Added more response infrastructure and implemented a purge command.

src/main/java/net/javadiscord/javabot2/command/ResponseException.java

@@ -0,0 +1,28 @@
+package net.javadiscord.javabot2.command;
+
+import lombok.Getter;
+import org.javacord.api.interaction.callback.InteractionImmediateResponseBuilder;
+
+import java.util.function.Supplier;
+
+/**
+ * An exception which can be thrown so that the bot can respond with a well
+ * formatted error or warning response, while still allowing you to take
+ * advantage of throwing an exception up the call stack.
+ */
+public class ResponseException extends Exception {
+	@Getter
+	private final InteractionImmediateResponseBuilder responseBuilder;
+
+	public ResponseException(InteractionImmediateResponseBuilder responseBuilder) {
+		this.responseBuilder = responseBuilder;
+	}
+
+	public static Supplier<ResponseException> warning(String message) {
+		return () -> new ResponseException(Responses.deferredWarningBuilder().message(message).build());
+	}
+
+	public static Supplier<ResponseException> error(String message) {
+		return () -> new ResponseException(Responses.deferredErrorBuilder().message(message).build());
+	}
+}

src/main/java/net/javadiscord/javabot2/command/Responses.java

@@ -0,0 +1,148 @@
+package net.javadiscord.javabot2.command;
+
+import org.javacord.api.entity.message.MessageFlag;
+import org.javacord.api.entity.message.embed.EmbedBuilder;
+import org.javacord.api.event.interaction.SlashCommandCreateEvent;
+import org.javacord.api.interaction.InteractionBase;
+import org.javacord.api.interaction.callback.InteractionImmediateResponseBuilder;
+import org.javacord.api.interaction.callback.InteractionOriginalResponseUpdater;
+
+import java.awt.*;
+import java.util.concurrent.CompletableFuture;
+
+/**
+ * Provides methods for standardized replies to interaction events.
+ */
+public class Responses {
+	public static InteractionImmediateResponseBuilder success(InteractionBase interaction, String title, String message) {
+		return reply(interaction, title, message, Color.GREEN, true);
+	}
+
+	public static ResponseBuilder successBuilder(InteractionBase interaction) {
+		return new ResponseBuilder(interaction, Color.GREEN).title("Success");
+	}
+
+	public static ResponseBuilder successBuilder(SlashCommandCreateEvent event) {
+		return successBuilder(event.getSlashCommandInteraction());
+	}
+
+	public static InteractionImmediateResponseBuilder info(InteractionBase interaction, String title, String message) {
+		return reply(interaction, title, message, Color.BLUE, true);
+	}
+
+	public static ResponseBuilder infoBuilder(InteractionBase interaction) {
+		return new ResponseBuilder(interaction, Color.BLUE).title("Info");
+	}
+
+	public static ResponseBuilder infoBuilder(SlashCommandCreateEvent event) {
+		return infoBuilder(event.getSlashCommandInteraction());
+	}
+
+	public static InteractionImmediateResponseBuilder warning(InteractionBase interaction, String title, String message) {
+		return reply(interaction, title, message, Color.ORANGE, true);
+	}
+
+	public static InteractionImmediateResponseBuilder warning(InteractionBase interaction, String message) {
+		return warning(interaction, "Warning", message);
+	}
+
+	public static ResponseBuilder warningBuilder(InteractionBase interaction) {
+		return new ResponseBuilder(interaction, Color.ORANGE).title("Warning");
+	}
+
+	public static ResponseBuilder warningBuilder(SlashCommandCreateEvent event) {
+		return warningBuilder(event.getSlashCommandInteraction());
+	}
+
+	public static ResponseBuilder deferredWarningBuilder() {
+		return new ResponseBuilder(Color.ORANGE).title("Warning");
+	}
+
+	public static InteractionImmediateResponseBuilder error(InteractionBase interaction, String message) {
+		return reply(interaction, "An Error Occurred", message, Color.RED, true);
+	}
+
+	public static ResponseBuilder errorBuilder(InteractionBase interaction) {
+		return new ResponseBuilder(interaction, Color.RED).title("An Error Occurred");
+	}
+
+	public static ResponseBuilder errorBuilder(SlashCommandCreateEvent event) {
+		return errorBuilder(event.getSlashCommandInteraction());
+	}
+
+	public static ResponseBuilder deferredErrorBuilder() {
+		return new ResponseBuilder(Color.RED).title("An Error Occurred");
+	}
+
+	private static InteractionImmediateResponseBuilder reply(
+			InteractionBase interaction,
+			String title,
+			String message,
+			Color color,
+			boolean ephemeral
+	) {
+		var responder = interaction.createImmediateResponder()
+				.addEmbed(new EmbedBuilder()
+					.setTitle(title)
+					.setColor(color)
+					.setTimestampToNow()
+					.setDescription(message));
+		if (ephemeral) {
+			responder.setFlags(MessageFlag.EPHEMERAL);
+		}
+		return responder;
+	}
+
+	/**
+	 * A builder that's used to construct a response using a fluent interface.
+	 */
+	public static class ResponseBuilder {
+		private InteractionBase interaction;
+		private String title = null;
+		private String message = null;
+		private final Color color;
+		private boolean ephemeral = true;
+
+		private ResponseBuilder(InteractionBase interaction, Color color) {
+			this.interaction = interaction;
+			this.color = color;
+		}
+
+		private ResponseBuilder(Color color) {
+			this(null, color);
+		}
+
+		public ResponseBuilder title(String title) {
+			this.title = title;
+			return this;
+		}
+
+		public ResponseBuilder message(String message) {
+			this.message = message;
+			return this;
+		}
+
+		public ResponseBuilder makePublic() {
+			this.ephemeral = false;
+			return this;
+		}
+
+		public InteractionImmediateResponseBuilder build() {
+			return reply(interaction, title, message, color, ephemeral);
+		}
+
+		public InteractionImmediateResponseBuilder build(InteractionBase interaction) {
+			this.interaction = interaction;
+			return build();
+		}
+
+		public CompletableFuture<InteractionOriginalResponseUpdater> respond(InteractionBase interaction) {
+			this.interaction = interaction;
+			return build().respond();
+		}
+
+		public CompletableFuture<InteractionOriginalResponseUpdater> respond() {
+			return this.build().respond();
+		}
+	}
+}

