package eu.siacs.conversations.crypto.axolotl;

import android.os.Bundle;
import android.security.KeyChain;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.util.Log;
import android.util.Pair;

import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.whispersystems.libsignal.SignalProtocolAddress;
import org.whispersystems.libsignal.IdentityKey;
import org.whispersystems.libsignal.IdentityKeyPair;
import org.whispersystems.libsignal.InvalidKeyException;
import org.whispersystems.libsignal.InvalidKeyIdException;
import org.whispersystems.libsignal.SessionBuilder;
import org.whispersystems.libsignal.UntrustedIdentityException;
import org.whispersystems.libsignal.ecc.ECPublicKey;
import org.whispersystems.libsignal.state.PreKeyBundle;
import org.whispersystems.libsignal.state.PreKeyRecord;
import org.whispersystems.libsignal.state.SignedPreKeyRecord;
import org.whispersystems.libsignal.util.KeyHelper;

import java.security.PrivateKey;
import java.security.Security;
import java.security.Signature;
import java.security.cert.X509Certificate;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Random;
import java.util.Set;
import java.util.concurrent.atomic.AtomicBoolean;

import eu.siacs.conversations.Config;
import eu.siacs.conversations.entities.Account;
import eu.siacs.conversations.entities.Contact;
import eu.siacs.conversations.entities.Conversation;
import eu.siacs.conversations.entities.Message;
import eu.siacs.conversations.parser.IqParser;
import eu.siacs.conversations.services.XmppConnectionService;
import eu.siacs.conversations.utils.CryptoHelper;
import eu.siacs.conversations.utils.SerialSingleThreadExecutor;
import eu.siacs.conversations.xml.Element;
import eu.siacs.conversations.xmpp.OnAdvancedStreamFeaturesLoaded;
import eu.siacs.conversations.xmpp.OnIqPacketReceived;
import eu.siacs.conversations.xmpp.pep.PublishOptions;
import eu.siacs.conversations.xmpp.stanzas.IqPacket;
import eu.siacs.conversations.xmpp.stanzas.MessagePacket;
import rocks.xmpp.addr.Jid;

public class AxolotlService implements OnAdvancedStreamFeaturesLoaded {

	public static final String PEP_PREFIX = "eu.siacs.conversations.axolotl";
	public static final String PEP_DEVICE_LIST = PEP_PREFIX + ".devicelist";
	public static final String PEP_DEVICE_LIST_NOTIFY = PEP_DEVICE_LIST + "+notify";
	public static final String PEP_BUNDLES = PEP_PREFIX + ".bundles";
	public static final String PEP_VERIFICATION = PEP_PREFIX + ".verification";
	public static final String PEP_OMEMO_WHITELISTED = PEP_PREFIX + ".whitelisted";

	public static final String LOGPREFIX = "AxolotlService";

	private static final int NUM_KEYS_TO_PUBLISH = 100;
	private static final int publishTriesThreshold = 3;

	private final Account account;
	private final XmppConnectionService mXmppConnectionService;
	private final SQLiteAxolotlStore axolotlStore;
	private final SessionMap sessions;
	private final Map<Jid, Set<Integer>> deviceIds;
	private final Map<String, XmppAxolotlMessage> messageCache;
	private final FetchStatusMap fetchStatusMap;
	private final Map<Jid, Boolean> fetchDeviceListStatus = new HashMap<>();
	private final HashMap<Jid, List<OnDeviceIdsFetched>> fetchDeviceIdsMap = new HashMap<>();
	private final SerialSingleThreadExecutor executor;
	private int numPublishTriesOnEmptyPep = 0;
	private boolean pepBroken = false;
	private final Set<SignalProtocolAddress> healingAttempts = new HashSet<>();
	private int lastDeviceListNotificationHash = 0;
	private final HashSet<Integer> cleanedOwnDeviceIds = new HashSet<>();
	private Set<XmppAxolotlSession> postponedSessions = new HashSet<>(); //sessions stored here will receive after mam catchup treatment
	private Set<SignalProtocolAddress> postponedHealing = new HashSet<>(); //addresses stored here will need a healing notification after mam catchup

	private AtomicBoolean changeAccessMode = new AtomicBoolean(false);

	@Override
	public void onAdvancedStreamFeaturesAvailable(Account account) {
		if (Config.supportOmemo()
				&& account.getXmppConnection() != null
				&& account.getXmppConnection().getFeatures().pep()) {
			publishBundlesIfNeeded(true, false);
		} else {
			Log.d(Config.LOGTAG, account.getJid().asBareJid() + ": skipping OMEMO initialization");
		}
	}

	private boolean hasErrorFetchingDeviceList(Jid jid) {
		Boolean status = fetchDeviceListStatus.get(jid);
		return status != null && !status;
	}

	public boolean hasErrorFetchingDeviceList(List<Jid> jids) {
		for(Jid jid : jids) {
			if (hasErrorFetchingDeviceList(jid)) {
				return true;
			}
		}
		return false;
	}

	public boolean fetchMapHasErrors(List<Jid> jids) {
		for (Jid jid : jids) {
			if (deviceIds.get(jid) != null) {
				for (Integer foreignId : this.deviceIds.get(jid)) {
					SignalProtocolAddress address = new SignalProtocolAddress(jid.toString(), foreignId);
					if (fetchStatusMap.getAll(address.getName()).containsValue(FetchStatus.ERROR)) {
						return true;
					}
				}
			}
		}
		return false;
	}

