/*!
 * viewer v0.5.1
 * https://github.com/fengyuanchen/viewer
 *
 * copyright (c) 2015-2016 fengyuan chen
 * released under the mit license
 *
 * date: 2016-03-11t07:57:59.486z
 */

(function (factory) {
  if (typeof define === 'function' && define.amd) {
    // amd. register as anonymous module.
    define('viewer', ['jquery'], factory);
  } else if (typeof exports === 'object') {
    // node / commonjs
    factory(require('jquery'));
  } else {
    // browser globals.
    factory(jquery);
  }
})(function ($) {

  'use strict';

  var $window = $(window);
  var $document = $(document);

  // constants
  var namespace = 'viewer';
  var element_viewer = document.createelement(namespace);

  // classes
  var class_fixed = 'viewer-fixed';
  var class_open = 'viewer-open';
  var class_show = 'viewer-show';
  var class_hide = 'viewer-hide';
  var class_hide_xs_down = 'viewer-hide-xs-down';
  var class_hide_sm_down = 'viewer-hide-sm-down';
  var class_hide_md_down = 'viewer-hide-md-down';
  var class_fade = 'viewer-fade';
  var class_in = 'viewer-in';
  var class_move = 'viewer-move';
  var class_active = 'viewer-active';
  var class_invisible = 'viewer-invisible';
  var class_transition = 'viewer-transition';
  var class_fullscreen = 'viewer-fullscreen';
  var class_fullscreen_exit = 'viewer-fullscreen-exit';
  var class_close = 'viewer-close';

  // selectors
  var selector_img = 'img';

  // events
  var event_mousedown = 'mousedown touchstart pointerdown mspointerdown';
  var event_mousemove = 'mousemove touchmove pointermove mspointermove';
  var event_mouseup = 'mouseup touchend touchcancel pointerup pointercancel mspointerup mspointercancel';
  var event_wheel = 'wheel mousewheel dommousescroll';
  var event_transitionend = 'transitionend';
  var event_load = 'load.' + namespace;
  var event_keydown = 'keydown.' + namespace;
  var event_click = 'click.' + namespace;
  var event_resize = 'resize.' + namespace;
  var event_build = 'build.' + namespace;
  var event_built = 'built.' + namespace;
  var event_show = 'show.' + namespace;
  var event_shown = 'shown.' + namespace;
  var event_hide = 'hide.' + namespace;
  var event_hidden = 'hidden.' + namespace;
  var event_view = 'view.' + namespace;
  var event_viewed = 'viewed.' + namespace;

  // supports
  var support_transition = typeof element_viewer.style.transition !== 'undefined';

  // others
  var round = math.round;
  var sqrt = math.sqrt;
  var abs = math.abs;
  var min = math.min;
  var max = math.max;
  var num = number;

  function isstring(s) {
    return typeof s === 'string';
  }

  function isnumber(n) {
    return typeof n === 'number' && !isnan(n);
  }

  function isundefined(u) {
    return typeof u === 'undefined';
  }

  function toarray(obj, offset) {
    var args = [];

    if (isnumber(offset)) { // it's necessary for ie8
      args.push(offset);
    }

    return args.slice.apply(obj, args);
  }

  // custom proxy to avoid jquery's guid
  function proxy(fn, context) {
    var args = toarray(arguments, 2);

    return function () {
      return fn.apply(context, args.concat(toarray(arguments)));
    };
  }

  function gettransform(options) {
    var transforms = [];
    var rotate = options.rotate;
    var scalex = options.scalex;
    var scaley = options.scaley;

    if (isnumber(rotate)) {
      transforms.push('rotate(' + rotate + 'deg)');
    }

    if (isnumber(scalex) && isnumber(scaley)) {
      transforms.push('scale(' + scalex + ',' + scaley + ')');
    }

    return transforms.length ? transforms.join(' ') : 'none';
  }

  // force reflow to enable css3 transition
  function forcereflow(element) {
    return element.offsetwidth;
  }

  // e.g.: http://domain.com/path/to/picture.jpg?size=1280×960 -> picture.jpg
  function getimagename(url) {
    return isstring(url) ? url.replace(/^.*\//, '').replace(/[\?&#].*$/, '') : '';
  }

  function getimagesize(image, callback) {
    var newimage;

    // modern browsers
    if (image.naturalwidth) {
      return callback(image.naturalwidth, image.naturalheight);
    }

    // ie8: don't use `new image()` here
    newimage = document.createelement('img');

    newimage.onload = function () {
      callback(this.width, this.height);
    };

    newimage.src = image.src;
  }

  function gettouchescenter(touches) {
    var length = touches.length;
    var pagex = 0;
    var pagey = 0;

    if (length) {
      $.each(touches, function (i, touch) {
        pagex += touch.pagex;
        pagey += touch.pagey;
      });

      pagex /= length;
      pagey /= length;
    }

    return {
      pagex: pagex,
      pagey: pagey
    };
  }

  function getresponsiveclass(option) {
    switch (option) {
      case 2:
        return class_hide_xs_down;

      case 3:
        return class_hide_sm_down;

      case 4:
        return class_hide_md_down;
    }
  }

  function viewer(element, options) {
    this.$element = $(element);
    this.options = $.extend({}, viewer.defaults, $.isplainobject(options) && options);
    this.isimg = false;
    this.isbuilt = false;
    this.isshown = false;
    this.isviewed = false;
    this.isfulled = false;
    this.isplayed = false;
    this.wheeling = false;
    this.playing = false;
    this.fading = false;
    this.tooltiping = false;
    this.transitioning = false;
    this.action = false;
    this.target = false;
    this.timeout = false;
    this.index = 0;
    this.length = 0;
    this.init();
  }

