aprs-parser/lib/Position/MICEParser.js

JavaScript library for parsing APRS packets

'use strict';
const AbstractParser = require('../AbstractParser.js');
const MICEPosition = require('./../MessageModels/MICEPosition');

const Utils = require('./MICEParserUtils.js');
const Base91Utils = require('./Base91ParserUtils.js');

function MICEParser() {

}


MICEParser.constructor = MICEParser;
MICEParser.prototype = Object.create(AbstractParser.prototype);

MICEParser.prototype.isMatching = function (bodyContent) {
    const first = bodyContent[0];
    return (first == '`' || first == '\'');
};

MICEParser.prototype.tryParse = function (bodyContent, aprsMessageHeader) {
    if (bodyContent.length < 9)
        throw new Error('Too short body for MIC-E (length < 9)');

    const fromDestinationAddress = Utils.readDataFromDestinationAddress(aprsMessageHeader.to.call);

    const longitude = Utils.parseLogitudeFormat(bodyContent.substr(1, 3), fromDestinationAddress.logitudeOffset, fromDestinationAddress.isWest);

    //order in MIC-E is symbol code then symbol table
    const symbol = bodyContent[8] + bodyContent[7];
    let comment = bodyContent.substr(9);

    const position = new MICEPosition(fromDestinationAddress.latitude, longitude);
    position.setMICEState(fromDestinationAddress.miceState);
    position.setSymbol(symbol);
    position.setExtension(Utils.parseCourseAndSpeed(bodyContent.substr(4, 3)));

    if (comment) {
        comment = position.setRadio(comment);

        const base91TelemetryData = Base91Utils.parseBase91Telemetry(comment);
        if (base91TelemetryData) {
            comment = base91TelemetryData.comment;
            position.setTelemetry(base91TelemetryData.telemetry);
        }
        position.setComment(comment);

        //altitude form mice overwrite altitude parsed from comment
        position.getAltitudeFromMICE(comment);
    }
    return position;
};

MICEParser.prototype.getParserName = function () {
    return 'MICEParser';
};

module.exports = MICEParser;