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

class AssetData
{
    // 枚举值为遍历的优先级，用于AssetData.Dependcies和AssetDataManager.Assets
    public static readonly int AssetTypeCount = 9;
    public enum AssetType
    {
        Scene = 0, 
        Prefab, 
        Mesh,
        Material,
        Asset, 
        Texture, 
        Shader, 
        Script, 
        CSV, 

        Unknown  = 255,
    }

    public AssetData(FileSystemInfo f)
    {
        for (int i = 0; i < AssetTypeCount; ++i)
            Dependencies[i] = new List<string>();
        AssetDataManager manager = AssetDataManager.Get();
        AssetPath = manager.FullPathToAssetPath(f.FullName);
        GUID = AssetDatabase.AssetPathToGUID(AssetPath);
        Name = f.Name;
        ObjType = AssetDatabase.GetMainAssetTypeAtPath(AssetPath);
        FileType = ExtensionToAssetType(f.Extension);
        Extension = f.Extension;
        string[] depsPath = AssetDatabase.GetDependencies(AssetPath, false); 
        for(int i = 0; i < depsPath.Length; ++i)
        {
            string path = depsPath[i];
            string guid = AssetDatabase.AssetPathToGUID(path);
            if (guid == GUID)
                continue;
            string extension = manager.GetExtension(path);
            AssetType type = ExtensionToAssetType(extension);
            if (type == AssetType.Unknown)
                continue;
            Dependencies[(int)type].Add(guid);
            ++RefCount;
            List<string> data;
            if (!AssetDataManager.AssetsReverse.TryGetValue(guid, out data))
            {
                data = new List<string>();
                AssetDataManager.AssetsReverse.Add(guid, data);
            }
            data.Add(GUID);
        }
        FileInfo finfo = new FileInfo(f.FullName);
        DiskSize = finfo.Length;
        DiskSizeStr = EditorUtility.FormatBytes(DiskSize);
    }

    #region 资源属性
    public string GUID;
    public string Name;
    public int    RefCount = 0;
    public int    RevRefCount = 0; 
    public long   DiskSize;
    public string DiskSizeStr;
    public string AssetPath;
    public Type   ObjType;
    public string Extension;
    public AssetType FileType;
    public List<string>[] Dependencies = new List<string>[AssetTypeCount];
    #endregion

    private AssetType ExtensionToAssetType(string extension)
    {
        if (extension == ".unity") return AssetType.Scene;
        else if (extension == ".prefab") return AssetType.Prefab;
        else if (extension == ".mat") return AssetType.Material;
        else if (extension == ".asset") return AssetType.Asset;
        else if (extension == ".fbx" || extension == ".FBX") return AssetType.Mesh;
        else if (extension == ".png" || extension == ".jpg" || extension == ".bmp") return AssetType.Texture;
        else if (extension == ".shader") return AssetType.Shader;
        else if (extension == ".cs") return AssetType.Script;
        else if (extension == ".csv") return AssetType.CSV;
        else return AssetType.Unknown;
    }
}

class AssetDataManager
{
    private static AssetDataManager manager;

    public static AssetDataManager Get()
    {
        if (manager == null)
            manager = new AssetDataManager();
        return manager;
    }

    public AssetDataManager()
    {
        for (int i = 0; i < AssetData.AssetTypeCount; ++i)
            Assets[i] = new Dictionary<string, AssetData>();
    }

    #region Asset字典
    // 所有资源
    public static Dictionary<string, AssetData> AllAssets = new Dictionary<string, AssetData>();
    // 分类统计
    public static Dictionary<string, AssetData>[] Assets = new Dictionary<string, AssetData>[AssetData.AssetTypeCount];
    // 反向依赖
    public static Dictionary<string, List<string>> AssetsReverse = new Dictionary<string, List<string>>();
    #endregion

