using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using TexturePacker;
using Unity.Mathematics;
using UnityEditor;
using UnityEngine;
using UnityEngine.Experimental.Rendering;
using UnityEngine.Rendering;
using UnityEngine.UIElements;

public sealed class TexturePackerEditor : EditorWindow
{
    [SerializeField]
    private VisualTreeAsset m_VisualTreeAsset = default;
    private TextureMapInfo textureMapInfo;

    private Texture2D textureAtlas;
    private Texture2DArray textureArray;

    private IMGUIContainer imageListContainer;
    private List<Texture2D> selectedTexs = new();
    private List<Rect> texRects = new();

    private Vector2 cellSize = new Vector2(100, 100);
    private const int MaxArraySize = 255;

    private int selectIndex = -1;
    private int selectIndexForMove = -1;
    private Vector2 toolbarOffset = new Vector2(0, 35);

    private int atlasPadding = 0;
    private static Func<UnityEngine.Object, bool, EditorWindow> fnOpenPropertyEditor;
    private int textureSize = 512;
    private EditorWindow atlasPropertiesWindow = null;
    private EditorWindow arrayPropertiesWindow = null;
    private Label imgCntLabel = null;
    private Label infoLabel = null;
    private GraphicsFormat graphicsFormat = GraphicsFormat.R32G32B32A32_SFloat;

    public enum ETextureSize
    {
        _128 = 1 << 7,
        _256 = 1 << 8,
        _512 = 1 << 9,
        _1024 = 1 << 10,
    }

    static TexturePackerEditor()
    {
        var editorCore = AppDomain.CurrentDomain.GetAssemblies().Where(a => a.GetName().Name.Equals("UnityEditor.CoreModule")).FirstOrDefault();
        var type = editorCore.GetType("UnityEditor.PropertyEditor");
        var methodInfo = type.GetMethod("OpenPropertyEditor", BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Static | BindingFlags.Instance, null, new Type[] { typeof(UnityEngine.Object), typeof(bool) }, null);
        fnOpenPropertyEditor = methodInfo.CreateDelegate(typeof(Func<UnityEngine.Object, bool, EditorWindow>)) as Func<UnityEngine.Object, bool, EditorWindow>;
    }

    [MenuItem("Tools/Performance/TexturePackerEditor")]
    public static void OpenTexturePackerEditor()
    {
        TexturePackerEditor wnd = GetWindow<TexturePackerEditor>();
        wnd.titleContent = new GUIContent("TexturePackerEditor");
    }

    [UnityEditor.Callbacks.OnOpenAsset(0)]
    private static bool OnOpenTextureMapInfo(int instanceID, int line)
    {
        var textureMapInfo = EditorUtility.InstanceIDToObject(instanceID) as TextureMapInfo;
        if(!textureMapInfo)
        {
            return false;
        }

        TexturePackerEditor wnd = GetWindow<TexturePackerEditor>();
        wnd.titleContent = new GUIContent("TexturePackerEditor");
        wnd.InitWithTextureMapInfo(textureMapInfo);
        EditorApplication.delayCall += () =>
        {
            wnd.UpdateResult();
        };
        return false;
    }

    private static readonly Color btNormalColor = ColorUtils.ToRGBA(0xFF585858);
    private static readonly Color btClikedColor = ColorUtils.ToRGBA(0xFF46607C);

    public void CreateGUI()
    {
        // Each editor window contains a root VisualElement object
        VisualElement root = rootVisualElement;

        // Instantiate UXML
        VisualElement labelFromUXML = m_VisualTreeAsset.Instantiate();
        root.Add(labelFromUXML);
        var btArray = root.Q<Button>("btArray");
        var btAtlas = root.Q<Button>("btAtlas");
        var btSave = root.Q<Button>("btSave");
        infoLabel = root.Q<Label>("infoLabel");

        var slAtlasPadding = root.Q<SliderInt>("slAtlasPadding");
        var textureSizeEnum = root.Q<EnumField>("textureSizeEnum");
        imgCntLabel = root.Q<Label>("imgCntLabel");
        root.Q<Toggle>("tgIsNormal").RegisterValueChangedCallback(b =>
        {
            textureMapInfo.IsNormalMap = b.newValue;
            SetNormalOriginTextureFormat(!textureMapInfo.IsNormalMap);
            UpdateResult();
        });

