using System;
using System.Collections;
using System.Collections.Generic;
using Ichni.RhythmGame.Beatmap;
using UniRx;
using UnityEngine;

namespace Ichni.RhythmGame
{
    /// <summary>
    /// 将物体的z轴指向目标物体，注意，LookAt的启用期间，物体的旋转将被锁定
    /// </summary>
    public partial class LookAt : AnimationBase
    {
        #region [暴露属性字段与关联] Exposed Fields & References
        public GameElement targetGameElement;
        public TransformSubmodule targetTransformSubmodule;
        public FlexibleBool enabling;
        #endregion

        #region [生命周期与工厂] Lifecycle & Factory
        public static LookAt GenerateElement(string elementName, Guid id,
            List<string> tags, bool isFirstGenerated, GameElement animatedObject,
            GameElement lookAtTarget, FlexibleBool enabling)
        {
            LookAt look = Instantiate(GameManager.Instance.basePrefabs.emptyObject).AddComponent<LookAt>();

            look.Initialize(elementName, id, tags, isFirstGenerated, animatedObject);

            look.animatedObject = animatedObject;
            look.enabling = enabling;
            look.animationReturnType = FlexibleReturnType.Before;

            look.targetGameElement = lookAtTarget;
            look.targetTransformSubmodule = (animatedObject as IHaveTransformSubmodule).transformSubmodule;
            //look.timeDurationSubmodule.SetDuration(-999f, 999f); //TODO: 换为(-delay, songLength)
            return look;
        }

        public override void SetDefaultSubmodules()
        {
            timeDurationSubmodule = new TimeDurationSubmodule(this);
        }

        public override void AfterInitialize()
        {
            base.AfterInitialize();
            // 注册 Phase 7（Effect），确保在 Track/TrackFollower（Phase 4/5）和 Note（Phase 6）
            // 全部更新完毕后再计算旋转覆盖，避免因位置尚未就绪导致的旋转抖动
            CoreServices.UpdateScheduler.Register(UpdatePhase.Effect, this);
        }

        public override void OnDelete()
        {
            base.OnDelete();
            CoreServices.UpdateScheduler.Unregister(UpdatePhase.Effect, this);
        }

        public override void ManualUpdate(float songTime, bool forceUpdate = false)
        {
            base.ManualUpdate(songTime, forceUpdate);
            // 动画结束时同步注销 Phase 7
            if (timeDurationSubmodule.CheckAfterEndTime(songTime))
            {
                CoreServices.UpdateScheduler.Unregister(UpdatePhase.Effect, this);
            }
        }

        #endregion
        
        #region [核心动画逻辑] Core Animation Logic
        public override void ScheduledUpdate(UpdatePhase phase, float songTime)
        {
            switch (phase)
            {
                case UpdatePhase.Animation:
                    base.ScheduledUpdate(phase, songTime);
                    break;
                case UpdatePhase.Effect:
                    // 在所有 Track/TrackFollower/Note 位置更新完毕后覆盖旋转
                    if (enabling.value)
                    {
                        (animatedObject as IHaveTransformSubmodule)?.UpdateLookAt(this);
                    }
                    break;
            }
        }

        protected override void UpdateAnimation(float songTime, bool forceUpdate)
        {
            if (targetGameElement is null) return;
            
            enabling.UpdateFlexibleBool(songTime);
            
            if (!targetTransformSubmodule.eulerAnglesOffsetLock || enabling.value)
            {
                targetTransformSubmodule.eulerAnglesOffsetLock = enabling.value;
            }
            
            if (enabling.value)
            {
                animationReturnType = FlexibleReturnType.MiddleExecuting;
                targetTransformSubmodule.eulerAnglesDirtyMark = true;
            }
            else if (animationReturnType != FlexibleReturnType.MiddleInterval)
            {
                animationReturnType = FlexibleReturnType.MiddleInterval;
                targetTransformSubmodule.eulerAnglesDirtyMark = true;
            }
        }
        
        public override void ApplyTimeOffset(float offset)
        {
            base.ApplyTimeOffset(offset);
            enabling.animations.ForEach(anim => anim.ApplyTimeOffset(offset));
        }
        #endregion
    }

}