    #region 过滤
    public static List<string> ValidExtension = new List<string>
    {
        ".unity",               // scene
        ".prefab",              // prefab
        ".mat",                 // material
        ".asset",               // asset
        ".fbx", ".FBX",         // mesh
        ".png", ".jpg", ".bmp", // texture
        ".shader",              // shader
        ".cs",                  // script
        ".csv"                  // CSV
    };

    public string GetExtension(string file)
    {
        if (file == null || file.Length == 0)
            return null;
        int len = file.Length;
        int idx = file.LastIndexOf('.');
        return file.Substring(idx, len - idx);
    }

    public bool IsValidFile(string file)
    {
        string extension = GetExtension(file);
        foreach (var ext in ValidExtension)
        {
            if (ext == extension)
                return true;
        }
        return false;
    }

    public List<string> InvalidFolder = new List<string>
    {
    };

    public bool IsValidFolder(string folderName)
    {
        foreach(var dir in InvalidFolder)
        {
            if(dir == folderName)
                return false;
        }
        return true; 
    }
    #endregion

    public string FullPathToAssetPath(string fullpath)
    {
        fullpath = fullpath.Replace('\\', '/');
        string path = "Assets" + fullpath.Replace(Application.dataPath, "");
        path = path.Replace('/', '\\');
        return path;
    }

    public string AssetPathToFullPath(string assetpath)
    {
        string fullpath = Application.dataPath.Replace("/Assets", "") + "/" + assetpath;
        return fullpath;
    }

    public void LoadAssets(string fullpath)
    {
        DirectoryInfo directoryInfo = new DirectoryInfo(fullpath);
        FileSystemInfo[] filesInfo = directoryInfo.GetFileSystemInfos();
        foreach(FileSystemInfo f in filesInfo)
        {
            if(f is DirectoryInfo && IsValidFolder(f.Name))
            {
                LoadAssets(f.FullName);
            }
            else if(f.Extension != ".meta" && IsValidFile(f.Name))
            {
                AssetData asset = new AssetData(f);
                AllAssets.Add(asset.GUID, asset);
                Assets[(int)asset.FileType].Add(asset.GUID, asset);
            }
        }
    }

    public void ClearAssets()
    {
        AllAssets.Clear();
        foreach (var assets in Assets)
            assets.Clear();
        AssetsReverse.Clear();
    }

}

class Drawer
{
    private Drawer()
    {
        SelectorButtonStyle = new GUIStyle(GUIStyle.none);
        SelectorButtonStyle.normal.background = CreateTexture(1, 1, new Color32(62, 95, 150, 255));
    }

    private Texture2D CreateTexture(int w, int h, Color col)
    {
        Color[] pixels = new Color[w * h];
        for(int i = 0; i < w * h; ++i)
            pixels[i] = col;
        Texture2D texture = new Texture2D(w, h);
        texture.SetPixels(pixels);
        return texture;
    }

    private static Drawer drawer = null; 

    public static Drawer Get()
    {
        if (drawer == null)
            drawer = new Drawer();
        return drawer; 
    }
    
    public void DrawButtonMid(Rect rect, string content)
    {
        GUI.Button(rect, content, EditorStyles.miniButtonMid);
    }

    public void DrawButton(Rect rect, string content, out bool click)
    {
        click = GUI.Button(rect, content);
    }

    public void DrawLabel(Rect rect, string content)
    {
        GUI.Label(rect, content);
    }

    public void DrawTextfield(Rect rect, string content, ref string value)
    {
        value = GUI.TextField(rect, content);
    }

    public void DrawCheckBox(Rect rect, string content, bool check, ref bool ischeck)
    {
        ischeck = GUI.Toggle(rect, check, content);
    }

    public void DrawBackground(Rect rect, Color col)
    {
        Color old = GUI.backgroundColor;
        GUI.backgroundColor = col;
        GUI.Box(rect, "");
        GUI.backgroundColor = old;
    }

    public void DrawFoldout(Rect rect, ref bool foldout)
    {
        foldout = EditorGUI.Foldout(rect, foldout, "");
    }

    public void DrawAssetIcon(Rect rect, AssetData asset)
    {
        GUIContent content = EditorGUIUtility.ObjectContent(null, asset.ObjType);
        content.text = asset.Name;
        GUI.Label(rect, content);
    }

    public void DrawSelector(Rect rect, bool selected, out bool clicked)
    {
        SelectorButtonStyle.normal.background = CreateTexture(1, 1, new Color32(62, 95, 150, 255));
        clicked = GUI.Button(rect, "",selected ? SelectorButtonStyle : GUIStyle.none);
    }

