using System;
using System.Net;
using System.Net.Sockets;
using UnityEngine;

namespace FloodSWE.Networking
{
    public sealed class SweQuestControlClient : MonoBehaviour
    {
        [Header("Server")]
        public string serverHost = "127.0.0.1";
        public int serverCommandPort = 29010;

        [Header("Connect")]
        public bool autoConnectOnEnable = true;
        public bool sendHelloOnConnect = true;
        public bool verboseLogging = false;
        public float ackTimeoutSeconds = 3.0f;
        public float helloKeepAliveIntervalSeconds = 1.0f;

        private UdpClient socket;
        private IPEndPoint serverEndpoint;
        private float lastAckTimeUnscaled = -1.0f;
        private float lastHelloSentTimeUnscaled = -1.0f;
        private float lastStateTimeUnscaled = -1.0f;
        private string lastAckMessage = "";
        private SweBoundaryStateMessage lastBoundaryState;
        private bool connectRequested;

        public event Action<SweBoundaryStateMessage> BoundaryStateReceived;

        public bool HasReceivedAck => lastAckTimeUnscaled >= 0.0f;
        public float LastAckAgeSeconds => HasReceivedAck ? Time.unscaledTime - lastAckTimeUnscaled : float.PositiveInfinity;
        public string LastAckMessage => lastAckMessage;
        public bool HasBoundaryState => lastStateTimeUnscaled >= 0.0f;
        public float LastBoundaryStateAgeSeconds =>
            HasBoundaryState ? Time.unscaledTime - lastStateTimeUnscaled : float.PositiveInfinity;
        public SweBoundaryStateMessage LastBoundaryState => lastBoundaryState;
        public bool IsConnectionAlive => HasReceivedAck && LastAckAgeSeconds <= Mathf.Max(0.1f, ackTimeoutSeconds);
        public bool IsWaitingForAck => connectRequested && !IsConnectionAlive && !HasReceivedAck;

        private void OnEnable()
        {
            if (autoConnectOnEnable && !Connect())
            {
                enabled = false;
            }
        }

        private void OnDisable()
        {
            Disconnect();
        }

        private void Update()
        {
            PollMessages();
            TickKeepAlive();
        }

        public bool Connect()
        {
            try
            {
                EnsureSocket();
                ResolveServerEndpoint();
                connectRequested = true;

                if (sendHelloOnConnect)
                {
                    SendHello();
                }

                if (verboseLogging)
                {
                    Debug.Log($"SweQuestControlClient: connected to {serverEndpoint}.");
                }

                return true;
            }
            catch (Exception ex)
            {
                Debug.LogError($"SweQuestControlClient: failed to connect UDP sender. {ex.Message}");
                connectRequested = false;
                Disconnect();
                return false;
            }
        }

        public void Disconnect()
        {
            if (socket != null)
            {
                socket.Close();
                socket = null;
            }

            serverEndpoint = null;
            lastAckTimeUnscaled = -1.0f;
            lastStateTimeUnscaled = -1.0f;
            lastAckMessage = "";
            lastBoundaryState = null;
            connectRequested = false;
        }

        public void SendHello()
        {
            Send(new SweControlCommand
            {
                command = "hello",
            });
            lastHelloSentTimeUnscaled = Time.unscaledTime;
        }

        public void SetSourceLevel(int sourceId, float level)
        {
            SetBoundaryProfile(
                "source_area",
                sourceId,
                true,
                0.0f,
                0.0f,
                0.0f,
                Mathf.Max(0.0f, level));
        }

        public void SetSinkLevel(int sinkId, float level)
        {
            SetBoundaryProfile(
                "sink",
                sinkId,
                true,
                0.0f,
                0.0f,
                0.0f,
                -Mathf.Max(0.0f, level));
        }

        public void SetBoundaryProfile(
            string boundaryKind,
            int boundaryId,
            bool enabled,
            float waterLevelM,
            float velocityUMps,
            float velocityVMps,
            float depthRateMps)
        {
            Send(new SweControlCommand
            {
                command = "set_boundary_profile",
                boundaryKind = boundaryKind,
                boundaryId = boundaryId,
                enabled = enabled ? 1 : 0,
                waterLevelM = waterLevelM,
                velocityUMps = velocityUMps,
                velocityVMps = velocityVMps,
                depthRateMps = depthRateMps,
            });
        }

        public void SetBoundariesBulk(SweBoundaryProfile[] profiles, bool replaceAll = false)
        {
            if (profiles == null)
            {
                return;
            }

