using System.Collections.Generic;
using System.IO;
using System.Linq;
using UnityEditor;
using UnityEngine;

namespace Streamingle.AnimationCleanup.Editor
{
    /// <summary>
    /// Removes contaminated keys at the boundaries of shared blend-shape recording gaps.
    /// No keys are generated and the original clip is never modified.
    /// </summary>
    public sealed class BlendShapeSpikeCleanupWindow : EditorWindow
    {
        private const float TimeEpsilon = 0.00001f;

        private AnimationClip sourceClip;
        private int minimumGapFrames = 6;
        private int keysBeforeGap = 2;
        private int keysAfterGap = 2;
        private int maximumBoundaryDistanceFrames = 3;
        private bool linearizeGapBridge = true;
        private string summary = "애니메이션 클립을 선택하세요.";

        [MenuItem("Tools/Streamingle Utilities/Animation/Blend Shape Gap Cleanup")]
        private static void Open()
        {
            GetWindow<BlendShapeSpikeCleanupWindow>("공백 경계 튐 정리");
        }

        private void OnEnable()
        {
            minSize = new Vector2(500f, 330f);
        }

        private void OnGUI()
        {
            EditorGUILayout.LabelField("블렌드셰이프 공백 경계 튐 정리", EditorStyles.boldLabel);
            EditorGUILayout.HelpBox(
                "모든 블렌드셰이프 키가 함께 비는 녹화 누락 구간을 찾습니다. " +
                "그 구간의 바로 앞·뒤에 남은 오염 키만 제거합니다. 새 키를 만들거나 스무스를 주지 않으며, 원본 대신 복제본을 만듭니다.",
                MessageType.Info);

            EditorGUI.BeginChangeCheck();
            sourceClip = (AnimationClip)EditorGUILayout.ObjectField("대상 애니메이션 클립", sourceClip, typeof(AnimationClip), false);
            if (EditorGUI.EndChangeCheck())
            {
                summary = sourceClip == null ? "애니메이션 클립을 선택하세요." : "분석 버튼을 눌러 공백 경계 키 수를 확인하세요.";
            }

            using (new EditorGUI.DisabledScope(sourceClip == null))
            {
                float frameRate = sourceClip == null ? 30f : Mathf.Max(1f, sourceClip.frameRate);
                EditorGUILayout.LabelField(string.Format("클립 프레임레이트: {0:F2}", frameRate), EditorStyles.miniLabel);
                minimumGapFrames = Mathf.Max(1, EditorGUILayout.IntField(new GUIContent("최소 공백 길이 (프레임)", "이 프레임 이상 모든 블렌드셰이프 키가 비는 구간만 처리합니다."), minimumGapFrames));
                keysBeforeGap = Mathf.Clamp(EditorGUILayout.IntField(new GUIContent("공백 직전 제거 키 수", "공백 시작 지점에서 과거 방향으로 제거할 키 수입니다."), keysBeforeGap), 0, 8);
                keysAfterGap = Mathf.Clamp(EditorGUILayout.IntField(new GUIContent("공백 직후 제거 키 수", "공백 종료 지점에서 미래 방향으로 제거할 키 수입니다."), keysAfterGap), 0, 8);
                int requiredDistance = Mathf.Max(keysBeforeGap, keysAfterGap);
                maximumBoundaryDistanceFrames = Mathf.Max(requiredDistance, EditorGUILayout.IntField(new GUIContent("최대 경계 거리 (프레임)", "키가 공백 경계에서 이 거리보다 멀면 안전하게 건너뜁니다."), maximumBoundaryDistanceFrames));
                linearizeGapBridge = EditorGUILayout.Toggle(new GUIContent("공백 구간 부드럽게 연결", "경계 키 제거 후 남은 양끝의 탄젠트를 같은 기울기로 맞춰, 공백 구간을 오버슈트 없이 직선으로 연결합니다."), linearizeGapBridge);

                EditorGUILayout.BeginHorizontal();
                if (GUILayout.Button("적용 대상 분석"))
                {
                    Analyze();
                }

                if (GUILayout.Button("복제본 만들기", GUILayout.Height(22f)))
                {
                    CreateCopy();
                }
                EditorGUILayout.EndHorizontal();
            }

