(function() {

var initPhotoSwipeFromDOM = function(gallerySelector) {

var parseThumbnailElements = function(el) {
var thumbElements = el.childNodes,numNodes = thumbElements.length,items = [],el,childElements,thumbnailEl,size,item;

for(var i = 0; i < numNodes; i++) {
 el = thumbElements[i];

 // include only element nodes
 if(el.nodeType !== 1) {
  continue;
 }

 childElements = el.children;

 size = el.getAttribute('data-size').split('x');

 // create slide object
 item = {
  src: el.getAttribute('href'),w: parseInt(size[0],10),h: parseInt(size[1],author: el.getAttribute('data-author')
 };

 item.el = el; // save link to element for getThumbBoundsFn

 if(childElements.length > 0) {
  item.msrc = childElements[0].getAttribute('src'); // thumbnail url
  if(childElements.length > 1) {
   item.title = childElements[1].innerHTML; // caption (contents of figure)
  }
 }


 var mediumSrc = el.getAttribute('data-med');
 if(mediumSrc) {
  size = el.getAttribute('data-med-size').split('x');
  // "medium-sized" image
  item.m = {
   src: mediumSrc,10)
  };
 }
 // original image
 item.o = {
  src: item.src,w: item.w,h: item.h
 };

 items.push(item);
}

return items;

};

// find nearest parent element
var closest = function closest(el,fn) {
return el && ( fn(el) ? el : closest(el.parentNode,fn) );
};

var onThumbnailsClick = function(e) {
e = e || window.event;
e.preventDefault ? e.preventDefault() : e.returnValue = false;

var eTarget = e.target || e.srcElement;

var clickedListItem = closest(eTarget,function(el) {
 return el.tagName === 'A';
});

if(!clickedListItem) {
 return;
}

var clickedGallery = clickedListItem.parentNode;

var childNodes = clickedListItem.parentNode.childNodes,numChildNodes = childNodes.length,nodeIndex = 0,index;

for (var i = 0; i < numChildNodes; i++) {
 if(childNodes[i].nodeType !== 1) {
  continue;
 }

 if(childNodes[i] === clickedListItem) {
  index = nodeIndex;
  break;
 }
 nodeIndex++;
}

if(index >= 0) {
 openPhotoSwipe( index,clickedGallery );
}
return false;

};

var photoswipeParseHash = function() {
var hash = window.location.hash.substring(1),params = {};

if(hash.length < 5) { // pid=1
 return params;
}

var vars = hash.split('&');
for (var i = 0; i < vars.length; i++) {
 if(!vars[i]) {
  continue;
 }
 var pair = vars[i].split('=');
 if(pair.length < 2) {
  continue;
 }
 params[pair[0]] = pair[1];
}

if(params.gid) {
 params.gid = parseInt(params.gid,10);
}

return params;

};

var openPhotoSwipe = function(index,galleryElement,disableAnimation,fromURL) {
var pswpElement = document.querySelectorAll('.pswp')[0],gallery,options,items;

items = parseThumbnailElements(galleryElement);

// define options (if needed)
options = {

 galleryUID: galleryElement.getAttribute('data-pswp-uid'),getThumbBoundsFn: function(index) {
  // See Options->getThumbBoundsFn section of docs for more info
  var thumbnail = items[index].el.children[0],pageYScroll = window.pageYOffset || document.documentElement.scrollTop,rect = thumbnail.getBoundingClientRect();

  return {x:rect.left,y:rect.top + pageYScroll,w:rect.width};
 },addCaptionHTMLFn: function(item,captionEl,isFake) {
  if(!item.title) {
   captionEl.children[0].innerText = '';
   return false;
  }
  captionEl.children[0].innerHTML = item.title + '<br/><small>Photo: ' + item.author + '</small>';
  return true;
 }

};

// options for control bar
options.shareEl = false;
options.fullscreenEl = false;

if(fromURL) {
 if(options.galleryPIDs) {
  // parse real index when custom PIDs are used
  // http://photoswipe.com/documentation/faq.html#custom-pid-in-url
  for(var j = 0; j < items.length; j++) {
   if(items[j].pid == index) {
    options.index = j;
    break;
   }
  }
 } else {
  options.index = parseInt(index,10) - 1;
 }
} else {
 options.index = parseInt(index,10);
}

// exit if index not found
if( isNaN(options.index) ) {
 return;
}



// Pass data to PhotoSwipe and initialize it
gallery = new PhotoSwipe( pswpElement,PhotoSwipeUI_Default,items,options);

// see: http://photoswipe.com/documentation/responsive-images.html
var realViewportWidth,useLargeImages = false,firstResize = true,imageSrcWillChange;

gallery.listen('beforeResize',function() {

 var dpiRatio = window.devicePixelRatio ? window.devicePixelRatio : 1;
 dpiRatio = Math.min(dpiRatio,2.5);
 realViewportWidth = gallery.viewportSize.x * dpiRatio;


 if(realViewportWidth >= 1200 || (!gallery.likelyTouchDevice && realViewportWidth > 800) || screen.width > 1200 ) {
  if(!useLargeImages) {
   useLargeImages = true;
   imageSrcWillChange = true;
  }

 } else {
  if(useLargeImages) {
   useLargeImages = false;
   imageSrcWillChange = true;
  }
 }

 if(imageSrcWillChange && !firstResize) {
  gallery.invalidateCurrItems();
 }

 if(firstResize) {
  firstResize = false;
 }

 imageSrcWillChange = false;

});

gallery.listen('gettingData',function(index,item) {
 if( useLargeImages ) {
  item.src = item.o.src;
  item.w = item.o.w;
  item.h = item.o.h;
 } else {
  item.src = item.m.src;
  item.w = item.m.w;
  item.h = item.m.h;
 }
});

gallery.init();

};

// select all gallery elements
var galleryElements = document.querySelectorAll( gallerySelector );
for(var i = 0,l = galleryElements.length; i < l; i++) {
galleryElements[i].setAttribute('data-pswp-uid',i+1);
galleryElements[i].onclick = onThumbnailsClick;
}

// Parse URL and open gallery if it contains #&pid=3&gid=1
var hashData = photoswipeParseHash();
if(hashData.pid && hashData.gid) {
openPhotoSwipe( hashData.pid,galleryElements[ hashData.gid - 1 ],true );
}
};

initPhotoSwipeFromDOM('.demo-gallery');

})();