/*!
 * smoothState.js is jQuery plugin that progressively enhances
 * page loads to behave more like a single-page application.
 *
 * @author  Miguel Ángel Pérez   reachme@miguel-perez.com
 * @see     http://smoothstate.com
 *
 */

(function (factory) {
  'use strict';

  if(typeof module === 'object' && typeof module.exports === 'object') {
    factory(require('jquery'), window, document);
  } else {
    factory(jQuery, window, document);
  }
}(function ( $, window, document, undefined ) {
  'use strict';

  /** Abort if browser does not support pushState */
  if(!window.history.pushState) {
    // setup a dummy fn, but don't intercept on link clicks
    $.fn.smoothState = function() { return this; };
    $.fn.smoothState.options = {};
    return;
  }

  /** Abort if smoothState is already present **/
  if($.fn.smoothState) { return; }

  var
    /** Used later to scroll page to the top */
    $body = $('html, body'),

    /** Used in debug mode to console out useful warnings */
    consl = window.console,

    /** Plugin default options, will be exposed as $fn.smoothState.options */
    defaults = {

      /** If set to true, smoothState will log useful debug information instead of aborting */
      debug: false,

      /** jQuery selector to specify which anchors smoothState should bind to */
      anchors: 'a',

      /** Regex to specify which href smoothState should load. If empty, every href will be permitted. */
      hrefRegex: '',

      /** jQuery selector to specify which forms smoothState should bind to */
      forms: 'form',

      /** If set to true, smoothState will store form responses in the cache. */
      allowFormCaching: false,

      /** Minimum number of milliseconds between click/submit events. Events ignored beyond this rate are ignored. */
      repeatDelay: 500,

      /** A selector that defines what should be ignored by smoothState */
      blacklist: '.no-smoothState',

      /** If set to true, smoothState will prefetch a link's contents on hover */
      prefetch: false,

      /** The name of the event we will listen to from anchors if we're prefetching */
      prefetchOn: 'mouseover touchstart',

      /** jQuery selector to specify elements which should not be prefetched */
      prefetchBlacklist: '.no-prefetch',

      /** The response header field name defining the request's final URI. Useful for resolving redirections. */
      locationHeader: 'X-SmoothState-Location',

      /** The number of pages smoothState will try to store in memory */
      cacheLength: 0,

      /** Class that will be applied to the body while the page is loading */
      loadingClass: 'is-loading',

      /** Scroll to top after onStart and scroll to hash after onReady */
      scroll: true,

      /**
       * A function that can be used to alter the ajax request settings before it is called
       * @param  {Object} request - jQuery.ajax settings object that will be used to make the request
       * @return {Object}         Altered request object
       */
      alterRequest: function (request) {
        return request;
      },

      /**
       * A function that can be used to alter the state object before it is updated or added to the browsers history
       * @param  {Object} state - An object that will be assigned to history entry
       * @param  {string} title - The history entry's title. For reference only
       * @param  {string} url   - The history entry's URL. For reference only
       * @return {Object}         Altered state object
       */
      alterChangeState: function (state, title, url) {
        return state;
      },

      /** Run before a page load has been activated */
      onBefore: function ($currentTarget, $container) {},

      /** Run when a page load has been activated */
      onStart: {
        duration: 0,
        render: function ($container) {}
      },

      /** Run if the page request is still pending and onStart has finished animating */
      onProgress: {
        duration: 0,
        render: function ($container) {}
      },

      /** Run when requested content is ready to be injected into the page  */
      onReady: {
        duration: 0,
        render: function ($container, $newContent) {
          $container.html($newContent);
        }
      },

      /** Run when content has been injected and all animations are complete  */
      onAfter: function($container, $newContent) {}
    },

