// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

/**
 * @fileoverview Classes for custom functions for the speech rule engine.
 *
 */

goog.provide('cvox.SpeechRuleFunctions');
goog.provide('cvox.SpeechRuleFunctions.ContextFunctions');
goog.provide('cvox.SpeechRuleFunctions.CustomQueries');
goog.provide('cvox.SpeechRuleFunctions.CustomStrings');



/**
 * @constructor
 */
cvox.SpeechRuleFunctions = function() { };


/**
 * Private superclass of all the custom function stores.
 * @constructor
 * @param {string} prefix A prefix string for the function names.
 * @param {Object<string, Function>} store Storage object.
 * @private
 */
cvox.SpeechRuleFunctions.Store_ = function(prefix, store) {
  /** @private */
  this.prefix_ = prefix;
  /** @private */
  this.store_ = store;
};


/**
 * Adds a new function for the function store.
 * @param {string} name A name.
 * @param {!Function} func A function.
 */
cvox.SpeechRuleFunctions.Store_.prototype.add = function(name, func) {
  if (this.checkCustomFunctionSyntax_(name)) {
    this.store_[name] = func;
  }
};


/**
 * Retrieves a function with the given name if one exists.
 * @param {string} name A name.
 * @return {Function} The function if it exists.
 */
cvox.SpeechRuleFunctions.Store_.prototype.lookup = function(name) {
  return this.store_[name];
};


/**
 * Context function for use in speech rules.
 * @typedef {function(!Node): Array<Node>}
 */
cvox.SpeechRuleFunctions.CustomQuery;


/**
 * @constructor
 * @extends {cvox.SpeechRuleFunctions.Store_}
 */
cvox.SpeechRuleFunctions.CustomQueries = function() {
  var store =
    /** @type {Object<string, cvox.SpeechRuleFunctions.CustomQuery>} */ ({});
  goog.base(this, 'CQF', store);
};
goog.inherits(cvox.SpeechRuleFunctions.CustomQueries,
              cvox.SpeechRuleFunctions.Store_);


/**
 * Context function for use in speech rules.
 * @typedef {function(!Node): string}
 */
cvox.SpeechRuleFunctions.CustomString;


/**
 * @constructor
 * @extends {cvox.SpeechRuleFunctions.Store_}
 */
cvox.SpeechRuleFunctions.CustomStrings = function() {
  var store =
    /** @type {Object<string, cvox.SpeechRuleFunctions.CustomString>} */ ({});
  goog.base(this, 'CSF', store);
};
goog.inherits(cvox.SpeechRuleFunctions.CustomStrings,
              cvox.SpeechRuleFunctions.Store_);


/**
 * Context function for use in speech rules.
 * @typedef {function(Array<Node>, ?string): (function(): string)}
 */
cvox.SpeechRuleFunctions.ContextFunction;


/**
 * @constructor
 * @extends {cvox.SpeechRuleFunctions.Store_}
 */
cvox.SpeechRuleFunctions.ContextFunctions = function() {
  var store =
    /** @type {Object<string, cvox.SpeechRuleFunctions.ContextFunction>} */
  ({});
  goog.base(this, 'CTXF', store);
};
goog.inherits(cvox.SpeechRuleFunctions.ContextFunctions,
              cvox.SpeechRuleFunctions.Store_);


/**
 * Checks validity for a custom function name.
 * @param {string} name The name of the custom function.
 * @return {!boolean} True if the name is valid.
 * @private
 */
cvox.SpeechRuleFunctions.Store_.prototype.
    checkCustomFunctionSyntax_ = function(name) {
      var reg = new RegExp('^' + this.prefix_);
      if (!name.match(reg)) {
        console.log(
            'FunctionError: Invalid function name. Expected prefix' +
                this.prefix_);
        return false;
      }
      return true;
    };