Dev api

api/build.gradle.kts

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+plugins {
+    `java-library`
+    `checkstyle`
+}
+
+java {
+    toolchain { languageVersion.set(JavaLanguageVersion.of(21)) }
+    withSourcesJar()
+    withJavadocJar()
+}
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    testImplementation(libs.junit.jupiter)
+}
+
+tasks.test {
+    useJUnitPlatform()
+}

api/src/main/java/dev/objz/commandbridge/api/CommandBridgeAPI.java

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+package dev.objz.commandbridge.api;
+
+import dev.objz.commandbridge.api.channel.ChannelPayload;
+import dev.objz.commandbridge.api.channel.ChannelType;
+import dev.objz.commandbridge.api.channel.MessageChannel;
+import dev.objz.commandbridge.api.message.ServerEventListener;
+import dev.objz.commandbridge.api.message.Subscription;
+import dev.objz.commandbridge.api.platform.ConnectionState;
+import dev.objz.commandbridge.api.platform.Platform;
+import dev.objz.commandbridge.api.platform.PlayerLocator;
+
+import java.util.Optional;
+import java.util.Set;
+import java.util.concurrent.CompletableFuture;
+import java.util.function.Consumer;
+
+/** Main entry point for interacting with the CommandBridge network. */
+public interface CommandBridgeAPI {
+
+    /**
+     * Obtains a {@link MessageChannel} for the given {@link ChannelType}.
+     *
+     * @param type the channel type identity
+     * @param <T> the payload type
+     * @param <C> the channel interface type
+     * @return the message channel
+     */
+    <T extends ChannelPayload, C extends MessageChannel<T>> C channel(ChannelType<T, C> type);
+
+    /**
+     * Broadcasts a payload to all connected servers on a specific channel.
+     *
+     * @param channel the channel to broadcast on
+     * @param payload the data to send
+     * @return a future that completes when the broadcast is dispatched
+     */
+    <P extends ChannelPayload> CompletableFuture<Void> broadcast(MessageChannel<P> channel, P payload);
+
+    /** @return the identity of the current server */
+    Platform.ServerTarget server();
+
+    /** @return the current connection state to the bridge network */
+    ConnectionState connectionState();
+
+    /** @return the IDs of all currently connected servers, if available */
+    Optional<Set<String>> connectedServers();
+
+    /** @return the player location lookup service, if available */
+    Optional<PlayerLocator> playerLocator();
+
+    /**
+     * Subscribes to server connection events.
+     *
+     * @param listener the listener to call when a server connects
+     * @return a subscription handle to cancel the listener
+     */
+    Subscription onServerConnected(ServerEventListener listener);
+
+    /**
+     * Subscribes to server disconnection events.
+     *
+     * @param listener the listener to call when a server disconnects
+     * @return a subscription handle to cancel the listener
+     */
+    Subscription onServerDisconnected(ServerEventListener listener);
+
+    /**
+     * Subscribes to connection state changes.
+     *
+     * @param listener the listener to call when the state changes
+     * @return a subscription handle to cancel the listener
+     */
+    Subscription onConnectionStateChanged(Consumer<ConnectionState> listener);
+}

api/src/main/java/dev/objz/commandbridge/api/CommandBridgeProvider.java

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+package dev.objz.commandbridge.api;
+
+import java.util.Objects;
+
+/** Static provider for accessing the {@link CommandBridgeAPI} instance. */
+public final class CommandBridgeProvider {
+
+    private static volatile CommandBridgeAPI instance;
+
+    private CommandBridgeProvider() {
+        throw new UnsupportedOperationException("Provider can't be instanced");
+    }
+
+    /**
+     * @return the registered API instance
+     * @throws IllegalStateException if the API is not registered
+     */
+    public static CommandBridgeAPI get() {
+        if (instance == null) {
+            throw new IllegalStateException("CommandBridge is not available. Is it installed and running?");
+        }
+        return instance;
+    }
+
+    /**
+     * Obtains the API instance cast to a specific type.
+     *
+     * @param type the API class type
+     * @param <T> the API type
+     * @return the cast API instance
+     * @throws IllegalStateException if the instance is not available or compatible
+     */
+    public static <T extends CommandBridgeAPI> T get(Class<T> type) {
+        CommandBridgeAPI api = get();
+        if (!type.isInstance(api)) {
+            throw new IllegalStateException(type.getSimpleName() + " is not available on this platform");
+        }
+        return type.cast(api);
+    }
+
+    /**
+     * Registers the API implementation.
+     *
+     * @param impl the implementation to register
+     * @throws IllegalStateException if an implementation is already registered
+     */
+    public static void register(CommandBridgeAPI impl) {
+        Objects.requireNonNull(impl);
+        if (instance != null) {
+            throw new IllegalStateException("CommandBridge already registered");
+        }
+        instance = impl;
+    }
+
+    /** Unregisters the current API implementation. */
+    public static void unregister() {
+        instance = null;
+    }
+}