    /** Utility functions that are decoupled from smoothState */
    utility = {

      /**
       * Checks to see if the url is external
       * @param   {string}    url - url being evaluated
       * @see     http://stackoverflow.com/questions/6238351/fastest-way-to-detect-external-urls
       *
       */
      isExternal: function (url) {
        var match = url.match(/^([^:\/?#]+:)?(?:\/\/([^\/?#]*))?([^?#]+)?(\?[^#]*)?(#.*)?/);
        if (typeof match[1] === 'string' && match[1].length > 0 && match[1].toLowerCase() !== window.location.protocol) {
          return true;
        }
        if (typeof match[2] === 'string' &&
          match[2].length > 0 &&
          match[2].replace(new RegExp(':(' + {'http:': 80, 'https:': 443}[window.location.protocol] +
            ')?$'), '') !== window.location.host) {
          return true;
        }
        return false;
      },

      /**
       * Strips the hash from a url and returns the new href
       * @param   {string}    href - url being evaluated
       *
       */
      stripHash: function(href) {
        return href.replace(/#.*/, '');
      },

      /**
       * Checks to see if the url is an internal hash
       * @param   {string}    href - url being evaluated
       * @param   {string}    prev - previous url (optional)
       *
       */
      isHash: function (href, prev) {
        prev = prev || window.location.href;

        var hasHash = (href.indexOf('#') > -1) ? true : false,
            samePath = (utility.stripHash(href) === utility.stripHash(prev)) ? true : false;

        return (hasHash && samePath);
      },

      /**
       * Translates a url string into a $.ajax settings obj
       * @param  {Object|String} request url or settings obj
       * @return {Object}        settings object
       */
      translate: function(request) {
          var defaults = {
            dataType: 'html',
            type: 'GET'
          };
          if(typeof request === 'string') {
            request = $.extend({}, defaults, { url: request });
          } else {
            request = $.extend({}, defaults, request);
          }
          return request;
      },

      /**
       * Checks to see if we should be loading this URL
       * @param   {string}    url - url being evaluated
       * @param   {string}    blacklist - jquery selector
       *
       */
      shouldLoadAnchor: function ($anchor, blacklist, hrefRegex) {
        var href = $anchor.prop('href');
        // URL will only be loaded if it's not an external link, hash, or
        // blacklisted
        return (
            !utility.isExternal(href) &&
            !utility.isHash(href) &&
            !$anchor.is(blacklist) &&
            !$anchor.prop('target')) &&
            (
              typeof hrefRegex === undefined ||
              hrefRegex === '' ||
              $anchor.prop('href').search(hrefRegex) !== -1
            );
      },

      /**
       * Resets an object if it has too many properties
       *
       * This is used to clear the 'cache' object that stores
       * all of the html. This would prevent the client from
       * running out of memory and allow the user to hit the
       * server for a fresh copy of the content.
       *
       * @param   {object}    obj
       * @param   {number}    cap
       *
       */
      clearIfOverCapacity: function (cache, cap) {
        // Polyfill Object.keys if it doesn't exist
        if (!Object.keys) {
          Object.keys = function (obj) {
            var keys = [],
              k;
            for (k in obj) {
              if (Object.prototype.hasOwnProperty.call(obj, k)) {
                keys.push(k);
              }
            }
            return keys;
          };
        }

        if (Object.keys(cache).length > cap) {
          cache = {};
        }

        return cache;
      },

      /**
       * Stores a document fragment into an object
       * @param   {object}           object - object where it will be stored
       * @param   {string}           url - name of the entry
       * @param   {string|document}  doc - entire html
       * @param   {string}           id - the id of the fragment
       * @param   {object}           [state] - the history entry's object
       * @param   {string}           [destUrl] - the destination url
       * @return  {object}           updated object store
       */
      storePageIn: function (object, url, doc, id, state, destUrl) {
        var $html = $( '<html></html>' ).append( $(doc) );
        if (typeof state === 'undefined') {
          state = {};
        }
        if (typeof destUrl === 'undefined') {
          destUrl = url;
        }
        object[url] = { // Content is indexed by the url
          status: 'loaded',
          // Stores the title of the page, .first() prevents getting svg titles
          title: $html.find('title').first().text(),
          html: $html.find('#' + id), // Stores the contents of the page
          doc: doc, // Stores the whole page document
          state: state, // Stores the history entry for comparisons,
          destUrl: destUrl // URL, which will be pushed to history stack
        };
        return object;
      },

