using System.Net;
using System.Net.Sockets;
using System.Text;

namespace RobotLib
{
    public static class IndependentRobotConfigurator
    {
        private static readonly NLog.Logger log = NLog.LogManager.GetCurrentClassLogger();
        private const int udpPortRobot = 1818;

        /// <summary>
        /// Sends a command via UDP to set the MQTT broker IP on a robot.
        /// This serves to adopt a robot (get it to communicate via MQTT).
        /// Consider rebooting ESP32 with <see cref="RebootEsp32(string)"/> to apply the newly set IP.
        /// </summary>
        /// <param name="hostnameRobot">hostname or IP address of the robot</param>
        /// <param name="brokerIp">ip address of the MQTT broker</param>
        public static void Adopt(string hostnameRobot, string brokerIp)
        {
           // test if IP valid
            if (IPAddress.TryParse(brokerIp, out _))
            {
                SendMessageUdp(hostnameRobot, udpPortRobot, $"@esp:mqtt setIp {brokerIp}!");
            }
            else
            {
                log.Error($"Invalid broker IP address: {brokerIp}");
            }
        }

        /// <summary>
        /// Sends a command via UDP to set the challenge mode of a robot.
        /// </summary>
        /// <param name="hostnameRobot">hostname or IP address of the robot</param>
        /// <param name="brokerIp">ip address of the MQTT broker</param>
        public static void SetRobotMode(string hostnameRobot, string mode)
        {
            // test if mode is valid
            if (mode == "stationary" || mode == "s" || mode == "mobile" || mode == "m")
            {
                SendMessageUdp(hostnameRobot, udpPortRobot, $"@esp:challenge setMode {mode}!");
            }
            else
            {
                log.Error($"Invalid robot mode: {mode}");
            }
        }

        /// <summary>
        /// Sends a command via UDP to reboot the ESP32 of a robot.
        /// For example when a new mqtt broker IP was set, the robot needs to reboot in order to apply the IP and reconnect to a new broker.
        /// </summary>
        /// <param name="hostnameRobot">hostname or IP address of the robot</param>
        public static void RebootEsp32(string hostnameRobot)
        {
            SendMessageUdp(hostnameRobot, udpPortRobot, $"@esp:challenge reboot!");
        }


        private static void SendMessageUdp(string hostname, int port, string message)
        {
            var udpClient = new UdpClient();
            try
            {
                udpClient.Connect(hostname, port);
            }
            catch (System.Exception ex)
            {
                log.Error($"Failed to send UDP message: {ex.Message}");
                return;
            }

            byte[] data = Encoding.ASCII.GetBytes(message);
            udpClient.Send(data, data.Length);
            log.Trace($"Msg sent to {udpClient.Client.RemoteEndPoint}: {message}");

            udpClient.Close();
        }
    }
}