        textureSizeEnum.RegisterCallback<ChangeEvent<Enum>>((e) =>
        {
            var newTextureSize = (int)(ETextureSize)e.newValue;
            if(textureSize != newTextureSize)
            {
                textureSize = newTextureSize;
                UpdateResult();
            }
        });

        btArray.clicked += () =>
        {
            btArray.style.backgroundColor = btClikedColor;
            btAtlas.style.backgroundColor = btNormalColor;
            textureMapInfo.PackType = TextureMapInfo.EPackType.Array;
            slAtlasPadding.visible = false;
            UpdateResult();
        };

        btAtlas.clicked += () =>
        {
            btAtlas.style.backgroundColor = btClikedColor;
            btArray.style.backgroundColor = btNormalColor;
            textureMapInfo.PackType = TextureMapInfo.EPackType.Atlas;
            slAtlasPadding.visible = true;
            UpdateResult();
        };


        btSave.clicked += Save;

        btAtlas.style.backgroundColor = btClikedColor;

        slAtlasPadding.RegisterCallback<ChangeEvent<int>>((i) =>
        {
            atlasPadding = i.newValue;
            UpdateResult();
        });

        imageListContainer = root.Q<IMGUIContainer>("imgList");
        imageListContainer.onGUIHandler = OnImageListGUI;
        imageListContainer.RegisterCallback<MouseDownEvent>((e) =>
        {
            var mousePos = Event.current.mousePosition - toolbarOffset;
            for (int i = 0; i < texRects.Count; i++)
            {
                if (texRects[i].Contains(mousePos))
                {
                    selectIndexForMove = i;
                    break;
                }
            }
        });

        imageListContainer.RegisterCallback<MouseUpEvent>((e) =>
        {
            var swpaIndex = -1;
            var mousePos = Event.current.mousePosition - toolbarOffset;
            for (int i = 0; i < texRects.Count; i++)
            {
                if (texRects[i].Contains(mousePos))
                {
                    swpaIndex = i;
                    break;
                }
            }

            if (swpaIndex != -1 && selectIndexForMove != -1)
            {
                if (selectIndexForMove != swpaIndex)
                {
                    (selectedTexs[selectIndexForMove], selectedTexs[swpaIndex]) = (selectedTexs[swpaIndex], selectedTexs[selectIndexForMove]);
                    (texRects[selectIndexForMove], texRects[swpaIndex]) = (texRects[swpaIndex], texRects[selectIndexForMove]);
                    UpdateResult();
                }
            }
            selectIndexForMove = -1;
        });
    }

    private void SetNormalOriginTextureFormat(bool toNormal)
    {
        foreach (var item in selectedTexs)
        {
            var ti = TextureImporter.GetAtPath(AssetDatabase.GetAssetPath(item)) as TextureImporter;
            if(toNormal)
            {
                ti.textureType = TextureImporterType.NormalMap;
            }
            else if (ti.textureType == TextureImporterType.NormalMap)
            {
                ti.textureType = TextureImporterType.Default;
                ti.sRGBTexture = false;
            }
            ti.SaveAndReimport();
        }
    }

    private void OnImageListGUI()
    {
        float windowWidth = position.width;
        int dynamicColumns = Mathf.FloorToInt(windowWidth / (cellSize.x + 5));

        int count = selectedTexs.Count;
        int currentColumn = 0;
        int currentRow = 0;

        var bkColor = GUI.backgroundColor;

        for (int i = 0; i < count; i++)
        {
            if (currentColumn == 0)
            {
                GUILayout.BeginHorizontal();
            }

            var rect = EditorGUILayout.GetControlRect(GUILayout.Width(cellSize.x), GUILayout.Height(cellSize.y));
            texRects[i] = rect;

            if (i == selectIndex || selectIndexForMove != -1 && rect.Contains(Event.current.mousePosition - toolbarOffset))
            {
                GUI.backgroundColor = Color.blue;
            }
            else
            {
                GUI.backgroundColor = bkColor;
            }