	public void preVerifyFingerprint(Contact contact, String fingerprint) {
		axolotlStore.preVerifyFingerprint(contact.getAccount(), contact.getJid().asBareJid().toString(), fingerprint);
	}

	public void preVerifyFingerprint(Account account, String fingerprint) {
		axolotlStore.preVerifyFingerprint(account, account.getJid().asBareJid().toString(), fingerprint);
	}

	public boolean hasVerifiedKeys(String name) {
		for (XmppAxolotlSession session : this.sessions.getAll(name).values()) {
			if (session.getTrust().isVerified()) {
				return true;
			}
		}
		return false;
	}

	private static class AxolotlAddressMap<T> {
		protected Map<String, Map<Integer, T>> map;
		protected final Object MAP_LOCK = new Object();

		public AxolotlAddressMap() {
			this.map = new HashMap<>();
		}

		public void put(SignalProtocolAddress address, T value) {
			synchronized (MAP_LOCK) {
				Map<Integer, T> devices = map.get(address.getName());
				if (devices == null) {
					devices = new HashMap<>();
					map.put(address.getName(), devices);
				}
				devices.put(address.getDeviceId(), value);
			}
		}

		public T get(SignalProtocolAddress address) {
			synchronized (MAP_LOCK) {
				Map<Integer, T> devices = map.get(address.getName());
				if (devices == null) {
					return null;
				}
				return devices.get(address.getDeviceId());
			}
		}

		public Map<Integer, T> getAll(String name) {
			synchronized (MAP_LOCK) {
				Map<Integer, T> devices = map.get(name);
				if (devices == null) {
					return new HashMap<>();
				}
				return devices;
			}
		}

		public boolean hasAny(SignalProtocolAddress address) {
			synchronized (MAP_LOCK) {
				Map<Integer, T> devices = map.get(address.getName());
				return devices != null && !devices.isEmpty();
			}
		}

		public void clear() {
			map.clear();
		}

	}

	private static class SessionMap extends AxolotlAddressMap<XmppAxolotlSession> {
		private final XmppConnectionService xmppConnectionService;
		private final Account account;

		public SessionMap(XmppConnectionService service, SQLiteAxolotlStore store, Account account) {
			super();
			this.xmppConnectionService = service;
			this.account = account;
			this.fillMap(store);
		}

		public Set<Jid> findCounterpartsForSourceId(Integer sid) {
			Set<Jid> candidates = new HashSet<>();
			synchronized (MAP_LOCK) {
				for(Map.Entry<String,Map<Integer,XmppAxolotlSession>> entry : map.entrySet()) {
					String key = entry.getKey();
					if (entry.getValue().containsKey(sid)) {
						candidates.add(Jid.of(key));
					}
				}
			}
			return candidates;
		}

		private void putDevicesForJid(String bareJid, List<Integer> deviceIds, SQLiteAxolotlStore store) {
			for (Integer deviceId : deviceIds) {
				SignalProtocolAddress axolotlAddress = new SignalProtocolAddress(bareJid, deviceId);
				IdentityKey identityKey = store.loadSession(axolotlAddress).getSessionState().getRemoteIdentityKey();
				if (Config.X509_VERIFICATION) {
					X509Certificate certificate = store.getFingerprintCertificate(CryptoHelper.bytesToHex(identityKey.getPublicKey().serialize()));
					if (certificate != null) {
						Bundle information = CryptoHelper.extractCertificateInformation(certificate);
						try {
							final String cn = information.getString("subject_cn");
							final Jid jid = Jid.of(bareJid);
							Log.d(Config.LOGTAG, "setting common name for " + jid + " to " + cn);
							account.getRoster().getContact(jid).setCommonName(cn);
						} catch (final IllegalArgumentException ignored) {
							//ignored
						}
					}
				}
				this.put(axolotlAddress, new XmppAxolotlSession(account, store, axolotlAddress, identityKey));
			}
		}

		private void fillMap(SQLiteAxolotlStore store) {
			List<Integer> deviceIds = store.getSubDeviceSessions(account.getJid().asBareJid().toString());
			putDevicesForJid(account.getJid().asBareJid().toString(), deviceIds, store);
			for (String address : store.getKnownAddresses()) {
				deviceIds = store.getSubDeviceSessions(address);
				putDevicesForJid(address, deviceIds, store);
			}
		}