      /**
       * Triggers an 'allanimationend' event when all animations are complete
       * @param   {object}    $element - jQuery object that should trigger event
       * @param   {string}    resetOn - which other events to trigger allanimationend on
       *
       */
      triggerAllAnimationEndEvent: function ($element, resetOn) {

        resetOn = ' ' + resetOn || '';

        var animationCount = 0,
          animationstart = 'animationstart webkitAnimationStart oanimationstart MSAnimationStart',
          animationend = 'animationend webkitAnimationEnd oanimationend MSAnimationEnd',
          eventname = 'allanimationend',
          onAnimationStart = function (e) {
            if ($(e.delegateTarget).is($element)) {
              e.stopPropagation();
              animationCount++;
            }
          },
          onAnimationEnd = function (e) {
            if ($(e.delegateTarget).is($element)) {
              e.stopPropagation();
              animationCount--;
              if(animationCount === 0) {
                $element.trigger(eventname);
              }
            }
          };

        $element.on(animationstart, onAnimationStart);
        $element.on(animationend, onAnimationEnd);

        $element.on('allanimationend' + resetOn, function(){
          animationCount = 0;
          utility.redraw($element);
        });
      },

      /** Forces browser to redraw elements */
      redraw: function ($element) {
        $element.height();
      }
    },

    /** Handles the popstate event, like when the user hits 'back' */
    onPopState = function ( e ) {
      if(e.state !== null) {
        var url = window.location.href,
          $page = $('#' + e.state.id),
          page = $page.data('smoothState'),
          diffUrl = (page.href !== url && !utility.isHash(url, page.href)),
          diffState = (e.state !== page.cache[page.href].state);

        if(diffUrl || diffState) {
          if (diffState) {
            page.clear(page.href);
          }
          page.load(url, false);
        }
      }
    },

    /** Constructor function */
    Smoothstate = function ( element, options ) {
      var
        /** Container element smoothState is run on */
        $container = $(element),

        /** ID of the main container */
        elementId = $container.prop('id'),

        /** If a hash was clicked, we'll store it here so we
         *  can scroll to it once the new page has been fully
         *  loaded.
         */
        targetHash = null,

        /** Used to prevent fetching while we transition so
         *  that we don't mistakenly override a cache entry
         *  we need.
         */
        isTransitioning = false,

        /** Variable that stores pages after they are requested */
        cache = {},

        /** Variable that stores data for a history entry */
        state = {},

        /** Url of the content that is currently displayed */
        currentHref = window.location.href,

        /**
         * Clears a given page from the cache, if no url is provided
         * it will clear the entire cache.
         * @param  {String} url entry that is to be deleted.
         */
        clear = function(url) {
          url = url || false;
          if(url && cache.hasOwnProperty(url)) {
            delete cache[url];
          } else {
            cache = {};
          }
          $container.data('smoothState').cache = cache;
        },

        /**
         * Fetches the contents of a url and stores it in the 'cache' variable
         * @param  {String|Object}   request  - url or request settings object
         * @param  {Function}        callback - function that will run as soon as it finishes
         */
        fetch = function (request, callback) {

          // Sets a default in case a callback is not defined
          callback = callback || $.noop;

          // Allows us to accept a url string or object as the ajax settings
          var settings = utility.translate(request);

          // Check the length of the cache and clear it if needed
          cache = utility.clearIfOverCapacity(cache, options.cacheLength);

          // Don't prefetch if we have the content already or if it's a form
          if(cache.hasOwnProperty(settings.url) && typeof settings.data === 'undefined') {
            return;
          }

