Signal-Android/src/org/thoughtcrime/securesms/sms/IncomingGroupMessage.java

package org.thoughtcrime.securesms.sms;

import com.google.protobuf.ByteString;

import org.thoughtcrime.securesms.util.GroupUtil;
import org.whispersystems.textsecure.push.PushMessageProtos;

import java.io.IOException;

import static org.whispersystems.textsecure.push.PushMessageProtos.PushMessageContent.GroupContext;

public class IncomingGroupMessage extends IncomingTextMessage {

  private final GroupContext groupContext;

  public IncomingGroupMessage(IncomingTextMessage base, GroupContext groupContext, String body) {
    super(base, body);
    this.groupContext = groupContext;
  }

  @Override
  public IncomingGroupMessage withMessageBody(String body) {
    return new IncomingGroupMessage(this, groupContext, body);
  }

  @Override
  public boolean isGroup() {
    return true;
  }

  public boolean isAdd() {
    return
        groupContext.getType().getNumber() == GroupContext.Type.ADD_VALUE ||
        groupContext.getType().getNumber() == GroupContext.Type.CREATE_VALUE;
  }

  public boolean isQuit() {
    return groupContext.getType().getNumber() == GroupContext.Type.QUIT_VALUE;
  }

  public boolean isModify() {
    return groupContext.getType().getNumber() == GroupContext.Type.MODIFY_VALUE;
  }

  public static IncomingGroupMessage createForQuit(String groupId, String user) throws IOException {
    IncomingTextMessage base    = new IncomingTextMessage(user, groupId);
    GroupContext        context = GroupContext.newBuilder()
                                              .setType(GroupContext.Type.QUIT)
                                              .setId(ByteString.copyFrom(GroupUtil.getDecodedId(groupId)))
                                              .build();

    return new IncomingGroupMessage(base, context, "");
  }

}