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

namespace BaseGames.Editor.Modules
{
    /// <summary>
    /// DataHub 事件频道反查模块 —— 列出项目中所有 EventChannelSO 子类资产；
    /// 选中后可扫描全项目中引用该频道的 Prefab / ScriptableObject，
    /// 解决"谁发布/谁订阅了某条事件"在大型项目中难以追踪的问题。
    ///
    /// 反查实现：遍历所有 Prefab 与 SO 资产，用 AssetDatabase.GetDependencies
    /// 检查依赖链是否包含目标频道资产路径。首次扫描会耗时较长（取决于资产规模），
    /// 之后按选中频道增量计算。
    /// </summary>
    public class EventChannelModule : IDataModule, IDataModuleOrdered
    {
        public string ModuleId    => "eventchannel";
        public string DisplayName => "事件频道";
        public string IconName    => "d_AudioMixerController Icon";
        public int    DisplayOrder => 200;

        private ListView _channelList;
        private readonly List<EventChannelEntry> _allChannels = new();
        private ScriptableObject _selected;
        private VisualElement _refsContainer;

        private struct EventChannelEntry
        {
            public string TypeName;
            public string AssetPath;
            public ScriptableObject Asset;
        }

        public void Initialize() => Refresh();

        public void OnActivated() => Refresh();

        private void Refresh()
        {
            _allChannels.Clear();
            // 扫描所有 ScriptableObject 子类，筛选名称以 "EventChannelSO" 结尾的（项目约定）。
            var types = TypeCache.GetTypesDerivedFrom<ScriptableObject>();
            foreach (var t in types)
            {
                if (t.IsAbstract) continue;
                if (!t.Name.EndsWith("EventChannelSO", StringComparison.Ordinal)) continue;
                var guids = AssetDatabase.FindAssets($"t:{t.Name}");
                foreach (var g in guids)
                {
                    var path  = AssetDatabase.GUIDToAssetPath(g);
                    var asset = AssetDatabase.LoadAssetAtPath<ScriptableObject>(path);
                    if (asset == null) continue;
                    _allChannels.Add(new EventChannelEntry
                    {
                        TypeName  = t.Name,
                        AssetPath = path,
                        Asset     = asset
                    });
                }
            }
            _allChannels.Sort((a, b) =>
            {
                int c = string.Compare(a.TypeName, b.TypeName, StringComparison.Ordinal);
                return c != 0 ? c : string.Compare(a.AssetPath, b.AssetPath, StringComparison.Ordinal);
            });
            _channelList?.Rebuild();
        }

        public void BuildListPane(VisualElement container, Action<UnityEngine.Object> onSelected)
        {
            var header = new Label($"频道总数：{_allChannels.Count}");
            header.style.unityFontStyleAndWeight = FontStyle.Bold;
            header.style.paddingLeft = 6;
            header.style.paddingTop  = 4;
            container.Add(header);

            _channelList = new ListView(_allChannels, 20,
                () => new Label { style = { paddingLeft = 6 } },
                (ve, i) =>
                {
                    var entry = _allChannels[i];
                    var label = (Label)ve;
                    label.text = $"[{entry.TypeName}] {System.IO.Path.GetFileNameWithoutExtension(entry.AssetPath)}";
                    label.tooltip = entry.AssetPath;
                });
            _channelList.style.flexGrow = 1;
            _channelList.selectionChanged += sel =>
            {
                var first = sel.FirstOrDefault();
                if (first is EventChannelEntry e)
                {
                    _selected = e.Asset;
                    onSelected?.Invoke(e.Asset);
                }
            };
            container.Add(_channelList);
        }

        public void BuildDetailPane(VisualElement container, UnityEngine.Object selected)
        {
            _selected = selected as ScriptableObject;
            container.Clear();

            if (_selected == null)
            {
                var hint = new Label("请在左侧选择一条频道资产。");
                hint.style.paddingLeft = 8; hint.style.paddingTop = 8;
                container.Add(hint);
                return;
            }

            // Header
            var title = new Label($"{_selected.GetType().Name}  ·  {_selected.name}");
            title.style.unityFontStyleAndWeight = FontStyle.Bold;
            title.style.fontSize = 14;
            title.style.paddingLeft = 8; title.style.paddingTop = 6;
            container.Add(title);

            var pathLabel = new Label(AssetDatabase.GetAssetPath(_selected))
            {
                style = { paddingLeft = 8, paddingBottom = 6, color = new StyleColor(new Color(0.7f, 0.7f, 0.7f)) }
            };
            container.Add(pathLabel);

            var scanBtn = new Button(() => ScanReferences(_selected))
            { text = "扫描全项目引用（Prefab / ScriptableObject）" };
            scanBtn.style.marginLeft = 8; scanBtn.style.marginRight = 8;
            container.Add(scanBtn);

            _refsContainer = new VisualElement();
            _refsContainer.style.paddingLeft = 8; _refsContainer.style.paddingTop = 6;
            container.Add(_refsContainer);
        }

        private void ScanReferences(ScriptableObject channel)
        {
            if (channel == null || _refsContainer == null) return;
            _refsContainer.Clear();

            var targetPath = AssetDatabase.GetAssetPath(channel);
            if (string.IsNullOrEmpty(targetPath)) return;

            var found = new List<string>();
            try
            {
                EditorUtility.DisplayProgressBar("扫描引用", "正在扫描 Prefab 与 SO …", 0f);

                var prefabGuids = AssetDatabase.FindAssets("t:Prefab");
                var soGuids     = AssetDatabase.FindAssets("t:ScriptableObject");
                var all         = prefabGuids.Concat(soGuids).ToArray();

                for (int i = 0; i < all.Length; i++)
                {
                    var p = AssetDatabase.GUIDToAssetPath(all[i]);
                    if (p == targetPath) continue;
                    if (i % 64 == 0)
                        EditorUtility.DisplayProgressBar("扫描引用", p, (float)i / all.Length);

                    var deps = AssetDatabase.GetDependencies(p, recursive: false);
                    if (System.Array.IndexOf(deps, targetPath) >= 0)
                        found.Add(p);
                }
            }
            finally { EditorUtility.ClearProgressBar(); }

            var summary = new Label($"找到 {found.Count} 个直接引用：");
            summary.style.unityFontStyleAndWeight = FontStyle.Bold;
            _refsContainer.Add(summary);

            foreach (var path in found)
            {
                var btn = new Button(() =>
                {
                    var obj = AssetDatabase.LoadMainAssetAtPath(path);
                    EditorGUIUtility.PingObject(obj);
                    Selection.activeObject = obj;
                })
                { text = path };
                btn.style.unityTextAlign = TextAnchor.MiddleLeft;
                btn.style.marginTop = 2;
                _refsContainer.Add(btn);
            }
        }
    }
}