using NLog;
using System;
using System.Collections.Generic;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Text.Json;
using System.Threading;

namespace ESPServer
{
	class UnitDataReceiver
	{
		private readonly Logger logger = LogManager.GetCurrentClassLogger();

		UnitsDatabase db;
		RegistersContainer registers;
		int port;

		public UnitDataReceiver(int port, UnitsDatabase db, RegistersContainer registers)
		{
			this.db = db;
			this.port = port;
			this.registers = registers;
		}

		public void Start()
		{
			var t = new Thread(new ThreadStart(this.Run));
			t.Start();
		}

		private void Run()
		{
			UdpClient listener = new UdpClient(port);
			IPEndPoint groupEP = new IPEndPoint(IPAddress.Any, port);

			try
			{
				logger.Info("Listening for UDP datagrams on port " + port);
				while (true)
				{
					byte[] bytes = listener.Receive(ref groupEP);
					string t = Encoding.ASCII.GetString(bytes, 0, bytes.Length);
					logger.Debug("Received: " + t);
					try
					{
						var received = JsonDocument.Parse(t);
						var id = received.RootElement.GetProperty("id").GetString();
						var unit = db.GetUnit(id);
						if (unit == null)
						{
							logger.Info("Packet from unknown unit " + id);
							unit = db.AddUnit(id);
						}
						ProcessUnit(unit, received.RootElement);
					}
					catch (Exception e)
					{
						logger.Error(e.Message);
					}
				}
			}
			catch (SocketException e)
			{
				Console.WriteLine(e);
			}
			finally
			{
				listener.Close();
			}
		}

		private void ProcessUnit(Unit unit, JsonElement data)
		{
			var ip = data.GetProperty("ip").GetString();
			lock (unit)
			{
				unit.ip = ip;
				foreach (var v in data.EnumerateObject())
				{
					if (v.Name == "id" || v.Name == "ip") continue;
					var uv = unit.GetValue(v.Name);
					if (uv == null)
					{
						logger.Info("Unit " + unit.id + " unknown value " + v.Name);
					}
					else
					{
						if (v.Value.ValueKind == JsonValueKind.Null) uv.value = float.NaN;
						if (v.Value.ValueKind == JsonValueKind.Number) uv.value = v.Value.GetSingle();
						else
						{
							if (!float.TryParse(v.Value.GetString(), out uv.value))
							{
								uv.value = float.NaN;
							}
						}
					}
				}
				FillRegisters(unit);
			}
		}

		private void FillRegisters(Unit unit)
		{
			foreach (var uv in unit.values)
			{
				registers.SetFloat(unit.baseAddress + uv.Value.addressOffset, uv.Value.value);
			}
		}
	}
}