src/main/java/net/javadiscord/javabot2/command/SlashCommandHandler.java

@@ -3,6 +3,10 @@
 import org.javacord.api.interaction.SlashCommandInteraction;
 import org.javacord.api.interaction.callback.InteractionImmediateResponseBuilder;
 
+/**
+ * An interface that should be implemented by any class that is defined as a
+ * handler in any command configuration file.
+ */
 public interface SlashCommandHandler {
 	InteractionImmediateResponseBuilder handle(SlashCommandInteraction interaction) throws Exception;
 }

src/main/java/net/javadiscord/javabot2/command/SlashCommandListener.java

@@ -1,8 +1,9 @@
 package net.javadiscord.javabot2.command;
 
 import lombok.extern.slf4j.Slf4j;
+import net.javadiscord.javabot2.command.data.CommandConfig;
+import net.javadiscord.javabot2.command.data.CommandDataLoader;
 import org.javacord.api.DiscordApi;
-import org.javacord.api.entity.message.MessageFlag;
 import org.javacord.api.event.interaction.SlashCommandCreateEvent;
 import org.javacord.api.interaction.ServerSlashCommandPermissionsBuilder;
 import org.javacord.api.interaction.SlashCommandBuilder;
@@ -21,6 +22,13 @@
 public final class SlashCommandListener implements SlashCommandCreateListener {
 	private final Map<Long, SlashCommandHandler> commandHandlers = new HashMap<>();
 
+	/**
+	 * Constructs a new slash command listener using the given Discord api, and
+	 * loads commands from configuration YAML files according to the list of
+	 * resources.
+	 * @param api The Discord api to use.
+	 * @param resources The list of classpath resources to load commands from.
+	 */
 	public SlashCommandListener(DiscordApi api, String... resources) {
 		registerSlashCommands(api, resources)
 				.thenAcceptAsync(commandHandlers::putAll);
@@ -32,17 +40,18 @@ public void onSlashCommandCreate(SlashCommandCreateEvent event) {
 		if (handler != null) {
 			try {
 				handler.handle(event.getSlashCommandInteraction()).respond();
+			} catch (ResponseException e) {
+				e.getResponseBuilder().respond();
 			} catch (Exception e) {
 				log.error("An error occurred while handling a slash command.", e);
-				event.getSlashCommandInteraction().createImmediateResponder()
-						.setFlags(MessageFlag.EPHEMERAL)
-						.append("An error occurred.")
+				Responses.errorBuilder(event)
+						.message("An error occurred while executing the command.")
 						.respond();
 			}
 		} else {
-			event.getSlashCommandInteraction().createImmediateResponder()
-					.setFlags(MessageFlag.EPHEMERAL)
-					.append("There is no associated handler for this command. Please contact an administrator if this error persists.")
+			Responses.warningBuilder(event)
+					.title("No Handler")
+					.message("There is no associated handler for this command. Please contact an administrator if this error persists.")
 					.respond();
 		}
 	}

src/main/java/net/javadiscord/javabot2/command/CommandConfig.java → src/main/java/net/javadiscord/javabot2/command/data/CommandConfig.java

@@ -1,4 +1,4 @@
-package net.javadiscord.javabot2.command;
+package net.javadiscord.javabot2.command.data;
 
 import lombok.Data;
 import org.javacord.api.interaction.SlashCommandBuilder;

src/main/java/net/javadiscord/javabot2/command/CommandDataLoader.java → src/main/java/net/javadiscord/javabot2/command/data/CommandDataLoader.java

@@ -1,4 +1,4 @@
-package net.javadiscord.javabot2.command;
+package net.javadiscord.javabot2.command.data;
 
 import org.yaml.snakeyaml.Yaml;
 

src/main/java/net/javadiscord/javabot2/command/CommandPrivilegeConfig.java → src/main/java/net/javadiscord/javabot2/command/data/CommandPrivilegeConfig.java