api/src/main/java/dev/objz/commandbridge/api/channel/ChannelPayload.java

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+package dev.objz.commandbridge.api.channel;
+
+/** Marker interface for data sent over a {@link MessageChannel}. */
+public interface ChannelPayload {
+}

api/src/main/java/dev/objz/commandbridge/api/channel/ChannelType.java

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+package dev.objz.commandbridge.api.channel;
+
+import java.util.Objects;
+
+/**
+ * Identity and type information for a {@link MessageChannel}.
+ *
+ * @param <T> the payload type
+ * @param <C> the channel interface type
+ */
+public abstract class ChannelType<T extends ChannelPayload, C extends MessageChannel<T>> {
+
+    private final Class<T> type;
+
+    protected ChannelType(Class<T> type) {
+        this.type = Objects.requireNonNull(type);
+    }
+
+    /** @return the class of the payload handled by this channel */
+    public Class<T> type() {
+        return type;
+    }
+}

api/src/main/java/dev/objz/commandbridge/api/channel/Channels.java

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+package dev.objz.commandbridge.api.channel;
+
+import dev.objz.commandbridge.api.channel.command.CommandChannelType;
+
+/** Registry of built-in {@link ChannelType}s. */
+public final class Channels {
+
+    /** The default channel for executing commands. */
+    public static final CommandChannelType COMMAND = new CommandChannelType();
+
+    private Channels() {
+        throw new UnsupportedOperationException("Channels can't be instanced");
+    }
+}

api/src/main/java/dev/objz/commandbridge/api/channel/MessageChannel.java

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+package dev.objz.commandbridge.api.channel;
+
+import dev.objz.commandbridge.api.message.MessageListener;
+import dev.objz.commandbridge.api.message.Subscription;
+import dev.objz.commandbridge.api.platform.Platform;
+
+import java.time.Duration;
+import java.util.concurrent.CompletableFuture;
+
+/**
+ * Communication pipe for sending and receiving {@link ChannelPayload}s.
+ *
+ * @param <P> the type of payload handled by this channel
+ */
+public interface MessageChannel<P extends ChannelPayload> {
+
+    /**
+     * Sends a payload to a target server without expecting a response.
+     *
+     * @param target the destination server
+     * @param payload the data to send
+     * @return a future that completes when the message is sent
+     */
+    CompletableFuture<Void> send(Platform.ServerTarget target, P payload);
+
+    /**
+     * Sends a request to a target server and waits for a response.
+     *
+     * @param target the destination server
+     * @param payload the request data
+     * @return a future containing the response payload
+     */
+    CompletableFuture<P> request(Platform.ServerTarget target, P payload);
+
+    /**
+     * Sends a request to a target server with a custom timeout.
+     *
+     * @param target the destination server
+     * @param payload the request data
+     * @param timeout the maximum time to wait for a response
+     * @return a future containing the response payload
+     */
+    CompletableFuture<P> request(Platform.ServerTarget target, P payload, Duration timeout);
+
+    /**
+     * Subscribes a listener to messages received on this channel.
+     *
+     * @param listener the listener to call for incoming messages
+     * @return a subscription handle to cancel the listener
+     */
+    Subscription listen(MessageListener<P> listener);
+}

