#if UNITY_EDITOR
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Text;
using UnityEditor;
#if UNITY_2021_2_OR_NEWER
using PrefabStageUtility = UnityEditor.SceneManagement.PrefabStageUtility;
#else
using PrefabStageUtility = UnityEditor.Experimental.SceneManagement.PrefabStageUtility;
#endif
using UnityEngine;
using UnityEngine.Playables;
using UnityEngine.Timeline;

public static class AutoBindTimelineByFieldNameMenu
{
    private const string MenuPath = "GameObject/Timeline/按字段名自动挂载 Timeline";
    private static readonly string[] PreferredFolderKeywords = { "timeline", "playable" };

    [MenuItem(MenuPath, false, 49)]
    private static void AutoBindTimelinesByFieldName()
    {
        if (!TryGetTargetBehaviours(Selection.activeGameObject, out var behaviours, out var error))
        {
            Debug.LogError(error);
            return;
        }

        if (!TryGetSearchFolders(Selection.activeGameObject, out var searchFolders, out error))
        {
            Debug.LogError(error, Selection.activeGameObject);
            return;
        }

        var changedCount = 0;
        var unchangedCount = 0;
        var missingCount = 0;
        var duplicateCount = 0;
        var details = new StringBuilder();

        foreach (var behaviour in behaviours)
        {
            var serializedObject = new SerializedObject(behaviour);
            var componentChanged = false;

            Undo.RecordObject(behaviour, "Auto Bind Timelines By Field Name");

            foreach (var field in GetPlayableAssetFields(behaviour.GetType()))
            {
                var property = serializedObject.FindProperty(field.Name);
                if (property == null || property.propertyType != SerializedPropertyType.ObjectReference)
                {
                    continue;
                }

                var searchResult = FindTimeline(field.Name, searchFolders);
                if (searchResult.Status == TimelineSearchStatus.Missing)
                {
                    missingCount++;
                    details.AppendLine($"未找到: {GetComponentLabel(behaviour)}.{field.Name}");
                    continue;
                }

                if (searchResult.Status == TimelineSearchStatus.Duplicate)
                {
                    duplicateCount++;
                    details.AppendLine($"重名冲突: {GetComponentLabel(behaviour)}.{field.Name}");
                    foreach (var path in searchResult.Paths)
                    {
                        details.AppendLine($"  - {path}");
                    }
                    continue;
                }

                if (property.objectReferenceValue == searchResult.Asset)
                {
                    unchangedCount++;
                    continue;
                }

                property.objectReferenceValue = searchResult.Asset;
                changedCount++;
                componentChanged = true;
                details.AppendLine($"已挂载: {GetComponentLabel(behaviour)}.{field.Name} -> {searchResult.Paths[0]}");
            }

            serializedObject.ApplyModifiedProperties();

            if (componentChanged)
            {
                EditorUtility.SetDirty(behaviour);
            }
        }

        var summary = new StringBuilder();
        summary.AppendLine($"Timeline 挂载完成: 修改 {changedCount}，未变更 {unchangedCount}，未找到 {missingCount}，重名冲突 {duplicateCount}。");
        summary.AppendLine($"搜索目录: {string.Join(" | ", searchFolders)}");

        if (details.Length > 0)
        {
            summary.AppendLine(details.ToString().TrimEnd());
        }

        if (missingCount > 0 || duplicateCount > 0)
        {
            Debug.LogError(summary.ToString(), Selection.activeGameObject);
            return;
        }

        Debug.Log(summary.ToString(), Selection.activeGameObject);
    }

    [MenuItem(MenuPath, true)]
    private static bool ValidateAutoBindTimelinesByFieldName()
    {
        return TryGetTargetBehaviours(Selection.activeGameObject, out _, out _);
    }

    private static bool TryGetTargetBehaviours(GameObject selectedObject, out List<MonoBehaviour> behaviours, out string error)
    {
        behaviours = new List<MonoBehaviour>();
        error = null;

        if (selectedObject == null)
        {
            error = "未选中任何 GameObject。";
            return false;
        }

        behaviours = selectedObject
            .GetComponentsInChildren<MonoBehaviour>(true)
            .Where(behaviour => behaviour != null && GetPlayableAssetFields(behaviour.GetType()).Any())
            .ToList();

        if (behaviours.Count > 0)
        {
            return true;
        }

        error = $"选中对象 `{selectedObject.name}` 层级下未找到包含序列化 PlayableAsset 字段的组件。";
        return false;
    }

    private static bool TryGetSearchFolders(GameObject selectedObject, out List<string> searchFolders, out string error)
    {
        searchFolders = new List<string>();
        error = null;

        var prefabPath = PrefabUtility.GetPrefabAssetPathOfNearestInstanceRoot(selectedObject);
        if (string.IsNullOrEmpty(prefabPath))
        {
            var prefabStage = PrefabStageUtility.GetCurrentPrefabStage();
            if (prefabStage != null)
            {
                prefabPath = prefabStage.assetPath;
            }
        }

        if (string.IsNullOrEmpty(prefabPath))
        {
            error = "当前选择对象不在 Prefab 实例或 Prefab 编辑模式中，无法确定搜索目录。";
            return false;
        }