    #region 配置项
    public Color ColorHeavy = new Color(0.2f, 0.2f, 0.2f);
    public Color ColorLight = new Color(0.3f, 0.3f, 0.3f);
    public GUIStyle SelectorButtonStyle;
    #endregion
}

// 文件树
class FileTree
{
    public class Node
    {
        public Node(string guid)
        {
            GUID = guid;
            Foldout = false;
        }
        public bool Foldout;                           // 是否展开
        public string GUID;                            // GUID
        public List<Node> Children = new List<Node>(); // 子节点
    }

    public List<Node> root = new List<Node>();
}

class AssetBrowser : EditorWindow
{
    private static AssetBrowser editor;
    private static Drawer drawer;

    private FileTree assetsTree = new FileTree();

    #region GUI 组件配置数值
    private Rect window = new Rect();
    private int contentWidth = 1600;
    private int contentHeight = 1000;
    private readonly int kLineHeight = 20; // 行高
    private Vector2 scrollPos = new Vector2(0, 0);
    private int directoryOffsetY = 5; // 资源目录Y偏移度
    private int filtersOffsetY = 27; // 过滤器Y偏移度
    private int headerOffsetY = 50; // 标题Y偏移度
    private int assetsTreeOffsetY = 70; // 列表偏移度
    private int kTabWidth = 15;
    #endregion

    #region 数据
    private string directory = "";
    private FileTree.Node selectedNode = null;
    #endregion

    #region 过滤器
    private string filterFile = "";
    private bool filterScene = false;
    private bool filterPrefab = false;
    private bool filterMaterial = false;
    private bool filterAsset = false;
    private bool filterMesh = false;
    private bool filterTexture = false;
    private bool filterShader = false;
    private bool filterScript = false;
    private bool filterCSV = false;
    #endregion

    [MenuItem("Window/Asset Browser")]
    public static void Show()
    {
        editor = GetWindow<AssetBrowser>();
        editor.titleContent = new GUIContent("Asset Browser");
        drawer = Drawer.Get();
    }

    private enum Colum
    {
        Name,     // 资源名
        Ref,      // 引用数
        RevRef,   // 被引用数
        Type,     // 资源类型
        DiskSize, // 硬盘大小
        Path,     // 资源路径 
    }

    private Dictionary<Colum, string> ColumHeader = new Dictionary<Colum, string>
    {
        {Colum.Name, "资源引用关系"},
        {Colum.Ref, "引用数"},
        {Colum.RevRef, "被引用数"},
        {Colum.Type, "资源类型"},
        {Colum.DiskSize, "硬盘大小"},
        {Colum.Path, "资源路径"},
    };

    private Dictionary<Colum, int> ColumWidth = new Dictionary<Colum, int>
    {
        {Colum.Name, 500},
        {Colum.Ref, 100},
        {Colum.RevRef, 100},
        {Colum.Type, 100},
        {Colum.DiskSize, 100},
        {Colum.Path, 500},
    };

    private Dictionary<Colum, int> ColumOffsetX = new Dictionary<Colum, int>();

    private void AdjustColumOffsetX()
    {
        if (ColumOffsetX == null)
            return;
        ColumOffsetX.Clear();
        ColumOffsetX.Add(Colum.Name, 0);
        ColumOffsetX.Add(Colum.Ref, ColumOffsetX[Colum.Name] + ColumWidth[Colum.Name]);
        ColumOffsetX.Add(Colum.RevRef, ColumOffsetX[Colum.Ref] + ColumWidth[Colum.Ref]);
        ColumOffsetX.Add(Colum.Type, ColumOffsetX[Colum.RevRef] + ColumWidth[Colum.RevRef]);
        ColumOffsetX.Add(Colum.DiskSize, ColumOffsetX[Colum.Type] + ColumWidth[Colum.Type]);
        ColumOffsetX.Add(Colum.Path, ColumOffsetX[Colum.DiskSize] + ColumWidth[Colum.DiskSize]);
    }

    private void AdjustWindow()
    {
        window = editor.position;
    }

    public void OnGUI()
    {
        // 调试
        if (editor == null)
            editor = GetWindow<AssetBrowser>();
        drawer = Drawer.Get();

