Angular commander

commander.js

var _ = require("lodash");

module.exports =
angular.module("plunker.service.commander", [])

.factory("commander", [ "$q", "$injector", function ($q, $injector) {
  var commands = {};
  
  var service = {
    addCommand: addCommand,
    addInterceptor: addInterceptor,
    addHotkey: addHotkey,
    execute: executeCommand,
    removeInterceptor: removeInterceptor
  };
  
  return service;
  
  function addCommand (commandDef) {
    commands[commandDef.name] = {
      handler: commandDef.handler,
      defaults: commandDef.defaults || {},
      hotkeys: [],
      interceptors: []
    };
    
    if (commandDef.hotkeys) this.addHotkey(commandDef.name, commandDef.hotkeys);
    
    if (commandDef.scope) {
      commandDef.scope.$on("$destroy", function () {
        delete commands[commandDef.name];
      });
    }
  }
  
  function addHotkey (commandId, hotkey, defaults) {
    var command = commands[commandId];
    
    if (!defaults) defaults = {};
    
    if (!command) throw new Error("Unable to run non-existent command: " + commandId);
    
    Mousetrap.bind(hotkey, function (event, hotkey) {
      $q.when(angular.isObject(defaults) ? defaults : $injector.invoke(command)).then(function (defaults) {
        executeCommand(commandId, _.defaults(defaults, {event: event, hotkey: hotkey}));
      });
      
      return false;
    });
    
    command.hotkeys.push(hotkey);
  }
  
  function addInterceptor (commandId, interceptor) {
    if (!commands[commandId]) throw new Error("Unable to add interceptor to a non-existent command: " + commandId);
    
    commands[commandId].interceptors.push(interceptor);
  }
  
  function executeCommand (commandId, locals) {
    var commandDef = commands[commandId];
    
    if (!commandDef) throw new Error("Unable to run non-existent command: " + commandId);
    
    if (!locals) locals = {};
    
    var defaultsPromise = angular.isObject(commandDef.defaults) ? commandDef.defaults : $injector.invoke(commandDef.defaults, commandDef);
    
    return $q.when(defaultsPromise).then(function (defaults) {
      var interceptors = angular.copy(commandDef.interceptors);
      
      locals = _.defaults(locals, defaults);
      
      return nextInterceptor();
      
      function nextInterceptor () {
        return interceptors.length
          ? $q.when($injector.invoke(interceptors.shift(), {}, {commandId: commandId, locals: locals})).then(nextInterceptor)
          : $q.when($injector.invoke(commandDef.handler, {}, locals));
      }
    });
  }
  
  function removeInterceptor (commandId, interceptor) {
    var command = commands[commandId];
    
    if (!command) throw new Error("Unable to remove interceptor for non-existent command: " + commandId);
    
    var idx = command.interceptors.indexOf(interceptor);
    
    if (idx >= 0) command.interceptors.splice(idx, 1);
  }
  
  
}]);