            // insert ?
            //EditorGUI.DrawRect
    
            if (GUI.Button(rect, selectedTexs[i]))
            {
                if (selectIndex == i)
                {
                    EditorGUIUtility.PingObject(selectedTexs[i]);
                }
                selectIndex = i;
            }

            currentColumn++;
            if (currentColumn >= dynamicColumns)
            {
                GUILayout.EndHorizontal();
                currentRow++;
                currentColumn = 0;
            }
        }
        GUI.backgroundColor = bkColor;
        if (selectIndexForMove != -1)
        {
            GUI.Button(new Rect(Event.current.mousePosition, cellSize), selectedTexs[selectIndexForMove]);
        }
        if (selectIndex != -1)
        {
            infoLabel.visible = true;
            var tex = selectedTexs[selectIndex];
            var tinfo = textureMapInfo.OriginTexture2TextureInfo[tex];
            if (textureMapInfo.PackType == TextureMapInfo.EPackType.Array)
            {
                infoLabel.text = $"{tex.name} array index:{tinfo.ArrayIndex}";
            }
            else
            {
                infoLabel.text = $"{tex.name} atlas offset:{tinfo.Offset}";
            }
        }
        else
        {
            infoLabel.visible = false;
        }
        if (currentColumn != 0)
        {
            GUILayout.EndHorizontal();
        }
    }

    private void InitWithTextureMapInfo(TextureMapInfo textureMapInfo)
    {
        this.textureMapInfo = textureMapInfo;
        VisualElement root = rootVisualElement;
        var btArray = root.Q<Button>("btArray");
        var btAtlas = root.Q<Button>("btAtlas");
        var slAtlasPadding = root.Q<SliderInt>("slAtlasPadding");
        if (textureMapInfo.PackType == TextureMapInfo.EPackType.Atlas)
        {
            btArray.style.backgroundColor = btNormalColor;
            btAtlas.style.backgroundColor = btClikedColor;
            slAtlasPadding.visible = true;
        }
        else
        {
            btArray.style.backgroundColor = btClikedColor;
            btAtlas.style.backgroundColor = btNormalColor;
            slAtlasPadding.visible = false;
        }

        if(textureMapInfo.IsNormalMap)
        {
            root.Q<Toggle>("tgIsNormal").value = true;
            SetNormalOriginTextureFormat(!textureMapInfo.IsNormalMap);
        }    

        selectedTexs = textureMapInfo.Textures;
        texRects = new List<Rect>(new Rect[selectedTexs.Count]);
    }

    private void OnGUI()
    {
        if (textureMapInfo == null)
        {
            textureMapInfo = ScriptableObject.CreateInstance<TextureMapInfo>();
        }

        switch (Event.current.type)
        {
            case EventType.MouseDrag:
                break;
            case EventType.MouseDown:
                selectIndex = -1;
                Repaint();
                break;
            case EventType.KeyDown:
                break;
            case EventType.KeyUp:
                if (Event.current.modifiers == EventModifiers.Control && Event.current.keyCode == KeyCode.S)
                {
                    Save();
                }

                if (Event.current.keyCode == KeyCode.Delete)
                {
                    if (selectIndex != -1)
                    {
                        RmTexture(selectedTexs[selectIndex]);
                        selectIndex = -1;
                    }
                }
                break;
            case EventType.DragUpdated:
                {

                    for (var i = 0; i < DragAndDrop.objectReferences.Length; i++)
                    {
                        if (DragAndDrop.objectReferences[i] is Texture)
                        {
                            DragAndDrop.visualMode = DragAndDropVisualMode.Generic;
                            break;
                        }
                    }
                    break;
                }
            case EventType.DragExited:
                {
                    for (var i = 0; i < DragAndDrop.objectReferences.Length; i++)
                    {
                        var tex = DragAndDrop.objectReferences[i] as Texture2D;
                        if (tex)
                        {
                            AddTexture(tex);
                        }
                    }
                }
                break;
            case EventType.ContextClick:
                break;
            case EventType.MouseEnterWindow:
                break;
            case EventType.MouseLeaveWindow:
                break;
            default:
                break;
        }
    }