@@ -1,4 +1,4 @@
-package net.javadiscord.javabot2.command;
+package net.javadiscord.javabot2.command.data;
 
 import lombok.Data;
 import lombok.extern.slf4j.Slf4j;

src/main/java/net/javadiscord/javabot2/command/OptionConfig.java → src/main/java/net/javadiscord/javabot2/command/data/OptionConfig.java

@@ -1,7 +1,8 @@
-package net.javadiscord.javabot2.command;
+package net.javadiscord.javabot2.command.data;
 
 import lombok.Data;
 import org.javacord.api.interaction.SlashCommandOptionBuilder;
+import org.javacord.api.interaction.SlashCommandOptionChoiceBuilder;
 import org.javacord.api.interaction.SlashCommandOptionType;
 
 /**
@@ -16,12 +17,11 @@ public class OptionConfig {
 	private boolean required;
 
 	public SlashCommandOptionBuilder toData() {
-		var builder = new SlashCommandOptionBuilder()
+		return new SlashCommandOptionBuilder()
 				.setType(SlashCommandOptionType.valueOf(this.type.toUpperCase()))
 				.setName(this.name)
 				.setDescription(this.description)
 				.setRequired(this.required);
-		return builder;
 	}
 
 	@Override

src/main/java/net/javadiscord/javabot2/command/SubCommandConfig.java → src/main/java/net/javadiscord/javabot2/command/data/SubCommandConfig.java

@@ -1,4 +1,4 @@
-package net.javadiscord.javabot2.command;
+package net.javadiscord.javabot2.command.data;
 
 import lombok.Data;
 import org.javacord.api.interaction.SlashCommandOptionBuilder;

src/main/java/net/javadiscord/javabot2/command/SubCommandGroupConfig.java → src/main/java/net/javadiscord/javabot2/command/data/SubCommandGroupConfig.java

@@ -1,4 +1,4 @@
-package net.javadiscord.javabot2.command;
+package net.javadiscord.javabot2.command.data;
 
 import lombok.Data;
 import org.javacord.api.interaction.SlashCommandOptionBuilder;

src/main/java/net/javadiscord/javabot2/systems/moderation/PurgeCommand.java

@@ -1,13 +1,36 @@
 package net.javadiscord.javabot2.systems.moderation;
 
+import lombok.extern.slf4j.Slf4j;
+import net.javadiscord.javabot2.Bot;
+import net.javadiscord.javabot2.command.ResponseException;
+import net.javadiscord.javabot2.command.Responses;
 import net.javadiscord.javabot2.command.SlashCommandHandler;
+import org.javacord.api.entity.message.Message;
+import org.javacord.api.entity.user.User;
 import org.javacord.api.interaction.SlashCommandInteraction;
 import org.javacord.api.interaction.callback.InteractionImmediateResponseBuilder;
 
+@Slf4j
 public class PurgeCommand implements SlashCommandHandler {
 	@Override
-	public InteractionImmediateResponseBuilder handle(SlashCommandInteraction interaction) {
-		return interaction.createImmediateResponder()
-				.append("Not yet implemented");
+	public InteractionImmediateResponseBuilder handle(SlashCommandInteraction interaction) throws Exception {
+		var until = interaction.getOptionStringValueByName("until")
+				.orElseThrow(ResponseException.warning("Missing required parameter."));
+		var userOption = interaction.getOptionUserValueByName("user");
+		var channel = interaction.getChannel()
+				.orElseThrow(ResponseException.warning("This command can only be used in text channels."));
+		channel.getMessageById(until).thenAcceptAsync(message -> Bot.asyncPool.submit(() -> purge(message, userOption.orElse(null))));
+		return Responses.info(interaction, "Purge Started", "Messages will be deleted!");
+	}
+
+	private void purge(Message until, User user) {
+		log.info("Purging all messages in {} until {}.", until.getServerTextChannel().orElseThrow().getName(), until.getId());
+		until.getMessagesAfterAsStream()
+				.filter(message -> (user == null || message.getAuthor().getId() == user.getId()))
+				.forEach(message -> message.delete().join());
+		if (user == null || until.getAuthor().getId() == user.getId()) {
+			until.delete().join();
+		}
+		log.info("Purge completed.");
 	}
 }

src/main/resources/commands/moderation.yaml

@@ -1,20 +1,16 @@
 - name: purge
   description: Deletes messages from a channel.
-  handler: net.javadiscord.javabot2.systems.moderation.PruneCommand
+  handler: net.javadiscord.javabot2.systems.moderation.PurgeCommand
   enabledByDefault: false
   privileges:
     - type: ROLE
       id: moderation.staffRoleId
   options:
-    - name: amount
-      description: Number of messages to remove. If left blank, all messages will be removed.
-      type: INTEGER
-      required: false
+    - name: until
+      description: All messages from now up to (and including) the given message id will be removed.
+      type: STRING
+      required: true
     - name: user
       description: The user whose messages to remove. If left blank, messages from any user are removed.
       type: USER
       required: false
-    - name: archive
-      description: If true, save removed messages in an archive.
-      type: BOOLEAN
-      required: false