  viewer.prototype = {
    constructor: viewer,

    init: function () {
      var options = this.options;
      var $this = this.$element;
      var isimg = $this.is(selector_img);
      var $images = isimg ? $this : $this.find(selector_img);
      var length = $images.length;
      var ready = $.proxy(this.ready, this);

      if (!length) {
        return;
      }

      if ($.isfunction(options.build)) {
        $this.one(event_build, options.build);
      }

      if (this.trigger(event_build).isdefaultprevented()) {
        return;
      }

      // override `transition` option if it is not supported
      if (!support_transition) {
        options.transition = false;
      }

      this.isimg = isimg;
      this.length = length;
      this.count = 0;
      this.$images = $images;
      this.$body = $('body');

      if (options.inline) {
        $this.one(event_built, $.proxy(function () {
          this.view();
        }, this));

        $images.each(function () {
          if (this.complete) {
            ready();
          } else {
            $(this).one(event_load, ready);
          }
        });
      } else {
        $this.on(event_click, $.proxy(this.start, this));
      }
    },

    ready: function () {
      this.count++;

      if (this.count === this.length) {
        this.build();
      }
    },

    build: function () {
      var options = this.options;
      var $this = this.$element;
      var $parent;
      var $viewer;
      var $title;
      var $toolbar;
      var $navbar;
      var $button;

      if (this.isbuilt) {
        return;
      }

      this.$parent = $parent = $this.parent();
      this.$viewer = $viewer = $(viewer.template);
      this.$canvas = $viewer.find('.viewer-canvas');
      this.$footer = $viewer.find('.viewer-footer');
      this.$title = $title = $viewer.find('.viewer-title');
      this.$toolbar = $toolbar = $viewer.find('.viewer-toolbar');
      this.$navbar = $navbar = $viewer.find('.viewer-navbar');
      this.$button = $button = $viewer.find('.viewer-button');
      this.$tooltip = $viewer.find('.viewer-tooltip');
      this.$player = $viewer.find('.viewer-player');
      this.$list = $viewer.find('.viewer-list');

      $title.addclass(!options.title ? class_hide : getresponsiveclass(options.title));

      $toolbar.addclass(!options.toolbar ? class_hide : getresponsiveclass(options.toolbar));
      $toolbar.find('li[class*=zoom]').toggleclass(class_invisible, !options.zoomable);
      $toolbar.find('li[class*=flip]').toggleclass(class_invisible, !options.scalable);

      if (!options.rotatable) {
        $toolbar.find('li[class*=rotate]').addclass(class_invisible).appendto($toolbar);
      }

      $navbar.addclass(!options.navbar ? class_hide : getresponsiveclass(options.navbar));
      $button.toggleclass(class_hide, !options.button);

      if (options.inline) {
        $button.addclass(class_fullscreen);
        $viewer.css('z-index', options.zindexinline);

        if ($parent.css('position') === 'static') {
          $parent.css('position', 'relative');
        }
      } else {
        $button.addclass(class_close);
        $viewer.
          css('z-index', options.zindex).
          addclass([class_fixed, class_fade, class_hide].join(' '));
      }

      $this.after($viewer);

      if (options.inline) {
        this.render();
        this.bind();
        this.isshown = true;
      }

      this.isbuilt = true;

      if ($.isfunction(options.built)) {
        $this.one(event_built, options.built);
      }

      this.trigger(event_built);
    },

    unbuild: function () {
      if (!this.isbuilt) {
        return;
      }

      this.isbuilt = false;
      this.$viewer.remove();
    },

    bind: function () {
      var options = this.options;
      var $this = this.$element;

      if ($.isfunction(options.view)) {
        $this.on(event_view, options.view);
      }

      if ($.isfunction(options.viewed)) {
        $this.on(event_viewed, options.viewed);
      }

      this.$viewer.
        on(event_click, $.proxy(this.click, this)).
        on(event_wheel, $.proxy(this.wheel, this));

      this.$canvas.on(event_mousedown, $.proxy(this.mousedown, this));

      $document.
        on(event_mousemove, (this._mousemove = proxy(this.mousemove, this))).
        on(event_mouseup, (this._mouseup = proxy(this.mouseup, this))).
        on(event_keydown, (this._keydown = proxy(this.keydown, this)));

      $window.on(event_resize, (this._resize = proxy(this.resize, this)));
    },

    unbind: function () {
      var options = this.options;
      var $this = this.$element;

      if ($.isfunction(options.view)) {
        $this.off(event_view, options.view);
      }

      if ($.isfunction(options.viewed)) {
        $this.off(event_viewed, options.viewed);
      }

      this.$viewer.
        off(event_click, this.click).
        off(event_wheel, this.wheel);

      this.$canvas.off(event_mousedown, this.mousedown);

      $document.
        off(event_mousemove, this._mousemove).
        off(event_mouseup, this._mouseup).
        off(event_keydown, this._keydown);