        var prefabFolder = NormalizePath(Path.GetDirectoryName(prefabPath));
        if (string.IsNullOrEmpty(prefabFolder))
        {
            error = $"Prefab 路径 `{prefabPath}` 无法转换为有效目录。";
            return false;
        }

        var fallbackFolders = new List<string>();
        var currentFolder = prefabFolder;
        while (!string.IsNullOrEmpty(currentFolder) && currentFolder.StartsWith("Assets", StringComparison.Ordinal))
        {
            fallbackFolders.Add(currentFolder);

            var preferredFolders = AssetDatabase
                .GetSubFolders(currentFolder)
                .Where(IsPreferredSearchFolder)
                .Select(NormalizePath)
                .OrderBy(path => path.Count(ch => ch == '/'))
                .ThenBy(path => path, StringComparer.Ordinal)
                .ToList();

            foreach (var folder in preferredFolders)
            {
                AddUnique(searchFolders, folder);
            }

            AddUnique(searchFolders, currentFolder);

            if (string.Equals(currentFolder, "Assets", StringComparison.Ordinal))
            {
                break;
            }

            currentFolder = NormalizePath(Path.GetDirectoryName(currentFolder));
        }

        if (searchFolders.Count == 0)
        {
            foreach (var folder in fallbackFolders)
            {
                AddUnique(searchFolders, folder);
            }
        }

        if (searchFolders.Count == 0)
        {
            error = $"Prefab 路径 `{prefabPath}` 无法生成有效搜索目录。";
            return false;
        }

        return true;
    }

    private static IEnumerable<FieldInfo> GetPlayableAssetFields(Type type)
    {
        return type
            .GetFields(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic)
            .Where(field =>
                typeof(PlayableAsset).IsAssignableFrom(field.FieldType) &&
                IsSerializedField(field));
    }

    private static bool IsSerializedField(FieldInfo field)
    {
        if (field.IsDefined(typeof(NonSerializedAttribute), true))
        {
            return false;
        }

        return field.IsPublic || field.IsDefined(typeof(SerializeField), true);
    }

    private static TimelineSearchResult FindTimeline(string fieldName, IReadOnlyList<string> searchFolders)
    {
        foreach (var folder in searchFolders)
        {
            var paths = AssetDatabase
                .FindAssets($"{fieldName} t:{nameof(TimelineAsset)}", new[] { folder })
                .Select(AssetDatabase.GUIDToAssetPath)
                .Where(path => string.Equals(Path.GetFileNameWithoutExtension(path), fieldName, StringComparison.Ordinal))
                .Distinct()
                .ToList();

            if (paths.Count == 0)
            {
                continue;
            }

            if (paths.Count > 1)
            {
                return TimelineSearchResult.CreateDuplicate(paths);
            }

            var asset = AssetDatabase.LoadAssetAtPath<TimelineAsset>(paths[0]);
            if (asset == null)
            {
                return TimelineSearchResult.CreateMissing();
            }

            return TimelineSearchResult.CreateFound(asset, paths[0]);
        }

        return TimelineSearchResult.CreateMissing();
    }

    private static bool IsPreferredSearchFolder(string folderPath)
    {
        var folderName = Path.GetFileName(folderPath);
        if (string.IsNullOrEmpty(folderName))
        {
            return false;
        }

        return PreferredFolderKeywords.Any(keyword =>
            folderName.IndexOf(keyword, StringComparison.OrdinalIgnoreCase) >= 0);
    }

    private static void AddUnique(List<string> folders, string folder)
    {
        if (!string.IsNullOrEmpty(folder) && !folders.Contains(folder))
        {
            folders.Add(folder);
        }
    }

    private static string NormalizePath(string path)
    {
        return string.IsNullOrEmpty(path) ? string.Empty : path.Replace('\\', '/');
    }

    private static string GetComponentLabel(MonoBehaviour behaviour)
    {
        return $"{behaviour.gameObject.name}/{behaviour.GetType().Name}";
    }

    private enum TimelineSearchStatus
    {
        Missing,
        Found,
        Duplicate,
    }

    private readonly struct TimelineSearchResult
    {
        public readonly TimelineSearchStatus Status;
        public readonly TimelineAsset Asset;
        public readonly IReadOnlyList<string> Paths;

        private TimelineSearchResult(TimelineSearchStatus status, TimelineAsset asset, IReadOnlyList<string> paths)
        {
            Status = status;
            Asset = asset;
            Paths = paths;
        }

        public static TimelineSearchResult CreateMissing()
        {
            return new TimelineSearchResult(TimelineSearchStatus.Missing, null, Array.Empty<string>());
        }

        public static TimelineSearchResult CreateFound(TimelineAsset asset, string path)
        {
            return new TimelineSearchResult(TimelineSearchStatus.Found, asset, new[] { path });
        }

        public static TimelineSearchResult CreateDuplicate(IReadOnlyList<string> paths)
        {
            return new TimelineSearchResult(TimelineSearchStatus.Duplicate, null, paths);
        }
    }
}
#endif