using System.Collections.Generic;
using SLSUtilities.Feedback;
using SLSUtilities.Rendering.PostProcessing;
using UnityEngine;

namespace Cielonos.MainGame.Effects.Feedback
{
    /// <summary>
    /// 径向模糊震动事件。
    /// </summary>
    public struct RadialBlurShakeEvent
    {
        private static event ShakeDelegate OnEvent;

        [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.SubsystemRegistration)]
        private static void RuntimeInitialization() { OnEvent = null; }

        public delegate void ShakeDelegate(FeedbackContext feedbackContext, FloatCurveChannel intensityCurve, 
            bool modifyCenter, Vector2 center, bool stop);

        public static void Register(ShakeDelegate callback) { OnEvent += callback; }
        public static void Unregister(ShakeDelegate callback) { OnEvent -= callback; }

        public static void Trigger(
            FeedbackContext feedbackContext, FloatCurveChannel intensityCurve,
            bool modifyCenter = false, Vector2 center = default, bool stop = false)
        {
            OnEvent?.Invoke(feedbackContext, intensityCurve, modifyCenter, center, stop);
        }
    }

    /// <summary>
    /// 径向模糊震动实例。
    /// </summary>
    public class RadialBlurShakeInstance : ShakeInstanceBase
    {
        public readonly FloatCurveChannel intensityCurve;
        public readonly bool modifyCenter;
        public readonly Vector2 center;

        public RadialBlurShakeInstance(
            FeedbackContext feedbackContext, FloatCurveChannel intensityCurve,  bool modifyCenter, Vector2 center) : 
            base(feedbackContext.timeSettings, feedbackContext.player.TimeProvider, feedbackContext.duration)
        {
            this.intensityCurve = intensityCurve;
            this.modifyCenter = modifyCenter;
            this.center = center;
        }
    }

    /// <summary>
    /// RadialBlur 的震动聚合器。
    /// </summary>
    [AddComponentMenu("SLS Utilities/Feedback Shakers/Radial Blur Shaker")]
    public class RadialBlurShaker : MonoBehaviour
    {
        private RadialBlur _component;
        private float _initialBlurRadius;
        private float _initialCenterX;
        private float _initialCenterY;
        private bool _resolved;

        private readonly List<RadialBlurShakeInstance> _activeShakes = new List<RadialBlurShakeInstance>();

        private void Awake()
        {
            _resolved = TryResolve();
        }

        private void OnEnable()
        {
            RadialBlurShakeEvent.Register(OnShakeEvent);
        }

        private void OnDisable()
        {
            RadialBlurShakeEvent.Unregister(OnShakeEvent);
            StopAll();
        }

        private void Update()
        {
            if (!_resolved || _activeShakes.Count == 0) return;
            
            float additiveDelta = 0f;
            float absoluteTarget = 0f;
            bool hasAbsolute = false;
            
            Vector2 latestCenter = new Vector2(_initialCenterX, _initialCenterY);
            bool hasCenter = false;

            for (int i = _activeShakes.Count - 1; i >= 0; i--)
            {
                RadialBlurShakeInstance shake = _activeShakes[i];
                shake.Tick();
        
                float normalizedTime = shake.timer / shake.duration;
        
                if (shake.intensityCurve.relativeToInitial)
                {
                    // 相对模式：累加曲线值
                    additiveDelta += shake.intensityCurve.Evaluate(normalizedTime);
                }
                else
                {
                    // 绝对模式：使用曲线值作为目标值
                    absoluteTarget = shake.intensityCurve.Evaluate(normalizedTime);
                    hasAbsolute = true;
                }
        
                if (shake.modifyCenter)
                {
                    latestCenter = shake.center;
                    hasCenter = true;
                }
        
                if (shake.IsFinished)
                {
                    _activeShakes.RemoveAt(i);
                }
            }
    
            float finalRadius = hasAbsolute ? absoluteTarget : _initialBlurRadius + additiveDelta;
            _component.blurRadius.value = finalRadius;

            if (hasCenter)
            {
                _component.radialCenterX.value = latestCenter.x;
                _component.radialCenterY.value = latestCenter.y;
            }

            if (_activeShakes.Count == 0)
            {
                Restore();
            }
        }

        private void OnShakeEvent( FeedbackContext feedbackContext, FloatCurveChannel intensityCurve,
            bool modifyCenter, Vector2 center, bool stop)
        {
            if (stop) { StopAll(); return; }
            if (!_resolved) _resolved = TryResolve();
            if (!_resolved) return;

            var instance = new RadialBlurShakeInstance(feedbackContext, intensityCurve, modifyCenter, center);
            _activeShakes.Add(instance);
        }

        private bool TryResolve()
        {
            if (_component != null) return true;
            if (PostProcessingManager.Instance == null) return false;
            if (!PostProcessingManager.Instance.GetVolumeComponent(out _component)) return false;

            _initialBlurRadius = _component.blurRadius.value;
            _initialCenterX = _component.radialCenterX.value;
            _initialCenterY = _component.radialCenterY.value;
            return true;
        }

        private void Restore()
        {
            if (!_resolved) return;
            _component.blurRadius.value = _initialBlurRadius;
            _component.radialCenterX.value = _initialCenterX;
            _component.radialCenterY.value = _initialCenterY;
        }

        private void StopAll()
        {
            _activeShakes.Clear();
            Restore();
        }
    }
}