      $window.off(event_resize, this._resize);
    },

    render: function () {
      this.initcontainer();
      this.initviewer();
      this.initlist();
      this.renderviewer();
    },

    initcontainer: function () {
      this.container = {
        width: $window.innerwidth(),
        height: $window.innerheight()
      };
    },

    initviewer: function () {
      var options = this.options;
      var $parent = this.$parent;
      var viewer;

      if (options.inline) {
        this.parent = viewer = {
          width: max($parent.width(), options.minwidth),
          height: max($parent.height(), options.minheight)
        };
      }

      if (this.isfulled || !viewer) {
        viewer = this.container;
      }

      this.viewer = $.extend({}, viewer);
    },

    renderviewer: function () {
      if (this.options.inline && !this.isfulled) {
        this.$viewer.css(this.viewer);
      }
    },

    initlist: function () {
      var options = this.options;
      var $this = this.$element;
      var $list = this.$list;
      var list = [];

      this.$images.each(function (i) {
        var src = this.src;
        var alt = this.alt || getimagename(src);
        var url = options.url;

        if (!src) {
          return;
        }

        if (isstring(url)) {
          url = this.getattribute(url);
        } else if ($.isfunction(url)) {
          url = url.call(this, this);
        }

        list.push(
          '<li>' +
            '<img' +
              ' src="' + src + '"' +
              ' data-action="view"' +
              ' data-index="' +  i + '"' +
              ' data-original-url="' +  (url || src) + '"' +
              ' alt="' +  alt + '"' +
            '>' +
          '</li>'
        );
      });

      $list.html(list.join('')).find(selector_img).one(event_load, {
        filled: true
      }, $.proxy(this.loadimage, this));

      this.$items = $list.children();

      if (options.transition) {
        $this.one(event_viewed, function () {
          $list.addclass(class_transition);
        });
      }
    },

    renderlist: function (index) {
      var i = index || this.index;
      var width = this.$items.eq(i).width();
      var outerwidth = width + 1; // 1 pixel of `margin-left` width

      // place the active item in the center of the screen
      this.$list.css({
        width: outerwidth * this.length,
        marginleft: (this.viewer.width - width) / 2 - outerwidth * i
      });
    },

    resetlist: function () {
      this.$list.empty().removeclass(class_transition).css('margin-left', 0);
    },

    initimage: function (callback) {
      var options = this.options;
      var $image = this.$image;
      var viewer = this.viewer;
      var footerheight = this.$footer.height();
      var viewerwidth = viewer.width;
      var viewerheight = max(viewer.height - footerheight, footerheight);
      var oldimage = this.image || {};

      getimagesize($image[0], $.proxy(function (naturalwidth, naturalheight) {
        var aspectratio = naturalwidth / naturalheight;
        var width = viewerwidth;
        var height = viewerheight;
        var initialimage;
        var image;

        if (viewerheight * aspectratio > viewerwidth) {
          height = viewerwidth / aspectratio;
        } else {
          width = viewerheight * aspectratio;
        }

        width = min(width * 0.9, naturalwidth);
        height = min(height * 0.9, naturalheight);

        image = {
          naturalwidth: naturalwidth,
          naturalheight: naturalheight,
          aspectratio: aspectratio,
          ratio: width / naturalwidth,
          width: width,
          height: height,
          left: (viewerwidth - width) / 2,
          top: (viewerheight - height) / 2
        };

        initialimage = $.extend({}, image);

        if (options.rotatable) {
          image.rotate = oldimage.rotate || 0;
          initialimage.rotate = 0;
        }

        if (options.scalable) {
          image.scalex = oldimage.scalex || 1;
          image.scaley = oldimage.scaley || 1;
          initialimage.scalex = 1;
          initialimage.scaley = 1;
        }

        this.image = image;
        this.initialimage = initialimage;

        if ($.isfunction(callback)) {
          callback();
        }
      }, this));
    },

    renderimage: function (callback) {
      var image = this.image;
      var $image = this.$image;

      $image.css({
        width: image.width,
        height: image.height,
        marginleft: image.left,
        margintop: image.top,
        transform: gettransform(image)
      });

      if ($.isfunction(callback)) {
        if (this.transitioning) {
          $image.one(event_transitionend, callback);
        } else {
          callback();
        }
      }
    },

    resetimage: function () {
      if (this.$image) {
        this.$image.remove();
        this.$image = null;
      }
    },

    start: function (e) {
      var target = e.target;

      if ($(target).is('img')) {
        this.target = target;
        this.show();
      }
    },

    click: function (e) {
      var $target = $(e.target);
      var action = $target.data('action');
      var image = this.image;

      switch (action) {
        case 'mix':
          if (this.isplayed) {
            this.stop();
          } else {
            if (this.options.inline) {
              if (this.isfulled) {
                this.exit();
              } else {
                this.full();
              }
            } else {
              this.hide();
            }
          }

          break;

        case 'view':
          this.view($target.data('index'));
          break;

        case 'zoom-in':
          this.zoom(0.1, true);
          break;

        case 'zoom-out':
          this.zoom(-0.1, true);
          break;

        case 'one-to-one':
          this.toggle();
          break;

        case 'reset':
          this.reset();
          break;

        case 'prev':
          this.prev();
          break;

        case 'play':
          this.play();
          break;

        case 'next':
          this.next();
          break;

        case 'rotate-left':
          this.rotate(-90);
          break;

        case 'rotate-right':
          this.rotate(90);
          break;

        case 'flip-horizontal':
          this.scalex(-image.scalex || -1);
          break;

        case 'flip-vertical':
          this.scaley(-image.scaley || -1);
          break;

        default:
          if (this.isplayed) {
            this.stop();
          }
      }
    },

    load: function () {
      var options = this.options;
      var viewer = this.viewer;
      var $image = this.$image;

      if (this.timeout) {
        cleartimeout(this.timeout);
        this.timeout = false;
      }

