using UnityEditor;
using UnityEditor.U2D;
using UnityEngine;

/// <summary>
/// 新资源导入时自动设置平台压缩格式：
///   - 纹理(Texture2D)：Android→ETC2（有Alpha→RGBA8 / 无Alpha→RGB4） iPhone→ASTC_6x6  WebGL→ASTC_6x6
///   - 图集(SpriteAtlas)：Android→ETC2_RGBA8  iPhone→ASTC_6x6  WebGL→ASTC_6x6
///   - PC(Standalone)：不设置覆盖，保持默认
/// 
/// 仅处理 Assets/ResourcesOut 下的资源。
/// </summary>
public class TexturePlatformAssetPostprocessor : AssetPostprocessor
{
    private static readonly string TARGET_FOLDER = TexturePlatformFormatHelper.TARGET_FOLDER;
    private static readonly bool AUTO_APPLY_ATLAS_SETTINGS = true;

    /// <summary>
    /// 防止回调中 SaveAndReimport 同步触发下一次 OnPostprocessAllAssets 造成嵌套重入。
    /// </summary>
    private static bool s_IsApplying;

    void OnPreprocessTexture()
    {
        if (!assetPath.StartsWith(TARGET_FOLDER))
            return;

        var importer = assetImporter as TextureImporter;
        if (importer == null)
            return;

        if (TexturePlatformFormatHelper.ApplyTexturePlatformSettings(importer))
        {
            Debug.Log($"[TexImport] 贴图: {assetPath}");
        }
    }

    static void OnPostprocessAllAssets(
        string[] importedAssets,
        string[] deletedAssets,
        string[] movedAssets,
        string[] movedFromAssetPaths)
    {
        if (!AUTO_APPLY_ATLAS_SETTINGS)
            return;
        // 回调里的 SaveAndReimport 会同步再次触发本回调，必须挡掉，否则会无限自触发
        if (s_IsApplying)
            return;

        s_IsApplying = true;
        try
        {
            foreach (var assetPath in importedAssets)
            {
                if (!assetPath.StartsWith(TARGET_FOLDER))
                    continue;
                if (!assetPath.EndsWith(".spriteatlasv2") && !assetPath.EndsWith(".spriteatlas"))
                    continue;

                try
                {
                    var importer = SpriteAtlasImporter.GetAtPath(assetPath) as SpriteAtlasImporter;
                    if (importer == null)
                        continue;

                    if (TexturePlatformFormatHelper.ApplyAtlasPlatformSettings(importer))
                    {
                        importer.SaveAndReimport();
                        Debug.Log($"[TexImport] 图集: {assetPath}");
                    }
                }
                catch (System.Exception ex)
                {
                    Debug.LogError($"[TexImport] 图集失败 {assetPath}: {ex.Message}");
                }
            }
        }
        finally
        {
            s_IsApplying = false;
        }
    }
}