Implement CG Version mismatch warning

Author: juho05

pom.xml

@@ -34,6 +34,11 @@
         <artifactId>commons-io</artifactId>
         <version>2.11.0</version>
     </dependency>
+    <dependency>
+      <groupId>org.fusesource.jansi</groupId>
+      <artifactId>jansi</artifactId>
+      <version>2.4.0</version>
+    </dependency>
   </dependencies>
 
   <build>

src/main/java/org/codegame/client/GameSocket.java

@@ -9,7 +9,13 @@
 import com.google.gson.annotations.SerializedName;
 import com.google.gson.reflect.TypeToken;
 
+import org.fusesource.jansi.Ansi;
+import org.fusesource.jansi.AnsiConsole;
+import org.fusesource.jansi.Ansi.*;
+
 public class GameSocket {
+	private static final String cgVersion = "0.8";
+
 	@FunctionalInterface
 	public interface EventCallback<T> {
 		void cb(T data);
@@ -33,8 +39,15 @@ private class Callbacks<T> {
 	private HashMap<String, Callbacks> eventListeners = new HashMap<>();
 	private CountDownLatch exitEvent = new CountDownLatch(1);
 
-	public GameSocket(String url) {
+	public GameSocket(String url) throws IOException {
+		AnsiConsole.systemInstall();
 		api = new Api(url);
+		var info = api.fetchInfo();
+		if (!isVersionCompatible(info.cgVersion)) {
+			System.out.println(Ansi.ansi().fg(Color.YELLOW)
+					.a("WARNING: CodeGame version mismatch. Server: v" + info.cgVersion + ", client: v" + cgVersion)
+					.reset());
+		}
 	}
 
 	public Api.GameData createGame(boolean makePublic, boolean protect, Object config) throws IOException {
@@ -156,7 +169,7 @@ public <T> String once(String eventName, Class<T> type, EventCallback<T> callbac
 	}
 
 	public <T> void send(String commandName, T data) {
-		if (websocket == null || session.getPlayerId() == "")
+		if (websocket == null || session.getPlayerId().isEmpty())
 			throw new IllegalStateException("The socket is not connected to a player.");
 		Event<T> e = new Event<>(commandName, data);
 		var json = Api.json.toJson(e, TypeToken.getParameterized(Event.class, data.getClass()).getType());
@@ -205,4 +218,27 @@ private void onMessage(String message) {
 	private void onClose() {
 		exitEvent.countDown();
 	}
+
+	private static boolean isVersionCompatible(String serverVersion) {
+		var serverParts = serverVersion.split("\\.");
+		if (serverParts.length == 1)
+			serverParts = new String[] { serverParts[0], "0" };
+		var clientParts = cgVersion.split("\\.");
+		if (clientParts.length == 1)
+			clientParts = new String[] { clientParts[0], "0" };
+
+		if (!serverParts[0].equals(clientParts[0]))
+			return false;
+
+		if (clientParts[0].equals("0"))
+			return serverParts[1].equals(clientParts[1]);
+
+		try {
+			var serverMinor = Integer.parseInt(serverParts[1]);
+			var clientMinor = Integer.parseInt(clientParts[1]);
+			return clientMinor <= serverMinor;
+		} catch (NumberFormatException e) {
+			return false;
+		}
+	}
 }

src/main/java/org/codegame/client/Session.java

@@ -43,8 +43,9 @@ public static Session load(String gameURL, String username) throws IOException {
                 FilenameUtils.concat(gamesPath, URLEncoder.encode(gameURL, "UTF-8") + "/" + username + ".json")));
         try {
             var session = Api.json.fromJson(reader, Session.class);
-            if (session.gameId == null || session.gameId == "" || session.playerId == null || session.playerId == ""
-                    || session.playerSecret == null || session.playerSecret == "") {
+            if (session.gameId == null || session.gameId.isEmpty() || session.playerId == null
+                    || session.playerId.isEmpty()
+                    || session.playerSecret == null || session.playerSecret.isEmpty()) {
                 throw new IOException("Incomplete session file.");
             }
             session.gameURL = gameURL;
@@ -56,7 +57,8 @@ public static Session load(String gameURL, String username) throws IOException {
     }
 
     public void save() throws IOException, Exception {
-        if (gameURL == "" || username == "" || gameId == "" || playerId == "" || playerSecret == "") {
+        if (gameURL.isEmpty() || username.isEmpty() || gameId.isEmpty() || playerId.isEmpty()
+                || playerSecret.isEmpty()) {
             throw new Exception("Incomplete session file.");
         }
         var dir = new File(FilenameUtils.concat(gamesPath, URLEncoder.encode(gameURL, "UTF-8")));
@@ -73,7 +75,7 @@ public void save() throws IOException, Exception {
 
     public void remove() {
         try {
-            if (gameURL == "")
+            if (gameURL.isEmpty())
                 return;
 
             var dir = new File(FilenameUtils.concat(gamesPath, URLEncoder.encode(gameURL, "UTF-8")));