using UnityEngine;

[DefaultExecutionOrder(16001)]
public class SimplePoseTransfer : MonoBehaviour
{
    [Header("Pose Transfer Settings")]
    public Animator sourceBone;
    public Animator[] targetBones;

    // 캐싱된 Transform들
    private Transform[] cachedSourceBones;
    private Transform[,] cachedTargetBones;

    // 각 targetBone의 초기 회전 차이를 저장
    private Quaternion[,] boneRotationDifferences;

    private void Start()
    {
        Init();
    }

    public void Init()
    {
        if (targetBones == null || targetBones.Length == 0)
        {
            Debug.LogError("Target bones are null or empty");
            return;
        }

        if (sourceBone == null)
        {
            Debug.LogError("Source bone is null");
            return;
        }

        InitializeTargetBones();
        CacheAllBoneTransforms();

        Debug.Log($"SimplePoseTransfer initialized with {targetBones.Length} targets");
    }

    private void InitializeTargetBones()
    {
        boneRotationDifferences = new Quaternion[targetBones.Length, 55];

        for (int i = 0; i < targetBones.Length; i++)
        {
            if (targetBones[i] == null)
            {
                Debug.LogError($"targetBones[{i}] is null");
                continue;
            }

            // 55개의 휴머노이드 본에 대해 회전 차이 계산
            for (int j = 0; j < 55; j++)
            {
                Transform sourceBoneTransform = sourceBone.GetBoneTransform((HumanBodyBones)j);
                Transform targetBoneTransform = targetBones[i].GetBoneTransform((HumanBodyBones)j);
                
                if (sourceBoneTransform != null && targetBoneTransform != null)
                {
                    boneRotationDifferences[i, j] = Quaternion.Inverse(sourceBoneTransform.rotation) * targetBoneTransform.rotation;
                }
            }
        }
    }

    private void CacheAllBoneTransforms()
    {
        // 소스 본 캐싱
        cachedSourceBones = new Transform[55];
        for (int i = 0; i < 55; i++)
        {
            cachedSourceBones[i] = sourceBone.GetBoneTransform((HumanBodyBones)i);
        }

        // 타겟 본 캐싱
        cachedTargetBones = new Transform[targetBones.Length, 55];
        for (int t = 0; t < targetBones.Length; t++)
        {
            for (int i = 0; i < 55; i++)
            {
                cachedTargetBones[t, i] = targetBones[t].GetBoneTransform((HumanBodyBones)i);
            }
        }
    }

    private void LateUpdate()
    {
        TransferPoses();
    }

    private void TransferPoses()
    {
        if (sourceBone == null)
        {
            return;
        }

        for (int i = 0; i < targetBones.Length; i++)
        {
            if (targetBones[i] != null && targetBones[i].gameObject.activeInHierarchy)
            {
                TransferPoseToTarget(i);
            }
        }
    }

    private void TransferPoseToTarget(int targetIndex)
    {
        Animator targetBone = targetBones[targetIndex];
        
        // 루트 회전 동기화
        targetBone.transform.rotation = sourceBone.transform.rotation;

        // 모든 본에 대해 포즈 전송
        for (int i = 0; i < 55; i++)
        {
            Transform targetBoneTransform = cachedTargetBones[targetIndex, i];
            Transform sourceBoneTransform = cachedSourceBones[i];

            if (targetBoneTransform != null && sourceBoneTransform != null)
            {
                // 회전 적용
                targetBoneTransform.rotation = sourceBoneTransform.rotation * boneRotationDifferences[targetIndex, i];

                // 펠비스 위치 동기화 (HumanBodyBones.Hips = 0)
                if (i == 0)
                {
                    targetBoneTransform.position = sourceBoneTransform.position;
                }
            }
        }
    }

}