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

namespace ESPServer
{
	class UnitPinger
	{
		const int PING_INTERVAL = 30 * 1000; // 30 seconds
		const int UNIT_TARGET_PORT = 7000;

		private readonly Logger logger = LogManager.GetCurrentClassLogger();
		UnitsDatabase db;

		public UnitPinger(UnitsDatabase db)
		{
			this.db = db;
		}

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

		private void Run()
		{
			logger.Info("Started UnitPinger");
			while (true)
			{
				try
				{
					Thread.Sleep(PING_INTERVAL);
					var ips = db.GetUnitIPs();
					foreach (var kv in ips)
					{
						var ip = kv.Value;
						using (var udpClient = new UdpClient())
						{
							udpClient.Connect(ip, UNIT_TARGET_PORT);
							var data = Encoding.ASCII.GetBytes("ping");
							udpClient.Send(data, data.Length);
							udpClient.Close();
						}
					}
				}
				catch (Exception e)
				{
					logger.Error(e.Message);
				}
			}
		}
	}
}