using UnityEngine;
using System.Collections;
using System.Collections.Generic;

[RequireComponent(typeof(Collider))]
public class CubeClash_BirdSwoop : MonoBehaviour
{
    [Header("Targeting")]
    public bool useStaticList = true;
    public string zibuTag = "Zibu";
    public bool autoDestroyIfNoTarget = true;

    [Header("Bird Movement (Seek)")]
    public float birdMoveSpeed = 8f;
    public float birdTurnSpeed = 10f;
    public float pickupRadius = 1.2f;
    public float approachHeightOffset = 2f;
    public float followAboveOffset = 1.0f;
    public bool faceVelocity = true;

    [Header("Lift Profile")]
    public float carryHeight = 5f;
    public float riseTime = 0.8f;
    public float hoverTime = 1.0f;
    public float dropKickImpulse = 0f;

    [Header("Force Tuning (Physics)")]
    public float posGain = 12f;
    public float velGain = 2.5f;
    public float maxDeltaVPerFixedUpdate = 12f;

    [Header("While Carried")]
    public bool disableGravityWhileCarried = true;
    public float extraDrag = 2f;
    public float extraStun = 0.1f;

    [Header("Lifecycle")]
    public bool destroyOnRelease = true;

    private enum SwoopState { Seeking, Carrying, Releasing, Idle }
    private SwoopState _state = SwoopState.Idle;

    private Rigidbody _targetRb;
    private CubeClash_ZibuController _targetController;

    // Bird’s own body (optional)
    private Rigidbody _birdRb;            // if present, we’ll MovePosition on it
    private bool _weMadeKinematic = false;

    // Carry bookkeeping
    private readonly HashSet<Rigidbody> _carried = new HashSet<Rigidbody>();
    private readonly Dictionary<Rigidbody, float> _origDrag = new Dictionary<Rigidbody, float>();
    private readonly Dictionary<Rigidbody, bool> _origGrav = new Dictionary<Rigidbody, bool>();

    void Reset()
    {
        var col = GetComponent<Collider>();
        if (col) col.isTrigger = true;
    }

    void Awake()
    {
        _birdRb = GetComponent<Rigidbody>();
        if (_birdRb != null)
        {
            // Ensure physics doesn’t fight our manual movement
            if (!_birdRb.isKinematic)
            {
                _birdRb.isKinematic = true;
                _weMadeKinematic = true;
            }
            _birdRb.interpolation = RigidbodyInterpolation.Interpolate;
        }
    }

    void OnEnable()
    {
        PickRandomZibuAndSeek();
    }

    private void PickRandomZibuAndSeek()
    {
        _targetRb = PickRandomZibuRigidbody();
        if (_targetRb == null)
        {
            if (autoDestroyIfNoTarget) Destroy(gameObject);
            return;
        }

        _targetController = _targetRb.GetComponent<CubeClash_ZibuController>();
        _state = SwoopState.Seeking;
    }

    private Rigidbody PickRandomZibuRigidbody()
    {
        List<Rigidbody> candidates = new List<Rigidbody>();

        if (useStaticList && CubeClash_ZibuController.AllZibus != null && CubeClash_ZibuController.AllZibus.Count > 0)
        {
            foreach (var z in CubeClash_ZibuController.AllZibus)
            {
                if (!z || !z.gameObject.activeInHierarchy) continue;
                var rb = z.GetComponent<Rigidbody>();
                if (rb) candidates.Add(rb);
            }
        }
        else
        {
            foreach (var go in GameObject.FindGameObjectsWithTag(zibuTag))
            {
                if (!go || !go.activeInHierarchy) continue;
                var rb = go.GetComponent<Rigidbody>();
                if (rb) candidates.Add(rb);
            }
        }

        if (candidates.Count == 0) return null;
        return candidates[Random.Range(0, candidates.Count)];
    }

    void FixedUpdate()
    {
        if (_targetRb == null) return;

        switch (_state)
        {
            case SwoopState.Seeking:
                SeekStep();
                break;
            case SwoopState.Carrying:
                EscortFollowStep();
                break;
        }
    }

    // --- Movement helpers that work with or without a Rigidbody on the bird ---
    private void MoveBirdTo(Vector3 newPos)
    {
        if (_birdRb != null) _birdRb.MovePosition(newPos);
        else transform.position = newPos;
    }

    private void RotateBirdTo(Quaternion newRot, float slerpFactor)
    {
        if (faceVelocity)
        {
            var current = (_birdRb != null) ? _birdRb.rotation : transform.rotation;
            var next = Quaternion.Slerp(current, newRot, slerpFactor);
            if (_birdRb != null) _birdRb.MoveRotation(next);
            else transform.rotation = next;
        }
    }

    private void SeekStep()
    {
        Vector3 aim = _targetRb.position + Vector3.up * approachHeightOffset;
        Vector3 to = aim - ((_birdRb != null) ? _birdRb.position : transform.position);
        float dist = to.magnitude;

        if (dist > 0.001f)
        {
            Vector3 dir = to / dist;
            Vector3 step = dir * birdMoveSpeed * Time.fixedDeltaTime;
            if (step.magnitude > dist) step = to;

