// ClassicalSharp copyright 2014-2016 UnknownShadow200 | Licensed under MIT
using System;
using System.Diagnostics;
using System.IO;
using System.Net;
using System.Runtime.InteropServices;
using System.Threading;
using ClassicalSharp;
using ClassicalSharp.TexturePack;
using Launcher.Web;

namespace Launcher.Updater {
	
	public static class Applier {
		
		public static DateTime PatchTime;
		
		public static void FetchUpdate( string dir ) {
			using( WebClient client = new WebClient() ) {
				WebRequest.DefaultWebProxy = null;
				byte[] zipData = client.DownloadData( UpdateCheckTask.UpdatesUri + dir );
				MakeUpdatesFolder( zipData );
			}
		}

		public static void ApplyUpdate() {
			ProcessStartInfo info = new ProcessStartInfo();
			info.CreateNoWindow = false;
			info.UseShellExecute = true;
			info.WorkingDirectory = Program.AppDirectory;
			
			if( OpenTK.Configuration.RunningOnWindows ) {
				string path = Path.Combine( Program.AppDirectory, "update.bat" );
				File.WriteAllText( path, Scripts.BatchFile );
				info.FileName = "cmd"; info.Arguments = "/C start cmd /C update.bat";
				Process.Start( info );
 			} else {
				string path = Path.Combine( Program.AppDirectory, "update.sh" );
				File.WriteAllText( path, Scripts.BashFile.Replace( "\r\n", "\n" ) );
				const int flags = 0x7;// read | write | executable
				int code = chmod( path, (flags << 6) | (flags << 3) | 4 );
				if( code != 0 )
					throw new InvalidOperationException( "chmod returned : " + code );
				
				//if( OpenTK.Configuration.RunningOnMacOS )
				//	info = new ProcessStartInfo( "open -a Terminal ",
				//	                            '"' + path + '"');
				//else
				info.FileName = "xterm"; info.Arguments = '"' + path + '"';
				Process.Start( info );
			}
		}

		[DllImport( "libc", SetLastError = true )]
		internal static extern int chmod( string path, int mode );
		
		static void MakeUpdatesFolder( byte[] zipData ) {
			using( MemoryStream stream = new MemoryStream( zipData ) ) {
				ZipReader reader = new ZipReader();
				string path = Path.Combine( Program.AppDirectory, "CS_Update" );
				Directory.CreateDirectory( path );
				
				reader.ShouldProcessZipEntry = (f) => true;
				reader.ProcessZipEntry = ProcessZipEntry;
				reader.Extract( stream );
			}
		}
		
		static void ProcessZipEntry( string filename, byte[] data, ZipEntry entry ) {
			string path = Path.Combine( Program.AppDirectory, "CS_Update" );
			path = Path.Combine( path, Path.GetFileName( filename ) );
			File.WriteAllBytes( path, data );
			
			try {
				File.SetLastWriteTimeUtc( path, PatchTime );
			} catch( IOException ex ) {
				ErrorHandler.LogError( "I/O exception when trying to set modified time for: " + filename, ex );
			} catch( UnauthorizedAccessException ex ) {
				ErrorHandler.LogError( "Permissions exception when trying to set modified time for: " + filename, ex );
			}
		}
	}
}