      $image.removeclass(class_invisible).css('csstext', (
        'width:0;' +
        'height:0;' +
        'margin-left:' + viewer.width / 2 + 'px;' +
        'margin-top:' + viewer.height / 2 + 'px;' +
        'max-width:none!important;' +
        'visibility:visible;'
      ));

      this.initimage($.proxy(function () {
        $image.
          toggleclass(class_transition, options.transition).
          toggleclass(class_move, options.movable);

        this.renderimage($.proxy(function () {
          this.isviewed = true;
          this.trigger(event_viewed);
        }, this));
      }, this));
    },

    loadimage: function (e) {
      var image = e.target;
      var $image = $(image);
      var $parent = $image.parent();
      var parentwidth = $parent.width();
      var parentheight = $parent.height();
      var filled = e.data && e.data.filled;

      getimagesize(image, function (naturalwidth, naturalheight) {
        var aspectratio = naturalwidth / naturalheight;
        var width = parentwidth;
        var height = parentheight;

        if (parentheight * aspectratio > parentwidth) {
          if (filled) {
            width = parentheight * aspectratio;
          } else {
            height = parentwidth / aspectratio;
          }
        } else {
          if (filled) {
            height = parentwidth / aspectratio;
          } else {
            width = parentheight * aspectratio;
          }
        }

        $image.css({
          width: width,
          height: height,
          marginleft: (parentwidth - width) / 2,
          margintop: (parentheight - height) / 2
        });
      });
    },

    resize: function () {
      this.initcontainer();
      this.initviewer();
      this.renderviewer();
      this.renderlist();

      if (this.isviewed) {
        this.initimage($.proxy(function () {
          this.renderimage();
        }, this));
      }

      if (this.isplayed) {
        this.$player.
          find(selector_img).
          one(event_load, $.proxy(this.loadimage, this)).
          trigger(event_load);
      }
    },

    wheel: function (event) {
      var e = event.originalevent || event;
      var ratio = num(this.options.zoomratio) || 0.1;
      var delta = 1;

      if (!this.isviewed) {
        return;
      }

      event.preventdefault();

      // limit wheel speed to prevent zoom too fast
      if (this.wheeling) {
        return;
      }

      this.wheeling = true;

      settimeout($.proxy(function () {
        this.wheeling = false;
      }, this), 50);

      if (e.deltay) {
        delta = e.deltay > 0 ? 1 : -1;
      } else if (e.wheeldelta) {
        delta = -e.wheeldelta / 120;
      } else if (e.detail) {
        delta = e.detail > 0 ? 1 : -1;
      }

      this.zoom(-delta * ratio, true, event);
    },

    keydown: function (e) {
      var options = this.options;
      var which = e.which;

      if (!this.isfulled || !options.keyboard) {
        return;
      }

      switch (which) {

        // (key: esc)
        case 27:
          if (this.isplayed) {
            this.stop();
          } else {
            if (options.inline) {
              if (this.isfulled) {
                this.exit();
              }
            } else {
              this.hide();
            }
          }

          break;

        // (key: space)
        case 32:
          if (this.isplayed) {
            this.stop();
          }

          break;

        // view previous (key: ←)
        case 37:
          this.prev();
          break;

        // zoom in (key: ↑)
        case 38:

          // prevent scroll on firefox
          e.preventdefault();

          this.zoom(options.zoomratio, true);
          break;

        // view next (key: →)
        case 39:
          this.next();
          break;

        // zoom out (key: ↓)
        case 40:

          // prevent scroll on firefox
          e.preventdefault();

          this.zoom(-options.zoomratio, true);
          break;

        // zoom out to initial size (key: ctrl + 0)
        case 48:
          // go to next

        // zoom in to natural size (key: ctrl + 1)
        case 49:
          if (e.ctrlkey || e.shiftkey) {
            e.preventdefault();
            this.toggle();
          }

          break;

        // no default
      }
    },

    mousedown: function (event) {
      var options = this.options;
      var originalevent = event.originalevent;
      var touches = originalevent && originalevent.touches;
      var e = event;
      var action = options.movable ? 'move' : false;
      var toucheslength;

      if (!this.isviewed) {
        return;
      }

      if (touches) {
        toucheslength = touches.length;

        if (toucheslength > 1) {
          if (options.zoomable && toucheslength === 2) {
            e = touches[1];
            this.startx2 = e.pagex;
            this.starty2 = e.pagey;
            action = 'zoom';
          } else {
            return;
          }
        } else {
          if (this.isswitchable()) {
            action = 'switch';
          }
        }

        e = touches[0];
      }

      if (action) {
        event.preventdefault();
        this.action = action;

        // ie8  has `event.pagex/y`, but not `event.originalevent.pagex/y`
        // ie10 has `event.originalevent.pagex/y`, but not `event.pagex/y`
        this.startx = e.pagex || originalevent && originalevent.pagex;
        this.starty = e.pagey || originalevent && originalevent.pagey;
      }
    },

    mousemove: function (event) {
      var options = this.options;
      var action = this.action;
      var $image = this.$image;
      var originalevent = event.originalevent;
      var touches = originalevent && originalevent.touches;
      var e = event;
      var toucheslength;

      if (!this.isviewed) {
        return;
      }

      if (touches) {
        toucheslength = touches.length;

        if (toucheslength > 1) {
          if (options.zoomable && toucheslength === 2) {
            e = touches[1];
            this.endx2 = e.pagex;
            this.endy2 = e.pagey;
          } else {
            return;
          }
        }

        e = touches[0];
      }

      if (action) {
        event.preventdefault();

        if (action === 'move' && options.transition && $image.hasclass(class_transition)) {
          $image.removeclass(class_transition);
        }

        this.endx = e.pagex || originalevent && originalevent.pagex;
        this.endy = e.pagey || originalevent && originalevent.pagey;

        this.change(event);
      }
    },

    mouseup: function (event) {
      var action = this.action;

      if (action) {
        event.preventdefault();

