// ClassicalSharp copyright 2014-2016 UnknownShadow200 | Licensed under MIT
using System;
using System.Drawing;
using System.IO;
using ClassicalSharp.GraphicsAPI;
using ClassicalSharp.Model;
using ClassicalSharp.Network;
#if ANDROID
using Android.Graphics;
#endif
using PathIO = System.IO.Path; // Android.Graphics.Path clash otherwise

namespace ClassicalSharp.Textures {
	
	/// <summary> Extracts resources from a .zip texture pack. </summary>
	public sealed class TexturePack {
		
		public const string Dir = "texpacks";
		Game game;
		public void Extract( string path, Game game ) {
			path = PathIO.Combine( Dir, path );
			path = PathIO.Combine( Program.AppDirectory, path );
			using( Stream fs = File.OpenRead( path ) )
				Extract( fs, game );
		}
		
		public void Extract( Stream stream, Game game ) {
			this.game = game;
			game.Events.RaiseTexturePackChanged();
			ZipReader reader = new ZipReader();
			
			reader.ShouldProcessZipEntry = (f) => true;
			reader.ProcessZipEntry = ProcessZipEntry;
			reader.Extract( stream );
		}
		
		void ProcessZipEntry( string filename, byte[] data, ZipEntry entry ) {
			// Ignore directories: convert x/name to name and x\name to name.
			string name = Utils.ToLower( filename );
			int i = name.LastIndexOf( '\\' );
			if( i >= 0 ) name = name.Substring( i + 1, name.Length - 1 - i );
			i = name.LastIndexOf( '/' );
			if( i >= 0 ) name = name.Substring( i + 1, name.Length - 1 - i );
			game.Events.RaiseTextureChanged( name, data );
		}
		
		
		internal static void ExtractTerrainPng( Game game, string url, DownloadedItem item ) {
			if( item != null && item.Data != null ) {
				Bitmap bmp = (Bitmap)item.Data;
				game.World.TextureUrl = item.Url;
				game.Events.RaiseTexturePackChanged();
				
				if( !Platform.Is32Bpp( bmp ) ) {
					Utils.LogDebug( "Converting terrain atlas to 32bpp image" );
					game.Drawer2D.ConvertTo32Bpp( ref bmp );
				}
				if( !game.ChangeTerrainAtlas( bmp, null ) ) { bmp.Dispose(); return; }
				
				TextureCache.Add( item.Url, bmp );
				TextureCache.AddETag( item.Url, item.ETag, game.ETags );
				TextureCache.AdddLastModified( item.Url, item.LastModified, game.LastModified );
			} else {
				FileStream data = TextureCache.GetStream( url );
				if( data == null ) { // e.g. 404 errors
					ExtractDefault( game );
				} else if( url != game.World.TextureUrl ) {
					Bitmap bmp = GetBitmap( data );
					if( bmp == null ) { data.Dispose(); return; }
					
					game.World.TextureUrl = url;
					game.Events.RaiseTexturePackChanged();
					if( game.ChangeTerrainAtlas( bmp, data ) ) return;	
					
					bmp.Dispose(); 
					data.Dispose();
				} else {
					data.Dispose();
				}
			}
		}
		
		internal static void ExtractTexturePack( Game game, string url, DownloadedItem item ) {
			if( item != null && item.Data != null ) {
				game.World.TextureUrl = item.Url;
				byte[] data = (byte[])item.Data;
				TexturePack extractor = new TexturePack();
				using( Stream ms = new MemoryStream( data ) ) {
					extractor.Extract( ms, game );
				}
				
				TextureCache.Add( item.Url, data );
				TextureCache.AddETag( item.Url, item.ETag, game.ETags );
				TextureCache.AdddLastModified( item.Url, item.LastModified, game.LastModified );
			} else {
				FileStream data = TextureCache.GetStream( url );
				if( data == null ) { // e.g. 404 errors
					ExtractDefault( game );
				} else if( url != game.World.TextureUrl ) {
					game.World.TextureUrl = url;
					TexturePack extractor = new TexturePack();
					extractor.Extract( data, game );
				}
			}
		}
		
		
		internal static void ExtractDefault( Game game ) {
			TexturePack extractor = new TexturePack();
			extractor.Extract( game.DefaultTexturePack, game );
			game.World.TextureUrl = null;
		}

		static Bitmap GetBitmap( FileStream fs ) {
			try {
				return Platform.ReadBmp( fs );
			} catch( ArgumentException ex ) {
				ErrorHandler.LogError( "Cache.GetBitmap", ex );
				return null;
			} catch( IOException ex ) {
				ErrorHandler.LogError( "Cache.GetBitmap", ex );
				return null;
			}
		}
	}
}