using UnityEngine;
using System.Collections;

[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);
    public float laserWidth = 0.05f;
    public float emissionStrength = 5f;
    public float scrollSpeed = 1f;

    [Header("Player Hit")]
    public string playerTag = "Player";
    public float hitRadius = 0.1f;
    public QueryTriggerInteraction queryTriggerMode = QueryTriggerInteraction.Collide;

    [Header("Intro Show")]
    public bool showIntro = true;
    public float initialShowDuration = 3f;
    public bool introIsDeadly = true;

    [Header("Deflection (Box side center)")]
    public bool deflectFromBoxSides = true;
    public string boxTag = "Box";
    public float outDistance = 12f;
    public float sideExitPush = 0.02f; // will be lifted to >= hitRadius + epsilon at runtime
    public float entryPush = 0.005f;   // will be lifted to >= 0.25*hitRadius at runtime

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

    private LineRenderer line;
    private float timer = 0f;

    public enum LaserPhase { Idle, Charging, Firing }
    private LaserPhase currentPhase = LaserPhase.Idle;

    private Vector3 laserStart;
    private Vector3 laserEnd;

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

    // Deflection
    private bool _routeViaSide;
    private Vector3 _entryPoint;
    private Vector3 _midPoint;
    private Collider _lastBox;
    private int _sideSign = 1;

    // External control hook (set by controller if used)
    public bool externalControl = true;

    void Awake()
    {
        SetupLaserRenderer();
    }

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

    void Update()
    {
        if (introRunning) return;

        timer += Time.deltaTime;

        switch (currentPhase)
        {
            case LaserPhase.Idle:
                hasTriggeredDeathThisBurst = false;
                if (timer >= chargeDuration)
                {
                    timer = 0f;
                    SetLaserPhase(LaserPhase.Charging);
                }
                break;

            case LaserPhase.Charging:
                if (timer >= 1f)
                {
                    timer = 0f;
                    SetLaserPhase(LaserPhase.Firing);
                }
                else
                {
                    TickLaserDuringCharging();
                }
                break;

            case LaserPhase.Firing:
                if (timer >= fireDuration)
                {
                    timer = 0f;
                    SetLaserPhase(LaserPhase.Idle);
                }
                else
                {
                    TickLaserDuringFiring();
                }
                break;
        }

        if (debugDraw)
            Debug.DrawLine(laserStart, laserEnd, Color.cyan);
    }

    public void SetLaserPhase(LaserPhase phase)
    {
        // When controller is driving, cancel any self-cycling
        if (externalControl)
        {
            StopAllCoroutines();
            introRunning = false;
        }

        if (!line) SetupLaserRenderer();

        // Clear 1-kill gate whenever we enter lead-in or lethal phases
        if (phase == LaserPhase.Charging || phase == LaserPhase.Firing)
            hasTriggeredDeathThisBurst = false;

        currentPhase = phase;

        switch (phase)
        {
            case LaserPhase.Idle:
                DisableLaser();
                break;

            case LaserPhase.Charging:
                UpdateLaserPath();
                line.enabled = true;
                SetLineColor(warningColor);
                break;

            case LaserPhase.Firing:
                UpdateLaserPath();
                line.enabled = true;
                SetLineColor(laserColor);
                CheckHit(); // immediate check on enter
                break;
        }
    }

    public void TickLaserDuringFiring()
    {
        if (currentPhase != LaserPhase.Firing) return;
        UpdateLaserPath();
        CheckHit();
    }

    public void TickLaserDuringCharging()
    {
        if (currentPhase != LaserPhase.Charging) return;
        BlinkWarning();
        UpdateLaserPath();
    }

    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;
        SetLaserPhase(LaserPhase.Idle);
        introRunning = false;
    }

    void DisableLaser()
    {
        line.enabled = false;
        // Optional: zero endpoints for clarity in debug
        laserStart = transform.position;
        laserEnd = laserStart;
    }

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

    void CheckHit()
    {
        // only lethal during Firing, or during Intro if flagged as deadly
        bool lethalNow = (currentPhase == LaserPhase.Firing) || (introRunning && introIsDeadly);
        if (!lethalNow || hasTriggeredDeathThisBurst) return;

        // local helper that can ignore a specific collider (e.g., the deflection box)
        bool CheckSegment(Vector3 a, Vector3 b, Collider ignoreCol = null)
        {
            Vector3 d = b - a;
            float len = d.magnitude;
            if (len <= 0.0001f) return false;
            d /= len;

            var hits = Physics.SphereCastAll(a, hitRadius, d, len, collisionMask, queryTriggerMode);
            if (hits == null || hits.Length == 0) return false;

            float best = float.MaxValue;
            Transform bestT = null;
            Collider bestCol = null;
            foreach (var h in hits)
            {
                if (!h.collider) continue;
                if (ignoreCol && h.collider == ignoreCol) continue; // NEW: ignore the deflection box
                if (h.collider.GetComponentInParent<LaserBeam>() == this) continue;
                if (h.distance < best) { best = h.distance; bestT = h.collider.transform; bestCol = h.collider; }
            }

            if (!bestT) return false;