    private void UpdateResult(Texture2D result, int cellCnt)
    {
        result.Apply();
        var scale = (float)textureSize / result.width;
        for (int i = 0; i < selectedTexs.Count; i++)
        {
            var tex = selectedTexs[i];
            if (tex.width != textureSize)
            {
                Debug.LogWarning($"{tex.name} 尺寸错误: {tex.width} 正确值: {textureSize}");
            }
            int cellx = i % cellCnt;
            int celly = i / cellCnt;
            var mip = 0;
            if (tex.width > textureSize)
            {
                mip = (int)Mathf.Log(2, tex.width / textureSize);
            }
            {
                var temp = new Texture2D(textureSize, textureSize, graphicsFormat, 0, TextureCreationFlags.None);
                Graphics.ConvertTexture(tex, temp);

                var offsetx = cellx * (textureSize + atlasPadding);
                var offsety = celly * (textureSize + atlasPadding);

                Graphics.CopyTexture(temp, 0, 0, 0, 0, textureSize, textureSize, result, 0, 0, offsetx, offsety);
                GameObject.DestroyImmediate(temp);
                textureMapInfo.AtlasScale = scale;
                textureMapInfo.OriginTexture2TextureInfo[tex] = new TextureMapInfo.TextureInfo()
                {
                    OriginTexture = tex,
                    Offset = new float2((float)offsetx / result.width, (float)offsety / result.height),
                };
            }
        }
    }

    private void UpdateResult(Texture2DArray result)
    {
        for (int i = 0; i < selectedTexs.Count; i++)
        {
            var tex = selectedTexs[i];
            if (tex.width != textureSize)
            {
                Debug.LogWarning($"{tex.name} 尺寸错误: {tex.width} 正确值: {textureSize}");
            }
   
            Graphics.ConvertTexture(tex, 0, result, i);
            textureMapInfo.OriginTexture2TextureInfo[tex] = new TextureMapInfo.TextureInfo()
            {
                OriginTexture = tex,
                ArrayIndex = i,
            };
        }
    }

    private void UpdateResult()
    {
        if(selectedTexs.Count < 2)
        {
            return;
        }

        if (textureMapInfo.PackType == TextureMapInfo.EPackType.Atlas)
        {
            arrayPropertiesWindow?.Close();
            arrayPropertiesWindow = null;

            var cellCnt = Mathf.CeilToInt(Mathf.Sqrt(selectedTexs.Count));
            var atlasPaddedSize = cellCnt * textureSize + (cellCnt - 1) * atlasPadding;
            if (textureAtlas == null || textureAtlas.width != atlasPaddedSize)
            {
                if (textureAtlas != null)
                {
                    GameObject.DestroyImmediate(textureAtlas, false);
                }

                textureAtlas = new Texture2D(atlasPaddedSize, atlasPaddedSize,
                    graphicsFormat, (int)Mathf.Log(2, atlasPaddedSize) + 1, TextureCreationFlags.None)
                {
                    wrapMode = TextureWrapMode.Clamp,
                };
                atlasPropertiesWindow?.Close();
                atlasPropertiesWindow = null;
            }

            UpdateResult(textureAtlas, cellCnt);
            if (!atlasPropertiesWindow)
            {
                atlasPropertiesWindow = fnOpenPropertyEditor(textureAtlas, true);
                try
                {
                    this.Dock(atlasPropertiesWindow, Docker.DockPosition.Right);
                }
                catch
                {
                }
            }
            atlasPropertiesWindow.Repaint();
        }
        else
        {
            atlasPropertiesWindow?.Close();
            atlasPropertiesWindow = null;
            if (textureArray == null || textureArray.depth != selectedTexs.Count || textureArray.width != textureSize)
            {
                if (textureArray != null)
                {
                    GameObject.DestroyImmediate(textureArray, false);
                }

                textureArray = new Texture2DArray(textureSize,
                    textureSize, selectedTexs.Count, graphicsFormat, TextureCreationFlags.None, 12)
                {
                    wrapMode = TextureWrapMode.Clamp,
                };

                arrayPropertiesWindow?.Close();
                arrayPropertiesWindow = null;
            }