		@Override
		public void put(SignalProtocolAddress address, XmppAxolotlSession value) {
			super.put(address, value);
			value.setNotFresh();
		}

		public void put(XmppAxolotlSession session) {
			this.put(session.getRemoteAddress(), session);
		}
	}

	public enum FetchStatus {
		PENDING,
		SUCCESS,
		SUCCESS_VERIFIED,
		TIMEOUT,
		SUCCESS_TRUSTED,
		ERROR
	}

	private static class FetchStatusMap extends AxolotlAddressMap<FetchStatus> {

		public void clearErrorFor(Jid jid) {
			synchronized (MAP_LOCK) {
				Map<Integer, FetchStatus> devices = this.map.get(jid.asBareJid().toString());
				if (devices == null) {
					return;
				}
				for (Map.Entry<Integer, FetchStatus> entry : devices.entrySet()) {
					if (entry.getValue() == FetchStatus.ERROR) {
						Log.d(Config.LOGTAG, "resetting error for " + jid.asBareJid() + "(" + entry.getKey() + ")");
						entry.setValue(FetchStatus.TIMEOUT);
					}
				}
			}
		}
	}

	public static String getLogprefix(Account account) {
		return LOGPREFIX + " (" + account.getJid().asBareJid().toString() + "): ";
	}

	public AxolotlService(Account account, XmppConnectionService connectionService) {
		if (account == null || connectionService == null) {
			throw new IllegalArgumentException("account and service cannot be null");
		}
		if (Security.getProvider("BC") == null) {
			Security.addProvider(new BouncyCastleProvider());
		}
		this.mXmppConnectionService = connectionService;
		this.account = account;
		this.axolotlStore = new SQLiteAxolotlStore(this.account, this.mXmppConnectionService);
		this.deviceIds = new HashMap<>();
		this.messageCache = new HashMap<>();
		this.sessions = new SessionMap(mXmppConnectionService, axolotlStore, account);
		this.fetchStatusMap = new FetchStatusMap();
		this.executor = new SerialSingleThreadExecutor("Axolotl");
	}

	public String getOwnFingerprint() {
		return CryptoHelper.bytesToHex(axolotlStore.getIdentityKeyPair().getPublicKey().serialize());
	}

	public Set<IdentityKey> getKeysWithTrust(FingerprintStatus status) {
		return axolotlStore.getContactKeysWithTrust(account.getJid().asBareJid().toString(), status);
	}

	public Set<IdentityKey> getKeysWithTrust(FingerprintStatus status, Jid jid) {
		return axolotlStore.getContactKeysWithTrust(jid.asBareJid().toString(), status);
	}

	public Set<IdentityKey> getKeysWithTrust(FingerprintStatus status, List<Jid> jids) {
		Set<IdentityKey> keys = new HashSet<>();
		for (Jid jid : jids) {
			keys.addAll(axolotlStore.getContactKeysWithTrust(jid.toString(), status));
		}
		return keys;
	}

	public Set<Jid> findCounterpartsBySourceId(int sid) {
		return sessions.findCounterpartsForSourceId(sid);
	}

	public long getNumTrustedKeys(Jid jid) {
		return axolotlStore.getContactNumTrustedKeys(jid.asBareJid().toString());
	}

	public boolean anyTargetHasNoTrustedKeys(List<Jid> jids) {
		for (Jid jid : jids) {
			if (axolotlStore.getContactNumTrustedKeys(jid.asBareJid().toString()) == 0) {
				return true;
			}
		}
		return false;
	}

	private SignalProtocolAddress getAddressForJid(Jid jid) {
		return new SignalProtocolAddress(jid.toString(), 0);
	}

	public Collection<XmppAxolotlSession> findOwnSessions() {
		SignalProtocolAddress ownAddress = getAddressForJid(account.getJid().asBareJid());
		ArrayList<XmppAxolotlSession> s = new ArrayList<>(this.sessions.getAll(ownAddress.getName()).values());
		Collections.sort(s);
		return s;
	}


	public Collection<XmppAxolotlSession> findSessionsForContact(Contact contact) {
		SignalProtocolAddress contactAddress = getAddressForJid(contact.getJid());
		ArrayList<XmppAxolotlSession> s = new ArrayList<>(this.sessions.getAll(contactAddress.getName()).values());
		Collections.sort(s);
		return s;
	}

	private Set<XmppAxolotlSession> findSessionsForConversation(Conversation conversation) {
		if (conversation.getContact().isSelf()) {
			//will be added in findOwnSessions()
			return Collections.emptySet();
		}
		HashSet<XmppAxolotlSession> sessions = new HashSet<>();
		for (Jid jid : conversation.getAcceptedCryptoTargets()) {
			sessions.addAll(this.sessions.getAll(getAddressForJid(jid).getName()).values());
		}
		return sessions;
	}

	private boolean hasAny(Jid jid) {
		return sessions.hasAny(getAddressForJid(jid));
	}

	public boolean isPepBroken() {
		return this.pepBroken;
	}

	public void resetBrokenness() {
		this.pepBroken = false;
		this.numPublishTriesOnEmptyPep = 0;
		this.lastDeviceListNotificationHash = 0;
		this.healingAttempts.clear();
	}

	public void clearErrorsInFetchStatusMap(Jid jid) {
		fetchStatusMap.clearErrorFor(jid);
		fetchDeviceListStatus.remove(jid);
	}

	public void regenerateKeys(boolean wipeOther) {
		axolotlStore.regenerate();
		sessions.clear();
		fetchStatusMap.clear();
		fetchDeviceIdsMap.clear();
		fetchDeviceListStatus.clear();
		publishBundlesIfNeeded(true, wipeOther);
	}

	public void destroy() {
		Log.d(Config.LOGTAG, account.getJid().asBareJid() + ": destroying old axolotl service. no longer in use");
		mXmppConnectionService.databaseBackend.wipeAxolotlDb(account);
	}