            EditorGUILayout.Space(8f);
            EditorGUILayout.LabelField("작업 상태", EditorStyles.miniBoldLabel);
            EditorGUILayout.LabelField(summary, EditorStyles.wordWrappedMiniLabel);
        }

        private void Analyze()
        {
            float frameRate = Mathf.Max(1f, sourceClip.frameRate);
            List<GapRange> gaps = FindSharedBlendShapeGaps(sourceClip, minimumGapFrames / frameRate);
            RemovalPlan plan = BuildPlan(sourceClip, gaps, frameRate);
            summary = string.Format(
                "공백 {0}개를 찾았습니다. {1}개 커브에서 경계 키 {2}개를 제거할 수 있습니다.",
                gaps.Count,
                plan.curveCount,
                plan.keyCount);
        }

        private void CreateCopy()
        {
            string sourcePath = AssetDatabase.GetAssetPath(sourceClip);
            if (string.IsNullOrEmpty(sourcePath))
            {
                EditorUtility.DisplayDialog("복제본 생성 불가", "프로젝트에 저장된 AnimationClip을 선택해야 합니다.", "확인");
                return;
            }

            float frameRate = Mathf.Max(1f, sourceClip.frameRate);
            List<GapRange> gaps = FindSharedBlendShapeGaps(sourceClip, minimumGapFrames / frameRate);
            RemovalPlan plan = BuildPlan(sourceClip, gaps, frameRate);
            if (plan.keyCount == 0)
            {
                summary = string.Format("공백 {0}개를 찾았지만 제거할 경계 키가 없습니다.", gaps.Count);
                return;
            }

            string directory = Path.GetDirectoryName(sourcePath)?.Replace('\\', '/') ?? "Assets";
            string destinationPath = AssetDatabase.GenerateUniqueAssetPath(directory + "/" + sourceClip.name + "_GapEdgeCleaned.anim");
            if (!AssetDatabase.CopyAsset(sourcePath, destinationPath))
            {
                EditorUtility.DisplayDialog("복제 실패", "선택한 AnimationClip의 복제본을 만들지 못했습니다.", "확인");
                return;
            }

            AnimationClip cleanedClip = AssetDatabase.LoadAssetAtPath<AnimationClip>(destinationPath);
            int removedKeyCount = ApplyPlan(cleanedClip, plan, gaps, linearizeGapBridge);
            EditorUtility.SetDirty(cleanedClip);
            AssetDatabase.SaveAssets();
            AssetDatabase.Refresh();
            Selection.activeObject = cleanedClip;
            EditorGUIUtility.PingObject(cleanedClip);
            summary = string.Format(
                "{0} 생성 완료: 공백 {1}개에서 {2}개 커브의 경계 키 {3}개를 제거{4}.",
                Path.GetFileName(destinationPath),
                gaps.Count,
                plan.curveCount,
                removedKeyCount,
                linearizeGapBridge ? "하고 부드럽게 연결했습니다" : "했습니다");
        }

        private RemovalPlan BuildPlan(AnimationClip clip, List<GapRange> gaps, float frameRate)
        {
            Dictionary<EditorCurveBinding, List<int>> indicesByBinding = new Dictionary<EditorCurveBinding, List<int>>();
            float maximumDistance = maximumBoundaryDistanceFrames / Mathf.Max(1f, frameRate);
            foreach (EditorCurveBinding binding in AnimationUtility.GetCurveBindings(clip))
            {
                if (!IsBlendShape(binding))
                {
                    continue;
                }

                AnimationCurve curve = AnimationUtility.GetEditorCurve(clip, binding);
                if (curve == null || curve.length < 3)
                {
                    continue;
                }

                Keyframe[] keys = curve.keys;
                HashSet<int> indices = new HashSet<int>();
                foreach (GapRange gap in gaps)
                {
                    AddBeforeGapKeys(keys, indices, gap.startTime, maximumDistance);
                    AddAfterGapKeys(keys, indices, gap.endTime, maximumDistance);
                }

                if (indices.Count > 0)
                {
                    indicesByBinding.Add(binding, indices.OrderByDescending(index => index).ToList());
                }
            }

            return new RemovalPlan(indicesByBinding);
        }

        private void AddBeforeGapKeys(Keyframe[] keys, HashSet<int> indices, float startTime, float maximumDistance)
        {
            int index = FindLastKeyAtOrBefore(keys, startTime);
            if (index < 0 || startTime - keys[index].time > maximumDistance)
            {
                return;
            }

            for (int count = 0; count < keysBeforeGap; count++, index--)
            {
                if (index <= 0 || startTime - keys[index].time > maximumDistance || keys.Length - indices.Count <= 2)
                {
                    break;
                }

                indices.Add(index);
            }
        }

        private void AddAfterGapKeys(Keyframe[] keys, HashSet<int> indices, float endTime, float maximumDistance)
        {
            int index = FindFirstKeyAtOrAfter(keys, endTime);
            if (index < 0 || keys[index].time - endTime > maximumDistance)
            {
                return;
            }

            for (int count = 0; count < keysAfterGap; count++, index++)
            {
                if (index >= keys.Length - 1 || keys[index].time - endTime > maximumDistance || keys.Length - indices.Count <= 2)
                {
                    break;
                }

