using System;
using UnityEngine;
using BumpCombat.Constants;

namespace BumpCombat.Defense
{
    [DisallowMultipleComponent]
    public sealed class DefenseSpriteSequence : MonoBehaviour
    {
        private SpriteRenderer target;
        private Sprite[] frames;
        private string key;
        private float durationScale = 1f;
        private bool useUnscaledTime;
        private float frameRemaining;
        private int frame;
        private Sprite[] nextFrames;
        private string nextKey;
        private bool destroyWhenFinished;
        private float delayRemaining;
        private bool animationFinished;
        private Vector2 travelStart;
        private System.Func<Vector2> travelStartProvider;
        private Vector2 travelEnd;
        private float travelDuration;
        private float travelElapsed;
        private Action travelArrival;
        private System.Func<Vector2> travelEndProvider;
        private System.Func<bool> travelCanAdvance;
        private bool travelArrivalInvoked;
        private bool hideRendererAtArrival;
        private System.Action completionCallback;
        private bool finished;
        private bool fitsLightningBeam;
        private Vector2 beamStart;
        private Vector2 beamEnd;
        private float beamThickness;
        private bool centersImpactWave;
        private Vector2 impactWaveCenter;
        private float impactWaveScale;
        private bool fitsLightningStormGround;
        private Vector2 lightningStormGroundCenter;
        private float lightningStormGroundRadius;

        public void Play(SpriteRenderer renderer, string sequenceKey, Sprite[] sequenceFrames,
            bool destroyOnFinish, string followingKey = null,
            Sprite[] followingFrames = null, float startDelay = 0f)
        {
            enabled = true;
            completionCallback = null;
            finished = false;
            animationFinished = false;
            durationScale = 1f;
            useUnscaledTime = false;
            target = renderer;
            key = sequenceKey;
            frames = sequenceFrames;
            destroyWhenFinished = destroyOnFinish;
            nextKey = followingKey;
            nextFrames = followingFrames;
            delayRemaining = Mathf.Max(0f, startDelay);
            travelStartProvider = null;
            travelEndProvider = null;
            travelCanAdvance = null;
            travelArrival = null;
            travelDuration = 0f;
            travelElapsed = 0f;
            travelArrivalInvoked = false;
            hideRendererAtArrival = false;
            if (target == null || frames == null || frames.Length == 0)
            {
                FinishSequence();
                return;
            }
            frame = 0;
            target.sprite = frames[frame];
            target.enabled = delayRemaining <= 0f;
            frameRemaining = DefenseTowerArt.FrameSeconds(key, frame) * durationScale;
            UpdateVisualAlignment();
        }

        public void FitLightningBeam(Vector2 start, Vector2 end, float thickness)
        {
            fitsLightningBeam = true;
            beamStart = start;
            beamEnd = end;
            beamThickness = thickness;
            UpdateVisualAlignment();
        }

        public void CenterImpactWave(Vector2 center, float uniformScale)
        {
            centersImpactWave = true;
            impactWaveCenter = center;
            impactWaveScale = uniformScale;
            UpdateVisualAlignment();
        }

        public void FitLightningStormGround(Vector2 center, float radius)
        {
            fitsLightningStormGround = true;
            lightningStormGroundCenter = center;
            lightningStormGroundRadius = Mathf.Max(0f, radius);
            UpdateVisualAlignment();
        }

        public bool IsFinished => finished;

        public void SetPlaybackTiming(float newDurationScale, bool useUnscaledTime)
        {
            if (float.IsNaN(newDurationScale) || float.IsInfinity(newDurationScale) || newDurationScale <= 0f)
                throw new ArgumentOutOfRangeException(nameof(newDurationScale), "Playback duration scale must be positive and finite.");

            float previousScale = durationScale;
            durationScale = newDurationScale;
            this.useUnscaledTime = useUnscaledTime;
            if (!finished && frames != null && frames.Length > 0)
                frameRemaining *= durationScale / previousScale;
        }

        public void SetCompletionCallback(System.Action callback)
        {
            if (callback == null) return;
            if (finished) callback();
            else completionCallback += callback;
        }

        public void SetCanAdvance(System.Func<bool> canAdvance)
        {
            travelCanAdvance = canAdvance;
        }

        public void Travel(Vector2 start, Vector2 end, float duration,
            Action onArrival = null, System.Func<Vector2> endProvider = null,
            System.Func<bool> canAdvance = null, bool hideAtArrival = false,
            System.Func<Vector2> startProvider = null)
        {
            travelStart = start;
            travelStartProvider = startProvider;
            travelEnd = end;
            travelDuration = Mathf.Max(0.001f, duration);
            travelElapsed = 0f;
            travelArrival = onArrival;
            travelEndProvider = endProvider;
            travelCanAdvance = canAdvance ?? travelCanAdvance;
            travelArrivalInvoked = false;
            hideRendererAtArrival = hideAtArrival;
            if (delayRemaining <= 0f) ResolveTravelStart();
            else transform.position = start;
        }

