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

    Abstractor | File writer | MIT License | ©2016 Hexagon <github.com/hexagon>

    Writes payload (string/buffer) to a file, encoding and flag are configurable.

    Possible flags:
       a  = append
       w  = overwrite

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


    Options

    -----------------+-----------------+----------------------+-----------------
    Option           |  Type           |  Default             |  Mandatory
    -----------------+-----------------+----------------------+-----------------
    path             |  string         |  undefined           |  yes
    encoding         |  string         |  utf8                |  yes
    mode             |  string         |  0o666               |  yes
    flag             |  string         |  a                   |  yes
    -----------------+-----------------+----------------------+-----------------


    I/O

    -------------------------------+----------------------+---------------------
    Input                          |  Possible triggers   |  Sets property
    -------------------------------+----------------------+---------------------
                                   |  success             |  <none>
    payload: <string/buffer>       +----------------------+---------------------
                                   |  error               |  error
    -------------------------------+----------------------+---------------------


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

"use strict";

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

class FileWrite extends Node {

    constructor(parameters) {
        
        var defaults = {
            encoding: "utf8",
            mode: 0o666,
            flag: "a"
        };

        super(parameters, defaults);

    }

    invoke(msg) {

        var 
            self = this,

            // Mandatory options
            filePath = this.getConfig("path", msg, true),

            // Optinal options, defaults are append, read/write permissions to all and utf8 encoding
            encoding = this.getConfig("encoding", msg, true),
            mode = this.getConfig("mode", msg, true),
            flag = this.getConfig("flag", msg, true);

        // File path is mandatory, bail out if not found
        if (filePath === undefined)
            // getConfig has already emitted an error about this
            return;

        // Supply file path to next node
        msg.path = filePath;

        fs.writeFile(filePath, msg.payload, { encoding, mode, flag }, function (err) {
            if(err) return self.error( msg, "Error while reading file, " + err );

            // No need to replace payload
            return self.success(msg, msg.payload);
        });

    }

}

module.exports = FileWrite;