            MoveBirdTo(((_birdRb != null) ? _birdRb.position : transform.position) + step);

            if (faceVelocity && step.sqrMagnitude > 1e-6f)
            {
                Quaternion targetRot = Quaternion.LookRotation(step.normalized, Vector3.up);
                RotateBirdTo(targetRot, birdTurnSpeed * Time.fixedDeltaTime);
            }
        }

        if (Vector3.Distance(((_birdRb != null) ? _birdRb.position : transform.position), _targetRb.position) <= pickupRadius)
        {
            StartCoroutine(CarryRoutine(_targetRb));
            _state = SwoopState.Carrying;
        }
    }

    private void EscortFollowStep()
    {
        if (_targetRb == null) return;

        Vector3 follow = _targetRb.position + Vector3.up * followAboveOffset;
        Vector3 to = follow - ((_birdRb != null) ? _birdRb.position : transform.position);
        float dist = to.magnitude;

        if (dist > 0.001f)
        {
            Vector3 dir = to / dist;
            Vector3 step = dir * birdMoveSpeed * Time.fixedDeltaTime;
            if (step.magnitude > dist) step = to;

            MoveBirdTo(((_birdRb != null) ? _birdRb.position : transform.position) + step);

            if (faceVelocity && step.sqrMagnitude > 1e-6f)
            {
                Quaternion targetRot = Quaternion.LookRotation(step.normalized, Vector3.up);
                RotateBirdTo(targetRot, birdTurnSpeed * Time.fixedDeltaTime);
            }
        }
    }

    private IEnumerator CarryRoutine(Rigidbody rb)
    {
        _carried.Add(rb);

        float plannedStun = Mathf.Max(0.05f, riseTime + hoverTime + extraStun);
        if (_targetController) _targetController.ApplyPushStun(plannedStun);

        if (!_origDrag.ContainsKey(rb)) _origDrag[rb] = rb.drag;
        if (!_origGrav.ContainsKey(rb)) _origGrav[rb] = rb.useGravity;

        if (disableGravityWhileCarried) rb.useGravity = false;
        rb.drag = _origDrag[rb] + Mathf.Max(0f, extraDrag);

        Vector3 startPos = rb.position;
        float targetY = startPos.y + carryHeight;

        // Rise
        float t = 0f;
        while (t < riseTime)
        {
            t += Time.fixedDeltaTime;
            float a = Mathf.Clamp01(t / Mathf.Max(0.0001f, riseTime));
            Vector3 targetPos = new Vector3(rb.position.x, Mathf.Lerp(startPos.y, targetY, a), rb.position.z);
            ApplyPDStep(rb, targetPos);
            yield return new WaitForFixedUpdate();
        }

        // Hover
        float h = 0f;
        while (h < hoverTime)
        {
            h += Time.fixedDeltaTime;
            Vector3 targetPos = new Vector3(rb.position.x, targetY, rb.position.z);
            ApplyPDStep(rb, targetPos);
            yield return new WaitForFixedUpdate();
        }

        // Release
        if (_origGrav.TryGetValue(rb, out bool g)) rb.useGravity = g;
        if (_origDrag.TryGetValue(rb, out float d)) rb.drag = d;

        if (dropKickImpulse > 0f)
            rb.AddForce(Vector3.down * dropKickImpulse, ForceMode.Impulse);

        _carried.Remove(rb);
        _origDrag.Remove(rb);
        _origGrav.Remove(rb);

        _state = SwoopState.Releasing;
        _targetRb = null;
        _targetController = null;

        if (destroyOnRelease) Destroy(gameObject);
        else _state = SwoopState.Idle;
    }

    private void ApplyPDStep(Rigidbody rb, Vector3 targetPos)
    {
        Vector3 to = targetPos - rb.position;
        Vector3 toXZ = new Vector3(to.x, 0f, to.z);
        Vector3 toY = new Vector3(0f, to.y, 0f);

        Vector3 dvXZ = posGain * toXZ - velGain * new Vector3(rb.velocity.x, 0f, rb.velocity.z);
        Vector3 dvY = posGain * toY - velGain * new Vector3(0f, rb.velocity.y, 0f);
        Vector3 deltaV = (dvXZ + dvY) * Time.fixedDeltaTime;

        if (maxDeltaVPerFixedUpdate > 0f && deltaV.magnitude > maxDeltaVPerFixedUpdate)
            deltaV = deltaV.normalized * maxDeltaVPerFixedUpdate;

        rb.AddForce(deltaV, ForceMode.VelocityChange);
    }

    private void OnDisable()
    {
        foreach (var rb in _carried)
        {
            if (!rb) continue;
            if (_origGrav.TryGetValue(rb, out bool g)) rb.useGravity = g;
            if (_origDrag.TryGetValue(rb, out float d)) rb.drag = d;
        }
        _carried.Clear();
        _origDrag.Clear();
        _origGrav.Clear();
    }

    // Debug gizmo to see pickup radius in Scene view
    void OnDrawGizmosSelected()
    {
        Gizmos.color = Color.cyan;
        Vector3 pos = (_birdRb != null) ? _birdRb.position : transform.position;
        Gizmos.DrawWireSphere(pos, pickupRadius);
    }
}