Added clear command and functionality

Author: C-Hess

src/main/java/com/github/bustedearlobes/themis/Themis.java

@@ -10,6 +10,7 @@
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
+import com.github.bustedearlobes.themis.commands.ClearCommand;
 import com.github.bustedearlobes.themis.commands.CommandListener;
 import com.github.bustedearlobes.themis.commands.HelpCommand;
 import com.github.bustedearlobes.themis.commands.MuteCommand;
@@ -107,6 +108,7 @@ private void initCommandListener() {
         commandListener.register(new UnmuteCommand());
         commandListener.register(new ShutdownCommand());
         commandListener.register(new HelpCommand());
+        commandListener.register(new ClearCommand());
     }
 
     /**

src/main/java/com/github/bustedearlobes/themis/commands/ClearCommand.java

@@ -0,0 +1,55 @@
+package com.github.bustedearlobes.themis.commands;
+
+import java.util.regex.Matcher;
+
+import com.github.bustedearlobes.themis.Themis;
+import com.github.bustedearlobes.themis.taskmanager.ClearMessagesTask;
+
+import net.dv8tion.jda.core.JDA;
+import net.dv8tion.jda.core.entities.Message;
+import net.dv8tion.jda.core.entities.TextChannel;
+
+public class ClearCommand extends Command {
+    private static final String REGEX = "^clear( @\\w+)+( #\\w+)+( (\\d+))*$";
+    private static final int DEFAULT_CLEAR_NUMBER = 100;
+    
+    public ClearCommand() {
+        super("clear", REGEX);
+    }
+
+    @Override
+    public void onCall(Matcher fullCommand, Message message, JDA jda, Themis themis) {
+        TextChannel targetChannel = message.getTextChannel();
+        if(message.getMentionedChannels().size() > 0) {
+           targetChannel = message.getMentionedChannels().get(0);
+        }
+        int numOfMessages = DEFAULT_CLEAR_NUMBER;
+        if(fullCommand.group(3) != null) {
+            numOfMessages = Integer.parseInt(fullCommand.group(4));
+        }
+        ClearMessagesTask cmt = new ClearMessagesTask(message.getMentionedUsers().get(0),
+                targetChannel,
+                numOfMessages,
+                message.getTextChannel());
+        themis.getTaskManager().addTaskToScheduler(cmt);
+    }
+    
+    @Override
+    public String getDiscription() {
+        return "Clears messages from a particular user. If no channel is defined, "
+                + "defaults to the channel the command was sent from. "
+                + "If no amount is defined, defaults to clearing last "
+                + DEFAULT_CLEAR_NUMBER + " messages.";
+    }
+    
+    @Override
+    public String getHumanReadablePattern() {
+        return "@user(0,1) #channel(0,1) number(0,1)";
+    }
+
+    @Override
+    public String getExampleUsage() {
+        return "@naughty#6436 #general 100";
+    }
+    
+}

src/main/java/com/github/bustedearlobes/themis/taskmanager/ClearMessagesTask.java

@@ -0,0 +1,69 @@
+
+package com.github.bustedearlobes.themis.taskmanager;
+
+import java.util.List;
+import java.util.logging.Logger;
+import java.util.stream.Collectors;
+
+import net.dv8tion.jda.core.entities.Guild;
+import net.dv8tion.jda.core.entities.Message;
+import net.dv8tion.jda.core.entities.TextChannel;
+import net.dv8tion.jda.core.entities.User;
+
+public class ClearMessagesTask extends InstantTask {
+    private static final long serialVersionUID = 1L;
+
+    private static final Logger LOG = Logger.getLogger("Themis");
+    
+    private String guildId;
+    private String targetUserId;
+    private String targetChannelId;
+    private String loggingChannelId;
+    private int numberOfMessages;
+    
+    public ClearMessagesTask(User user, TextChannel targetChannel, int messages, TextChannel loggingChannel) {
+        targetUserId = user.getId();
+        guildId = targetChannel.getGuild().getId();
+        targetChannelId = targetChannel.getId();
+        loggingChannelId = loggingChannel.getId();
+        numberOfMessages = messages;
+    }
+
+    @Override
+    protected void runTask() {
+        Guild guild = getGuildById(guildId);
+        TextChannel targetChannel = getTextChannelById(targetChannelId, guild);
+        List<Message> messages = targetChannel.getIterableHistory().stream()
+            .limit(numberOfMessages)
+            .filter(m -> m.getAuthor().getId().equals(targetUserId))
+            .collect(Collectors.toList());
+        if(messages.size() < 2) {
+            if(messages.size() > 0) {
+                messages.get(0).delete().complete();
+            }
+        } else {
+            targetChannel.deleteMessages(messages).complete();
+        }
+        String messageString = messages.size() == 1 ? "message" : "messages";
+        String userName = getUserById(targetUserId).getName();
+        LOG.info("Cleared "
+                + messages.size()
+                + " "
+                + messageString
+                + " from "
+                + userName
+                + "@"
+                + targetChannel.getName()
+                + " in guild "
+                + guild.getName());
+        TextChannel loggingChannel = getTextChannelById(loggingChannelId, guild);
+        loggingChannel.sendMessage("Cleared "
+                + messages.size()
+                + " "
+                + messageString
+                + " from "
+                + userName).complete();
+        
+    }
+
+}