using TMPro;
using UnityEngine;

namespace FloodSWE.Networking
{
    /// <summary>
    /// Binds SweServerRuntime diagnostics to user-provided TMP text fields.
    /// </summary>
    public sealed class SweServerDiagnosticsHud : MonoBehaviour
    {
        [Header("References")]
        [SerializeField] private SweServerRuntime serverRuntime;
        [SerializeField] private TMP_Text simulationText;
        [SerializeField] private TMP_Text connectionText;
        [SerializeField] private TMP_Text commandText;
        [SerializeField] private TMP_Text forcingText;
        [SerializeField] private TMP_Text tileLoadText;

        [Header("Behavior")]
        [SerializeField] private bool autoFindRuntime = true;
        [SerializeField] private float refreshIntervalSeconds = 0.15f;

        [Header("Labels")]
        [SerializeField] private string connectedLabel = "Connected";
        [SerializeField] private string staleLabel = "Stale";
        [SerializeField] private string disconnectedLabel = "Disconnected";
        [SerializeField] private string unknownAgeLabel = "n/a";
        [SerializeField] private string numberFormat = "0.00";

        [Header("Colors")]
        [SerializeField] private Color connectedColor = new Color(0.4f, 1.0f, 0.4f);
        [SerializeField] private Color staleColor = new Color(1.0f, 0.9f, 0.3f);
        [SerializeField] private Color disconnectedColor = new Color(1.0f, 0.5f, 0.5f);

        private float nextRefreshTime;

        private void OnEnable()
        {
            if (serverRuntime == null && autoFindRuntime)
            {
                serverRuntime = FindFirstObjectByType<SweServerRuntime>();
            }

            Refresh(true);
        }

        private void Update()
        {
            if (Time.unscaledTime < nextRefreshTime)
            {
                return;
            }

            Refresh(false);
        }

        private void Refresh(bool immediate)
        {
            nextRefreshTime = Time.unscaledTime + Mathf.Max(0.02f, refreshIntervalSeconds);
            if (serverRuntime == null)
            {
                SetText(simulationText, "Sim Speed: n/a");
                SetText(connectionText, "Connection: runtime missing");
                SetText(commandText, "Last Command: n/a");
                SetText(forcingText, "Forcing: n/a");
                SetText(tileLoadText, "Tile Load: runtime missing");
                if (connectionText != null)
                {
                    connectionText.color = disconnectedColor;
                }
                return;
            }

            string simLine = $"Sim Speed: {serverRuntime.SimulatedSecondsPerSecond.ToString(numberFormat)} sim-s/s";
            if (!serverRuntime.HasSimulationThroughput)
            {
                simLine = "Sim Speed: warming up";
            }
            SetText(simulationText, simLine);

            string state;
            Color stateColor;
            if (!serverRuntime.HasConnectedClients)
            {
                state = disconnectedLabel;
                stateColor = disconnectedColor;
            }
            else if (serverRuntime.HasRecentClientSignal)
            {
                state = connectedLabel;
                stateColor = connectedColor;
            }
            else
            {
                state = staleLabel;
                stateColor = staleColor;
            }

            string connectionLine =
                $"Connection: {state} | clients={serverRuntime.ConnectedClientCount} | endpoint={serverRuntime.QuestEndpointLabel}";
            SetText(connectionText, connectionLine);
            if (connectionText != null)
            {
                connectionText.color = stateColor;
            }

            string age = float.IsInfinity(serverRuntime.LastCommandAgeSeconds)
                ? unknownAgeLabel
                : $"{serverRuntime.LastCommandAgeSeconds.ToString(numberFormat)}s";
            string commandLine =
                $"Last Command: {serverRuntime.LastCommandName} from {serverRuntime.LastCommandSender} ({age}) | " +
                $"ctrl={serverRuntime.DecodedControlPackets}/{serverRuntime.ReceivedControlPackets} invalid={serverRuntime.InvalidControlPackets} ack={serverRuntime.AckPacketsSent}";
            SetText(commandText, commandLine);

            string forcingLine =
                $"Forcing: {serverRuntime.LastForcingStatus} | cells={serverRuntime.LastForcedCellCount} | tile={serverRuntime.ActiveTileLabel}";
            SetText(forcingText, forcingLine);

            string tileLine =
                $"Tile Load: {serverRuntime.TileLoadSummary} | framePayload={serverRuntime.LastFramePayloadBytes}B " +
                $"frames={serverRuntime.TransmittedFramePackets} dropped={serverRuntime.DroppedFramePackets}";
            SetText(tileLoadText, tileLine);

            if (immediate)
            {
                nextRefreshTime = Time.unscaledTime;
            }
        }

        private static void SetText(TMP_Text target, string value)
        {
            if (target == null || target.text == value)
            {
                return;
            }

            target.text = value;
        }
    }
}