          // Let other parts of the code know we're working on getting the content
          cache[settings.url] = { status: 'fetching' };

          // Make the ajax request
          var ajaxRequest = $.ajax(settings);

          // Store contents in cache variable if successful
          ajaxRequest.done(function (html) {
            utility.storePageIn(cache, settings.url, html, elementId);
            $container.data('smoothState').cache = cache;
          });

          // Mark as error to be acted on later
          ajaxRequest.fail(function () {
            cache[settings.url].status = 'error';
          });

          if (options.locationHeader) {
            ajaxRequest.always(function(htmlOrXhr, status, errorOrXhr){
              // Resolve where the XHR is based on done() or fail() argument positions
              var xhr = (htmlOrXhr.statusCode ? htmlOrXhr : errorOrXhr),
                  redirectedLocation = xhr.getResponseHeader(options.locationHeader);

              if (redirectedLocation) {
                cache[settings.url].destUrl = redirectedLocation;
              }
            });
          }

          // Call fetch callback
          if(callback) {
            ajaxRequest.always(callback);
          }
        },

        repositionWindow = function(){
          // Scroll to a hash anchor on destination page
          if(targetHash) {
            var $targetHashEl = $(targetHash, $container);
            if($targetHashEl.length){
              var newPosition = $targetHashEl.offset().top;
              $body.scrollTop(newPosition);
            }
            targetHash = null;
          }
        },

        /** Updates the contents from cache[url] */
        updateContent = function (url) {
          // If the content has been requested and is done:
          var containerId = '#' + elementId,
              $newContent = cache[url] ? $(cache[url].html.html()) : null;

          if($newContent.length) {

            // Update the title
            document.title = cache[url].title;

            // Update current url
            $container.data('smoothState').href = url;

            // Remove loading class
            if(options.loadingClass) {
              $body.removeClass(options.loadingClass);
            }

            // Call the onReady callback and set delay
            options.onReady.render($container, $newContent);

            $container.one('ss.onReadyEnd', function(){

              // Allow prefetches to be made again
              isTransitioning = false;

              // Run callback
              options.onAfter($container, $newContent);

              if (options.scroll) {
                repositionWindow();
              }
              
              bindPrefetchHandlers($container);

            });

            window.setTimeout(function(){
              $container.trigger('ss.onReadyEnd');
            }, options.onReady.duration);

          } else if (!$newContent && options.debug && consl) {
            // Throw warning to help debug in debug mode
            consl.warn('No element with an id of ' + containerId + ' in response from ' + url + ' in ' + cache);
          } else {
            // No content availble to update with, aborting...
            window.location = url;
          }
        },

        /**
         * Loads the contents of a url into our container
         * @param   {string}    url
         * @param   {bool}      push - used to determine if we should
         *                      add a new item into the history object
         * @param   {bool}      cacheResponse - used to determine if
         *                      we should allow the cache to forget this
         *                      page after this load completes.
         */
        load = function (request, push, cacheResponse) {

          var settings = utility.translate(request);

          /** Makes these optional variables by setting defaults. */
          if (typeof push === 'undefined') {
            push = true;
          }
          if (typeof cacheResponse === 'undefined') {
            cacheResponse = true;
          }

          var
            /** Used to check if the onProgress function has been run */
            hasRunCallback = false,

            callbBackEnded = false,

            /** List of responses for the states of the page request */
            responses = {

              /** Page is ready, update the content */
              loaded: function () {
                var eventName = hasRunCallback ? 'ss.onProgressEnd' : 'ss.onStartEnd';

                if (!callbBackEnded || !hasRunCallback) {
                  $container.one(eventName, function(){
                    updateContent(settings.url);
                    if (!cacheResponse) {
                      clear(settings.url);
                    }
                  });
                }
                else if (callbBackEnded) {
                  updateContent(settings.url);
                }

                if (push) {
                  var destUrl = cache[settings.url].destUrl;

