/**
 * RDR Payload Decoders
 *
 * THIS SOFTWARE IS PROVIDED BY PARAMETRIC GMBH AND ITS CONTRIBUTORS “AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

function app_payload_r0_decoder(bytes) {
  var obj = {};

  // check for Parametric RDR R0 Payload
  if (bytes[0] == 0xbe && bytes[1] == 0x05 && bytes[2] === 0x00) {
    // Uplink Timestamp (Linux Epoche)
    var timestampUL = bytes[3] << 24;
    timestampUL += bytes[4] << 16;
    timestampUL += bytes[5] << 8;
    timestampUL += bytes[6];
    var ULInMs = new Date(timestampUL * 1000).getTime();
    var nowInMs = new Date().getTime();
    var diffUL = nowInMs - ULInMs;
    var actualULTIME = new Date(ULInMs + diffUL);
    obj.ULTIME = actualULTIME.toISOString();

    // Number of scan records
    obj.RECCNT = bytes[7];

    // Number of records still in device buffer
    obj.BUFF = bytes[8];

    obj.Records = [];

    // scan records
    var nextRecPos = 9; // scan position
    for (var i = 0; i < obj.RECCNT; i++) {
      var rec = {};

      // scan timestamp
      var timestampSCAN = bytes[nextRecPos] << 24;
      timestampSCAN += bytes[nextRecPos + 1] << 16;
      timestampSCAN += bytes[nextRecPos + 2] << 8;
      timestampSCAN += bytes[nextRecPos + 3];
      var diff = ULInMs - new Date(timestampSCAN * 1000).getTime();
      var actualSCANTIME = new Date(nowInMs - diff);
      rec.SCANTIME = actualSCANTIME.toISOString();

      // nfc serial
      rec.SERIAL = bytes.slice(nextRecPos + 4, nextRecPos + 12);
      rec.LEN = bytes[nextRecPos + 12];
      rec.DATA = bytes.slice(nextRecPos + 12, nextRecPos + 13 + rec.LEN);
      obj.Records.push(rec);

      nextRecPos = nextRecPos + 12 + rec.LEN + 2;
    }
  }
  return obj;
}

function bin16dec(bin) {
  var num = bin & 0xffff;
  if (0x8000 & num) num = -(0x010000 - num);
  return num;
}

function hexToBytes(hex) {
  hex = hex.replace(/\s+/g, '');
  hex = hex.toLowerCase();
  for (var bytes = [], c = 0; c < hex.length; c += 2) bytes.push(parseInt(hex.substr(c, 2), 16));
  return bytes;
}

function decodeUplink(input) {
  var bytes = input.bytes;
  var port = input.fPort;
  var obj = {};

  if (bytes[0] == 0xbe && bytes[1] == 0x05 && port == 5) {
    if (bytes[2] === 0x00) {
      // it's the application payload v0
      obj = app_payload_r0_decoder(bytes, port);
    }
  } else if (port != 5) {
    obj.error = 'ERROR: Wrong port! RDR devices are using port 5 for application payloads.';
  } else {
    obj.error = 'ERROR: RDR application payload R0 should start with be0500..  ';
  }

  return {
    data: obj,
  };
}

//Example Payload: BE05005F9BEB2C01005F9BAB2C9EAF5126002302E0010C