,
							'z-index': 1
						};
						break;
					case 'outright':
						return {
							'left': '0',
							'opacity': 0,
							'visibility': 'hidden',
							'height': "420px",
							'top': 20,
							'z-index': 1
						};
						break;
					case 'left':
						return {
							'left': '250px',
							'opacity': 1,
							'visibility': 'visible',
							'height': "420px",
							'top': 20,
							'z-index': 1
						};
						break;
					case 'right':
						return {
							'left': '-250px',
							'opacity': 1,
							'visibility': 'visible',
							'height': "420px",
							'top': 20,
							'z-index': 1
						};
						break;
					case 'center':
						return {
							'left': '0',
							'opacity': 1,
							'visibility': 'visible',
							'height': '462px',
							'top': 0,
							'z-index': 999
						};
						break;
				};

			}

		},
		_navigate: function (dir) {

			if (this.supportTrans && this.isAnim)
				return false;

			this.isAnim = true;

			switch (dir) {

				case 'next':

					this.current = this.$rightItm.index();

					if (this.support2d && this.supportTrans) {

						// current item moves left
						this.$currentItm.addClass('dg-transition').css(this._getCoordinates('right'));

						// right item moves to the center
						this.$rightItm.addClass('dg-transition').css(this._getCoordinates('center'));

						// next item moves to the right
						if (this.$nextItm) {

							// left item moves out
							this.$leftItm.addClass('dg-transition').css(this._getCoordinates('outright'));

							this.$nextItm.addClass('dg-transition').css(this._getCoordinates('left'));

						}
						else {

							// left item moves right
							this.$leftItm.addClass('dg-transition').css(this._getCoordinates('left'));

						}
					} else {
						// current item moves left
						this.$currentItm.addClass('dg-transition').animate(this._getCoordinates('right'), 400);

						// right item moves to the center
						this.$rightItm.addClass('dg-transition').animate(this._getCoordinates('center'), 400);

						// next item moves to the right
						if (this.$nextItm) {

							// left item moves out
							this.$leftItm.addClass('dg-transition').animate(this._getCoordinates('outright'), 400);

							this.$nextItm.addClass('dg-transition').animate(this._getCoordinates('left'), 400);

						}
						else {

							// left item moves left
							this.$leftItm.addClass('dg-transition').animate(this._getCoordinates('left'), 400);

						}
					}
					break;

				case 'prev':

					this.current = this.$leftItm.index();

					if (this.support2d && this.supportTrans) {
						// current item moves right
						this.$currentItm.addClass('dg-transition').css(this._getCoordinates('right'));

						// left item moves to the center
						this.$leftItm.addClass('dg-transition').css(this._getCoordinates('center'));

						// prev item moves to the left
						if (this.$prevItm) {

							// right item moves out
							this.$rightItm.addClass('dg-transition').css(this._getCoordinates('outright'));

							this.$prevItm.addClass('dg-transition').css(this._getCoordinates('left'));

						}
						else {

							// right item moves left
							this.$rightItm.addClass('dg-transition').css(this._getCoordinates('left'));

						}
					} else {
						// current item moves right
						this.$currentItm.addClass('dg-transition').animate(this._getCoordinates('right'), 400);

						// left item moves to the center
						this.$leftItm.addClass('dg-transition').animate(this._getCoordinates('center'), 400);

						// prev item moves to the left
						if (this.$prevItm) {

							// right item moves out
							this.$rightItm.addClass('dg-transition').animate(this._getCoordinates('outright'), 400);

							this.$prevItm.addClass('dg-transition').animate(this._getCoordinates('left'), 400);

						}
						else {

							// right item moves left
							this.$rightItm.addClass('dg-transition').animate(this._getCoordinates('left'), 400);

						}
					}
					break;

			};

			this._setItems();

			if (!this.supportTrans)
				this.$currentItm.addClass('dg-center');

		},
		_startSlideshow: function () {
			var _self = this;
			this.slideshow = setTimeout(function () {

				_self._navigate('next');

				if (_self.options.autoplay) {

					_self._startSlideshow();

				}

			}, this.options.interval);

		},
		destroy: function () {

			this.$navPrev.off('.gallery');
			this.$navNext.off('.gallery');
			this.$wrapper.off('.gallery');

		}
	};

	var logError = function (message) {
		if (this.console) {
			console.error(message);
		}
	};

	$.fn.gallery = function (options) {

		if (typeof options === 'string') {

			var args = Array.prototype.slice.call(arguments, 1);

			this.each(function () {

				var instance = $.data(this, 'gallery');

				if (!instance) {
					logError("cannot call methods on gallery prior to initialization; " +
						"attempted to call method '" + options + "'");
					return;
				}

				if (!$.isFunction(instance[options]) || options.charAt(0) === "_") {
					logError("no such method '" + options + "' for gallery instance");
					return;
				}

				instance[options].apply(instance, args);

			});

		}
		else {

			this.each(function () {

				var instance = $.data(this, 'gallery');
				if (!instance) {
					$.data(this, 'gallery', new $.Gallery(options, this));
				}
			});

		}

		return this;

	};

})(jQuery);