	public AxolotlService makeNew() {
		Log.d(Config.LOGTAG, account.getJid().asBareJid() + ": make new axolotl service");
		return new AxolotlService(this.account, this.mXmppConnectionService);
	}

	public int getOwnDeviceId() {
		return axolotlStore.getLocalRegistrationId();
	}

	public SignalProtocolAddress getOwnAxolotlAddress() {
		return new SignalProtocolAddress(account.getJid().asBareJid().toString(), getOwnDeviceId());
	}

	public Set<Integer> getOwnDeviceIds() {
		return this.deviceIds.get(account.getJid().asBareJid());
	}

	public void registerDevices(final Jid jid, @NonNull final Set<Integer> deviceIds) {
		final int hash = deviceIds.hashCode();
		final boolean me = jid.asBareJid().equals(account.getJid().asBareJid());
		if (me) {
			if (hash != 0 && hash == this.lastDeviceListNotificationHash) {
				Log.d(Config.LOGTAG, account.getJid().asBareJid() + ": ignoring duplicate own device id list");
				return;
			}
			this.lastDeviceListNotificationHash = hash;
		}
		boolean needsPublishing = me && !deviceIds.contains(getOwnDeviceId());
		if (me) {
			deviceIds.remove(getOwnDeviceId());
		}
		Set<Integer> expiredDevices = new HashSet<>(axolotlStore.getSubDeviceSessions(jid.asBareJid().toString()));
		expiredDevices.removeAll(deviceIds);
		for (Integer deviceId : expiredDevices) {
			SignalProtocolAddress address = new SignalProtocolAddress(jid.asBareJid().toString(), deviceId);
			XmppAxolotlSession session = sessions.get(address);
			if (session != null && session.getFingerprint() != null) {
				if (session.getTrust().isActive()) {
					session.setTrust(session.getTrust().toInactive());
				}
			}
		}
		Set<Integer> newDevices = new HashSet<>(deviceIds);
		for (Integer deviceId : newDevices) {
			SignalProtocolAddress address = new SignalProtocolAddress(jid.asBareJid().toString(), deviceId);
			XmppAxolotlSession session = sessions.get(address);
			if (session != null && session.getFingerprint() != null) {
				if (!session.getTrust().isActive()) {
					Log.d(Config.LOGTAG, "reactivating device with fingerprint " + session.getFingerprint());
					session.setTrust(session.getTrust().toActive());
				}
			}
		}
		if (me) {
			if (Config.OMEMO_AUTO_EXPIRY != 0) {
				needsPublishing |= deviceIds.removeAll(getExpiredDevices());
			}
			needsPublishing |= this.changeAccessMode.get();
			for (Integer deviceId : deviceIds) {
				SignalProtocolAddress ownDeviceAddress = new SignalProtocolAddress(jid.asBareJid().toString(), deviceId);
				if (sessions.get(ownDeviceAddress) == null) {
					FetchStatus status = fetchStatusMap.get(ownDeviceAddress);
					if (status == null || status == FetchStatus.TIMEOUT) {
						fetchStatusMap.put(ownDeviceAddress, FetchStatus.PENDING);
						this.buildSessionFromPEP(ownDeviceAddress);
					}
				}
			}
			if (needsPublishing) {
				publishOwnDeviceId(deviceIds);
			}
		}
		final Set<Integer> oldSet = this.deviceIds.get(jid);
		final boolean changed = oldSet == null || oldSet.hashCode() != hash;
		this.deviceIds.put(jid, deviceIds);
		if (changed) {
			mXmppConnectionService.updateConversationUi(); //update the lock icon
			mXmppConnectionService.keyStatusUpdated(null);
			if (me) {
				mXmppConnectionService.updateAccountUi();
			}
		} else {
			Log.d(Config.LOGTAG,"skipped device list update because it hasn't changed");
		}
	}

	public void wipeOtherPepDevices() {
		if (pepBroken) {
			Log.d(Config.LOGTAG, getLogprefix(account) + "wipeOtherPepDevices called, but PEP is broken. Ignoring... ");
			return;
		}
		Set<Integer> deviceIds = new HashSet<>();
		deviceIds.add(getOwnDeviceId());
		publishDeviceIdsAndRefineAccessModel(deviceIds);
	}

	public void distrustFingerprint(final String fingerprint) {
		final String fp = fingerprint.replaceAll("\\s", "");
		final FingerprintStatus fingerprintStatus = axolotlStore.getFingerprintStatus(fp);
		axolotlStore.setFingerprintStatus(fp, fingerprintStatus.toUntrusted());
	}

	private void publishOwnDeviceIdIfNeeded() {
		if (pepBroken) {
			Log.d(Config.LOGTAG, getLogprefix(account) + "publishOwnDeviceIdIfNeeded called, but PEP is broken. Ignoring... ");
			return;
		}
		IqPacket packet = mXmppConnectionService.getIqGenerator().retrieveDeviceIds(account.getJid().asBareJid());
		mXmppConnectionService.sendIqPacket(account, packet, new OnIqPacketReceived() {
			@Override
			public void onIqPacketReceived(Account account, IqPacket packet) {
				if (packet.getType() == IqPacket.TYPE.TIMEOUT) {
					Log.d(Config.LOGTAG, getLogprefix(account) + "Timeout received while retrieving own Device Ids.");
				} else {
					//TODO consider calling registerDevices only after item-not-found to account for broken PEPs
					Element item = mXmppConnectionService.getIqParser().getItem(packet);
					Set<Integer> deviceIds = mXmppConnectionService.getIqParser().deviceIds(item);
					Log.d(Config.LOGTAG, account.getJid().asBareJid() + ": retrieved own device list: " + deviceIds);
					registerDevices(account.getJid().asBareJid(), deviceIds);
				}
			}
		});
	}

