"use strict";

// utilities

var noop = function() {}; // simple no operation function

var offloadFn = function(fn) { setTimeout(fn || noop, 0) }; // offload a functions execution

// check browser capabilities

var browser = {

addEventListener: !!window.addEventListener,

touch: ('ontouchstart' in window) || window.DocumentTouch && document instanceof DocumentTouch,

transitions: (function(temp) {

var props = ['transitionProperty', 'WebkitTransition', 'MozTransition', 'OTransition', 'msTransition'];

for ( var i in props ) if (temp.style[ props[i] ] !== undefined) return true;

return false;

})(document.createElement('swipe'))

};

// quit if no root element

if (!container) return;

var element = container.children[0];

var slides, slidePos, width, length;

options = options || {};

var index = parseInt(options.startSlide, 10) || 0;

var speed = options.speed || 300;

options.continuous = options.continuous !== undefined ? options.continuous : true;

function setup() {

// cache slides

slides = element.children;

length = slides.length;

// set continuous to false if only one slide

if (slides.length < 2) options.continuous = false;

//special case if two slides

if (browser.transitions && options.continuous && slides.length < 3) {

element.appendChild(slides[0].cloneNode(true));

element.appendChild(element.children[1].cloneNode(true));

slides = element.children;

}

// create an array to store current positions of each slide

slidePos = new Array(slides.length);

// determine width of each slide

width = container.getBoundingClientRect().width || container.offsetWidth;

element.style.width = (slides.length * width) 'px';

// stack elements

var pos = slides.length;

while(pos--) {

var slide = slides[pos];

slide.style.width = width 'px';

slide.setAttribute('data-index', pos);

if (browser.transitions) {

slide.style.left = (pos * -width) 'px';

move(pos, index > pos ? -width : (index < pos ? width : 0), 0);

}

}

// reposition elements before and after index

if (options.continuous && browser.transitions) {

move(circle(index-1), -width, 0);

move(circle(index 1), width, 0);

}

if (!browser.transitions) element.style.left = (index * -width) 'px';

container.style.visibility = 'visible';

}

function prev() {

if (options.continuous) slide(index-1);

else if (index) slide(index-1);

}

function next() {

if (options.continuous) slide(index 1);

else if (index < slides.length - 1) slide(index 1);

}

function circle(index) {

// a simple positive modulo using slides.length

return (slides.length (index % slides.length)) % slides.length;

}

function slide(to, slideSpeed) {

// do nothing if already on requested slide

if (index == to) return;

if (browser.transitions) {

var direction = Math.abs(index-to) / (index-to); // 1: backward, -1: forward

// get the actual position of the slide

if (options.continuous) {

var natural_direction = direction;

direction = -slidePos[circle(to)] / width;

// if going forward but to < index, use to = slides.length to

// if going backward but to > index, use to = -slides.length to

if (direction !== natural_direction) to = -direction * slides.length to;

}

var diff = Math.abs(index-to) - 1;

// move all the slides between index and to in the right direction

while (diff--) move( circle((to > index ? to : index) - diff - 1), width * direction, 0);

to = circle(to);

move(index, width * direction, slideSpeed || speed);

move(to, 0, slideSpeed || speed);

if (options.continuous) move(circle(to - direction), -(width * direction), 0); // we need to get the next in place

} else {

to = circle(to);

animate(index * -width, to * -width, slideSpeed || speed);

//no fallback for a circular continuous if the browser does not accept transitions

}

index = to;

offloadFn(options.callback && options.callback(index, slides[index]));

}

function move(index, dist, speed) {

translate(index, dist, speed);

slidePos[index] = dist;

}

function translate(index, dist, speed) {

var slide = slides[index];

var style = slide && slide.style;

if (!style) return;

style.webkitTransitionDuration =

style.MozTransitionDuration =

style.msTransitionDuration =

style.OTransitionDuration =

style.transitionDuration = speed 'ms';

style.webkitTransform = 'translate(' dist 'px,0)' 'translateZ(0)';

style.msTransform =

style.MozTransform =

style.OTransform = 'translateX(' dist 'px)';

}

function animate(from, to, speed) {

// if not an animation, just reposition

if (!speed) {

element.style.left = to 'px';

return;

}

var start = new Date;

var timer = setInterval(function() {

var timeElap = new Date - start;

if (timeElap > speed) {

element.style.left = to 'px';

if (delay) begin();

options.transitionEnd && options.transitionEnd.call(event, index, slides[index]);

clearInterval(timer);

return;

}

element.style.left = (( (to - from) * (Math.floor((timeElap / speed) * 100) / 100) ) from) 'px';

}, 4);

}

// setup auto slideshow

var delay = options.auto || 0;

var interval;

function begin() {

interval = setTimeout(next, delay);

}

function stop() {

delay = 0;

clearTimeout(interval);

}

// setup initial vars

var start = {};

var delta = {};

var isScrolling;

// setup event capturing

var events = {

handleEvent: function(event) {

switch (event.type) {

case 'touchstart': this.start(event); break;

case 'touchmove': this.move(event); break;

case 'touchend': offloadFn(this.end(event)); break;

case 'webkitTransitionEnd':

case 'msTransitionEnd':

case 'oTransitionEnd':

case 'otransitionend':

case 'transitionend': offloadFn(this.transitionEnd(event)); break;

case 'resize': offloadFn(setup); break;

}

if (options.stopPropagation) event.stopPropagation();

},

start: function(event) {

var touches = event.touches[0];

// measure start values

start = {

// get initial touch coords

x: touches.pageX,

y: touches.pageY,

// store time to determine touch duration

time: new Date

};

// used for testing first move event

isScrolling = undefined;

// reset delta and end measurements

delta = {};

