using UnityEngine;

[RequireComponent(typeof(LineRenderer))]
public class LaserBeam : MonoBehaviour
{
    [Header("Laser Settings")]
    public float maxDistance = 20f;
    public LayerMask collisionMask = ~0;
    public float chargeDuration = 3f;
    public float fireDuration = 1f;

    [Header("Laser Appearance")]
    public Color laserColor = Color.red;
    public Color warningColor = new Color(1f, 0.5f, 0f); // Orange
    public float laserWidth = 0.05f;
    public float emissionStrength = 5f;
    public float scrollSpeed = 1f;

    [Header("Player Hit")]
    public string playerTag = "Player";
    [Tooltip("Approximate beam thickness for hit tests.")]
    public float hitRadius = 0.1f;
    [Tooltip("Should raycasts consider trigger colliders? (Player often uses triggers)")]
    public QueryTriggerInteraction queryTriggerMode = QueryTriggerInteraction.Collide;

    [Header("Intro Show")]
    public bool showIntro = true;
    public float initialShowDuration = 3f;
    [Tooltip("If true, the intro beam can kill the player too.")]
    public bool introIsDeadly = true;

    [Header("Debug")]
    public bool debugDraw = false;

    private LineRenderer line;
    private float timer = 0f;

    private enum LaserState { Idle, Charging, Firing }
    private LaserState currentState = LaserState.Idle;

    private Vector3 laserStart;
    private Vector3 laserEnd;

    private bool introRunning = false;
    private bool hasTriggeredDeathThisBurst = false;

    // cache root to ignore self-hits
    Transform _selfRoot;

    void Awake()
    {
        _selfRoot = transform.root;
        SetupLaserRenderer();
    }

    void Start()
    {
        if (showIntro)
            StartCoroutine(IntroShow());
    }

    void Update()
    {
        if (introRunning) return;

        timer += Time.deltaTime;

        switch (currentState)
        {
            case LaserState.Idle:
                hasTriggeredDeathThisBurst = false; // reset per cycle
                if (timer >= chargeDuration)
                {
                    timer = 0f;
                    currentState = LaserState.Charging;
                    StartCharging();
                }
                break;

            case LaserState.Charging:
                if (timer >= 1f)
                {
                    timer = 0f;
                    currentState = LaserState.Firing;
                    FireLaser();
                }
                else
                {
                    BlinkWarning();
                }
                break;

            case LaserState.Firing:
                if (timer >= fireDuration)
                {
                    timer = 0f;
                    currentState = LaserState.Idle;
                    DisableLaser();
                }
                else
                {
                    UpdateLaserPath();
                    CheckHit();
                }
                break;
        }

        if (debugDraw)
        {
            Debug.DrawLine(laserStart, laserEnd, Color.cyan, 0f, false);
        }
    }

    // ---------------- Intro show ----------------
    System.Collections.IEnumerator IntroShow()
    {
        introRunning = true;

        float t = 0f;
        line.enabled = true;
        SetLineColor(laserColor);

        hasTriggeredDeathThisBurst = false;

        while (t < initialShowDuration)
        {
            UpdateLaserPath();
            if (introIsDeadly && !hasTriggeredDeathThisBurst)
                CheckHit();

            t += Time.deltaTime;
            yield return null;
        }

        line.enabled = false;
        timer = 0f;
        currentState = LaserState.Idle;
        introRunning = false;
    }

    // ---------------- States ----------------
    void StartCharging()
    {
        UpdateLaserPath();
        line.enabled = true;
        SetLineColor(warningColor);
    }

    void BlinkWarning()
    {
        float blink = Mathf.PingPong(Time.time * 5f, 1f);
        Color blinkColor = Color.Lerp(Color.clear, warningColor, blink);
        SetLineColor(blinkColor);
    }

    void FireLaser()
    {
        UpdateLaserPath();
        SetLineColor(laserColor);

        hasTriggeredDeathThisBurst = false;
        CheckHit(); // initial frame
    }

    void DisableLaser()
    {
        line.enabled = false;
    }

    // ---------------- Hit Detection (robust) ----------------
    void CheckHit()
    {
        if (hasTriggeredDeathThisBurst) return;

