using UnityEngine;
using UnityEditor;
using System;
using System.IO;
using System.Linq;
using System.Reflection;

namespace FlashTools.Internal {
	public class SwfAnimationAssetPostprocessor : AssetPostprocessor {
		static void OnPostprocessAllAssets(
			string[] imported_assets,
			string[] deleted_assets,
			string[] moved_assets,
			string[] moved_from_asset_paths)
		{
			var asset_paths = imported_assets
				.Where(p => Path.GetExtension(p).ToLower().Equals(".asset"));
			foreach ( var asset_path in asset_paths ) {
				var asset = AssetDatabase.LoadAssetAtPath<SwfAnimationAsset>(asset_path);
				if ( asset ) {
					AssetProcess(asset_path, asset);
				}
			}
		}

		static void AssetProcess(string asset_path, SwfAnimationAsset asset) {
			try {
				var atlas_asset = LoadAtlasAsset(asset_path);
				if ( atlas_asset != asset.Atlas ) {
					asset.Atlas = atlas_asset;
					ConfigureAtlas(asset_path, asset);
					EditorUtility.SetDirty(asset);
					AssetDatabase.SaveAssets();
				}
			} catch ( Exception e ) {
				Debug.LogErrorFormat(
					"Postprocess swf animation asset error: {0}",
					e.Message);
			}
		}

		static Texture2D LoadAtlasAsset(string asset_path) {
			return AssetDatabase.LoadAssetAtPath<Texture2D>(
				GetAtlasPath(asset_path));
		}

		static string GetAtlasPath(string asset_path) {
			return Path.ChangeExtension(asset_path, ".png");
		}

		static void ConfigureAtlas(string asset_path, SwfAnimationAsset asset) {
			var atlas_importer      = GetBitmapsAtlasImporter(asset_path);
			var atlas_importer_size = GetSizeFromTextureImporter(atlas_importer);
			atlas_importer.spritesheet = asset.Data.Bitmaps
				.Select(bitmap => new SpriteMetaData{
					name = bitmap.Id.ToString(),
					rect = new Rect(
						bitmap.SourceRect.xMin   * atlas_importer_size.x,
						bitmap.SourceRect.yMin   * atlas_importer_size.y,
						bitmap.SourceRect.width  * atlas_importer_size.x,
						bitmap.SourceRect.height * atlas_importer_size.y)})
				.ToArray();
			atlas_importer.textureType         = TextureImporterType.Sprite;
			atlas_importer.spriteImportMode    = SpriteImportMode.Multiple;
			atlas_importer.spritePixelsPerUnit = asset.Settings.PixelsPerUnit;
			atlas_importer.mipmapEnabled       = asset.Settings.GenerateMipMaps;
			atlas_importer.filterMode          = SwfAtlasFilterToImporterFilter(asset.Settings.AtlasTextureFilter);
			atlas_importer.textureFormat       = SwfAtlasFormatToImporterFormat(asset.Settings.AtlasTextureFormat);
			AssetDatabase.ImportAsset(
				GetAtlasPath(asset_path),
				ImportAssetOptions.ForceUpdate);
		}

		static TextureImporter GetBitmapsAtlasImporter(string asset_path) {
			var atlas_path     = GetAtlasPath(asset_path);
			var atlas_importer = AssetImporter.GetAtPath(atlas_path) as TextureImporter;
			if ( !atlas_importer ) {
				throw new UnityException(string.Format(
					"atlas texture importer not found ({0})",
					atlas_path));
			}
			return atlas_importer;
		}

		static Vector2 GetSizeFromTextureImporter(TextureImporter importer) {
			var method_args = new object[2]{0,0};
			typeof(TextureImporter)
				.GetMethod("GetWidthAndHeight", BindingFlags.NonPublic | BindingFlags.Instance)
				.Invoke(importer, method_args);
			return new Vector2((int)method_args[0], (int)method_args[1]);
		}

		static FilterMode SwfAtlasFilterToImporterFilter(
			SwfConverterSettings.SwfAtlasFilter filter)
		{
			switch ( filter ) {
			case SwfConverterSettings.SwfAtlasFilter.Point:
				return FilterMode.Point;
			case SwfConverterSettings.SwfAtlasFilter.Bilinear:
				return FilterMode.Bilinear;
			case SwfConverterSettings.SwfAtlasFilter.Trilinear:
				return FilterMode.Trilinear;
			default:
				throw new UnityException(string.Format(
					"incorrect swf atlas filter ({0})",
					filter));
			}
		}

		static TextureImporterFormat SwfAtlasFormatToImporterFormat(
			SwfConverterSettings.SwfAtlasFormat format)
		{
			switch ( format ) {
			case SwfConverterSettings.SwfAtlasFormat.AutomaticCompressed:
				return TextureImporterFormat.AutomaticCompressed;
			case SwfConverterSettings.SwfAtlasFormat.Automatic16bit:
				return TextureImporterFormat.Automatic16bit;
			case SwfConverterSettings.SwfAtlasFormat.AutomaticTruecolor:
				return TextureImporterFormat.AutomaticTruecolor;
			case SwfConverterSettings.SwfAtlasFormat.AutomaticCrunched:
				return TextureImporterFormat.AutomaticCrunched;
			default:
				throw new UnityException(string.Format(
					"incorrect swf atlas format ({0})",
					format));
			}
		}
	}
}