/*************************************************************
 *
 *  [Contrib]/a11y/accessibility-menu.js
 *  
 *  A thin extension to add opt-in menu items for the accessibility
 *  extensions in the a11y contributed directory.
 *
 *  ---------------------------------------------------------------------
 *  
 *  Copyright (c) 2016-2017 The MathJax Consortium
 * 
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

(function(HUB,EXTENSIONS) {
  var SETTINGS = HUB.config.menuSettings;
  var ITEM, MENU; // filled in when MathMenu extension loads
  
  var BIND = (Function.prototype.bind ? function (f,t) {return f.bind(t)} :
              function (f,t) {return function () {f.apply(t,arguments)}});
  var KEYS = Object.keys || function (obj) {
    var keys = [];
    for (var id in obj) {if (obj.hasOwnProperty(id)) keys.push(id)}
    return keys;
  };
  
  //
  //  Set up the a11y path,if it isn't already in place
  //
  var PATH = MathJax.Ajax.config.path;
  if (!PATH.a11y) PATH.a11y = HUB.config.root + "/extensions/a11y";

  var Accessibility = EXTENSIONS["accessibility-menu"] = {
    version: '1.2.3',
    prefix: '', //'Accessibility-',
    defaults: {},
    modules: [],
    MakeOption: function(name) {
      return Accessibility.prefix + name;
    },
    GetOption: function(option) {
      return SETTINGS[Accessibility.MakeOption(option)];
    },
    AddDefaults: function() {
      var keys = KEYS(Accessibility.defaults);
      for (var i = 0, key; key = keys[i]; i++) {
        var option = Accessibility.MakeOption(key);
        if (typeof(SETTINGS[option]) === 'undefined') {
          SETTINGS[option] = Accessibility.defaults[key];
        }
      }
    },
    // Attaches the menu items;
    AddMenu: function() {
      var items = Array(this.modules.length);
      for (var i = 0, module; module = this.modules[i]; i++) items[i] = module.placeHolder;
      var menu = MENU.FindId('Accessibility');
      if (menu) {
        items.unshift(ITEM.RULE());
        menu.submenu.items.push.apply(menu.submenu.items,items);
      } else {
        var renderer = (MENU.FindId("Settings","Renderer")||{}).submenu;
        if (renderer) {
          // move AssitiveMML and InTabOrder from Renderer to Accessibility menu
          items.unshift(ITEM.RULE());
          items.unshift(renderer.items.pop());
          items.unshift(renderer.items.pop());
        }
        items.unshift("Accessibility");
        var menu = ITEM.SUBMENU.apply(ITEM.SUBMENU,items);
        var locale = MENU.IndexOfId('Locale');
        if (locale) {
          MENU.items.splice(locale,0,menu);
        } else {
          MENU.items.push(ITEM.RULE(), menu);
        }
      }
    },
    Register: function(module) {
      Accessibility.defaults[module.option] = false;
      Accessibility.modules.push(module);
    },
    Startup: function() {
      ITEM = MathJax.Menu.ITEM;
      MENU = MathJax.Menu.menu;
      for (var i = 0, module; module = this.modules[i]; i++) module.CreateMenu();
      this.AddMenu();
    },
    LoadExtensions: function () {
      var extensions = [];
      for (var i = 0, module; module = this.modules[i]; i++) {
        if (SETTINGS[module.option]) extensions.push(module.module);
      }
      return (extensions.length ? HUB.Startup.loadArray(extensions) : null);
    }
  };

  var ModuleLoader = MathJax.Extension.ModuleLoader = MathJax.Object.Subclass({
    option: '',
    name: ['',''],
    module: '',
    placeHolder: null,
    submenu: false,
    extension: null,
    Init: function(option, name, module, extension, submenu) {
      this.option = option;
      this.name = [name.replace(/ /g,''),name];
      this.module = module;
      this.extension = extension;
      this.submenu = (submenu || false);
    },
    CreateMenu: function() {
      var load = BIND(this.Load,this);
      if (this.submenu) {
        this.placeHolder =
          ITEM.SUBMENU(this.name,
            ITEM.CHECKBOX(["Activate","Activate"],
                          Accessibility.MakeOption(this.option), {action: load}),
            ITEM.RULE(),
            ITEM.COMMAND(["OptionsWhenActive","(Options when Active)"],null,{disabled:true})
          );
      } else {
        this.placeHolder = ITEM.CHECKBOX(
          this.name, Accessibility.MakeOption(this.option), {action: load}
        );
      }
    },
    Load: function() {
      HUB.Queue(["Require",MathJax.Ajax,this.module,["Enable",this]]);
    },
    Enable: function(menu) {
      var extension = MathJax.Extension[this.extension];
      if (extension) {
        extension.Enable(true,true);
        MathJax.Menu.saveCookie();
      }
    }
  });

  Accessibility.Register(
    ModuleLoader(
      'collapsible', 'Collapsible Math', '[a11y]/collapsible.js', 'collapsible'
    )
  );
  Accessibility.Register(
    ModuleLoader(
      'autocollapse', 'Auto Collapse', '[a11y]/auto-collapse.js', 'auto-collapse'
    )
  );
  Accessibility.Register(
    ModuleLoader(
      'explorer', 'Explorer', '[a11y]/explorer.js', 'explorer', true
    )
  );

  Accessibility.AddDefaults();
  
  HUB.Register.StartupHook('End Extensions', function () {
    HUB.Register.StartupHook('MathMenu Ready', function () {
      Accessibility.Startup();
      HUB.Startup.signal.Post('Accessibility Menu Ready');
    },5);   // run before other extensions' menu hooks even if they are loaded first
  },5);
  
  MathJax.Hub.Register.StartupHook("End Cookie", function () {
    MathJax.Callback.Queue(
      ["LoadExtensions",Accessibility],
      ["loadComplete",MathJax.Ajax,"[a11y]/accessibility-menu.js"]
    );
  });

})(MathJax.Hub,MathJax.Extension);