milojs/milo-core

'use strict';

var MessengerAPI = require('./m_api')
    , _ = require('protojs');


/**
 * A generic subsclass of [MessengerAPI](./m_api.js.html) that supports pattern subscriptions to source.
 * Can be useful if the source is another Messenger.
 */
 var MessengerRegexpAPI = _.createSubclass(MessengerAPI, 'MessengerRegexpAPI');

 module.exports = MessengerRegexpAPI;


_.extendProto(MessengerRegexpAPI, {
    init: init,
    addInternalMessage: addInternalMessage,
    removeInternalMessage: removeInternalMessage,
    getInternalMessages: getInternalMessages
});


/**
 * MessengerRegexpAPI instance method
 * Called by MessengerRegexpAPI constructor.
 */
function init() {
    MessengerAPI.prototype.init.apply(this, arguments);
    _.defineProperties(this, {
        _patternInternalMessages: {}
    });
    this._catchAllSubscribed = false;
}


/**
 * MessengerRegexpAPI instance method
 * Augments MessengerAPI method by storing regexp
 *
 * @param {String} message internal message to be translated and added
 * @return {String|RegExp|undefined}
 */
function addInternalMessage(message) {
    var sourceMessage = MessengerAPI.prototype.addInternalMessage.apply(this, arguments);
    
    // store regexp itself if sourceMessage is regexp
    if (sourceMessage && sourceMessage instanceof RegExp) {
        this._internalMessages[sourceMessage].pattern = sourceMessage;
        this._patternInternalMessages[sourceMessage] = this._internalMessages[sourceMessage];
        if (this._catchAllSubscribed) return;
            this._catchAllSubscribed = true;
        return /.*/;
    }

    return sourceMessage;
}


/**
 * MessengerRegexpAPI instance method
 * Augments MessengerAPI method by removing regexp subscirption
 * 
 * @param {String} message internal message to be translated and added
 * @return {String|RegExp|undefined}
 */
function removeInternalMessage(message) {
    var sourceMessage = MessengerAPI.prototype.removeInternalMessage.apply(this, arguments);

    if (sourceMessage && sourceMessage instanceof RegExp) {
        delete this._patternInternalMessages[sourceMessage];
        var noPatternInternalMessages = ! Object.keys(this._patternInternalMessages).length;
        if (noPatternInternalMessages) {
            this._catchAllSubscribed = false;
            return /.*/;
        }
    }

    return sourceMessage;
}


/**
 * MessengerAPI instance method
 * Augments MessengerAPI method by returning messages subscribed with regexp
 * This method is used by `MessageSource` to dispatch source message on the `Mesenger`.
 *
 * @param {String|RegExp} sourceMessage source message
 * @return {Array[String]}
 */
function getInternalMessages(sourceMessage) {
    var internalMessages = MessengerAPI.prototype.getInternalMessages.apply(this, arguments);

    // add internal messages for regexp source subscriptions
    if (typeof sourceMessage == 'string') {
        internalMessages = internalMessages || [];
        var internalMessagesHash = _.object(internalMessages, true);

        _.eachKey(this._patternInternalMessages, function(patternMessages) {
            var sourcePattern = patternMessages.pattern;

            if (sourcePattern.test(sourceMessage))
                patternMessages.forEach(function(message) {
                    if (internalMessagesHash[message]) return;
                    internalMessages.push(message);
                    internalMessagesHash[message] = true;
                });
        });
    } 

    return internalMessages;
}