        if (action === 'move' && this.options.transition) {
          this.$image.addclass(class_transition);
        }

        this.action = false;
      }
    },

    // show the viewer (only available in modal mode)
    show: function () {
      var options = this.options;
      var $viewer;

      if (options.inline || this.transitioning) {
        return;
      }

      if (!this.isbuilt) {
        this.build();
      }

      if ($.isfunction(options.show)) {
        this.$element.one(event_show, options.show);
      }

      if (this.trigger(event_show).isdefaultprevented()) {
        return;
      }

      this.$body.addclass(class_open);
      $viewer = this.$viewer.removeclass(class_hide);

      this.$element.one(event_shown, $.proxy(function () {
        this.view(this.target ? this.$images.index(this.target) : this.index);
        this.target = false;
      }, this));

      if (options.transition) {
        this.transitioning = true;
        $viewer.addclass(class_transition);
        forcereflow($viewer[0]);
        $viewer.one(event_transitionend, $.proxy(this.shown, this)).addclass(class_in);
      } else {
        $viewer.addclass(class_in);
        this.shown();
      }
    },

    // hide the viewer (only available in modal mode)
    hide: function () {
      var options = this.options;
      var $viewer = this.$viewer;

      if (options.inline || this.transitioning || !this.isshown) {
        return;
      }

      if ($.isfunction(options.hide)) {
        this.$element.one(event_hide, options.hide);
      }

      if (this.trigger(event_hide).isdefaultprevented()) {
        return;
      }

      if (this.isviewed && options.transition) {
        this.transitioning = true;
        this.$image.one(event_transitionend, $.proxy(function () {
          $viewer.one(event_transitionend, $.proxy(this.hidden, this)).removeclass(class_in);
        }, this));
        this.zoomto(0, false, false, true);
      } else {
        $viewer.removeclass(class_in);
        this.hidden();
      }
    },

    /**
     * view one of the images with image's index
     *
     * @param {number} index
     */
    view: function (index) {
      var $title = this.$title;
      var $image;
      var $item;
      var $img;
      var url;
      var alt;

      index = number(index) || 0;

      if (!this.isshown || this.isplayed || index < 0 || index >= this.length ||
        this.isviewed && index === this.index) {
        return;
      }

      if (this.trigger(event_view).isdefaultprevented()) {
        return;
      }

      $item = this.$items.eq(index);
      $img = $item.find(selector_img);
      url = $img.data('originalurl');
      alt = $img.attr('alt');

      this.$image = $image = $('<img src="' + url + '" alt="' + alt + '">');

      if (this.isviewed) {
        this.$items.eq(this.index).removeclass(class_active);
      }

      $item.addclass(class_active);

      this.isviewed = false;
      this.index = index;
      this.image = null;
      this.$canvas.html($image.addclass(class_invisible));

      // center current item
      this.renderlist();

      // clear title
      $title.empty();

      // generate title after viewed
      this.$element.one(event_viewed, $.proxy(function () {
        var image = this.image;
        var width = image.naturalwidth;
        var height = image.naturalheight;

        $title.html(alt);
      }, this));

      if ($image[0].complete) {
        this.load();
      } else {
        $image.one(event_load, $.proxy(this.load, this));

        if (this.timeout) {
          cleartimeout(this.timeout);
        }

        // make the image visible if it fails to load within 1s
        this.timeout = settimeout($.proxy(function () {
          $image.removeclass(class_invisible);
          this.timeout = false;
        }, this), 1000);
      }
    },

    // view the previous image
    prev: function () {
      this.view(max(this.index - 1, 0));
    },

    // view the next image
    next: function () {
      this.view(min(this.index + 1, this.length - 1));
    },

    /**
     * move the image with relative offsets
     *
     * @param {number} offsetx
     * @param {number} offsety (optional)
     */
    move: function (offsetx, offsety) {
      var image = this.image;

      this.moveto(
        isundefined(offsetx) ? offsetx : image.left + num(offsetx),
        isundefined(offsety) ? offsety : image.top + num(offsety)
      );
    },

    /**
     * move the image to an absolute point
     *
     * @param {number} x
     * @param {number} y (optional)
     */
    moveto: function (x, y) {
      var image = this.image;
      var changed = false;

      // if "y" is not present, its default value is "x"
      if (isundefined(y)) {
        y = x;
      }

      x = num(x);
      y = num(y);

      if (this.isviewed && !this.isplayed && this.options.movable) {
        if (isnumber(x)) {
          image.left = x;
          changed = true;
        }

        if (isnumber(y)) {
          image.top = y;
          changed = true;
        }

        if (changed) {
          this.renderimage();
        }
      }
    },

    /**
     * zoom the image with a relative ratio
     *
     * @param {number} ratio
     * @param {boolean} hastooltip (optional)
     * @param {jquery event} _event (private)
     */
    zoom: function (ratio, hastooltip, _event) {
      var image = this.image;

      ratio = num(ratio);

      if (ratio < 0) {
        ratio =  1 / (1 - ratio);
      } else {
        ratio = 1 + ratio;
      }

      this.zoomto(image.width * ratio / image.naturalwidth, hastooltip, _event);
    },