                  /** Prepare a history entry */
                  state = options.alterChangeState({ id: elementId }, cache[settings.url].title, destUrl);

                  /** Update the cache to include the history entry for future comparisons */
                  cache[settings.url].state = state;

                  /** Add history entry */
                  window.history.pushState(state, cache[settings.url].title, destUrl);
                }

                if (callbBackEnded && !cacheResponse) {
                  clear(settings.url);
                }
              },

              /** Loading, wait 10 ms and check again */
              fetching: function () {

                if (!hasRunCallback) {

                  hasRunCallback = true;

                  // Run the onProgress callback and set trigger
                  $container.one('ss.onStartEnd', function(){

                    // Add loading class
                    if (options.loadingClass) {
                      $body.addClass(options.loadingClass);
                    }

                    options.onProgress.render($container);

                    window.setTimeout(function (){
                      $container.trigger('ss.onProgressEnd');
                      callbBackEnded = true;
                    }, options.onProgress.duration);

                  });
                }

                window.setTimeout(function () {
                  // Might of been canceled, better check!
                  if (cache.hasOwnProperty(settings.url)){
                    responses[cache[settings.url].status]();
                  }
                }, 10);
              },

              /** Error, abort and redirect */
              error: function (){
                if(options.debug && consl) {
                  consl.log('There was an error loading: ' + settings.url);
                } else {
                  window.location = settings.url;
                }
              }
            };

          if (!cache.hasOwnProperty(settings.url)) {
            fetch(settings);
          }

          // Run the onStart callback and set trigger
          options.onStart.render($container);

          window.setTimeout(function(){
            if (options.scroll) {
              $body.scrollTop(0);
            }
            $container.trigger('ss.onStartEnd');
          }, options.onStart.duration);

          // Start checking for the status of content
          responses[cache[settings.url].status]();
        },

        /**
         * Binds to the hover event of a link, used for prefetching content
         * @param   {object}    event
         */
        hoverAnchor = function (event) {
          var request,
              $anchor = $(event.currentTarget);

          if (utility.shouldLoadAnchor($anchor, options.blacklist, options.hrefRegex) && !isTransitioning) {
            event.stopPropagation();
            request = utility.translate($anchor.prop('href'));
            request = options.alterRequest(request);
            fetch(request);
          }
        },

        /**
         * Binds to the click event of a link, used to show the content
         * @param   {object}    event
         */
        clickAnchor = function (event) {

          // Ctrl (or Cmd) + click must open a new tab
          var $anchor = $(event.currentTarget);
          if (!event.metaKey && !event.ctrlKey && utility.shouldLoadAnchor($anchor, options.blacklist, options.hrefRegex)) {

            // stopPropagation so that event doesn't fire on parent containers.
            event.stopPropagation();
            event.preventDefault();

            // Apply rate limiting.
            if (!isRateLimited()) {

              // Set the delay timeout until the next event is allowed.
              setRateLimitRepeatTime();

              var request = utility.translate($anchor.prop('href'));
              isTransitioning = true;
              targetHash = $anchor.prop('hash');

              // Allows modifications to the request
              request = options.alterRequest(request);

              options.onBefore($anchor, $container);

              load(request);
            }
          }
        },

        /**
         * Binds to form submissions
         * @param  {Event} event
         */
        submitForm = function (event) {
          var $form = $(event.currentTarget);

          if (!$form.is(options.blacklist)) {

            event.preventDefault();
            event.stopPropagation();

            // Apply rate limiting.
            if (!isRateLimited()) {

              // Set the delay timeout until the next event is allowed.
              setRateLimitRepeatTime();

              var request = {
                url: $form.prop('action'),
                data: $form.serialize(),
                type: $form.prop('method')
              };

              isTransitioning = true;
              request = options.alterRequest(request);

              if (request.type.toLowerCase() === 'get') {
                request.url = request.url + '?' + request.data;
              }

