Add update checker to notify about new versions (#22)

Checks GitHub releases API on startup and logs a message if a newer
version is available. The check runs asynchronously to avoid blocking
server startup.

Author: robinbraemer

core/src/main/java/com/minekube/connect/ConnectPlatform.java

@@ -43,6 +43,7 @@
 import com.minekube.connect.register.WatcherRegister;
 import com.minekube.connect.tunnel.Tunneler;
 import com.minekube.connect.util.Metrics;
+import com.minekube.connect.util.UpdateChecker;
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
@@ -127,6 +128,9 @@ public boolean enable(Module... postInitializeModules) {
         }
         logger.info("Your public address: " + config.getEndpoint() + DOMAIN_SUFFIX);
 
+        // Check for updates asynchronously
+        guice.getInstance(UpdateChecker.class).checkForUpdates();
+
         return true;
     }
 

core/src/main/java/com/minekube/connect/util/UpdateChecker.java

@@ -0,0 +1,90 @@
+package com.minekube.connect.util;
+
+import com.google.gson.JsonObject;
+import com.google.inject.Inject;
+import com.minekube.connect.api.logger.ConnectLogger;
+
+public class UpdateChecker {
+    private static final String GITHUB_API_URL =
+            "https://api.github.com/repos/minekube/connect-java/releases/latest";
+
+    private final ConnectLogger logger;
+
+    @Inject
+    public UpdateChecker(ConnectLogger logger) {
+        this.logger = logger;
+    }
+
+    public void checkForUpdates() {
+        HttpUtils.asyncGet(GITHUB_API_URL).thenAccept(response -> {
+            if (!response.isCodeOk()) {
+                logger.debug("Failed to check for updates: HTTP " + response.getHttpCode());
+                return;
+            }
+
+            JsonObject json = response.getResponse();
+            if (json == null || !json.has("tag_name")) {
+                logger.debug("Failed to parse update response");
+                return;
+            }
+
+            String latestVersion = json.get("tag_name").getAsString();
+            String currentVersion = Constants.VERSION;
+
+            // Remove 'v' prefix if present
+            if (latestVersion.startsWith("v")) {
+                latestVersion = latestVersion.substring(1);
+            }
+
+            // Skip check for development versions
+            if (currentVersion.contains("SNAPSHOT") || currentVersion.contains("${")) {
+                logger.debug("Running development version, skipping update check");
+                return;
+            }
+
+            if (isNewerVersion(latestVersion, currentVersion)) {
+                logger.info("A new version of Connect is available: " + latestVersion
+                        + " (current: " + currentVersion + ")");
+                logger.info("Download: https://github.com/minekube/connect-java/releases/latest");
+            } else {
+                logger.debug("Connect is up to date (version " + currentVersion + ")");
+            }
+        }).exceptionally(throwable -> {
+            logger.debug("Failed to check for updates: " + throwable.getMessage());
+            return null;
+        });
+    }
+
+    /**
+     * Compares two semantic version strings.
+     * @return true if latestVersion is newer than currentVersion
+     */
+    private boolean isNewerVersion(String latestVersion, String currentVersion) {
+        try {
+            int[] latest = parseVersion(latestVersion);
+            int[] current = parseVersion(currentVersion);
+
+            for (int i = 0; i < Math.max(latest.length, current.length); i++) {
+                int l = i < latest.length ? latest[i] : 0;
+                int c = i < current.length ? current[i] : 0;
+                if (l > c) return true;
+                if (l < c) return false;
+            }
+            return false;
+        } catch (Exception e) {
+            // If parsing fails, do string comparison
+            return !latestVersion.equals(currentVersion);
+        }
+    }
+
+    private int[] parseVersion(String version) {
+        // Remove any suffix like -SNAPSHOT, -beta, etc.
+        String cleanVersion = version.split("-")[0];
+        String[] parts = cleanVersion.split("\\.");
+        int[] result = new int[parts.length];
+        for (int i = 0; i < parts.length; i++) {
+            result[i] = Integer.parseInt(parts[i]);
+        }
+        return result;
+    }
+}