        AdjustColumOffsetX();
        AdjustWindow();

        BeginScrollView();
        // 绘制工具栏
        OnToolset();
        // 绘制资源列表
        OnAsset();
        EndScrollView();
    }

    private void BeginScrollView()
    {
        scrollPos = GUI.BeginScrollView(new Rect(0, 0, window.width, window.height), scrollPos, new Rect(0, 0, contentWidth, contentHeight), true, true);
    }

    private void EndScrollView()
    {
        GUI.EndScrollView();
    }

    private void OnToolset()
    {
        OnDirectory();
        OnFilters();
    }

    private void OnDirectory()
    {
        float offsetY = directoryOffsetY + scrollPos.y;
        drawer.DrawLabel(new Rect(0, offsetY, 95, kLineHeight), "资源目录 Assets/");
        drawer.DrawTextfield(new Rect(95, offsetY, 250, kLineHeight), directory, ref directory);
        bool load; 
        drawer.DrawButton(new Rect(350, offsetY, 50, kLineHeight), "载入", out load);
        if(load)
        {
            ProcessAssets();
            ProcessTree();
            EditorUtility.DisplayDialog("载入完毕", "载入完毕", "确定");
        }
    }

    private void OnFilters()
    {
        // 文件匹配
        drawer.DrawLabel(new Rect(0, filtersOffsetY + scrollPos.y, 100, kLineHeight), "匹配文件");
        drawer.DrawTextfield(new Rect(50, filtersOffsetY + scrollPos.y, 150, kLineHeight), filterFile, ref filterFile);
        // 类型过滤
        float offsetX = 250;
        float offsetY = filtersOffsetY + scrollPos.y;
        int width = 70; 
        drawer.DrawCheckBox(new Rect(offsetX, offsetY, width, kLineHeight), "场景", filterScene, ref filterScene);
        drawer.DrawCheckBox(new Rect(offsetX + width, offsetY, width, kLineHeight), "Prefab", filterPrefab, ref filterPrefab);
        drawer.DrawCheckBox(new Rect(offsetX + width * 2, offsetY, width, kLineHeight), "材质", filterMaterial, ref filterMaterial);
        drawer.DrawCheckBox(new Rect(offsetX + width * 3, offsetY, width, kLineHeight), "Asset", filterAsset, ref filterAsset);
        drawer.DrawCheckBox(new Rect(offsetX + width * 4, offsetY, width, kLineHeight), "Mesh", filterMesh, ref filterMesh);
        drawer.DrawCheckBox(new Rect(offsetX + width * 5, offsetY, width, kLineHeight), "贴图", filterTexture, ref filterTexture);
        drawer.DrawCheckBox(new Rect(offsetX + width * 6, offsetY, width, kLineHeight), "Shader", filterShader, ref filterShader);
        drawer.DrawCheckBox(new Rect(offsetX + width * 7, offsetY, width, kLineHeight), "脚本", filterScript, ref filterScript);
        drawer.DrawCheckBox(new Rect(offsetX + width * 8, offsetY, width, kLineHeight), "CSV", filterCSV, ref filterCSV);
    }

    private void OnAsset()
    {
        OnHeader();
        BeginFileTreeView();
        OnAssetsTree();
        EndFileTreeView();
    }

    private void BeginFileTreeView()
    {
        scrollPos = GUI.BeginScrollView(
            new Rect(scrollPos.x, scrollPos.y + assetsTreeOffsetY, window.width, window.height - assetsTreeOffsetY),
            scrollPos,
            new Rect(0, 0, contentWidth, contentHeight - assetsTreeOffsetY),
            false , false
        );
    }