    /**
     * zoom the image to an absolute ratio
     *
     * @param {number} ratio
     * @param {boolean} hastooltip (optional)
     * @param {jquery event} _event (private)
     * @param {boolean} _zoomable (private)
     */
    zoomto: function (ratio, hastooltip, _event, _zoomable) {
      var options = this.options;
      var minzoomratio = 0.01;
      var maxzoomratio = 100;
      var image = this.image;
      var width = image.width;
      var height = image.height;
      var originalevent;
      var newwidth;
      var newheight;
      var offset;
      var center;

      ratio = max(0, ratio);

      if (isnumber(ratio) && this.isviewed && !this.isplayed && (_zoomable || options.zoomable)) {
        if (!_zoomable) {
          minzoomratio = max(minzoomratio, options.minzoomratio);
          maxzoomratio = min(maxzoomratio, options.maxzoomratio);
          ratio = min(max(ratio, minzoomratio), maxzoomratio);
        }

        if (ratio > 0.95 && ratio < 1.05) {
          ratio = 1;
        }

        newwidth = image.naturalwidth * ratio;
        newheight = image.naturalheight * ratio;

        if (_event && (originalevent = _event.originalevent)) {
          offset = this.$viewer.offset();
          center = originalevent.touches ? gettouchescenter(originalevent.touches) : {
            pagex: _event.pagex || originalevent.pagex || 0,
            pagey: _event.pagey || originalevent.pagey || 0
          };

          // zoom from the triggering point of the event
          image.left -= (newwidth - width) * (
            ((center.pagex - offset.left) - image.left) / width
          );
          image.top -= (newheight - height) * (
            ((center.pagey - offset.top) - image.top) / height
          );
        } else {

          // zoom from the center of the image
          image.left -= (newwidth - width) / 2;
          image.top -= (newheight - height) / 2;
        }

        image.width = newwidth;
        image.height = newheight;
        image.ratio = ratio;
        this.renderimage();

        if (hastooltip) {
          this.tooltip();
        }
      }
    },

    /**
     * rotate the image with a relative degree
     *
     * @param {number} degree
     */
    rotate: function (degree) {
      this.rotateto((this.image.rotate || 0) + num(degree));
    },

    /**
     * rotate the image to an absolute degree
     * https://developer.mozilla.org/en-us/docs/web/css/transform-function#rotate()
     *
     * @param {number} degree
     */
    rotateto: function (degree) {
      var image = this.image;

      degree = num(degree);

      if (isnumber(degree) && this.isviewed && !this.isplayed && this.options.rotatable) {
        image.rotate = degree;
        this.renderimage();
      }
    },

    /**
     * scale the image
     * https://developer.mozilla.org/en-us/docs/web/css/transform-function#scale()
     *
     * @param {number} scalex
     * @param {number} scaley (optional)
     */
    scale: function (scalex, scaley) {
      var image = this.image;
      var changed = false;

      // if "scaley" is not present, its default value is "scalex"
      if (isundefined(scaley)) {
        scaley = scalex;
      }

      scalex = num(scalex);
      scaley = num(scaley);

      if (this.isviewed && !this.isplayed && this.options.scalable) {
        if (isnumber(scalex)) {
          image.scalex = scalex;
          changed = true;
        }

        if (isnumber(scaley)) {
          image.scaley = scaley;
          changed = true;
        }

        if (changed) {
          this.renderimage();
        }
      }
    },

    /**
     * scale the abscissa of the image
     *
     * @param {number} scalex
     */
    scalex: function (scalex) {
      this.scale(scalex, this.image.scaley);
    },

    /**
     * scale the ordinate of the image
     *
     * @param {number} scaley
     */
    scaley: function (scaley) {
      this.scale(this.image.scalex, scaley);
    },

    // play the images
    play: function () {
      var options = this.options;
      var $player = this.$player;
      var load = $.proxy(this.loadimage, this);
      var list = [];
      var total = 0;
      var index = 0;
      var playing;

      if (!this.isshown || this.isplayed) {
        return;
      }

      if (options.fullscreen) {
        this.requestfullscreen();
      }

      this.isplayed = true;
      $player.addclass(class_show);

      this.$items.each(function (i) {
        var $this = $(this);
        var $img = $this.find(selector_img);
        var $image = $('<img src="' + $img.data('originalurl') + '" alt="' + $img.attr('alt') + '">');

        total++;

        $image.addclass(class_fade).toggleclass(class_transition, options.transition);

        if ($this.hasclass(class_active)) {
          $image.addclass(class_in);
          index = i;
        }

        list.push($image);
        $image.one(event_load, {
          filled: false
        }, load);
        $player.append($image);
      });

      if (isnumber(options.interval) && options.interval > 0) {
        playing = $.proxy(function () {
          this.playing = settimeout(function () {
            list[index].removeclass(class_in);
            index++;
            index = index < total ? index : 0;
            list[index].addclass(class_in);

            playing();
          }, options.interval);
        }, this);

        if (total > 1) {
          playing();
        }
      }
    },

    // stop play
    stop: function () {
      if (!this.isplayed) {
        return;
      }

      if (this.options.fullscreen) {
        this.exitfullscreen();
      }

      this.isplayed = false;
      cleartimeout(this.playing);
      this.$player.removeclass(class_show).empty();
    },

    // enter modal mode (only available in inline mode)
    full: function () {
      var options = this.options;
      var $image = this.$image;
      var $list = this.$list;

      if (!this.isshown || this.isplayed || this.isfulled || !options.inline) {
        return;
      }

      this.isfulled = true;
      this.$body.addclass(class_open);
      this.$button.addclass(class_fullscreen_exit);

      if (options.transition) {
        $image.removeclass(class_transition);
        $list.removeclass(class_transition);
      }

      this.$viewer.addclass(class_fixed).removeattr('style').css('z-index', options.zindex);
      this.initcontainer();
      this.viewer = $.extend({}, this.container);
      this.renderlist();
      this.initimage($.proxy(function () {
        this.renderimage(function () {
          if (options.transition) {
            settimeout(function () {
              $image.addclass(class_transition);
              $list.addclass(class_transition);
            }, 0);
          }
        });
      }, this));
    },

