piskel/js/LocalStorageService.js

/*
 * @provide pskl.LocalStrageService
 *
 * @require Constants
 * @require Events
 */
$.namespace("pskl");

pskl.LocalStorageService = (function() {

	var frameSheet_;

	/**
	 * @private
	 */
	var localStorageThrottler_ = null;
	
	/**
	 * @private
	 */
	var persistToLocalStorageRequest_ = function() {
      // Persist to localStorage when drawing. We throttle localStorage accesses
      // for high frequency drawing (eg mousemove).
      if(localStorageThrottler_ != null) {
          window.clearTimeout(localStorageThrottler_);
      }
      localStorageThrottler_ = window.setTimeout(function() {
        persistToLocalStorage_();
        localStorageThrottler_ = null;
      }, 1000);
    };

    /**
	 * @private
	 */
	var persistToLocalStorage_ = function() {
      console.log('[LocalStorage service]: Snapshot stored')
      window.localStorage['snapShot'] = frameSheet_.serialize();
    };

    /**
	 * @private
	 */
	var restoreFromLocalStorage_ = function() {
      frameSheet_.deserialize(window.localStorage['snapShot']);
    };

    /**
	 * @private
	 */
	var cleanLocalStorage_ = function() {
      console.log('[LocalStorage service]: Snapshot removed')
      delete window.localStorage['snapShot'];
    };  

	return {
		init: function(frameSheet) {

			if(frameSheet == undefined) {
				throw "Bad LocalStorageService initialization: <undefined frameSheet>"
			}
			frameSheet_ = frameSheet;

		    $.subscribe(Events.LOCALSTORAGE_REQUEST, persistToLocalStorageRequest_);
		},

		// TODO(vincz): Find a good place to put this UI rendering, a service should not render UI.
		displayRestoreNotification: function() {
			if(window.localStorage && window.localStorage['snapShot']) {
		        var reloadLink = "<a href='#' class='localstorage-restore onclick='piskel.restoreFromLocalStorage()'>reload</a>";
		        var discardLink = "<a href='#' class='localstorage-discard' onclick='piskel.cleanLocalStorage()'>discard</a>";
		        var content = "Non saved version found. " + reloadLink + " or " + discardLink;

		        $.publish(Events.SHOW_NOTIFICATION, [{
		        	"content": content,
		        	"behavior": function(rootNode) {
		        		rootNode = $(rootNode);
		        		rootNode.click(function(evt) {
				        	var target = $(evt.target);
				        	if(target.hasClass("localstorage-restore")) {
				        		restoreFromLocalStorage_();
				        	}
				        	else if (target.hasClass("localstorage-discard")) {
				        		cleanLocalStorage_();
				        	}
				        	$.publish(Events.HIDE_NOTIFICATION);
				        });
		        	}
		        }]);
		    }
		}
	};
})();