// GateCenterDetector.cs
// Zweck: Prüft jedes Frame, welches Gate am nächsten zur Bildmitte liegt, und zeigt dessen Text im HUD.
using UnityEngine;

public class GateCenterDetector : MonoBehaviour
{
    [Header("XR Camera")]
    [SerializeField] private Camera xrCamera;

    [Header("References")]
    [SerializeField] private GateSpawner gateSpawner;
    [SerializeField] private CockpitGateHUD cockpitHUD;

    [Header("Selection")]
    [Tooltip("Max. Weltdistanz (0 = ignorieren).")]
    [SerializeField] private float maxWorldDistance = 0f;
    [Tooltip("Max. quadratische Distanz zur Bildschirmmitte im Viewport (0..1).")]
    [SerializeField] private float maxCenterDistSqr = 0.05f;

    [Header("Debug")]
    [SerializeField] private bool debugLogs = false;

    private GateText currentGate;

    private void Awake()
    {
        if (!xrCamera)
        {
            xrCamera = GetComponent<Camera>();
            if (!xrCamera && Camera.main != null)
                xrCamera = Camera.main;
        }

        if (debugLogs)
        {
            if (!xrCamera) Debug.LogWarning("[GateCenterDetector] XR Camera fehlt.");
            if (!gateSpawner) Debug.LogWarning("[GateCenterDetector] GateSpawner fehlt.");
            if (!cockpitHUD) Debug.LogWarning("[GateCenterDetector] CockpitGateHUD fehlt.");
        }
    }

    private void Update()
    {
        if (!xrCamera || !gateSpawner || !cockpitHUD)
            return;

        var gates = gateSpawner.ActiveGates;
        if (gates == null || gates.Count == 0)
        {
            ClearCurrentGate();
            return;
        }

        GateText bestGate = null;
        float bestScore = float.MaxValue;

        Vector3 camPos = xrCamera.transform.position;

        foreach (var gateObj in gates)
        {
            if (!gateObj) continue;

            var gateQuestion = gateObj.GetComponentInChildren<GateText>();
            if (!gateQuestion) continue;

            Vector3 worldPos = gateObj.transform.position;

            // optional: Distanzlimit
            if (maxWorldDistance > 0f)
            {
                float dist = Vector3.Distance(camPos, worldPos);
                if (dist > maxWorldDistance) continue;
            }

            // in Viewport projizieren
            Vector3 v = xrCamera.WorldToViewportPoint(worldPos);
            if (v.z <= 0f) continue;                       // hinter Kamera
            if (v.x < 0f || v.x > 1f || v.y < 0f || v.y > 1f) continue; // off-screen

            // Distanz zur Mitte (0.5/0.5)
            float dx = v.x - 0.5f;
            float dy = v.y - 0.5f;
            float distSqr = dx * dx + dy * dy;

            if (distSqr < bestScore)
            {
                bestScore = distSqr;
                bestGate = gateQuestion;
            }
        }

        if (bestGate != null && (maxCenterDistSqr <= 0f || bestScore <= maxCenterDistSqr))
        {
            if (bestGate != currentGate)
            {
                currentGate = bestGate;
                string text = currentGate.GetQuestionText();
                cockpitHUD.ShowWithReveal(text);

                if (debugLogs)
                    Debug.Log($"[GateCenterDetector] Fokus: {currentGate.name} | Text: {text}");
            }
        }
        else
        {
            ClearCurrentGate();
        }
    }

    private void ClearCurrentGate()
    {
        if (currentGate != null)
        {
            if (debugLogs) Debug.Log("[GateCenterDetector] Fokus verloren, HUD aus.");
            currentGate = null;
            cockpitHUD.Hide();
        }
    }
}