Implemented a simple cli

cli/build.gradle

@@ -0,0 +1,31 @@
+plugins {
+    id 'application'
+    id 'java'
+    id 'com.github.spotbugs'
+    id 'idea'
+}
+
+group = 'lt.pow.nukagit'
+version = '0.1.0-SNAPSHOT'
+mainClassName = 'lt.pow.nukagit.cli.Main'
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation project(":proto")
+    implementation 'com.google.protobuf:protobuf-java:_'
+    implementation 'io.grpc:grpc-stub:_'
+    implementation 'io.grpc:grpc-protobuf:_'
+    implementation 'javax.annotation:javax.annotation-api:_'
+    implementation 'io.grpc:grpc-netty:_'
+
+    // Command line parsing
+    implementation 'info.picocli:picocli:_'
+}
+
+java {
+    sourceCompatibility = JavaVersion.toVersion("17")
+    targetCompatibility = JavaVersion.toVersion("17")
+}

cli/src/main/java/lt/pow/nukagit/cli/AddUser.java

@@ -0,0 +1,56 @@
+package lt.pow.nukagit.cli;
+
+import lt.pow.nukagit.proto.Users;
+import picocli.CommandLine;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+
+@CommandLine.Command(name = "add_user", description = "Add user")
+public class AddUser implements Runnable {
+
+    @CommandLine.ParentCommand
+    private Main parent;
+
+    @CommandLine.Parameters(index = "0", description = "Username to add.")
+    private String username;
+
+    @CommandLine.Option(names = {"-k", "--key"}, description = "Specify a key (exclusive with --key-file)")
+    private String keyString;
+
+    @CommandLine.Option(names = {"-F", "--key-file"}, description = "Specify a key file (exclusive with --key)")
+    private File keyFile;
+
+    @Override
+    public void run() {
+        if (keyString != null && keyFile != null) {
+            System.err.println("Cannot specify both --key and --key-file");
+            System.exit(1);
+        } else if (keyString == null && keyFile == null) {
+            System.err.println("Must specify either --key or --key-file");
+            System.exit(1);
+        }
+
+        if (keyFile != null) {
+            // read key from file
+            byte[] keyBytes;
+            try {
+                keyBytes = Files.readAllBytes(keyFile.toPath());
+            } catch (IOException e) {
+                System.err.println("Failed to read key file: " + e.getMessage());
+                System.exit(1);
+                return;
+            }
+            keyString = new String(keyBytes, StandardCharsets.UTF_8);
+        }
+
+        System.out.println("Adding User " + username + " with key " + keyString);
+        parent.usersGrpcClient().createUser(Users.CreateUserRequest.newBuilder()
+                .setUsername(username)
+                .setPublicKey(keyString)
+                .build());
+        System.out.println("User added");
+    }
+}

cli/src/main/java/lt/pow/nukagit/cli/Main.java

@@ -0,0 +1,65 @@
+package lt.pow.nukagit.cli;
+
+import io.grpc.ManagedChannel;
+import io.grpc.ManagedChannelBuilder;
+import lt.pow.nukagit.proto.RepositoriesServiceGrpc;
+import lt.pow.nukagit.proto.UsersServiceGrpc;
+import picocli.CommandLine;
+
+@CommandLine.Command(name = "nuka_cli", description = "NukaGit CLI client",
+        subcommands = {
+                AddUser.class
+        })
+public class Main implements Runnable {
+    @CommandLine.Option(names = {"-h", "--help"}, usageHelp = true, description = "Display this help message")
+    private boolean helpRequested;
+
+    @CommandLine.Option(names = {"-H", "--host"}, description = "host to connect to", defaultValue = "localhost")
+    private String host;
+
+    @CommandLine.Option(names = {"-p", "--port"}, description = "port to connect to", defaultValue = "50051")
+    private Integer port;
+
+    private ManagedChannel channel;
+    RepositoriesServiceGrpc.RepositoriesServiceBlockingStub repositoriesGrpcClient;
+    UsersServiceGrpc.UsersServiceBlockingStub usersGrpcClient;
+
+    ManagedChannel getChannel() {
+        if (channel == null) {
+            channel = ManagedChannelBuilder.forAddress(host, port)
+                    .usePlaintext()
+                    .build();
+        }
+        return channel;
+    }
+
+    public RepositoriesServiceGrpc.RepositoriesServiceBlockingStub repositoriesGrpcClient() {
+        if (repositoriesGrpcClient == null) {
+            repositoriesGrpcClient = RepositoriesServiceGrpc.newBlockingStub(getChannel());
+        }
+        return repositoriesGrpcClient;
+    }
+
+    public UsersServiceGrpc.UsersServiceBlockingStub usersGrpcClient() {
+        if (usersGrpcClient == null) {
+            usersGrpcClient = UsersServiceGrpc.newBlockingStub(getChannel());
+        }
+        return usersGrpcClient;
+    }
+
+    @Override
+    public void run() {
+        CommandLine cmd = new CommandLine(this);
+        // This method is called if no subcommands are specified
+        if (helpRequested || cmd.getUnmatchedArguments().isEmpty()) {
+            cmd.usage(System.out);
+        } else {
+            System.out.println("No valid subcommands provided. Use -h or --help for usage information.");
+        }
+    }
+
+    public static void main(String[] args) {
+        CommandLine commandLine = new CommandLine(new Main());
+        commandLine.execute(args);
+    }
+}

settings.gradle

@@ -3,7 +3,7 @@ plugins {
 }
 
 rootProject.name = 'nukagit'
-include 'proto'
+include 'proto', 'cli'
 
 refreshVersions {
     rejectVersionIf {