using ECSAnimator.Runtime.Product.Data;
using ECSAnimator.Runtime.Product.ECS;
using Unity.Mathematics;
using UnityEngine;

namespace ECSAnimator.Runtime.Product.Samples.Newcomer
{
    /// <summary>Sample bridge from a committed ECS attachment pose to this GameObject hierarchy.</summary>
    public sealed class CharacterAttachmentFollower : MonoBehaviour
    {
        [SerializeField] private string _attachmentKey = "attachment.weapon";
        [SerializeField] private Vector3 _localPosition;
        [SerializeField] private Vector3 _localEulerAngles;

        private CharacterRuntime _runtime;
        private CharacterInstanceHandle _instance;
        private ResolvedAttachmentHandle _attachment;
        private float4x4 _localOffset;

        public bool TryFollow(CharacterRuntime runtime, CharacterPreparedAsset prepared,
            CharacterSpawnResult spawn) => TryFollow(runtime, prepared, spawn.SpawnId);

        public void StopFollowing()
        { _runtime = null; _instance = default; _attachment = default; }

        private bool TryFollow(CharacterRuntime runtime, CharacterPreparedAsset prepared,
            CharacterInstanceHandle instance)
        {
            StopFollowing();
            if (runtime == null || prepared == null || !instance.IsValid ||
                !runtime.TryResolveAttachment(prepared.Bindings, _attachmentKey, out var attachment))
                return false;
            _runtime = runtime; _instance = instance; _attachment = attachment;
            _localOffset = float4x4.TRS(_localPosition,
                quaternion.EulerXYZ(math.radians((float3)_localEulerAngles)), new float3(1f));
            return true;
        }

        private void LateUpdate()
        {
            if (_runtime == null || !_runtime.TryGetAttachmentPose(_instance, _attachment,
                    _localOffset, out var pose)) return;
            transform.SetPositionAndRotation(pose.LocalToWorld.c3.xyz,
                quaternion.LookRotationSafe(pose.LocalToWorld.c2.xyz,
                    pose.LocalToWorld.c1.xyz));
        }
    }
}