        Vector3 dir = (laserEnd - laserStart).normalized;
        float distToEnd = Vector3.Distance(laserStart, laserEnd);

        // Cast along visible beam, then pick the nearest valid hit
        RaycastHit[] hits = Physics.SphereCastAll(
            laserStart, hitRadius, dir,
            distToEnd, collisionMask, queryTriggerMode
        );

        if (hits == null || hits.Length == 0) return;

        float bestDist = float.MaxValue;
        Transform best = null;

        foreach (var h in hits)
        {
            // Ignore self (any collider in our own hierarchy)
            if (h.collider && h.collider.GetComponentInParent<LaserBeam>() == this)
                continue;
            // Keep the nearest hit under our visible segment
            if (h.distance < bestDist)
            {
                bestDist = h.distance;
                best = h.collider.transform;
            }
        }

        if (best == null) return;

        // Player detection: check both object and its root
        bool isPlayer =
            best.CompareTag(playerTag) ||
            (best.root != null && best.root.CompareTag(playerTag));

        if (isPlayer)
        {
            Debug.Log("Laser hit player: " + best.name);
            hasTriggeredDeathThisBurst = true;
            CrateEscapeGameManager.Instance?.OnPlayerHitByLaser();
        }
    }

    void UpdateLaserPath()
    {
        laserStart = transform.position;
        Vector3 dir = transform.forward;

        // SphereCast to find the FIRST valid hit along the visible beam,
        // ignoring ONLY this laser's own colliders.
        float radius = Mathf.Max(0.0001f, hitRadius);
        RaycastHit[] hits = Physics.SphereCastAll(
            laserStart, radius, dir, maxDistance, collisionMask, queryTriggerMode
        );

        Vector3 end = laserStart + dir * maxDistance;
        float bestDist = float.MaxValue;

        if (hits != null && hits.Length > 0)
        {
            foreach (var h in hits)
            {
                if (!h.collider) continue;

                // Ignore ONLY this LaserBeam's colliders (not the whole root/level)
                if (h.collider.GetComponentInParent<LaserBeam>() == this)
                    continue;

                if (h.distance < bestDist)
                {
                    bestDist = h.distance;
                    end = h.point;
                }
            }
        }

        laserEnd = end;

        line.SetPosition(0, laserStart);
        line.SetPosition(1, laserEnd);
    }

    // ---------------- Utils ----------------
    void SetLineColor(Color c)
    {
        line.material.color = c;
        line.startColor = c;
        line.endColor = c;
    }

    public void SetupLaserRenderer()
    {
        line = GetComponent<LineRenderer>();
        if (!line) line = gameObject.AddComponent<LineRenderer>();

        line.positionCount = 2;
        line.useWorldSpace = true;
        line.loop = false;
        line.shadowCastingMode = UnityEngine.Rendering.ShadowCastingMode.Off;
        line.receiveShadows = false;
        line.widthMultiplier = laserWidth;

        Shader laserShader = Shader.Find("Custom/EmissiveLaser");
        if (laserShader != null)
        {
            Material laserMat = new Material(laserShader);
            laserMat.SetColor("_Color", laserColor);
            laserMat.SetFloat("_Emission", emissionStrength);
            laserMat.SetFloat("_ScrollSpeed", scrollSpeed);
            line.material = laserMat;
        }
        else
        {
            Debug.LogWarning("Custom/EmissiveLaser shader not found. Using fallback.");
            line.material = new Material(Shader.Find("Sprites/Default"));
            line.material.color = laserColor;
        }

        line.enabled = false;
    }

    void OnDrawGizmosSelected()
    {
        if (!debugDraw) return;
        Gizmos.color = Color.magenta;
        Gizmos.DrawWireSphere(transform.position, hitRadius);
    }
}