	private Set<Integer> getExpiredDevices() {
		Set<Integer> devices = new HashSet<>();
		for (XmppAxolotlSession session : findOwnSessions()) {
			if (session.getTrust().isActive()) {
				long diff = System.currentTimeMillis() - session.getTrust().getLastActivation();
				if (diff > Config.OMEMO_AUTO_EXPIRY) {
					long lastMessageDiff = System.currentTimeMillis() - mXmppConnectionService.databaseBackend.getLastTimeFingerprintUsed(account, session.getFingerprint());
					long hours = Math.round(lastMessageDiff / (1000 * 60.0 * 60.0));
					if (lastMessageDiff > Config.OMEMO_AUTO_EXPIRY) {
						devices.add(session.getRemoteAddress().getDeviceId());
						session.setTrust(session.getTrust().toInactive());
						Log.d(Config.LOGTAG, account.getJid().asBareJid() + ": added own device " + session.getFingerprint() + " to list of expired devices. Last message received " + hours + " hours ago");
					} else {
						Log.d(Config.LOGTAG, account.getJid().asBareJid() + ": own device " + session.getFingerprint() + " was active " + hours + " hours ago");
					}
				} //TODO print last activation diff
			}
		}
		return devices;
	}

	private void publishOwnDeviceId(Set<Integer> deviceIds) {
		Set<Integer> deviceIdsCopy = new HashSet<>(deviceIds);
		Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "publishing own device ids");
		if (deviceIdsCopy.isEmpty()) {
			if (numPublishTriesOnEmptyPep >= publishTriesThreshold) {
				Log.w(Config.LOGTAG, getLogprefix(account) + "Own device publish attempt threshold exceeded, aborting...");
				pepBroken = true;
				return;
			} else {
				numPublishTriesOnEmptyPep++;
				Log.w(Config.LOGTAG, getLogprefix(account) + "Own device list empty, attempting to publish (try " + numPublishTriesOnEmptyPep + ")");
			}
		} else {
			numPublishTriesOnEmptyPep = 0;
		}
		deviceIdsCopy.add(getOwnDeviceId());
		publishDeviceIdsAndRefineAccessModel(deviceIdsCopy);
	}

	private void publishDeviceIdsAndRefineAccessModel(Set<Integer> ids) {
		publishDeviceIdsAndRefineAccessModel(ids, true);
	}

	private void publishDeviceIdsAndRefineAccessModel(final Set<Integer> ids, final boolean firstAttempt) {
		final Bundle publishOptions = account.getXmppConnection().getFeatures().pepPublishOptions() ? PublishOptions.openAccess() : null;
		IqPacket publish = mXmppConnectionService.getIqGenerator().publishDeviceIds(ids, publishOptions);
		mXmppConnectionService.sendIqPacket(account, publish, new OnIqPacketReceived() {
			@Override
			public void onIqPacketReceived(Account account, IqPacket packet) {
				final Element error = packet.getType() == IqPacket.TYPE.ERROR ? packet.findChild("error") : null;
				final boolean preConditionNotMet = PublishOptions.preconditionNotMet(packet);
				if (firstAttempt && preConditionNotMet) {
					Log.d(Config.LOGTAG, account.getJid().asBareJid() + ": precondition wasn't met for device list. pushing node configuration");
					mXmppConnectionService.pushNodeConfiguration(account, AxolotlService.PEP_DEVICE_LIST, publishOptions, new XmppConnectionService.OnConfigurationPushed() {
						@Override
						public void onPushSucceeded() {
							publishDeviceIdsAndRefineAccessModel(ids, false);
						}

						@Override
						public void onPushFailed() {
							publishDeviceIdsAndRefineAccessModel(ids, false);
						}
					});
				} else {
					if (AxolotlService.this.changeAccessMode.compareAndSet(true, false)) {
						Log.d(Config.LOGTAG, account.getJid().asBareJid() + ": done changing access mode");
						account.setOption(Account.OPTION_REQUIRES_ACCESS_MODE_CHANGE, false);
						mXmppConnectionService.databaseBackend.updateAccount(account);
					}
					if (packet.getType() == IqPacket.TYPE.ERROR) {
						if (preConditionNotMet) {
							Log.d(Config.LOGTAG,account.getJid().asBareJid()+": device list pre condition still not met on second attempt");
						} else if (error != null) {
							pepBroken = true;
							Log.d(Config.LOGTAG, getLogprefix(account) + "Error received while publishing own device id" + packet.findChild("error"));
						}