            UpdateResult(textureArray);
            if (!arrayPropertiesWindow)
            {
                arrayPropertiesWindow = fnOpenPropertyEditor(textureArray, true);
                this.Dock(arrayPropertiesWindow, Docker.DockPosition.Right);
            }
            arrayPropertiesWindow.Repaint();
        }
    }

    private void AddTexture(Texture2D texture2D)
    {
        if(TextureMapIndex.Instance.ResultGuid2TextureMap.TryGetValue(AssetDatabase.AssetPathToGUID(AssetDatabase.GetAssetPath(texture2D)), out var mapInfo))
        {
            selectedTexs.Clear();
            textureMapInfo = mapInfo;
            InitWithTextureMapInfo(textureMapInfo);
        }

        if (texture2D.width % textureSize != 0)
        {
            EditorUtility.DisplayDialog("提示", $"贴图 {texture2D.name} 尺寸错误", "ok");
            return;
        }

        if(selectedTexs.Count == MaxArraySize)
        {
            EditorUtility.DisplayDialog("提示", $"贴图数量最多 {MaxArraySize}", "ok");
            return;
        }
        
        if (!selectedTexs.Contains(texture2D))
        {
            selectedTexs.Add(texture2D);
            texRects.Add(new Rect());
        }
        else
        {
            ToastManager.ShowNotification(new Toast.ToastArgs()
            {
                Title = "Info",
                Message = "当前图片已存在",
                LifeTime = 2f, 
                Severity = Toast.ToastSeverity.Info,
                ToastPosition = Toast.ToastPosition.TopCenter
            });
            return;
        }

        imgCntLabel.text = selectedTexs.Count.ToString();
        UpdateResult();
    }

    private void RmTexture(Texture2D texture2D)
    {
        var idx = selectedTexs.IndexOf(texture2D);
        if (idx != -1)
        {
            texRects.RemoveAt(idx);
            selectedTexs.RemoveAt(idx);
        }

        imgCntLabel.text = selectedTexs.Count.ToString();
        UpdateResult();
    }

    private void UpdateMapinfoBeforeSave()
    {
        textureMapInfo.Textures = selectedTexs;
        var hasAlpha = GraphicsFormatUtility.HasAlphaChannel(selectedTexs[0].graphicsFormat);
        for (int i = 1; i < selectedTexs.Count; i++)
        {
            var tex = selectedTexs[i];
            if (hasAlpha != GraphicsFormatUtility.HasAlphaChannel(tex.graphicsFormat))
            {
                if(!EditorUtility.DisplayDialog("警告", $"源贴图 alpha 不一致 :{tex.name}", "继续", "取消"))
                {
                    return;
                }
            }
        }
        
        var rmLs = textureMapInfo.OriginTexture2TextureInfo.Keys.Where(t => !selectedTexs.Contains(t)).ToList();
        foreach (var rm in rmLs)
        {
            textureMapInfo.OriginTexture2TextureInfo.Remove(rm);
        }

        if (textureMapInfo.PackType == TextureMapInfo.EPackType.Atlas)
        {
            GameObject.DestroyImmediate(textureArray);
            textureArray = null;
            textureMapInfo.TextureArray = null;

            if (string.IsNullOrEmpty(textureMapInfo.TextureAtlasPath))
            {
                var savePath = EditorUtility.SaveFilePanelInProject("保存", "", "png", "");
                if (string.IsNullOrEmpty(savePath))
                {
                    return;
                }
                textureMapInfo.TextureAtlasPath = savePath;
            }

            AsyncGPUReadback.Request(textureAtlas, 0, (req) =>
            {
                if (!req.hasError)
                {
                    {
                        using var dataArray = ImageConversion.EncodeNativeArrayToPNG(req.GetData<byte>(), textureAtlas.graphicsFormat, (uint)textureAtlas.width, (uint)textureAtlas.height);
                        using var fr = File.OpenWrite(textureMapInfo.TextureAtlasPath);
                        fr.Write(dataArray);
                    }
               
                    AssetDatabase.ImportAsset(textureMapInfo.TextureAtlasPath);
                    if(TextureImporter.GetAtPath(textureMapInfo.TextureAtlasPath) is TextureImporter ti)
                    {
                        ti.SetTextureSettings(new TextureImporterSettings()
                        {
                            textureShape = TextureImporterShape.Texture2D,
                            flipbookColumns = 1,
                            flipbookRows = 1,
                            sRGBTexture = false,
                            readable = false,
                            mipmapEnabled = true,
                            wrapMode = TextureWrapMode.Clamp,
                        });
                        ti.SaveAndReimport();
                    }