                indices.Add(index);
            }
        }

        private static int ApplyPlan(AnimationClip clip, RemovalPlan plan, List<GapRange> gaps, bool linearizeGaps)
        {
            int removedKeyCount = 0;
            foreach (KeyValuePair<EditorCurveBinding, List<int>> entry in plan.indicesByBinding)
            {
                AnimationCurve curve = AnimationUtility.GetEditorCurve(clip, entry.Key);
                if (curve == null)
                {
                    continue;
                }

                foreach (int index in entry.Value)
                {
                    if (index > 0 && index < curve.length - 1)
                    {
                        curve.RemoveKey(index);
                        removedKeyCount++;
                    }
                }

                if (linearizeGaps)
                {
                    foreach (GapRange gap in gaps)
                    {
                        LinearizeGapBridge(curve, gap);
                    }
                }

                AnimationUtility.SetEditorCurve(clip, entry.Key, curve);
            }

            return removedKeyCount;
        }

        private static void LinearizeGapBridge(AnimationCurve curve, GapRange gap)
        {
            Keyframe[] keys = curve.keys;
            int startIndex = FindLastKeyAtOrBefore(keys, gap.startTime);
            int endIndex = FindFirstKeyAtOrAfter(keys, gap.endTime);
            if (startIndex < 0 || endIndex < 0 || startIndex >= endIndex)
            {
                return;
            }

            float duration = keys[endIndex].time - keys[startIndex].time;
            if (duration <= TimeEpsilon)
            {
                return;
            }

            float slope = (keys[endIndex].value - keys[startIndex].value) / duration;
            AnimationUtility.SetKeyBroken(curve, startIndex, true);
            AnimationUtility.SetKeyBroken(curve, endIndex, true);
            AnimationUtility.SetKeyRightTangentMode(curve, startIndex, AnimationUtility.TangentMode.Free);
            AnimationUtility.SetKeyLeftTangentMode(curve, endIndex, AnimationUtility.TangentMode.Free);

            keys = curve.keys;
            Keyframe startKey = keys[startIndex];
            Keyframe endKey = keys[endIndex];
            startKey.outTangent = slope;
            endKey.inTangent = slope;
            keys[startIndex] = startKey;
            keys[endIndex] = endKey;
            curve.keys = keys;
        }

        private static List<GapRange> FindSharedBlendShapeGaps(AnimationClip clip, float minimumGapDuration)
        {
            List<float> keyTimes = new List<float>();
            foreach (EditorCurveBinding binding in AnimationUtility.GetCurveBindings(clip))
            {
                if (!IsBlendShape(binding))
                {
                    continue;
                }

                AnimationCurve curve = AnimationUtility.GetEditorCurve(clip, binding);
                if (curve != null)
                {
                    keyTimes.AddRange(curve.keys.Select(key => key.time));
                }
            }

            keyTimes.Sort();
            List<GapRange> gaps = new List<GapRange>();
            for (int index = 1; index < keyTimes.Count; index++)
            {
                float previous = keyTimes[index - 1];
                float current = keyTimes[index];
                if (current - previous >= minimumGapDuration)
                {
                    gaps.Add(new GapRange(previous, current));
                }
            }

            return gaps;
        }

        private static int FindLastKeyAtOrBefore(Keyframe[] keys, float time)
        {
            for (int index = keys.Length - 1; index >= 0; index--)
            {
                if (keys[index].time <= time + TimeEpsilon)
                {
                    return index;
                }
            }

            return -1;
        }

        private static int FindFirstKeyAtOrAfter(Keyframe[] keys, float time)
        {
            for (int index = 0; index < keys.Length; index++)
            {
                if (keys[index].time >= time - TimeEpsilon)
                {
                    return index;
                }
            }

            return -1;
        }

        private static bool IsBlendShape(EditorCurveBinding binding)
        {
            return binding.propertyName.IndexOf("blendShape.", System.StringComparison.OrdinalIgnoreCase) >= 0;
        }

        private readonly struct GapRange
        {
            public readonly float startTime;
            public readonly float endTime;

            public GapRange(float startTime, float endTime)
            {
                this.startTime = startTime;
                this.endTime = endTime;
            }
        }

        private sealed class RemovalPlan
        {
            public readonly Dictionary<EditorCurveBinding, List<int>> indicesByBinding;
            public readonly int curveCount;
            public readonly int keyCount;

            public RemovalPlan(Dictionary<EditorCurveBinding, List<int>> indicesByBinding)
            {
                this.indicesByBinding = indicesByBinding;
                curveCount = indicesByBinding.Count;
                keyCount = indicesByBinding.Sum(pair => pair.Value.Count);
            }
        }
    }
}