					}
				}
			}
		});
	}

	public void publishDeviceVerificationAndBundle(final SignedPreKeyRecord signedPreKeyRecord,
	                                               final Set<PreKeyRecord> preKeyRecords,
	                                               final boolean announceAfter,
	                                               final boolean wipe) {
		try {
			IdentityKey axolotlPublicKey = axolotlStore.getIdentityKeyPair().getPublicKey();
			PrivateKey x509PrivateKey = KeyChain.getPrivateKey(mXmppConnectionService, account.getPrivateKeyAlias());
			X509Certificate[] chain = KeyChain.getCertificateChain(mXmppConnectionService, account.getPrivateKeyAlias());
			Signature verifier = Signature.getInstance("sha256WithRSA");
			verifier.initSign(x509PrivateKey, mXmppConnectionService.getRNG());
			verifier.update(axolotlPublicKey.serialize());
			byte[] signature = verifier.sign();
			IqPacket packet = mXmppConnectionService.getIqGenerator().publishVerification(signature, chain, getOwnDeviceId());
			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + ": publish verification for device " + getOwnDeviceId());
			mXmppConnectionService.sendIqPacket(account, packet, new OnIqPacketReceived() {
				@Override
				public void onIqPacketReceived(final Account account, IqPacket packet) {
					String node = AxolotlService.PEP_VERIFICATION + ":" + getOwnDeviceId();
					mXmppConnectionService.pushNodeConfiguration(account, node, PublishOptions.openAccess(), new XmppConnectionService.OnConfigurationPushed() {
						@Override
						public void onPushSucceeded() {
							Log.d(Config.LOGTAG, getLogprefix(account) + "configured verification node to be world readable");
							publishDeviceBundle(signedPreKeyRecord, preKeyRecords, announceAfter, wipe);
						}

						@Override
						public void onPushFailed() {
							Log.d(Config.LOGTAG, getLogprefix(account) + "unable to set access model on verification node");
							publishDeviceBundle(signedPreKeyRecord, preKeyRecords, announceAfter, wipe);
						}
					});
				}
			});
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	public void publishBundlesIfNeeded(final boolean announce, final boolean wipe) {
		if (pepBroken) {
			Log.d(Config.LOGTAG, getLogprefix(account) + "publishBundlesIfNeeded called, but PEP is broken. Ignoring... ");
			return;
		}

		if (account.getXmppConnection().getFeatures().pepPublishOptions()) {
			this.changeAccessMode.set(account.isOptionSet(Account.OPTION_REQUIRES_ACCESS_MODE_CHANGE));
		} else {
			if (account.setOption(Account.OPTION_REQUIRES_ACCESS_MODE_CHANGE, true)) {
				Log.d(Config.LOGTAG, account.getJid().asBareJid() + ": server doesn’t support publish-options. setting for later access mode change");
				mXmppConnectionService.databaseBackend.updateAccount(account);
			}
		}
		if (this.changeAccessMode.get()) {
			Log.d(Config.LOGTAG, account.getJid().asBareJid() + ": server gained publish-options capabilities. changing access model");
		}
		IqPacket packet = mXmppConnectionService.getIqGenerator().retrieveBundlesForDevice(account.getJid().asBareJid(), getOwnDeviceId());
		mXmppConnectionService.sendIqPacket(account, packet, new OnIqPacketReceived() {
			@Override
			public void onIqPacketReceived(Account account, IqPacket packet) {

				if (packet.getType() == IqPacket.TYPE.TIMEOUT) {
					return; //ignore timeout. do nothing
				}

				if (packet.getType() == IqPacket.TYPE.ERROR) {
					Element error = packet.findChild("error");
					if (error == null || !error.hasChild("item-not-found")) {
						pepBroken = true;
						Log.w(Config.LOGTAG, AxolotlService.getLogprefix(account) + "request for device bundles came back with something other than item-not-found" + packet);
						return;
					}
				}

				PreKeyBundle bundle = mXmppConnectionService.getIqParser().bundle(packet);
				Map<Integer, ECPublicKey> keys = mXmppConnectionService.getIqParser().preKeyPublics(packet);
				boolean flush = false;
				if (bundle == null) {
					Log.w(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Received invalid bundle:" + packet);
					bundle = new PreKeyBundle(-1, -1, -1, null, -1, null, null, null);
					flush = true;
				}
				if (keys == null) {
					Log.w(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Received invalid prekeys:" + packet);
				}
				try {
					boolean changed = false;
					// Validate IdentityKey
					IdentityKeyPair identityKeyPair = axolotlStore.getIdentityKeyPair();
					if (flush || !identityKeyPair.getPublicKey().equals(bundle.getIdentityKey())) {
						Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Adding own IdentityKey " + identityKeyPair.getPublicKey() + " to PEP.");
						changed = true;
					}

