using System.Collections.Generic;
using System.IO;
using Superlazy;
using UnityEditor;
using UnityEditor.U2D;
using UnityEngine;
using UnityEngine.U2D;

public interface IPostProcessorSpriteAtlas
{
    void OnAddSprite(SpriteAtlasAsset atlas);
}

public static class SLAssetPostprocessorSprite
{
    private static readonly HashSet<string> targetPaths = new HashSet<string>();

    public static void OnPreprocessTexture(TextureImporter importer)
    {
        importer.textureType = TextureImporterType.Sprite;
        importer.spriteImportMode = SpriteImportMode.Single;

        importer.sRGBTexture = true;
        importer.isReadable = false;
        importer.mipmapEnabled = false;
        importer.streamingMipmaps = false;
        importer.wrapMode = TextureWrapMode.Clamp;
        importer.filterMode = FilterMode.Bilinear;

        importer.textureCompression = TextureImporterCompression.Uncompressed;
        importer.crunchedCompression = false;
        importer.spritePixelsPerUnit = 100;

        var textureSettings = new TextureImporterSettings();
        importer.ReadTextureSettings(textureSettings);
        textureSettings.spriteMeshType = SpriteMeshType.FullRect;
        textureSettings.spriteExtrude = 2;
        importer.SetTextureSettings(textureSettings);
    }

    public static void OnRemove(string path, string movePath)
    {
        var upperPath = path.ToUpper();
        if (upperPath.Contains("ASSETS/RAW/SPRITES/") == false || upperPath.Contains(".PNG") == false) return;

        if (targetPaths.Contains(SLFileUtility.FolderPath(path)) == false)
        {
            targetPaths.Add(SLFileUtility.FolderPath(path));
        }
    }

    public static void OnAdd(string path)
    {
        var upperPath = path.ToUpper();
        if (upperPath.Contains("ASSETS/RAW/SPRITES/") == false || upperPath.Contains(".PNG") == false) return;

        if (targetPaths.Contains(SLFileUtility.FolderPath(path)) == false)
        {
            targetPaths.Add(SLFileUtility.FolderPath(path));
        }
    }

    public static void CreateAtlas(string path, string destPath)
    {
        var oldAtlas = AssetDatabase.LoadAssetAtPath<SpriteAtlas>(destPath);

        if (oldAtlas != null)
        {
            AssetDatabase.DeleteAsset(destPath);
        }

        var di = new DirectoryInfo(path);
        if (di.Exists == false) return;

        var objects = new List<Object>();
        foreach (var file in di.GetFiles())
        {
            if (file.Name.ToUpper().IsRight(".PNG") == false) continue;
            var filePath = path + "/" + file.Name;
            var fileName = file.Name.Substring(0, file.Name.Length - ".png".Length);

            var sprite = AssetDatabase.LoadAssetAtPath<Sprite>(filePath);
            var maxSize = sprite.rect.size.x > sprite.rect.size.y ? sprite.rect.size.x : sprite.rect.size.y;
            if (maxSize > 1024)
            {
                CreateSingleAtlas(filePath, path.Replace("/Raw/", "/Addressables/") + $"_{fileName}.spriteatlasv2");
                continue;
            }

            objects.Add(sprite);
        }

        if (objects.Count == 0) return;

        SLFileUtility.MakeFolderFromFilePath(destPath);
        var atlas = new SpriteAtlasAsset();

        var spriteAtlasComponents = new List<IPostProcessorSpriteAtlas>();
        spriteAtlasComponents.CreateInstanceList();
        foreach (var component in spriteAtlasComponents)
        {
            component.OnAddSprite(atlas);
        }

        atlas.Add(objects.ToArray());

        SpriteAtlasAsset.Save(atlas, destPath);
        AssetDatabase.Refresh();

        var sai = (SpriteAtlasImporter)AssetImporter.GetAtPath(destPath);
        sai.packingSettings = new SpriteAtlasPackingSettings
        {
            enableRotation = false,
            enableTightPacking = false,
            enableAlphaDilation = false,
            padding = 4,
            blockOffset = 0
        };

        sai.textureSettings = new SpriteAtlasTextureSettings
        {
            filterMode = FilterMode.Bilinear,
            sRGB = true,
            generateMipMaps = false
        };
    }

    public static void CreateSingleAtlas(string path, string destPath)
    {
        var oldAtlas = AssetDatabase.LoadAssetAtPath<SpriteAtlas>(destPath);

        if (oldAtlas != null)
        {
            AssetDatabase.DeleteAsset(destPath);
        }

        SLFileUtility.MakeFolderFromFilePath(destPath);
        var atlas = new SpriteAtlasAsset();

        var sprite = AssetDatabase.LoadAssetAtPath<Sprite>(path);
        atlas.Add(new Object[] { sprite });

        var spriteAtlasComponents = new List<IPostProcessorSpriteAtlas>();
        spriteAtlasComponents.CreateInstanceList();
        foreach (var component in spriteAtlasComponents)
        {
            component.OnAddSprite(atlas);
        }

        SpriteAtlasAsset.Save(atlas, destPath);
        AssetDatabase.Refresh();

        var sai = (SpriteAtlasImporter)AssetImporter.GetAtPath(destPath);
        sai.packingSettings = new SpriteAtlasPackingSettings
        {
            enableRotation = false,
            enableTightPacking = false,
            enableAlphaDilation = false,
            padding = 4,
            blockOffset = 0
        };

        sai.textureSettings = new SpriteAtlasTextureSettings
        {
            filterMode = FilterMode.Bilinear,
            sRGB = true,
            generateMipMaps = false
        };
    }

    public static void BuildTarget()
    {
        foreach (var path in targetPaths)
        {
            CreateAtlas(path, path.Replace("/Raw/", "/Addressables/") + ".spriteatlasv2");
        }

        targetPaths.Clear();
    }
}