/*!
 * # Range slider for Semantic UI.
 *
 */

;(function ( $, window, document, undefined ) {

"use strict";

$.fn.range = function(parameters) {

	var
		$allModules    = $(this),

		offset         = 10,

		query          = arguments[0],
    methodInvoked  = (typeof query == 'string'),
    queryArguments = [].slice.call(arguments, 1)
	;

  $allModules
    .each(function() {

			var
				settings          = ( $.isPlainObject(parameters) )
					? $.extend(true, {}, $.fn.range.settings, parameters)
					: $.extend({}, $.fn.range.settings),

				namespace       = settings.namespace,
				min             = settings.min,
				max             = settings.max,
				step            = settings.step,
				start           = settings.start,
				input           = settings.input,

				eventNamespace  = '.' + namespace,
				moduleNamespace = 'module-' + namespace,

				$module         = $(this),

				element         = this,
				instance        = $module.data(moduleNamespace),

				inner,
				thumb,
				trackLeft,
				precision,

				module
			;

			module = {

				initialize: function() {
					module.instantiate();
					module.sanitize();
				},

				instantiate: function() {
					instance = module;
					$module
						.data(moduleNamespace, module)
					;
					$(element).html("<div class='inner'><div class='track'></div><div class='track-fill'></div><div class='thumb'></div></div>");
					inner = $(element).children('.inner')[0];
					thumb = $(element).find('.thumb')[0];
					trackLeft = $(element).find('.track-fill')[0];
					// find precision of step, used in calculating the value
					module.determinePrecision();
					// set start location
					module.setValuePosition(settings.start);
					// event listeners
					$(element).find('.track, .thumb, .inner').on('mousedown', function(event) {
						event.stopImmediatePropagation();
						event.preventDefault();
						$(this).closest(".range").trigger('mousedown', event);
					});
					$(element).find('.track, .thumb, .inner').on('touchstart', function(event) {
						event.stopImmediatePropagation();
						event.preventDefault();
						$(this).closest(".range").trigger('touchstart', event);
					});
					$(element).on('mousedown', function(event, originalEvent) {
						module.rangeMousedown(event, false, originalEvent);
					});
					$(element).on('touchstart', function(event, originalEvent) {
						module.rangeMousedown(event, true, originalEvent);
					});
                    module.addVisibilityListener(element);
				},

				sanitize: function() {
					if (typeof settings.min != 'number') {
						settings.min = parseInt(settings.min) || 0;
					}
					if (typeof settings.max != 'number') {
						settings.max = parseInt(settings.max) || false;
					}
					if (typeof settings.start != 'number') {
						settings.start = parseInt(settings.start) || 0;
					}
				},

				determinePrecision: function() {
					var split = String(settings.step).split('.');
					var decimalPlaces;
					if(split.length == 2) {
						decimalPlaces = split[1].length;
					} else {
						decimalPlaces = 0;
					}
					precision = Math.pow(10, decimalPlaces);
				},

				determineValue: function(startPos, endPos, currentPos) {
					var ratio = (currentPos - startPos) / (endPos - startPos);
					var range = settings.max - settings.min;
					var difference = Math.round(ratio * range / step) * step;
					// Use precision to avoid ugly Javascript floating point rounding issues
					// (like 35 * .01 = 0.35000000000000003)
					difference = Math.round(difference * precision) / precision;
					return difference + settings.min;
				},

				determinePosition: function(value) {
					var ratio = (value - settings.min) / (settings.max - settings.min);
					return Math.round(ratio * $(inner).width()) + $(trackLeft).position().left - offset;
				},

				setValue: function(newValue, triggeredByUser) {
					if(typeof triggeredByUser === 'undefined') {
						triggeredByUser = true;
					}
					if(settings.input) {
						$(settings.input).val(newValue);
					}
					if(settings.onChange) {
						settings.onChange(newValue, {triggeredByUser: triggeredByUser});
					}
				},

				setPosition: function(value) {
					$(thumb).css({left: String(value) + 'px'});
					$(trackLeft).css({width: String(value + offset) + 'px'});
				},

				rangeMousedown: function(mdEvent, isTouch, originalEvent) {
					if( !$(element).hasClass('disabled') ) {
						mdEvent.preventDefault();
						var left = $(inner).offset().left;
						var right = left + $(inner).width();
						var pageX;
						if(isTouch) {
							pageX = originalEvent.originalEvent.touches[0].pageX;
						} else {
							pageX = (typeof mdEvent.pageX != 'undefined') ? mdEvent.pageX : originalEvent.pageX;
						}
						var value = module.determineValue(left, right, pageX);
						if(pageX >= left && pageX <= right) {
							module.setPosition(pageX - left - offset);
							module.setValue(value);
						}
						var rangeMousemove = function(mmEvent) {
							mmEvent.preventDefault();
							if(isTouch) {
								pageX = mmEvent.originalEvent.touches[0].pageX;
							} else {
								pageX = mmEvent.pageX;
							}
							value = module.determineValue(left, right, pageX);
							if(pageX >= left && pageX <= right) {
								if(value >= settings.min && value <= settings.max) {
									module.setPosition(pageX - left - offset);
									module.setValue(value);
								}
							}
						}
						var rangeMouseup = function(muEvent) {
							if(isTouch) {
								$(document).off('touchmove', rangeMousemove);
								$(document).off('touchend', rangeMouseup);
							} else {
								$(document).off('mousemove', rangeMousemove);
								$(document).off('mouseup', rangeMouseup);
							}
						}
						if(isTouch) {
							$(document).on('touchmove', rangeMousemove);
							$(document).on('touchend', rangeMouseup);
						}
						else {
							$(document).on('mousemove', rangeMousemove);
							$(document).on('mouseup', rangeMouseup);
						}
					}
				},

				setValuePosition: function(val, triggeredByUser) {
					if(typeof triggeredByUser === 'undefined') {
						triggeredByUser = true;
					}
					var position = module.determinePosition(val);
					module.setPosition(position);
					module.setValue(val, triggeredByUser);
				},

				invoke: function(query) {
					switch(query) {
						case 'set value':
							if(queryArguments.length > 0) {
								instance.setValuePosition(queryArguments[0], false);
							}
							break;
					}
				},

                addVisibilityListener: function(elem) {

                    // Add a mutation observer (https://developer.mozilla.org/en-US/docs/Web/API/MutationObserver)
                    // to detect when root invisible element is behing shown in order to initialize the thumb correctly
                    // when position and offets are available (https://stackoverflow.com/a/5974377)

                    var observer = new MutationObserver(function(mutationList) {
                        if ($(elem).is(':visible')) {
                            observer.disconnect(); // Avoid infinite recursion because « module.setValuePosition » will trigger this observer
                            module.setValuePosition(settings.start);
                        }
                    });

                    var closestHiddenParent = $(elem).parentsUntil(':visible');

					if (closestHiddenParent.length != 0) {
						observer.observe(closestHiddenParent[closestHiddenParent.length - 1], {attributes: true});
					}
                },

			};

      if(methodInvoked) {
        if(instance === undefined) {
          module.initialize();
        }
        module.invoke(query);
      }
      else {
        module.initialize();
      }

    })
  ;

  return this;

};

$.fn.range.settings = {

  name         : 'Range',
  namespace    : 'range',

	min          : 0,
	max          : false,
	step         : 1,
	start        : 0,
	input        : false,

	onChange     : function(value){},

};


})( jQuery, window, document );