              // Call the onReady callback and set delay
              options.onBefore($form, $container);

              load(request, undefined, options.allowFormCaching);
            }
          }
        },

        /**
         * DigitalMachinist (Jeff Rose)
         * I figured to keep these together with this above functions since they're all related.
         * Feel free to move these somewhere more appropriate if you have such places.
         */
        rateLimitRepeatTime = 0,
        isRateLimited = function () {
          var isFirstClick = (options.repeatDelay === null);
          var isDelayOver = (parseInt(Date.now()) > rateLimitRepeatTime);
          return !(isFirstClick || isDelayOver);
        },
        setRateLimitRepeatTime = function () {
          rateLimitRepeatTime = parseInt(Date.now()) + parseInt(options.repeatDelay);
        },
        
        /**
         * Binds prefetch events
         * @param   {object}    event
         */
        bindPrefetchHandlers = function ($element) {
            		
          if (options.anchors && options.prefetch) {
            $element.find(options.anchors).not(options.prefetchBlacklist).on(options.prefetchOn, null, hoverAnchor);
          }
        },
		
        /**
         * Binds all events and inits functionality
         * @param   {object}    event
         */
        bindEventHandlers = function ($element) {

          if (options.anchors) {
            $element.on('click', options.anchors, clickAnchor);

            bindPrefetchHandlers($element);
          }

          if (options.forms) {
            $element.on('submit', options.forms, submitForm);
          }
        },

        /** Restart the container's css animations */
        restartCSSAnimations = function () {
          var classes = $container.prop('class');
          $container.removeClass(classes);
          utility.redraw($container);
          $container.addClass(classes);
        };

      /** Merge defaults and global options into current configuration */
      options = $.extend( {}, $.fn.smoothState.options, options );

      /** Sets a default state */
      if(window.history.state === null) {
        state = options.alterChangeState({ id: elementId }, document.title, currentHref);

        /** Update history entry */
        window.history.replaceState(state, document.title, currentHref);
      } else {
        state = {};
      }

      /** Stores the current page in cache variable */
      utility.storePageIn(cache, currentHref, document.documentElement.outerHTML, elementId, state);

      /** Bind all of the event handlers on the container, not anchors */
      utility.triggerAllAnimationEndEvent($container, 'ss.onStartEnd ss.onProgressEnd ss.onEndEnd');

      /** Bind all of the event handlers on the container, not anchors */
      bindEventHandlers($container);


      /** Public methods */
      return {
        href: currentHref,
        cache: cache,
        clear: clear,
        load: load,
        fetch: fetch,
        restartCSSAnimations: restartCSSAnimations
      };
    },

    /** Returns elements with smoothState attached to it */
    declaresmoothState = function ( options ) {
      return this.each(function () {
        var tagname = this.tagName.toLowerCase();
        // Checks to make sure the smoothState element has an id and isn't already bound
        if(this.id && tagname !== 'body' && tagname !== 'html' && !$.data(this, 'smoothState')) {
          // Makes public methods available via $('element').data('smoothState');
          $.data(this, 'smoothState', new Smoothstate(this, options));
        } else if (!this.id && consl) {
          // Throw warning if in debug mode
          consl.warn('Every smoothState container needs an id but the following one does not have one:', this);
        } else if ((tagname === 'body' || tagname === 'html') && consl) {
          // We dont support making th html or the body element the smoothstate container
          consl.warn('The smoothstate container cannot be the ' + this.tagName + ' tag');
        }
      });
    };

  /** Sets the popstate function */
  window.onpopstate = onPopState;

  /** Makes utility functions public for unit tests */
  $.smoothStateUtility = utility;

  /** Defines the smoothState plugin */
  $.fn.smoothState = declaresmoothState;

  /* expose the default options */
  $.fn.smoothState.options = defaults;

}));