api/src/main/java/dev/objz/commandbridge/api/channel/command/CommandChannel.java

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+package dev.objz.commandbridge.api.channel.command;
+
+import dev.objz.commandbridge.api.channel.MessageChannel;
+import dev.objz.commandbridge.api.platform.Platform;
+
+import java.util.UUID;
+import java.util.concurrent.CompletableFuture;
+
+/** Specialized channel for dispatching commands to servers. */
+public interface CommandChannel extends MessageChannel<CommandPayload> {
+
+    /**
+     * Executes a command as the console.
+     *
+     * @param target the destination server
+     * @param command the command string to run
+     * @return a future that completes when the command is sent
+     */
+    default CompletableFuture<Void> console(Platform.ServerTarget target, String command) {
+        return send(target, CommandPayload.console(command));
+    }
+
+    /**
+     * Executes a command as a specific player.
+     *
+     * @param target the destination server
+     * @param command the command string to run
+     * @param player the UUID of the player to run as
+     * @return a future that completes when the command is sent
+     */
+    default CompletableFuture<Void> player(Platform.ServerTarget target, String command, UUID player) {
+        return send(target, CommandPayload.player(command, player));
+    }
+
+    /**
+     * Executes a command with operator permissions, bypassing standard checks.
+     *
+     * @param target the destination server
+     * @param command the command string to run
+     * @param player the UUID of the player to run as
+     * @return a future that completes when the command is sent
+     */
+    default CompletableFuture<Void> operator(Platform.ServerTarget target, String command, UUID player) {
+        return send(target, CommandPayload.operator(command, player));
+    }
+}

api/src/main/java/dev/objz/commandbridge/api/channel/command/CommandChannelType.java

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+package dev.objz.commandbridge.api.channel.command;
+
+import dev.objz.commandbridge.api.channel.ChannelType;
+
+/** Identity for the {@link CommandChannel}. */
+public final class CommandChannelType extends ChannelType<CommandPayload, CommandChannel> {
+
+    /** Creates a new command channel type. */
+    public CommandChannelType() {
+        super(CommandPayload.class);
+    }
+}

api/src/main/java/dev/objz/commandbridge/api/channel/command/CommandPayload.java

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+package dev.objz.commandbridge.api.channel.command;
+
+import dev.objz.commandbridge.api.channel.ChannelPayload;
+
+import java.util.UUID;
+
+/**
+ * Payload for command execution.
+ *
+ * @param command the command string to run
+ * @param runAs the execution mode
+ * @param player the optional player context
+ */
+public record CommandPayload(String command, RunAs runAs, UUID player) implements ChannelPayload {
+
+    /** Creates a payload for console execution. */
+    public static CommandPayload console(String command) {
+        return new CommandPayload(command, RunAs.CONSOLE, null);
+    }
+
+    /** Creates a payload for player execution. */
+    public static CommandPayload player(String command, UUID player) {
+        return new CommandPayload(command, RunAs.PLAYER, player);
+    }
+
+    /** Creates a payload for operator execution. */
+    public static CommandPayload operator(String command, UUID player) {
+        return new CommandPayload(command, RunAs.OPERATOR, player);
+    }
+}

api/src/main/java/dev/objz/commandbridge/api/channel/command/RunAs.java

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+package dev.objz.commandbridge.api.channel.command;
+
+/** Defines the execution context for a command. */
+public enum RunAs {
+    /** Run as the server console. */
+    CONSOLE,
+    /** Run as a specific player. */
+    PLAYER,
+    /** Run as a player with temporary operator permissions. */
+    OPERATOR
+}

api/src/main/java/dev/objz/commandbridge/api/message/MessageContext.java

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+package dev.objz.commandbridge.api.message;
+
+import dev.objz.commandbridge.api.channel.ChannelPayload;
+import dev.objz.commandbridge.api.channel.ChannelType;
+import dev.objz.commandbridge.api.channel.MessageChannel;
+import dev.objz.commandbridge.api.platform.Platform;
+
+/**
+ * Metadata for a received message.
+ *
+ * @param channel the channel the message was received on
+ * @param from the server that sent the message
+ * @param timestamp the time the message was sent
+ * @param <T> the payload type
+ */
+public record MessageContext<T extends ChannelPayload>(
+        ChannelType<T, ? extends MessageChannel<T>> channel,
+        Platform.ServerTarget from,
+        long timestamp
+) {
+}