    // exit modal mode (only available in inline mode)
    exit: function () {
      var options = this.options;
      var $image = this.$image;
      var $list = this.$list;

      if (!this.isfulled) {
        return;
      }

      this.isfulled = false;
      this.$body.removeclass(class_open);
      this.$button.removeclass(class_fullscreen_exit);

      if (options.transition) {
        $image.removeclass(class_transition);
        $list.removeclass(class_transition);
      }

      this.$viewer.removeclass(class_fixed).css('z-index', options.zindexinline);
      this.viewer = $.extend({}, this.parent);
      this.renderviewer();
      this.renderlist();
      this.initimage($.proxy(function () {
        this.renderimage(function () {
          if (options.transition) {
            settimeout(function () {
              $image.addclass(class_transition);
              $list.addclass(class_transition);
            }, 0);
          }
        });
      }, this));
    },

    // show the current ratio of the image with percentage
    tooltip: function () {
      var options = this.options;
      var $tooltip = this.$tooltip;
      var image = this.image;
      var classes = [
            class_show,
            class_fade,
            class_transition
          ].join(' ');

      if (!this.isviewed || this.isplayed || !options.tooltip) {
        return;
      }

      $tooltip.text(round(image.ratio * 100) + '%');

      if (!this.tooltiping) {
        if (options.transition) {
          if (this.fading) {
            $tooltip.trigger(event_transitionend);
          }

          $tooltip.addclass(classes);
          forcereflow($tooltip[0]);
          $tooltip.addclass(class_in);
        } else {
          $tooltip.addclass(class_show);
        }
      } else {
        cleartimeout(this.tooltiping);
      }

      this.tooltiping = settimeout($.proxy(function () {
        if (options.transition) {
          $tooltip.one(event_transitionend, $.proxy(function () {
            $tooltip.removeclass(classes);
            this.fading = false;
          }, this)).removeclass(class_in);

          this.fading = true;
        } else {
          $tooltip.removeclass(class_show);
        }

        this.tooltiping = false;
      }, this), 1000);
    },

    // toggle the image size between its natural size and initial size
    toggle: function () {
      if (this.image.ratio === 1) {
        this.zoomto(this.initialimage.ratio, true);
      } else {
        this.zoomto(1, true);
      }
    },

    // reset the image to its initial state
    reset: function () {
      if (this.isviewed && !this.isplayed) {
        this.image = $.extend({}, this.initialimage);
        this.renderimage();
      }
    },

    // update viewer when images changed
    update: function () {
      var $this = this.$element;
      var $images = this.$images;
      var indexes = [];
      var index;

      if (this.isimg) {

        // destroy viewer if the target image was deleted
        if (!$this.parent().length) {
          return this.destroy();
        }
      } else {
        this.$images = $images = $this.find(selector_img);
        this.length = $images.length;
      }

      if (this.isbuilt) {
        $.each(this.$items, function (i) {
          var img = $(this).find('img')[0];
          var image = $images[i];

          if (image) {
            if (image.src !== img.src) {
              indexes.push(i);
            }
          } else {
            indexes.push(i);
          }
        });

        this.$list.width('auto');
        this.initlist();

        if (this.isshown) {
          if (this.length) {
            if (this.isviewed) {
              index = $.inarray(this.index, indexes);

              if (index >= 0) {
                this.isviewed = false;
                this.view(max(this.index - (index + 1), 0));
              } else {
                this.$items.eq(this.index).addclass(class_active);
              }
            }
          } else {
            this.$image = null;
            this.isviewed = false;
            this.index = 0;
            this.image = null;
            this.$canvas.empty();
            this.$title.empty();
          }
        }
      }
    },

    // destroy the viewer
    destroy: function () {
      var $this = this.$element;

      if (this.options.inline) {
        this.unbind();
      } else {
        if (this.isshown) {
          this.unbind();
        }

        $this.off(event_click, this.start);
      }

      this.unbuild();
      $this.removedata(namespace);
    },

    // a shortcut for triggering custom events
    trigger: function (type, data) {
      var e = $.event(type, data);

      this.$element.trigger(e);

      return e;
    },

    shown: function () {
      var options = this.options;

      this.transitioning = false;
      this.isfulled = true;
      this.isshown = true;
      this.isvisible = true;
      this.render();
      this.bind();

      if ($.isfunction(options.shown)) {
        this.$element.one(event_shown, options.shown);
      }

      this.trigger(event_shown);
    },

    hidden: function () {
      var options = this.options;

      this.transitioning = false;
      this.isviewed = false;
      this.isfulled = false;
      this.isshown = false;
      this.isvisible = false;
      this.unbind();
      this.$body.removeclass(class_open);
      this.$viewer.addclass(class_hide);
      this.resetlist();
      this.resetimage();

      if ($.isfunction(options.hidden)) {
        this.$element.one(event_hidden, options.hidden);
      }

      this.trigger(event_hidden);
    },

    requestfullscreen: function () {
      var documentelement = document.documentelement;

      if (this.isfulled && !document.fullscreenelement && !document.mozfullscreenelement &&
        !document.webkitfullscreenelement && !document.msfullscreenelement) {

        if (documentelement.requestfullscreen) {
          documentelement.requestfullscreen();
        } else if (documentelement.msrequestfullscreen) {
          documentelement.msrequestfullscreen();
        } else if (documentelement.mozrequestfullscreen) {
          documentelement.mozrequestfullscreen();
        } else if (documentelement.webkitrequestfullscreen) {
          documentelement.webkitrequestfullscreen(element.allow_keyboard_input);
        }
      }
    },

    exitfullscreen: function () {
      if (this.isfulled) {
        if (document.exitfullscreen) {
          document.exitfullscreen();
        } else if (document.msexitfullscreen) {
          document.msexitfullscreen();
        } else if (document.mozcancelfullscreen) {
          document.mozcancelfullscreen();
        } else if (document.webkitexitfullscreen) {
          document.webkitexitfullscreen();
        }
      }
    },

    change: function (event) {
      var offsetx = this.endx - this.startx;
      var offsety = this.endy - this.starty;

      switch (this.action) {

        // move the current image
        case 'move':
          this.move(offsetx, offsety);
          break;

