/***********************************************************************************

    Abstractor | Heartbeat monitor | MIT L. | ©2016 Hexagon <github.com/hexagon>

    Monitors the frequency of messages received, outputs "timeout" when no 
    message has arrived in x ms.

    ----------------------------------------------------------------------------


    Options

    -----------------+-----------------+----------------------+-----------------
    Option           |  Type           |  Default             |  Mandatory
    -----------------+-----------------+----------------------+-----------------
    timeout          |  number         |  60 000              |  yes
    -----------------+-----------------+----------------------+-----------------


    I/O

    -------------------------------+----------------------+---------------------
    Input                          |  Possible triggers   |  Output
    -------------------------------+----------------------+---------------------
    <any message>                  |  timeout             |  <last recv msg>
    -------------------------------+----------------------+---------------------


***********************************************************************************/

"use strict";

const   Node = require("../node.js");

class Heartbeat extends Node {

    constructor(parameters) {
        
        var defaults = {
            timeout: 600000
        };

        super(parameters, defaults);

        this.lastGood = undefined;

        this.reset();

    }

    timeout() {
        this.trigger( "timeout", this.lastGood );
    }

    reset() {
        let self = this;

        if (this.timer) clearTimeout(this.timer);

        this.timer = setTimeout(
            function () { 
                self.timeout();
            }, 
            this.config.timeout 
        );

    }

    invoke(msg) {
        this.reset();
        this.lastGood = msg;
    }

}

module.exports = Heartbeat;