        private void ResolveTravelStart()
        {
            if (travelStartProvider != null)
            {
                travelStart = travelStartProvider();
                travelStartProvider = null;
            }
            transform.position = travelStart;
        }

        private void Update()
        {
            if (target == null || frames == null || frames.Length == 0)
            {
                FinishSequence();
                return;
            }
            if (travelCanAdvance != null && !travelCanAdvance()) return;
            float deltaTime = useUnscaledTime ? Time.unscaledDeltaTime : Time.deltaTime;
            if (delayRemaining > 0f)
            {
                delayRemaining -= deltaTime;
                if (delayRemaining > 0f) return;
                if (travelDuration > 0f || travelStartProvider != null)
                    ResolveTravelStart();
                target.enabled = true;
            }
            if (travelDuration > 0f && travelElapsed < travelDuration)
            {
                travelElapsed += deltaTime;
                Vector2 currentEnd = travelEndProvider != null
                    ? travelEndProvider() : travelEnd;
                transform.position = Vector2.Lerp(
                    travelStart, currentEnd, Mathf.Clamp01(travelElapsed / travelDuration));
                if (travelElapsed >= travelDuration && !travelArrivalInvoked)
                {
                    travelArrivalInvoked = true;
                    if (hideRendererAtArrival && target != null) target.enabled = false;
                    travelArrival?.Invoke();
                }
            }
            if (animationFinished)
            {
                if (travelDuration <= 0f || travelElapsed >= travelDuration) FinishSequence();
                return;
            }

            frameRemaining -= deltaTime;
            while (frameRemaining <= 0f)
            {
                frame++;
                if (frame >= frames.Length)
                {
                    if (nextFrames != null && nextFrames.Length > 0)
                    {
                        frames = nextFrames;
                        key = nextKey;
                        nextFrames = null;
                        frame = 0;
                    }
                    else
                    {
                        animationFinished = true;
                        if (travelDuration <= 0f || travelElapsed >= travelDuration) FinishSequence();
                        return;
                    }
                }
                target.sprite = frames[frame];
                UpdateVisualAlignment();
                frameRemaining += DefenseTowerArt.FrameSeconds(key, frame) * durationScale;
            }
        }

        private void UpdateVisualAlignment()
        {
            if (target == null || target.sprite == null) return;
            if (fitsLightningBeam)
            {
                Vector2 direction = beamEnd - beamStart;
                float distance = direction.magnitude;
                Vector2Int bounds = DefenseTowerArtBounds.LightningBeamXBounds(frame);
                float pixelsPerUnit = target.sprite.pixelsPerUnit;
                float visibleWidth = (bounds.y - bounds.x) / pixelsPerUnit;
                float scaleX = distance <= 0f || visibleWidth <= 0f
                    ? 0f : distance / visibleWidth;
                float localStart = (bounds.x - target.sprite.pivot.x) / pixelsPerUnit * scaleX;
                transform.rotation = Quaternion.Euler(0f, 0f,
                    distance > 0f ? Mathf.Atan2(direction.y, direction.x) * Mathf.Rad2Deg : 0f);
                transform.position = beamStart - (Vector2)(transform.right * localStart);
                transform.localScale = new Vector3(scaleX, beamThickness, 1f);
            }
            if (fitsLightningStormGround)
            {
                float scale = lightningStormGroundRadius * target.sprite.pixelsPerUnit
                    / DefenseTowerArtBounds.LightningStormGroundRadiusPixels;
                transform.localScale = Vector3.one * scale;
                Vector2 localCenter = (DefenseTowerArtBounds.LightningStormGroundCenterPixels
                    - target.sprite.pivot) / target.sprite.pixelsPerUnit;
                transform.position = lightningStormGroundCenter
                    - (Vector2)transform.TransformVector(localCenter);
            }
            if (centersImpactWave)
            {
                transform.localScale = Vector3.one * impactWaveScale;
                Vector2 localCenter = (DefenseTowerArtBounds.ImpactWaveCenterPixels(frame, target.sprite)
                    - target.sprite.pivot) / target.sprite.pixelsPerUnit;
                transform.position = impactWaveCenter - (Vector2)transform.TransformVector(localCenter);
            }
        }

        private void FinishSequence()
        {
            if (finished) return;
            finished = true;
            if (destroyWhenFinished)
            {
                Destroy(gameObject);
            }
            else
            {
                if (target != null) target.enabled = false;
                enabled = false;
            }

            System.Action callback = completionCallback;
            completionCallback = null;
            callback?.Invoke();
        }
    }
}