					// Validate signedPreKeyRecord + ID
					SignedPreKeyRecord signedPreKeyRecord;
					int numSignedPreKeys = axolotlStore.getSignedPreKeysCount();
					try {
						signedPreKeyRecord = axolotlStore.loadSignedPreKey(bundle.getSignedPreKeyId());
						if (flush
								|| !bundle.getSignedPreKey().equals(signedPreKeyRecord.getKeyPair().getPublicKey())
								|| !Arrays.equals(bundle.getSignedPreKeySignature(), signedPreKeyRecord.getSignature())) {
							Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Adding new signedPreKey with ID " + (numSignedPreKeys + 1) + " to PEP.");
							signedPreKeyRecord = KeyHelper.generateSignedPreKey(identityKeyPair, numSignedPreKeys + 1);
							axolotlStore.storeSignedPreKey(signedPreKeyRecord.getId(), signedPreKeyRecord);
							changed = true;
						}
					} catch (InvalidKeyIdException e) {
						Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Adding new signedPreKey with ID " + (numSignedPreKeys + 1) + " to PEP.");
						signedPreKeyRecord = KeyHelper.generateSignedPreKey(identityKeyPair, numSignedPreKeys + 1);
						axolotlStore.storeSignedPreKey(signedPreKeyRecord.getId(), signedPreKeyRecord);
						changed = true;
					}

					// Validate PreKeys
					Set<PreKeyRecord> preKeyRecords = new HashSet<>();
					if (keys != null) {
						for (Integer id : keys.keySet()) {
							try {
								PreKeyRecord preKeyRecord = axolotlStore.loadPreKey(id);
								if (preKeyRecord.getKeyPair().getPublicKey().equals(keys.get(id))) {
									preKeyRecords.add(preKeyRecord);
								}
							} catch (InvalidKeyIdException ignored) {
							}
						}
					}
					int newKeys = NUM_KEYS_TO_PUBLISH - preKeyRecords.size();
					if (newKeys > 0) {
						List<PreKeyRecord> newRecords = KeyHelper.generatePreKeys(
								axolotlStore.getCurrentPreKeyId() + 1, newKeys);
						preKeyRecords.addAll(newRecords);
						for (PreKeyRecord record : newRecords) {
							axolotlStore.storePreKey(record.getId(), record);
						}
						changed = true;
						Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Adding " + newKeys + " new preKeys to PEP.");
					}


					if (changed || changeAccessMode.get()) {
						if (account.getPrivateKeyAlias() != null && Config.X509_VERIFICATION) {
							mXmppConnectionService.publishDisplayName(account);
							publishDeviceVerificationAndBundle(signedPreKeyRecord, preKeyRecords, announce, wipe);
						} else {
							publishDeviceBundle(signedPreKeyRecord, preKeyRecords, announce, wipe);
						}
					} else {
						Log.d(Config.LOGTAG, getLogprefix(account) + "Bundle " + getOwnDeviceId() + " in PEP was current");
						if (wipe) {
							wipeOtherPepDevices();
						} else if (announce) {
							Log.d(Config.LOGTAG, getLogprefix(account) + "Announcing device " + getOwnDeviceId());
							publishOwnDeviceIdIfNeeded();
						}
					}
				} catch (InvalidKeyException e) {
					Log.e(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Failed to publish bundle " + getOwnDeviceId() + ", reason: " + e.getMessage());
				}
			}
		});
	}

	private void publishDeviceBundle(SignedPreKeyRecord signedPreKeyRecord,
	                                 Set<PreKeyRecord> preKeyRecords,
	                                 final boolean announceAfter,
	                                 final boolean wipe) {
		publishDeviceBundle(signedPreKeyRecord, preKeyRecords, announceAfter, wipe, true);
	}

	private void publishDeviceBundle(final SignedPreKeyRecord signedPreKeyRecord,
	                                 final Set<PreKeyRecord> preKeyRecords,
	                                 final boolean announceAfter,
	                                 final boolean wipe,
	                                 final boolean firstAttempt) {
		final Bundle publishOptions = account.getXmppConnection().getFeatures().pepPublishOptions() ? PublishOptions.openAccess() : null;
		IqPacket publish = mXmppConnectionService.getIqGenerator().publishBundles(
				signedPreKeyRecord, axolotlStore.getIdentityKeyPair().getPublicKey(),
				preKeyRecords, getOwnDeviceId(), publishOptions);
		Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + ": Bundle " + getOwnDeviceId() + " in PEP not current. Publishing...");
		mXmppConnectionService.sendIqPacket(account, publish, new OnIqPacketReceived() {
			@Override
			public void onIqPacketReceived(final Account account, IqPacket packet) {
				final boolean preconditionNotMet = PublishOptions.preconditionNotMet(packet);
				if (firstAttempt && preconditionNotMet) {
					Log.d(Config.LOGTAG, account.getJid().asBareJid() + ": precondition wasn't met for bundle. pushing node configuration");
					final String node = AxolotlService.PEP_BUNDLES + ":" + getOwnDeviceId();
					mXmppConnectionService.pushNodeConfiguration(account, node, publishOptions, new XmppConnectionService.OnConfigurationPushed() {
						@Override
						public void onPushSucceeded() {
							publishDeviceBundle(signedPreKeyRecord, preKeyRecords, announceAfter, wipe, false);
						}