    private void EndFileTreeView()
    {
        GUI.EndScrollView();
    }

    private void OnHeader()
    {
        float scrollY = scrollPos.y;
        drawer.DrawButtonMid(new Rect(ColumOffsetX[Colum.Name], headerOffsetY + scrollY, ColumWidth[Colum.Name], kLineHeight), ColumHeader[Colum.Name]);
        drawer.DrawButtonMid(new Rect(ColumOffsetX[Colum.Ref], headerOffsetY + scrollY, ColumWidth[Colum.Ref], kLineHeight), ColumHeader[Colum.Ref]);
        drawer.DrawButtonMid(new Rect(ColumOffsetX[Colum.RevRef], headerOffsetY + scrollY, ColumWidth[Colum.RevRef], kLineHeight), ColumHeader[Colum.RevRef]);
        drawer.DrawButtonMid(new Rect(ColumOffsetX[Colum.Type], headerOffsetY + scrollY, ColumWidth[Colum.Type], kLineHeight), ColumHeader[Colum.Type]);
        drawer.DrawButtonMid(new Rect(ColumOffsetX[Colum.DiskSize], headerOffsetY + scrollY, ColumWidth[Colum.DiskSize], kLineHeight), ColumHeader[Colum.DiskSize]);
        drawer.DrawButtonMid(new Rect(ColumOffsetX[Colum.Path], headerOffsetY + scrollY, ColumWidth[Colum.Path], kLineHeight), ColumHeader[Colum.Path]);
    }

    private void OnAssetsTree()
    {
        int count = 0;
        foreach(FileTree.Node node in assetsTree.root)
        {
            DrawNode(node, 0, ref count);
        }
    }

    private bool Filter(FileTree.Node node, int hierachy)
    {
        if(hierachy == 0)
        {
            AssetData asset;
            if (!AssetDataManager.AllAssets.TryGetValue(node.GUID, out asset))
                return false;
            // 文件类型过滤
            if (asset.FileType == AssetData.AssetType.Scene && !filterScene) return false;
            else if (asset.FileType == AssetData.AssetType.Prefab&& !filterPrefab) return false;
            else if (asset.FileType == AssetData.AssetType.Material&& !filterMaterial) return false;
            else if (asset.FileType == AssetData.AssetType.Asset&& !filterAsset) return false;
            else if (asset.FileType == AssetData.AssetType.Mesh&& !filterMesh) return false;
            else if (asset.FileType == AssetData.AssetType.CSV&& !filterCSV) return false;
            else if (asset.FileType == AssetData.AssetType.Script&& !filterScript) return false;
            else if (asset.FileType == AssetData.AssetType.Shader&& !filterShader) return false;
            else if (asset.FileType == AssetData.AssetType.Texture&& !filterTexture) return false;
            // 文件名
            if (asset.Name.IndexOf(filterFile) == -1)
                return false;
        }

        return true;
    }

    // 按照深度绘制
    private void DrawNode(FileTree.Node node, int hierachy, ref int count)
    {
        if (!Filter(node, hierachy))
            return;
        ++count;
        contentHeight = count * kLineHeight + assetsTreeOffsetY;
        DrawAssetInfo(node, hierachy, count - 1);
        if (!node.Foldout || node.Children.Count == 0)
            return;
        foreach (FileTree.Node child in node.Children)
        {
            DrawNode(child, hierachy + 1, ref count);
        }
    }

    // 绘制单个
    private void DrawAssetInfo(FileTree.Node node, int hierachy, int index)
    {
        Drawer drawer = Drawer.Get();
        AssetData asset;
        if (!AssetDataManager.AllAssets.TryGetValue(node.GUID, out asset))
            return;
        int offsetY = index * kLineHeight;
        // 绘制背景
        drawer.DrawBackground(new Rect(0, offsetY, contentWidth, kLineHeight), (index & 1) == 1 ? drawer.ColorHeavy : drawer.ColorLight);
        // 绘制折叠按钮
        if (node.Children.Count > 0)
            drawer.DrawFoldout(new Rect(hierachy * kTabWidth, offsetY, 10, kLineHeight), ref node.Foldout);
        // 绘制选择按钮
        bool clicked;
        drawer.DrawSelector(new Rect(hierachy * kTabWidth + 12, offsetY, contentWidth, kLineHeight), selectedNode == node, out clicked);
        if (clicked)
        {
            if(selectedNode != node)
                selectedNode = node;
            else
            {
                AssetReverse.Show(node.GUID);
                selectedNode = null; 
            }
        } 
        // 绘制图标
        drawer.DrawAssetIcon(new Rect(hierachy * kTabWidth + 12, offsetY, ColumWidth[Colum.Name], kLineHeight), asset);
        // 绘制引用数
        drawer.DrawLabel(new Rect(ColumOffsetX[Colum.Ref], offsetY, 100, kLineHeight), asset.RefCount.ToString());
        // 绘制反向引用数
        List<string> revRef;
        int revRefCount = 0;
        if (AssetDataManager.AssetsReverse.TryGetValue(node.GUID, out revRef))
            revRefCount = revRef.Count;
        drawer.DrawLabel(new Rect(ColumOffsetX[Colum.RevRef], offsetY, 100, kLineHeight), revRefCount.ToString());
        // 绘制资源类型
        drawer.DrawLabel(new Rect(ColumOffsetX[Colum.Type], offsetY, 100, kLineHeight), asset.Extension);
        // 绘制硬盘大小
        drawer.DrawLabel(new Rect(ColumOffsetX[Colum.DiskSize], offsetY, 100, kLineHeight), asset.DiskSizeStr);
        // 绘制资源路径
        drawer.DrawLabel(new Rect(ColumOffsetX[Colum.Path], offsetY, 1000, kLineHeight), asset.AssetPath);
    }

