// Wio-E5 LoRa to RabbitMQ Gateway

// Copyright (C)2025, Philip Munts dba Munts Technologies.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice,
//   this list of conditions and the following disclaimer.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT HOLDER OR 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.

using RabbitMQ.Client;

using static System.Text.Encoding;

string GetEnv(string name, string default_value)
{
  var v = System.Environment.GetEnvironmentVariable(name);
  return v is null ? default_value : v;
}

// Configure the Wio-E5 LoRa transceiver module

var dev = new IO.Devices.WioE5.Ham1.Device();

// Configure RabbitMQ.Client

var factory         = new RabbitMQ.Client.ConnectionFactory();
factory.UserName    = GetEnv("RABBITMQ_USER",     "guest");
factory.Password    = GetEnv("RABBITMQ_PASS",     "guest");
factory.HostName    = GetEnv("RABBITMQ_SERVER",   "localhost");
factory.Port        = int.Parse(GetEnv("RABBITMQ_PORT", "5672"));
factory.VirtualHost = GetEnv("RABBITMQ_VHOST",    "/");
var exchange        = GetEnv("RABBITMQ_EXCHANGE", "amq.topic");

IConnection connection;
IChannel channel;

// Connect to the RabbitMQ server.  Keep trying once a second until the
// connection succeeds, because it will fail before the network interface
// has been configured.

for (;;)
{
  try
  {
    connection = await factory.CreateConnectionAsync();
    channel    = await connection.CreateChannelAsync();
    break;
  }

  catch
  {
    System.Threading.Thread.Sleep(1000);
  }
}

// Start the watchdog timer

var wd = new IO.Objects.SimpleIO.Watchdog.Timer("/dev/watchdog");
wd.timeout = 5;

// Message loop

var inbuf = new byte[255];

for (;;)
{
  dev.Receive(inbuf, out int len, out string srcnet, out int srcnode,
    out string dstnet, out int dstnode, out int RSS, out int SNR);

  var msg = UTF8.GetString(inbuf, 0, len);

  if (len > 0)
  {
    var topic = $"{dstnet}-{dstnode}.{srcnet}-{srcnode}";

    // Check for topic string suffix at the beginning of the message

    if (msg.StartsWith("."))
    {
      var words = msg.Split(' ');
      topic += words[0];
      msg = msg.Remove(0, words[0].Length + 1);
    }

    var outbuf = $"{msg}\t{System.DateTime.Now}\t" +
      $"{srcnet}-{srcnode} {dstnet}-{dstnode} "  +
      $"{len} bytes RSS:{RSS} dBm SNR: {SNR} dB";

    await channel.BasicPublishAsync(exchange, topic, UTF8.GetBytes(outbuf));
  }

  wd.Kick();
}