// attach touchmove and touchend listeners

element.addEventListener('touchmove', this, false);

element.addEventListener('touchend', this, false);

},

move: function(event) {

// ensure swiping with one touch and not pinching

if ( event.touches.length > 1 || event.scale && event.scale !== 1) return

if (options.disableScroll) event.preventDefault();

var touches = event.touches[0];

// measure change in x and y

delta = {

x: touches.pageX - start.x,

y: touches.pageY - start.y

}

// determine if scrolling test has run - one time test

if ( typeof isScrolling == 'undefined') {

isScrolling = !!( isScrolling || Math.abs(delta.x) < Math.abs(delta.y) );

}

// if user is not trying to scroll vertically

if (!isScrolling) {

// prevent native scrolling

event.preventDefault();

// stop slideshow

stop();

// increase resistance if first or last slide

if (options.continuous) { // we don't add resistance at the end

translate(circle(index-1), delta.x slidePos[circle(index-1)], 0);

translate(index, delta.x slidePos[index], 0);

translate(circle(index 1), delta.x slidePos[circle(index 1)], 0);

} else {

delta.x =

delta.x /

( (!index && delta.x > 0 // if first slide and sliding left

|| index == slides.length - 1 // or if last slide and sliding right

&& delta.x < 0 // and if sliding at all

) ?

( Math.abs(delta.x) / width 1 ) // determine resistance level

: 1 ); // no resistance if false

// translate 1:1

translate(index-1, delta.x slidePos[index-1], 0);

translate(index, delta.x slidePos[index], 0);

translate(index 1, delta.x slidePos[index 1], 0);

}

}

},

end: function(event) {

// measure duration

var duration = new Date - start.time;

// determine if slide attempt triggers next/prev slide

var isValidSlide =

Number(duration) < 250 // if slide duration is less than 250ms

&& Math.abs(delta.x) > 20 // and if slide amt is greater than 20px

|| Math.abs(delta.x) > width/2; // or if slide amt is greater than half the width

// determine if slide attempt is past start and end

var isPastBounds =

!index && delta.x > 0 // if first slide and slide amt is greater than 0

|| index == slides.length - 1 && delta.x < 0; // or if last slide and slide amt is less than 0

if (options.continuous) isPastBounds = false;

// determine direction of swipe (true:right, false:left)

var direction = delta.x < 0;

// if not scrolling vertically

if (!isScrolling) {

if (isValidSlide && !isPastBounds) {

if (direction) {

if (options.continuous) { // we need to get the next in this direction in place

move(circle(index-1), -width, 0);

move(circle(index 2), width, 0);

} else {

move(index-1, -width, 0);

}

move(index, slidePos[index]-width, speed);

move(circle(index 1), slidePos[circle(index 1)]-width, speed);

index = circle(index 1);

} else {

if (options.continuous) { // we need to get the next in this direction in place

move(circle(index 1), width, 0);

move(circle(index-2), -width, 0);

} else {

move(index 1, width, 0);

}

move(index, slidePos[index] width, speed);

move(circle(index-1), slidePos[circle(index-1)] width, speed);

index = circle(index-1);

}

options.callback && options.callback(index, slides[index]);

} else {

if (options.continuous) {

move(circle(index-1), -width, speed);

move(index, 0, speed);

move(circle(index 1), width, speed);

} else {

move(index-1, -width, speed);

move(index, 0, speed);

move(index 1, width, speed);

}

}

}

// kill touchmove and touchend event listeners until touchstart called again

element.removeEventListener('touchmove', events, false)

element.removeEventListener('touchend', events, false)

},

transitionEnd: function(event) {

if (parseInt(event.target.getAttribute('data-index'), 10) == index) {

if (delay) begin();

options.transitionEnd && options.transitionEnd.call(event, index, slides[index]);

}

}

}

// trigger setup

setup();

// start auto slideshow if applicable

if (delay) begin();

// add event listeners

if (browser.addEventListener) {

// set touchstart event on element

if (browser.touch) element.addEventListener('touchstart', events, false);

if (browser.transitions) {

element.addEventListener('webkitTransitionEnd', events, false);

element.addEventListener('msTransitionEnd', events, false);

element.addEventListener('oTransitionEnd', events, false);

element.addEventListener('otransitionend', events, false);

element.addEventListener('transitionend', events, false);

}

// set resize event on window

window.addEventListener('resize', events, false);

} else {

window.onresize = function () { setup() }; // to play nice with old IE

}

// expose the Swipe API

return {

setup: function() {

setup();

},

slide: function(to, speed) {

// cancel slideshow

stop();

slide(to, speed);

},

prev: function() {

// cancel slideshow

stop();

prev();

},

next: function() {

// cancel slideshow

stop();

next();

},

stop: function() {

// cancel slideshow

stop();

},

getPos: function() {

// return current index position

return index;

},

getNumSlides: function() {

// return total number of slides

return length;

},

kill: function() {

// cancel slideshow

stop();

// reset element

element.style.width = '';

element.style.left = '';

// reset slides

var pos = slides.length;

while(pos--) {

var slide = slides[pos];

slide.style.width = '';

slide.style.left = '';

if (browser.transitions) translate(pos, 0, 0);

}

// removed event listeners

if (browser.addEventListener) {

// remove current event listeners

element.removeEventListener('touchstart', events, false);

element.removeEventListener('webkitTransitionEnd', events, false);

element.removeEventListener('msTransitionEnd', events, false);

element.removeEventListener('oTransitionEnd', events, false);

element.removeEventListener('otransitionend', events, false);

element.removeEventListener('transitionend', events, false);

window.removeEventListener('resize', events, false);

}

else {

window.onresize = null;

}

}

}

return this.each(function() {

$(this).data('Swipe', new Swipe($(this)[0], params));

});