using System.Collections.Generic;
using SLSUtilities.Feedback;
using Unity.Cinemachine;
using UnityEngine;

namespace Cielonos.MainGame.Effects.Feedback
{
    public class CameraDistanceShakeInstance : ShakeInstanceBase
    {
        public FloatCurveChannel distanceCurve;

        public CameraDistanceShakeInstance(FeedbackTimeSettings timeSettings, IFeedbackTimeProvider timeProvider, 
            FloatCurveChannel distanceCurve, float duration) : base(timeSettings, timeProvider, duration)
        {
            this.distanceCurve = distanceCurve;
        }
    }

    public struct CameraDistanceShakeEvent
    {
        private static event ShakeDelegate OnEvent;

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

        public delegate void ShakeDelegate(
            FeedbackContext feedbackContext,
            FloatCurveChannel distanceCurve,
            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 distanceCurve,
            bool stop = false)
        {
            OnEvent?.Invoke(feedbackContext, distanceCurve, stop);
        }
    }

    [AddComponentMenu("Cielonos/Feedback Shakers/Camera Distance Shaker")]
    [RequireComponent(typeof(CinemachineCamera))]
    [RequireComponent(typeof(CinemachineOrbitalFollow))]
    public class CameraDistanceShaker : MonoBehaviour
    {
        private CinemachineCamera _camera;
        private CinemachineOrbitalFollow _orbitalFollow;
        
        public float initialDistance;
        
        [Tooltip("防止因为同类 Feedback 叠加导致距离过小")]
        public float minDistance = 1f;
        [Tooltip("防止因为同类 Feedback 叠加导致距离过大")]
        public float maxDistance = 30f;
        
        private readonly List<CameraDistanceShakeInstance> _activeShakes = new List<CameraDistanceShakeInstance>();

        private void Awake()
        {
            _camera = GetComponent<CinemachineCamera>();
            _orbitalFollow = GetComponent<CinemachineOrbitalFollow>();
            initialDistance = _orbitalFollow.Radius;
        }

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

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

        private void Update()
        {
            if (_orbitalFollow == null) return;

            if (_activeShakes.Count == 0)
            {
                SetDistance(initialDistance);
                return;
            }
            
            float additiveDistance = 0f;
            float absoluteDistance = 0f;
            bool hasAbsolute = false;

            for (int i = _activeShakes.Count - 1; i >= 0; i--)
            {
                CameraDistanceShakeInstance shake = _activeShakes[i];
                shake.Tick();
                float normalizedTime = shake.timer / shake.duration;
                
                if (shake.distanceCurve.relativeToInitial)
                {
                    additiveDistance += shake.distanceCurve.Evaluate(normalizedTime);
                }
                else
                {
                    absoluteDistance = shake.distanceCurve.Evaluate(normalizedTime);
                    hasAbsolute = true;
                }

                if (shake.IsFinished)
                {
                    _activeShakes.RemoveAt(i);
                }
            }

            float finalDistance = hasAbsolute ? absoluteDistance : initialDistance + additiveDistance;
            
            // 核心防御：钳制最终距离，防止多技能/反馈叠加导致的距离暴走
            finalDistance = Mathf.Clamp(finalDistance, minDistance, maxDistance);
            
            SetDistance(finalDistance);
        }

        private void OnShakeEvent(
            FeedbackContext feedbackContext,
            FloatCurveChannel distanceCurve,
            bool stop)
        {
            if (stop) { StopAll(); return; }

            var instance = new CameraDistanceShakeInstance(
                feedbackContext.timeSettings,
                feedbackContext.player.TimeProvider,
                distanceCurve,
                feedbackContext.duration
            );
            _activeShakes.Add(instance);
        }

        private void SetDistance(float distance)
        {
            _orbitalFollow.Radius = distance;
        }

        private void StopAll()
        {
            _activeShakes.Clear();
            if (_orbitalFollow != null)
            {
                SetDistance(initialDistance);
            }
        }
    }
}