using System.IO;
using UnityEditor;
using UnityEngine;

namespace TKS.EditorTools
{
    /// <summary>
    /// Assets/Resources/Units/&lt;art&gt;/&lt;clip&gt;/f###.png 임포트 설정: 단일 스프라이트 · 피벗 = meta.json pivot(발) · PPU = meta.ppu · 밉맵 없음 · 무압축.
    /// meta.json 은 skeletal-anim-pipeline `rig_frames_export.py` 가 쓴다.
    /// </summary>
    public class UnitArtImporter : AssetPostprocessor
    {
        public const string Root = "Assets/Resources/Units/";
        /// <summary>전장 배경(원화 세션 납품 · 5:8 불투명 · PPU 100 = 전장 20×32 월드).</summary>
        public const string BoardRoot = "Assets/Resources/Board/";
        /// <summary>챕터 월드맵(Maps = 2160×3840 불투명) · 거점 UI 부품(UI = 투명 · pivot·9-slice·PPU = UI/import.json).</summary>
        public const string ChapterMapRoot = "Assets/Resources/ChapterMap/";

        [System.Serializable]
        class ChapterUiImport
        {
            public string file;
            public float[] pivot;
            public float[] border;
            public float ppu;
        }

        [System.Serializable]
        class ChapterUiImportList
        {
            public ChapterUiImport[] items;
        }

        void OnPreprocessTexture()
        {
            string path = assetPath.Replace('\\', '/');
            if (path.StartsWith(ChapterMapRoot))
            {
                PreprocessChapterMap(path);
                return;
            }
            if (path.StartsWith(BoardRoot))
            {
                var bi = (TextureImporter)assetImporter;
                bi.textureType = TextureImporterType.Sprite;
                bi.spriteImportMode = SpriteImportMode.Single;
                bi.mipmapEnabled = false;
                bi.filterMode = FilterMode.Bilinear;
                bi.alphaIsTransparency = false;
                bi.textureCompression = TextureImporterCompression.Compressed;
                bi.maxTextureSize = 4096;
                bi.spritePixelsPerUnit = 100f;
                var bs = new TextureImporterSettings();
                bi.ReadTextureSettings(bs);
                bs.spriteMeshType = SpriteMeshType.FullRect;
                bs.spriteAlignment = (int)SpriteAlignment.Center;
                bi.SetTextureSettings(bs);
                return;
            }
            if (!path.StartsWith(Root)) return;
            var ti = (TextureImporter)assetImporter;
            ti.textureType = TextureImporterType.Sprite;
            ti.spriteImportMode = SpriteImportMode.Single;
            ti.mipmapEnabled = false;
            ti.filterMode = FilterMode.Bilinear;
            ti.alphaIsTransparency = true;
            ti.textureCompression = TextureImporterCompression.Uncompressed;
            ti.maxTextureSize = 2048;

            var meta = LoadMeta(path);
            var s = new TextureImporterSettings();
            ti.ReadTextureSettings(s);
            s.spriteMeshType = SpriteMeshType.FullRect;
            if (meta != null && meta.pivot != null && meta.pivot.Length == 2)
            {
                s.spriteAlignment = (int)SpriteAlignment.Custom;
                s.spritePivot = new Vector2(meta.pivot[0], meta.pivot[1]);
            }
            if (meta != null && meta.ppu > 0.01f) s.spritePixelsPerUnit = meta.ppu;
            ti.SetTextureSettings(s);
        }

        void PreprocessChapterMap(string path)
        {
            var ti = (TextureImporter)assetImporter;
            ti.textureType = TextureImporterType.Sprite;
            ti.spriteImportMode = SpriteImportMode.Single;
            ti.mipmapEnabled = false;
            ti.filterMode = FilterMode.Bilinear;
            var s = new TextureImporterSettings();
            if (path.StartsWith(ChapterMapRoot + "Maps/"))
            {
                ti.alphaIsTransparency = false;
                ti.textureCompression = TextureImporterCompression.Compressed;
                ti.maxTextureSize = 4096;
                ti.spritePixelsPerUnit = 100f;
                ti.ReadTextureSettings(s);
                s.spriteMeshType = SpriteMeshType.FullRect;
                s.spriteAlignment = (int)SpriteAlignment.Center;
                ti.SetTextureSettings(s);
                return;
            }
            ti.alphaIsTransparency = true;
            ti.textureCompression = TextureImporterCompression.Uncompressed;
            ti.maxTextureSize = 1024;
            ti.ReadTextureSettings(s);
            s.spriteMeshType = SpriteMeshType.FullRect;
            var item = FindChapterUi(path);
            if (item != null)
            {
                if (item.pivot != null && item.pivot.Length == 2)
                {
                    s.spriteAlignment = (int)SpriteAlignment.Custom;
                    s.spritePivot = new Vector2(item.pivot[0], 1f - item.pivot[1]); // import.json = 이미지 좌표(위 → 아래)
                }
                if (item.border != null && item.border.Length == 4)
                    s.spriteBorder = new Vector4(item.border[0], item.border[1], item.border[2], item.border[3]);
                if (item.ppu > 0.01f) s.spritePixelsPerUnit = item.ppu;
            }
            ti.SetTextureSettings(s);
        }

        static ChapterUiImport FindChapterUi(string texPath)
        {
            string dir = Path.GetDirectoryName(texPath);
            if (string.IsNullOrEmpty(dir)) return null;
            string json = Path.Combine(dir, "import.json");
            if (!File.Exists(json)) return null;
            try
            {
                var list = JsonUtility.FromJson<ChapterUiImportList>(File.ReadAllText(json));
                string name = Path.GetFileName(texPath);
                if (list != null && list.items != null)
                    foreach (var it in list.items)
                        if (it.file == name) return it;
            }
            catch
            {
                // 표가 깨졌으면 기본 설정
            }
            return null;
        }

        static UnitArtMeta LoadMeta(string texPath)
        {
            string clipDir = Path.GetDirectoryName(texPath);
            string artDir = clipDir != null ? Path.GetDirectoryName(clipDir) : null;
            if (string.IsNullOrEmpty(artDir)) return null;
            string metaPath = Path.Combine(artDir, "meta.json");
            if (!File.Exists(metaPath)) return null;
            try
            {
                return JsonUtility.FromJson<UnitArtMeta>(File.ReadAllText(metaPath));
            }
            catch
            {
                return null;
            }
        }

        /// <summary>프레임을 새로 넣거나 meta.json 피벗을 바꾼 뒤 임포트 설정을 다시 적용한다(메뉴 · CLI `-executeMethod TKS.EditorTools.UnitArtImporter.ReimportAll`).</summary>
        [MenuItem("TKS/Reimport Unit Art (유닛 아트 재임포트)")]
        public static void ReimportAll()
        {
            foreach (var root in new[] { Root, BoardRoot, ChapterMapRoot })
            {
                string dir = root.TrimEnd('/');
                if (!AssetDatabase.IsValidFolder(dir))
                {
                    Debug.Log("[TKS] " + dir + " 없음");
                    continue;
                }
                AssetDatabase.ImportAsset(dir, ImportAssetOptions.ImportRecursive | ImportAssetOptions.ForceUpdate);
                Debug.Log("[TKS] 아트 재임포트 완료 · " + dir);
            }
            AssetDatabase.Refresh();
        }
    }
}