using System.Collections.Generic;

using UnityEngine;

using UnityEditor;

/// <summary>
/// 선택한 .anim 클립의 마지막 프레임에 모든 커브 키를 보강합니다.
/// 애니메이션을 잘라서 연결할 때 마지막 포즈가 정확히 유지되도록 돕는 도구입니다.
/// </summary>
public static class AnimationClipEndKeyBaker
{
    private const string MenuPath = "Tools/Animation/Bake End Frame Keys";

    [MenuItem(MenuPath, false, 23)]
    public static void BakeSelectedClipEndKeys()
    {
        AnimationClip[] clips = Selection.GetFiltered<AnimationClip>(SelectionMode.Assets);
        if (clips == null || clips.Length == 0)
        {
            EditorUtility.DisplayDialog(
                "Bake End Frame Keys",
                "마지막 프레임 키를 보강할 AnimationClip을 1개 이상 선택해 주세요.",
                "확인");
            return;
        }

        int processedClipCount = 0;
        int addedFloatKeyCount = 0;
        int addedObjectKeyCount = 0;
        List<string> skippedClips = new List<string>();

        for (int i = 0; i < clips.Length; i++)
        {
            AnimationClip clip = clips[i];
            string clipPath = AssetDatabase.GetAssetPath(clip);
            if (clip == null || string.IsNullOrEmpty(clipPath) || !clipPath.EndsWith(".anim"))
            {
                skippedClips.Add(clip != null ? clip.name : "(null)");
                continue;
            }

            processedClipCount++;
            float lastFrameTime = clip.length;

            EditorCurveBinding[] floatBindings = AnimationUtility.GetCurveBindings(clip);
            for (int bindingIndex = 0; bindingIndex < floatBindings.Length; bindingIndex++)
            {
                EditorCurveBinding binding = floatBindings[bindingIndex];
                AnimationCurve curve = AnimationUtility.GetEditorCurve(clip, binding);
                if (curve == null)
                    continue;

                if (HasFloatKeyAtTime(curve, lastFrameTime))
                    continue;

                float value = curve.Evaluate(lastFrameTime);
                int keyIndex = curve.AddKey(new Keyframe(lastFrameTime, value));
                if (keyIndex >= 0)
                {
                    AnimationUtility.SetKeyLeftTangentMode(curve, keyIndex, AnimationUtility.TangentMode.ClampedAuto);
                    AnimationUtility.SetKeyRightTangentMode(curve, keyIndex, AnimationUtility.TangentMode.ClampedAuto);
                }

                AnimationUtility.SetEditorCurve(clip, binding, curve);
                addedFloatKeyCount++;
            }

            EditorCurveBinding[] objectBindings = AnimationUtility.GetObjectReferenceCurveBindings(clip);
            for (int bindingIndex = 0; bindingIndex < objectBindings.Length; bindingIndex++)
            {
                EditorCurveBinding binding = objectBindings[bindingIndex];
                ObjectReferenceKeyframe[] keys = AnimationUtility.GetObjectReferenceCurve(clip, binding);
                if (keys == null || keys.Length == 0)
                    continue;

                if (HasObjectKeyAtTime(keys, lastFrameTime))
                    continue;

                Object sampledValue = SampleObjectReferenceValue(keys, lastFrameTime);
                List<ObjectReferenceKeyframe> bakedKeys = new List<ObjectReferenceKeyframe>(keys)
                {
                    new ObjectReferenceKeyframe
                    {
                        time = lastFrameTime,
                        value = sampledValue
                    }
                };

                bakedKeys.Sort((a, b) => a.time.CompareTo(b.time));
                AnimationUtility.SetObjectReferenceCurve(clip, binding, bakedKeys.ToArray());
                addedObjectKeyCount++;
            }

            EditorUtility.SetDirty(clip);
            AssetDatabase.ImportAsset(clipPath, ImportAssetOptions.ForceUpdate);
        }

        AssetDatabase.SaveAssets();
        AssetDatabase.Refresh();

        string message =
            $"처리한 클립: {processedClipCount}개\n" +
            $"추가한 Float 키: {addedFloatKeyCount}개\n" +
            $"추가한 Object 키: {addedObjectKeyCount}개";

        if (skippedClips.Count > 0)
            message += $"\n\n건너뛴 클립: {string.Join(", ", skippedClips)}";

        Debug.Log($"[AnimationClipEndKeyBaker] {message.Replace('\n', ' ')}");
        EditorUtility.DisplayDialog("Bake End Frame Keys", message, "확인");
    }

    [MenuItem(MenuPath, true)]
    public static bool ValidateBakeSelectedClipEndKeys()
    {
        return Selection.GetFiltered<AnimationClip>(SelectionMode.Assets).Length > 0;
    }

    private static bool HasFloatKeyAtTime(AnimationCurve curve, float time)
    {
        if (curve == null)
            return false;

        Keyframe[] keys = curve.keys;
        for (int i = 0; i < keys.Length; i++)
        {
            if (Mathf.Abs(keys[i].time - time) <= 0.0001f)
                return true;
        }

        return false;
    }

    private static bool HasObjectKeyAtTime(ObjectReferenceKeyframe[] keys, float time)
    {
        if (keys == null)
            return false;

        for (int i = 0; i < keys.Length; i++)
        {
            if (Mathf.Abs(keys[i].time - time) <= 0.0001f)
                return true;
        }

        return false;
    }

    private static Object SampleObjectReferenceValue(ObjectReferenceKeyframe[] keys, float time)
    {
        if (keys == null || keys.Length == 0)
            return null;

        Object value = keys[0].value;
        for (int i = 0; i < keys.Length; i++)
        {
            if (keys[i].time > time)
                break;

            value = keys[i].value;
        }

        return value;
    }
}