Add option to fetch resources. (thanks Jonty800)

Launcher/Launcher.csproj

@@ -80,6 +80,7 @@
     <Compile Include="MinecraftSession.cs" />
     <Compile Include="Program.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="ResourceFetcher.cs" />
     <Compile Include="ServerListEntry.cs" />
     <Compile Include="WebUtility.cs" />
   </ItemGroup>

Launcher/MainForm.cs

@@ -24,6 +24,20 @@ namespace Launcher {
 			tabMC.TabPages.Remove( tabMCServer );
 			tabCC.TabPages.Remove( tabCCServers );
 			tabCC.TabPages.Remove( tabCCServer );
+			Shown += DisplayResourcesDialog;
+		}
+		
+		void DisplayResourcesDialog( object sender, EventArgs e ) {
+			// TODO: async fetching
+			ResourceFetcher fetcher = new ResourceFetcher();
+			if( !fetcher.CheckAllResourcesExist() ) {
+				DialogResult result = MessageBox.Show(
+					"Some required resources weren't found. Would you like to download them now?", "Missing resources",
+					MessageBoxButtons.OKCancel );
+				if( result == DialogResult.OK ) {				
+					fetcher.Run();
+				}			
+			}
 		}
 		
 		delegate void Action<T1, T2>( T1 arg1, T2 arg2 );

Launcher/ResourceFetcher.cs

@@ -0,0 +1,47 @@
+using System;
+using System.IO;
+using System.Net;
+using System.Windows.Forms;
+
+namespace Launcher {
+	
+	public class ResourceFetcher {
+		
+		const string terrainUri = "https://raw.githubusercontent.com/andrewphorn/ClassiCube-Client/master/src/main/resources/terrain.png";
+		const string cloudsUri = "https://raw.githubusercontent.com/andrewphorn/ClassiCube-Client/master/src/main/resources/clouds.png";
+		const string charUri = "https://raw.githubusercontent.com/andrewphorn/ClassiCube-Client/master/src/main/resources/char.png";
+		
+		public void Run() {
+			using( WebClient client = new WebClient() ) {
+				client.Proxy = null;
+				if( !DownloadData( terrainUri, client, "terrain.png" ) ) return;
+				if( !DownloadData( cloudsUri, client, "clouds.png" ) ) return;
+				if( !DownloadData( charUri, client, "char.png" ) ) return;
+			}
+		}
+		
+		static bool DownloadData( string uri, WebClient client, string output ) {
+			if( File.Exists( output ) ) return true;
+			
+			byte[] data = null;
+			try {
+				data = client.DownloadData( uri );
+			} catch( WebException ) {
+				MessageBox.Show( "Unable to download " + output, "Failed to download resource", MessageBoxButtons.OK, MessageBoxIcon.Error );
+				return false;
+			}
+			
+			try {
+				File.WriteAllBytes( output, data );
+			} catch( IOException ) {
+				MessageBox.Show( "Unable to save " + output, "Failed to save resource", MessageBoxButtons.OK, MessageBoxIcon.Error );
+				return false;
+			}
+			return true;
+		}
+		
+		public bool CheckAllResourcesExist() {
+			return File.Exists( "terrain.png" ) && File.Exists( "clouds.png" ) && File.Exists( "char.png" );
+		}
+	}
+}