            // Player?
            if (bestT.CompareTag(playerTag) || (bestT.root && bestT.root.CompareTag(playerTag)))
            {
                hasTriggeredDeathThisBurst = true;
                CrateEscapeGameManager.Instance?.OnPlayerHitByLaser();
                return true;
            }

            // Box? (still allow box damage feedback)
            if (bestCol && bestCol.CompareTag(boxTag))
            {
                var boxHealth = bestCol.GetComponent<LaserBoxHealth>();
                if (boxHealth != null)
                    boxHealth.TakeLaserDamage();
            }

            return false;
        }

        // segmented checks if we’re deflecting
        if (_routeViaSide)
        {
            if (CheckSegment(laserStart, _entryPoint)) return;
            if (CheckSegment(_entryPoint, _midPoint, _lastBox)) return; // ignore the box while exiting
            CheckSegment(_midPoint, laserEnd, _lastBox);                 // ignore it on the last leg too
        }
        else
        {
            CheckSegment(laserStart, laserEnd);
        }
    }

    void UpdateLaserPath()
    {
        laserStart = transform.position;
        Vector3 dir = transform.forward;
        float radius = Mathf.Max(0.0001f, hitRadius);

        RaycastHit[] hits = Physics.SphereCastAll(laserStart, radius, dir, maxDistance, collisionMask, queryTriggerMode);
        Vector3 straightEnd = laserStart + dir * maxDistance;
        RaycastHit bestHit = default;
        float bestDist = float.MaxValue;
        bool gotHit = false;

        if (hits != null)
        {
            foreach (var h in hits)
            {
                if (!h.collider) continue;
                if (h.collider.GetComponentInParent<LaserBeam>() == this) continue;
                if (h.distance < bestDist)
                {
                    bestDist = h.distance;
                    bestHit = h;
                    gotHit = true;
                    straightEnd = h.point;
                }
            }
        }

        _routeViaSide = false;
        laserEnd = straightEnd;
        line.positionCount = 2;
        line.SetPosition(0, laserStart);
        line.SetPosition(1, laserEnd);

        // No deflect?
        if (!deflectFromBoxSides || !gotHit || !bestHit.collider.CompareTag(boxTag)) return;

        var box = bestHit.collider.GetComponent<BoxCollider>();
        if (!box) return;

        if (_lastBox != bestHit.collider)
        {
            _lastBox = bestHit.collider;
            _sideSign = (Random.value < 0.5f) ? -1 : 1;
        }

        Transform t = box.transform;

        // ensure we don’t start the entry segment inside the box
        float safeEntry = Mathf.Max(entryPush, hitRadius * 0.25f);
        _entryPoint = bestHit.point + bestHit.normal * safeEntry;

        // compute the midpoint on the box side we’re exiting from
        Vector3 centerW = t.TransformPoint(box.center);
        Vector3 half = Vector3.Scale(box.size * 0.5f, t.lossyScale);
        Vector3 rightW = t.right.normalized;
        Vector3 outDir = rightW * _sideSign;
        _midPoint = centerW + rightW * (_sideSign * half.x);

        // how much distance remains for leg 2
        float traveled = bestHit.distance + Vector3.Distance(bestHit.point, _midPoint);
        float remain = Mathf.Max(0f, maxDistance - traveled);
        float leg = Mathf.Min(outDistance, remain);

        // Choose a second start that is definitely OUTSIDE the box surface
        float minExit = Mathf.Max(sideExitPush, radius + 0.02f);
        Vector3 secondStart = _midPoint + outDir * minExit;

        // If somehow still overlapping the box bounds, nudge out a bit more (guarded)
        for (int i = 0; i < 3; i++)
        {
            // AABBs are conservative; this is cheap and “good enough”
            if (box.bounds.Contains(secondStart))
                secondStart += outDir * (radius + 0.02f);
            else
                break;
        }

        Vector3 secondEnd = secondStart + outDir * leg;

        // Trim second leg if it hits something early
        if (Physics.SphereCast(secondStart, radius, outDir, out var h2, leg, collisionMask, queryTriggerMode))
        {
            if (!(h2.collider && h2.collider.GetComponentInParent<LaserBeam>() == this))
                secondEnd = h2.point;
        }

        _routeViaSide = true;
        laserEnd = secondEnd;

        line.positionCount = 4;
        line.SetPosition(0, laserStart);
        line.SetPosition(1, _entryPoint);
        line.SetPosition(2, _midPoint);
        line.SetPosition(3, laserEnd);
    }

    public void ResetCycle()
    {
        StopAllCoroutines();
        introRunning = false;
        timer = 0f;
        currentPhase = LaserPhase.Idle;
        hasTriggeredDeathThisBurst = false;
        DisableLaser();
    }

    void SetLineColor(Color c)
    {
        if (line.material.HasProperty("_Color"))
            line.material.SetColor("_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
        {
            line.material = new Material(Shader.Find("Sprites/Default"));
            line.material.color = laserColor;
        }

        line.enabled = false;
    }
}