src/main/java/de/thedevstack/conversationsplus/crypto/otr/OtrMessageParser.java


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package de.thedevstack.conversationsplus.crypto.otr;

import net.java.otr4j.session.Session;
import net.java.otr4j.session.SessionStatus;

import de.thedevstack.conversationsplus.crypto.OtrService;
import de.thedevstack.conversationsplus.entities.Conversation;
import de.thedevstack.conversationsplus.entities.Message;
import de.thedevstack.conversationsplus.utils.CryptoHelper;
import de.thedevstack.conversationsplus.utils.UiUpdateHelper;
import de.thedevstack.conversationsplus.utils.XmppConnectionServiceAccessor;
import de.thedevstack.conversationsplus.xmpp.jid.Jid;

/**
 */
public class OtrMessageParser {
    public static Message parseOtrChat(String body, Jid from, String id, Conversation conversation) {
        String presence;
        if (from.isBareJid()) {
            presence = "";
        } else {
            presence = from.getResourcepart();
        }
        if (body.matches("^\\?OTRv\\d{1,2}\\?.*")) {
            conversation.endOtrIfNeeded();
        }
        if (!conversation.hasValidOtrSession()) {
            conversation.startOtrSession(presence,false);
        } else {
            String foreignPresence = conversation.getOtrSession().getSessionID().getUserID();
            if (!foreignPresence.equals(presence)) {
                conversation.endOtrIfNeeded();
                conversation.startOtrSession(presence, false);
            }
        }
        try {
            conversation.setLastReceivedOtrMessageId(id);
            Session otrSession = conversation.getOtrSession();
            body = otrSession.transformReceiving(body);
            SessionStatus status = otrSession.getSessionStatus();
            if (body == null && status == SessionStatus.ENCRYPTED) {
                XmppConnectionServiceAccessor.xmppConnectionService.onOtrSessionEstablished(conversation);
                return null;
            } else if (body == null && status == SessionStatus.FINISHED) {
                conversation.resetOtrSession();
                UiUpdateHelper.updateConversationUi();
                return null;
            } else if (body == null || (body.isEmpty())) {
                return null;
            }
            if (body.startsWith(CryptoHelper.FILETRANSFER)) {
                String key = body.substring(CryptoHelper.FILETRANSFER.length());
                conversation.setSymmetricKey(CryptoHelper.hexToBytes(key));
                return null;
            }
            final OtrService otrService = conversation.getAccount().getOtrService();
            Message finishedMessage = new Message(conversation, body, Message.ENCRYPTION_OTR);
            finishedMessage.setFingerprint(otrService.getFingerprint(otrSession.getRemotePublicKey()));
            conversation.setLastReceivedOtrMessageId(null);

            return finishedMessage;
        } catch (Exception e) {
            conversation.resetOtrSession();
            return null;
        }
    }
}