    private void ProcessAssets()
    {
        AssetDataManager assetManager = AssetDataManager.Get();
        assetManager.ClearAssets();
        assetManager.LoadAssets(assetManager.AssetPathToFullPath("Assets/" + directory));
    }

    private void ProcessTree()
    {
        AssetDataManager assetManager = AssetDataManager.Get();
        assetsTree.root.Clear();
        for(int i = 0; i < AssetData.AssetTypeCount; ++i)
        {
            Dictionary<string, AssetData> assets = AssetDataManager.Assets[i];
            foreach(var asset in assets)
            {
                AssetData data = asset.Value;
                FileTree.Node node = ProcessNode(data);
                assetsTree.root.Add(node); 
            }
        }
    }

    private FileTree.Node ProcessNode(AssetData data)
    {
        AssetDataManager assetManager = AssetDataManager.Get();
        FileTree.Node node = new FileTree.Node(data.GUID);
        foreach(List<string> deps in data.Dependencies)
        {
            foreach(string guid in deps)
            {
                AssetData dep;
                if(AssetDataManager.AllAssets.TryGetValue(guid, out dep))
                {
                    FileTree.Node child = ProcessNode(dep);
                    node.Children.Add(child);
                }
            }
        }
        return node;
    }

}

class AssetReverse : EditorWindow
{
    private static AssetReverse editor;
    private static Drawer drawer;

    private static string GUID;
    private static AssetData asset;
    private Vector2 scrollPos = new Vector2(0, 0);

    private int kLineHeight = 20;
    private int contentHeight = 0;

    public static void Show(string guid)
    {
        editor = GetWindow<AssetReverse>();
        editor.titleContent = new GUIContent("Asset Reverse");
        GUID = guid;
        if(AssetDataManager.AllAssets.TryGetValue(GUID, out asset))
        {
        }
        Drawer dawer = Drawer.Get();
    }

    public void OnGUI()
    {
        if (asset == null)
            return;
        drawer = Drawer.Get();
        drawer.DrawAssetIcon(new Rect(0, 0, 200, kLineHeight), asset);
        scrollPos = GUI.BeginScrollView(new Rect(0, kLineHeight, editor.position.width, editor.position.height - kLineHeight), scrollPos, new Rect(0, 0, 1500, contentHeight));
        // 标题
        drawer.DrawButtonMid(new Rect(0, 0, 400, 20), "资源名");
        drawer.DrawButtonMid(new Rect(400, 0, 400, 20), "资源路径");
        // 
        List<string> revRef;
        if(AssetDataManager.AssetsReverse.TryGetValue(GUID, out revRef))
        {
            int count = 0;
            foreach(string guid in revRef)
            {
                AssetData data; 
                if(AssetDataManager.AllAssets.TryGetValue(guid, out data))
                {
                    drawer.DrawAssetIcon(new Rect(0, kLineHeight + count * kLineHeight, 400, kLineHeight), data);
                    drawer.DrawLabel(new Rect(400, kLineHeight + count * kLineHeight, 400, kLineHeight), data.AssetPath);
                    ++count;
                    contentHeight = count * kLineHeight + kLineHeight;
                }
            }
        }
        GUI.EndScrollView();
    }
}