// .photoswipe_gallery
(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], 10),
          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,
            w: parseInt(size[0], 10),
            h: parseInt(size[1], 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 = {

        //ここからオプション追加
        //          showHideOpacity: true,
        //          bgOpacity: 1,
        //          spacing: 0.12,
        //          maxSpreadZoom: 2,
        //          loop: true,
        //          pinchToClose: true,
        //          closeOnScroll: true,
        //          closeOnVerticalDrag: true,
        //          preload: [1,1],
        //ここまでオプション追加

        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;
        }

      };


      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;
      }



      if(disableAnimation) {
        options.showAnimationDuration = 0;
      }

      // 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, true );
    }
  };

  initPhotoSwipeFromDOM('.photoswipe_gallery');
})();