            Send(new SweControlCommand
            {
                command = "set_boundaries_bulk",
                replaceAll = replaceAll,
                boundaries = profiles,
            });
        }

        public void RequestBoundaryConfig()
        {
            Send(new SweControlCommand
            {
                command = "get_boundary_config",
            });
        }

        public void SubscribeBoundaryUpdates(bool subscribe = true)
        {
            Send(new SweControlCommand
            {
                command = "subscribe_boundary_updates",
                subscribe = subscribe,
            });
        }

        public void SetActiveTile(string lod, int tileX, int tileY)
        {
            Send(new SweControlCommand
            {
                command = "set_active_tile",
                lod = lod,
                tileX = tileX,
                tileY = tileY,
            });
        }

        public void SaveCheckpoint(string checkpointName)
        {
            Send(new SweControlCommand
            {
                command = "save_checkpoint",
                checkpoint = checkpointName,
            });
        }

        public void ResetCheckpoint(string checkpointName)
        {
            Send(new SweControlCommand
            {
                command = "reset_checkpoint",
                checkpoint = checkpointName,
            });
        }

        public void ApplyPorosityStamp(float u, float v, float radius, float porosity)
        {
            Send(new SweControlCommand
            {
                command = "apply_porosity_stamp",
                u = Mathf.Clamp01(u),
                v = Mathf.Clamp01(v),
                radius = Mathf.Clamp01(radius),
                porosity = Mathf.Clamp01(porosity),
            });
        }

        public void SendDisconnect()
        {
            Send(new SweControlCommand
            {
                command = "disconnect",
            });
        }

        private void ResolveServerEndpoint()
        {
            IPAddress[] addresses = Dns.GetHostAddresses(serverHost.Trim());
            if (addresses.Length == 0)
            {
                throw new InvalidOperationException($"No address found for '{serverHost}'.");
            }

            serverEndpoint = new IPEndPoint(addresses[0], serverCommandPort);
        }

        private void EnsureSocket()
        {
            if (socket == null)
            {
                socket = new UdpClient();
                socket.Client.Blocking = false;
            }
        }

        private void Send(SweControlCommand command)
        {
            if (socket == null)
            {
                return;
            }

            if (serverEndpoint == null)
            {
                try
                {
                    ResolveServerEndpoint();
                }
                catch
                {
                    return;
                }
            }

            byte[] payload = SweUdpProtocol.EncodeControl(command);
            socket.Send(payload, payload.Length, serverEndpoint);
        }

        private void PollMessages()
        {
            if (socket == null)
            {
                return;
            }

            while (socket.Available > 0)
            {
                IPEndPoint sender = new IPEndPoint(IPAddress.Any, 0);
                byte[] payload;
                try
                {
                    payload = socket.Receive(ref sender);
                }
                catch (SocketException)
                {
                    break;
                }

                if (SweUdpProtocol.TryDecodeAck(payload, out string message))
                {
                    lastAckTimeUnscaled = Time.unscaledTime;
                    lastAckMessage = message ?? "";

                    if (verboseLogging)
                    {
                        Debug.Log($"SweQuestControlClient: ack from {sender}: {lastAckMessage}");
                    }

                    continue;
                }

                if (SweUdpProtocol.TryDecodeState(payload, out SweBoundaryStateMessage state))
                {
                    lastStateTimeUnscaled = Time.unscaledTime;
                    lastBoundaryState = state;
                    BoundaryStateReceived?.Invoke(state);

                    if (verboseLogging)
                    {
                        int count = state != null && state.boundaries != null ? state.boundaries.Length : 0;
                        Debug.Log(
                            $"SweQuestControlClient: boundary state from {sender}: type={state?.messageType} entries={count}");
                    }

                    continue;
                }
            }
        }

        private void TickKeepAlive()
        {
            if (!connectRequested || socket == null || serverEndpoint == null)
            {
                return;
            }

            float interval = Mathf.Max(0.1f, helloKeepAliveIntervalSeconds);
            if (lastHelloSentTimeUnscaled < 0.0f || (Time.unscaledTime - lastHelloSentTimeUnscaled) >= interval)
            {
                SendHello();
            }
        }
    }
}