                    EditorApplication.delayCall += () =>
                    {
                        textureMapInfo.TextureAtlas = AssetDatabase.LoadAssetAtPath<Texture2D>(textureMapInfo.TextureAtlasPath);
                        var guid = AssetDatabase.AssetPathToGUID(textureMapInfo.TextureAtlasPath);
                        TextureMapIndex.Instance.ResultGuid2TextureMap[guid] = textureMapInfo;
                        EditorGUIUtility.PingObject(textureMapInfo.TextureAtlas);
                    };
                }
            });
        }
        else
        {
            GameObject.DestroyImmediate(textureAtlas);
            textureAtlas = null;
            textureMapInfo.TextureAtlas = null;
            if (string.IsNullOrEmpty(textureMapInfo.TextureArrayPath))
            {
                var savePath = EditorUtility.SaveFilePanelInProject("保存", "", "png", "");
                if (string.IsNullOrEmpty(savePath))
                {
                    return;
                }
                textureMapInfo.TextureArrayPath = savePath;
            }
            
            AsyncGPUReadback.Request(textureArray, 0, 0, textureArray.width, 0, textureArray.height, 0, textureArray.depth, (req) =>
            {
                if (!req.hasError)
                {
                    {
                        using var fr = File.Open(textureMapInfo.TextureArrayPath, FileMode.OpenOrCreate);
                        using MemoryStream memoryStream = new MemoryStream();
                        for (int i = textureArray.depth - 1; i >=0 ; --i)
                        {
                            var array = req.GetData<byte>(i);
                            memoryStream.Write(array);
                        }
                        memoryStream.Seek(0, SeekOrigin.Begin);
                     
                        var dataArray = ImageConversion.EncodeArrayToPNG(memoryStream.GetBuffer(), textureArray.graphicsFormat, (uint)textureArray.width, (uint)textureArray.height * (uint)textureArray.depth);
                        fr.Write(dataArray);
                    }
                    
                    AssetDatabase.ImportAsset(textureMapInfo.TextureArrayPath);
                    if (TextureImporter.GetAtPath(textureMapInfo.TextureArrayPath) is TextureImporter ti)
                    {
                        ti.SetTextureSettings(new TextureImporterSettings()
                        {
                            textureShape = TextureImporterShape.Texture2DArray,
                            flipbookColumns = 1,
                            flipbookRows = textureArray.depth,
                            sRGBTexture = false,
                            readable = false,
                            mipmapEnabled = true,
                            wrapMode = TextureWrapMode.Clamp,
                        });
                        ti.SaveAndReimport();
                    }

                    textureMapInfo.TextureArray = AssetDatabase.LoadAssetAtPath<Texture2DArray>(textureMapInfo.TextureArrayPath);
                    var guid = AssetDatabase.AssetPathToGUID(textureMapInfo.TextureArrayPath);
                    TextureMapIndex.Instance.ResultGuid2TextureMap[guid] = textureMapInfo;
                    EditorGUIUtility.PingObject(textureMapInfo.TextureArray);
                }
            });
        }

        AssetDatabase.SaveAssetIfDirty(TextureMapIndex.Instance);
    }

    private void Save()
    {
        if (AssetDatabase.IsMainAsset(textureMapInfo))
        {
            UpdateMapinfoBeforeSave();
            AssetDatabase.SaveAssetIfDirty(textureMapInfo);
        }
        else
        {
            var path = EditorUtility.SaveFilePanelInProject("保存映射关系", DateTime.Now.ToString("yy_MM_dd_hhmmss"), "asset", "保存源贴图到 atlas 对应关系", TextureMapInfo.TextureMapDir);
            if(string.IsNullOrEmpty(path))
            {
                return;
            }

            AssetDatabase.CreateAsset(textureMapInfo, path);
            UpdateMapinfoBeforeSave();
            AssetDatabase.SaveAssetIfDirty(textureMapInfo);
        }
        base.SaveChanges();
        AssetDatabase.Refresh();
    }

    private void OnDestroy()
    {
        SetNormalOriginTextureFormat(textureMapInfo.IsNormalMap);
        AssetDatabase.SaveAssetIfDirty(textureMapInfo);
    }
}