        // zoom the current image
        case 'zoom':
          this.zoom(function (x1, y1, x2, y2) {
            var z1 = sqrt(x1 * x1 + y1 * y1);
            var z2 = sqrt(x2 * x2 + y2 * y2);

            return (z2 - z1) / z1;
          }(
            abs(this.startx - this.startx2),
            abs(this.starty - this.starty2),
            abs(this.endx - this.endx2),
            abs(this.endy - this.endy2)
          ), false, event);

          this.startx2 = this.endx2;
          this.starty2 = this.endy2;
          break;

        case 'switch':
          this.action = 'switched';

          if (abs(offsetx) > abs(offsety)) {
            if (offsetx > 1) {
              this.prev();
            } else if (offsetx < -1) {
              this.next();
            }
          }

          break;

        // no default
      }

      // override
      this.startx = this.endx;
      this.starty = this.endy;
    },

    isswitchable: function () {
      var image = this.image;
      var viewer = this.viewer;

      return (image.left >= 0 && image.top >= 0 && image.width <= viewer.width &&
        image.height <= viewer.height);
    }
  };

  viewer.defaults = {
    // enable inline mode
    inline: false,

    // show the button on the top-right of the viewer
    button: true,

    // show the navbar
    navbar: true,

    // show the title
    title: true,

    // show the toolbar
    toolbar: true,

    // show the tooltip with image ratio (percentage) when zoom in or zoom out
    tooltip: true,

    // enable to move the image
    movable: true,

    // enable to zoom the image
    zoomable: true,

    // enable to rotate the image
    rotatable: true,

    // enable to scale the image
    scalable: true,

    // enable css3 transition for some special elements
    transition: true,

    // enable to request fullscreen when play
    fullscreen: true,

    // enable keyboard support
    keyboard: true,

    // define interval of each image when playing
    interval: 5000,

    // min width of the viewer in inline mode
    minwidth: 200,

    // min height of the viewer in inline mode
    minheight: 100,

    // define the ratio when zoom the image by wheeling mouse
    zoomratio: 0.1,

    // define the min ratio of the image when zoom out
    minzoomratio: 0.01,

    // define the max ratio of the image when zoom in
    maxzoomratio: 100,

    // define the css `z-index` value of viewer in modal mode.
    zindex: 2015,

    // define the css `z-index` value of viewer in inline mode.
    zindexinline: 0,

    // define where to get the original image url for viewing
    // type: string (an image attribute) or function (should return an image url)
    url: 'src',

    // event shortcuts
    build: null,
    built: null,
    show: null,
    shown: null,
    hide: null,
    hidden: null,
    view: null,
    viewed: null
  };

  viewer.setdefaults = function (options) {
    $.extend(viewer.defaults, options);
  };

  viewer.template = (
    '<div class="viewer-container">' +
      '<div class="viewer-canvas"></div>' +
      '<div class="viewer-footer">' +
        '<div class="viewer-title"></div>' +
        '<ul class="viewer-toolbar">' +
          '<li class="viewer-zoom-in" data-action="zoom-in"></li>' +
          '<li class="viewer-zoom-out" data-action="zoom-out"></li>' +
          '<li class="viewer-one-to-one" data-action="one-to-one"></li>' +
          '<li class="viewer-reset" data-action="reset"></li>' +
          '<li class="viewer-prev" data-action="prev"></li>' +
          '<li class="viewer-play" data-action="play"></li>' +
          '<li class="viewer-next" data-action="next"></li>' +
          '<li class="viewer-rotate-left" data-action="rotate-left"></li>' +
          '<li class="viewer-rotate-right" data-action="rotate-right"></li>' +
          '<li class="viewer-flip-horizontal" data-action="flip-horizontal"></li>' +
          '<li class="viewer-flip-vertical" data-action="flip-vertical"></li>' +
        '</ul>' +
        '<div class="viewer-navbar">' +
          '<ul class="viewer-list"></ul>' +
        '</div>' +
      '</div>' +
      '<div class="viewer-tooltip"></div>' +
      '<div class="viewer-button" data-action="mix"></div>' +
      '<div class="viewer-player"></div>' +
    '</div>'
  );

  // save the other viewer
  viewer.other = $.fn.viewer;

  // register as jquery plugin
  $.fn.viewer = function (options) {
    var args = toarray(arguments, 1);
    var result;

    this.each(function () {
      var $this = $(this);
      var data = $this.data(namespace);
      var fn;

      if (!data) {
        if (/destroy|hide|exit|stop|reset/.test(options)) {
          return;
        }

        $this.data(namespace, (data = new viewer(this, options)));
      }

      if (isstring(options) && $.isfunction(fn = data[options])) {
        result = fn.apply(data, args);
      }
    });

    return isundefined(result) ? this : result;
  };

  $.fn.viewer.constructor = viewer;
  $.fn.viewer.setdefaults = viewer.setdefaults;

  // no conflict
  $.fn.viewer.noconflict = function () {
    $.fn.viewer = viewer.other;
    return this;
  };

});