airbug/bugcore

/*
 * Copyright (c) 2016 airbug Inc. http://airbug.com
 *
 * bugcore may be freely distributed under the MIT license.
 */


//-------------------------------------------------------------------------------
// Annotations
//-------------------------------------------------------------------------------

//@Export('CommandProcessor')

//@Require('ArgumentBug')
//@Require('Class')
//@Require('Command')
//@Require('CommandBatch')
//@Require('IList')
//@Require('Obj')
//@Require('Queue')
//@Require('TypeUtil')


//-------------------------------------------------------------------------------
// Context
//-------------------------------------------------------------------------------

require('bugpack').context("*", function(bugpack) {

    //-------------------------------------------------------------------------------
    // BugPack
    //-------------------------------------------------------------------------------

    var ArgumentBug     = bugpack.require('ArgumentBug');
    var Class           = bugpack.require('Class');
    var Command         = bugpack.require('Command');
    var CommandBatch    = bugpack.require('CommandBatch');
    var IList           = bugpack.require('IList');
    var Obj             = bugpack.require('Obj');
    var Queue           = bugpack.require('Queue');
    var TypeUtil        = bugpack.require('TypeUtil');


    //-------------------------------------------------------------------------------
    // Declare Class
    //-------------------------------------------------------------------------------

    /**
     * @class
     * @extends {Obj}
     */
    var CommandProcessor = Class.extend(Obj, {

        _name: "CommandProcessor",


        //-------------------------------------------------------------------------------
        // Constructor
        //-------------------------------------------------------------------------------

        /**
         * @constructs
         */
        _constructor: function() {

            this._super();


            //-------------------------------------------------------------------------------
            // Private Properties
            //-------------------------------------------------------------------------------

            /**
             * @private
             * @type {Queue.<CommandBatch>}
             */
            this.commandBatchQueue      = new Queue();

            /**
             * @private
             * @type {boolean}
             */
            this.processing             = false;
        },


        //-------------------------------------------------------------------------------
        // Getters and Setters
        //-------------------------------------------------------------------------------

        /**
         * @return {Queue.<CommandBatch>}
         */
        getCommandBatchQueue: function() {
            return this.commandBatchQueue;
        },

        /**
         * @return {boolean}
         */
        getProcessing: function() {
            return this.processing;
        },


        //-------------------------------------------------------------------------------
        // Convenience Methods
        //-------------------------------------------------------------------------------

        /**
         * @return {boolean}
         */
        isProcessing: function() {
            return this.processing;
        },


        //-------------------------------------------------------------------------------
        // Public Methods
        //-------------------------------------------------------------------------------

        /**
         * @param {(Command | Array.<Command> | List.<Command> | CommandBatch)} commands
         * @param {function(Throwable=)} callback
         */
        processCommands: function(commands, callback) {
            var commandBatch = null;
            if (Class.doesExtend(commands, Command)) {
                commandBatch = this.factoryCommandBatch([commands], callback);
            } else if (Class.doesExtend(commands, CommandBatch)) {
                commandBatch = commands;
            } else if (Class.doesImplement(commands, IList) || TypeUtil.isArray(commands)) {
                commandBatch = this.factoryCommandBatch(commands, callback);
            } else {
                return callback(new ArgumentBug(ArgumentBug.ILLEGAL, "commands", commands, "parameter must be a Command, array of Commands, a List of Commands, or a CommandBatch"));
            }
            this.queueCommandBatch(commandBatch);
            this.processCommandQueue();
        },


        //-------------------------------------------------------------------------------
        // Private Methods
        //-------------------------------------------------------------------------------

        /**
         * @private
         */
        dequeueAndExecuteCommandBatch: function() {
            if (this.commandBatchQueue.getCount() > 0) {
                var commandBatch = this.commandBatchQueue.dequeue();
                this.executeCommandBatch(commandBatch);
            } else {
                this.processing = false;
            }
        },

        /**
         * @private
         * @param {CommandBatch} commandBatch
         */
        executeCommandBatch: function(commandBatch) {
            var _this = this;
            commandBatch.execute(function() {
                _this.dequeueAndExecuteCommandBatch();
            });
        },

        /**
         * @private
         * @param {(Array.<Command> | List.<Command>)} commands
         * @param {function(Throwable=)} callback
         * @return {CommandBatch}
         */
        factoryCommandBatch: function(commands, callback) {
            return new CommandBatch(commands, callback);
        },

        /**
         * @private
         */
        processCommandQueue: function() {
            if (!this.isProcessing()) {
                this.processing = true;
                this.dequeueAndExecuteCommandBatch();
            }
        },

        /**
         * @private
         * @param {CommandBatch} commandBatch
         */
        queueCommandBatch: function(commandBatch) {
            this.commandBatchQueue.enqueue(commandBatch);
        }
    });


    //-------------------------------------------------------------------------------
    // Exports
    //-------------------------------------------------------------------------------

    bugpack.export('CommandProcessor', CommandProcessor);
});