// Decode an uplink message from a buffer

/** Decoder **/

// decode payload to JSON
var message = decodeToJson(payload);

//Message should already be in JSON
var deviceName = message.group + ":" + message.device_properties.deveui;
var group = message.group;

// Temporary telemetry object
var telemetryObj = {
   ts: Date.parse(message.timestamp),
   values: message.data
};

// Result object with device attributes/telemetry data
var result = {
   deviceName: deviceName,
   deviceType: message.profile,
   telemetry:telemetryObj,
   attributes: {
       appEui: message.device_properties.appeui,
       devEui: message.device_properties.deveui,
       latitude: message.lat,
       longitude: message.lng,
       geolocation_type: message.geolocation_type
   }
};

function decodeToJson(payload) {
   // covert payload to string.
   var str = decodeToString(payload);
   str = str.replace(/\|&;\$%@"<>\(\)\+,/g, "");

   // parse string to JSON
   var data = JSON.parse(str);
   return data;
}

function decodeToString(payload) {
   return String.fromCharCode.apply('', payload);
}

return result;