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

    Abstractor | CSV module | MIT License | ©2016 Hexagon <github.com/hexagon>

    CSV parser and generator. Parser uses fast-csv.

    If input payload is an array width objects, the contained objects are
    converted to CSV rows.

    If input payload is a string, the string is parsed to an array of objects.

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


    Dependencies

    fast-csv


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


    Options

    -----------------+-----------------+----------------------+-----------------
    Option           |  Type           |  Default             |  Mandatory
    -----------------+-----------------+----------------------+-----------------
    headers          |  boolean        |  true                |  no
    -----------------+-----------------+----------------------+-----------------


    I/O

    -------------------------------+----------------------+---------------------
    Incoming property              |  Possible triggers   |  Sets property
    -------------------------------+----------------------+---------------------
                                   |  success             |  payload
    payload: <csv string>          +----------------------+---------------------
                                   |  error               |  error
    -------------------------------+----------------------+---------------------
                                   |  success             |  payload
    payload: <object>              +----------------------+---------------------
                                   |  error               |  error
    -------------------------------+----------------------+---------------------


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

"use strict";

const
    Node = require("../node.js"),
    csvHelper = require("fast-csv");

class CSV extends Node {

    quote(s) {
        
        // Strings containing double quote, crLf or comma require quoting
        var needQuotes = false;
        if(     s.indexOf && (s.indexOf("\"") !== -1
            ||  s.indexOf("\r\n") !== -1 
            ||  s.indexOf(",") !== -1 )
        ) needQuotes = true;

        // Return regular string by default, or double quoted string if needed
        return needQuotes ? "\"" + s.replace(/\"/g,"\"\"") + "\"" : s;  

    }

    invoke(msg) {
        
        var self = this;

        // ToDo, headers should have a default, and be passed to this.getConfig

        // Parse if we got a string
        if ( typeof msg.payload == "string" ) {

            var rows = [],
                headers = (this.config.headers === undefined ? true : this.config.headers);

            try {
                var csvFile = csvHelper.fromString(msg.payload, {headers: headers, trim:true});

                csvFile.on("data", function(data){
                    rows.push(data);    
                }); 

                csvFile.on("end", function(){
                    self.success( msg, rows);       
                });
            } catch (e) {
                self.error( msg, "Error whild parsing CSV-file: " + e);
            }

        // Stringify if we got an object
        } else if ( typeof msg.payload == "object" ) {

            // ToDo: Add headers if it is the first object/row of file, and if it is requested
            
            // Force first level to be array
            if( !Array.isArray(msg.payload) ) {
                msg.payload = [msg.payload];
            }
            
            let rowString = "",
                wasFirstLevel = false;

            msg.payload.forEach((row) => {
        
                // If second level is an array
                if( Array.isArray(row) ) {
                    row.forEach(function(col) {
                        rowString += self.quote(col.toString()) + ",";
                    });

                    // Finalize this row
                    if (rowString.length>0) {
                        rowString = rowString.substring(0, rowString.length - 1) + "\r\n";
                    }

                // If second level is an object
                } else if ( typeof row === "object" ) {
                    Object.keys(row).forEach(function(key) {
                        let col = row[key];
                        rowString += self.quote(col.toString()) + ",";
                    }); 

                    // Finalize this row
                    if (rowString.length>0) {
                        rowString = rowString.substring(0, rowString.length - 1) + "\r\n";
                    }

                // If second level is something else, we're actually at "first level"
                } else {

                    wasFirstLevel = true;
                    rowString += self.quote(row) + ",";

                }

            });

            if( wasFirstLevel ) {
                // Finalize row
                if (rowString.length>0) {
                    rowString = rowString.substring(0, rowString.length - 1) + "\r\n";
                }
            }

            this.success( msg, rowString );

        } else {
            return this.error(msg, "CSV node could not determine what to do with payload of type " + typeof msg.payload);

        }
        

    }

}

module.exports = CSV;