						@Override
						public void onPushFailed() {
							publishDeviceBundle(signedPreKeyRecord, preKeyRecords, announceAfter, wipe, false);
						}
					});
				} else if (packet.getType() == IqPacket.TYPE.RESULT) {
					Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Successfully published bundle. ");
					if (wipe) {
						wipeOtherPepDevices();
					} else if (announceAfter) {
						Log.d(Config.LOGTAG, getLogprefix(account) + "Announcing device " + getOwnDeviceId());
						publishOwnDeviceIdIfNeeded();
					}
				} else if (packet.getType() == IqPacket.TYPE.ERROR) {
					if (preconditionNotMet) {
						Log.d(Config.LOGTAG,getLogprefix(account) + "bundle precondition still not met after second attempt");
					} else {
						Log.d(Config.LOGTAG, getLogprefix(account) + "Error received while publishing bundle: " + packet.toString());
					}
					pepBroken = true;
				}
			}
		});
	}

	public void deleteOmemoIdentity() {
		final String node = AxolotlService.PEP_BUNDLES + ":" + getOwnDeviceId();
		final IqPacket deleteBundleNode = mXmppConnectionService.getIqGenerator().deleteNode(node);
		mXmppConnectionService.sendIqPacket(account, deleteBundleNode, null);
		final Set<Integer> ownDeviceIds = getOwnDeviceIds();
		publishDeviceIdsAndRefineAccessModel(ownDeviceIds == null ? Collections.emptySet() : ownDeviceIds);
	}

	public List<Jid> getCryptoTargets(Conversation conversation) {
		final List<Jid> jids;
		if (conversation.getMode() == Conversation.MODE_SINGLE) {
			jids = new ArrayList<>();
			jids.add(conversation.getJid().asBareJid());
		} else {
			jids = conversation.getMucOptions().getMembers(false);
		}
		return jids;
	}

	public FingerprintStatus getFingerprintTrust(String fingerprint) {
		return axolotlStore.getFingerprintStatus(fingerprint);
	}

	public X509Certificate getFingerprintCertificate(String fingerprint) {
		return axolotlStore.getFingerprintCertificate(fingerprint);
	}

	public void setFingerprintTrust(String fingerprint, FingerprintStatus status) {
		axolotlStore.setFingerprintStatus(fingerprint, status);
	}

	private void verifySessionWithPEP(final XmppAxolotlSession session) {
		Log.d(Config.LOGTAG, "trying to verify fresh session (" + session.getRemoteAddress().getName() + ") with pep");
		final SignalProtocolAddress address = session.getRemoteAddress();
		final IdentityKey identityKey = session.getIdentityKey();
		try {
			IqPacket packet = mXmppConnectionService.getIqGenerator().retrieveVerificationForDevice(Jid.of(address.getName()), address.getDeviceId());
			mXmppConnectionService.sendIqPacket(account, packet, new OnIqPacketReceived() {
				@Override
				public void onIqPacketReceived(Account account, IqPacket packet) {
					Pair<X509Certificate[], byte[]> verification = mXmppConnectionService.getIqParser().verification(packet);
					if (verification != null) {
						try {
							Signature verifier = Signature.getInstance("sha256WithRSA");
							verifier.initVerify(verification.first[0]);
							verifier.update(identityKey.serialize());
							if (verifier.verify(verification.second)) {
								try {
									mXmppConnectionService.getMemorizingTrustManager().getNonInteractive().checkClientTrusted(verification.first, "RSA");
									String fingerprint = session.getFingerprint();
									Log.d(Config.LOGTAG, "verified session with x.509 signature. fingerprint was: " + fingerprint);
									setFingerprintTrust(fingerprint, FingerprintStatus.createActiveVerified(true));
									axolotlStore.setFingerprintCertificate(fingerprint, verification.first[0]);
									fetchStatusMap.put(address, FetchStatus.SUCCESS_VERIFIED);
									Bundle information = CryptoHelper.extractCertificateInformation(verification.first[0]);
									try {
										final String cn = information.getString("subject_cn");
										final Jid jid = Jid.of(address.getName());
										Log.d(Config.LOGTAG, "setting common name for " + jid + " to " + cn);
										account.getRoster().getContact(jid).setCommonName(cn);
									} catch (final IllegalArgumentException ignored) {
										//ignored
									}
									finishBuildingSessionsFromPEP(address);
									return;
								} catch (Exception e) {
									Log.d(Config.LOGTAG, "could not verify certificate");
								}
							}
						} catch (Exception e) {
							Log.d(Config.LOGTAG, "error during verification " + e.getMessage());
						}
					} else {
						Log.d(Config.LOGTAG, "no verification found");
					}
					fetchStatusMap.put(address, FetchStatus.SUCCESS);
					finishBuildingSessionsFromPEP(address);
				}
			});
		} catch (IllegalArgumentException e) {
			fetchStatusMap.put(address, FetchStatus.SUCCESS);
			finishBuildingSessionsFromPEP(address);
		}
	}

	private final Set<Integer> PREVIOUSLY_REMOVED_FROM_ANNOUNCEMENT = new HashSet<>();

	private void finishBuildingSessionsFromPEP(final SignalProtocolAddress address) {
		SignalProtocolAddress ownAddress = new SignalProtocolAddress(account.getJid().asBareJid().toString(), 0);
		Map<Integer, FetchStatus> own = fetchStatusMap.getAll(ownAddress.getName());
		Map<Integer, FetchStatus> remote = fetchStatusMap.getAll(address.getName());
		if (!own.containsValue(FetchStatus.PENDING) && !remote.containsValue(FetchStatus.PENDING)) {
			FetchStatus report = null;
			if (own.containsValue(FetchStatus.SUCCESS) || remote.containsValue(FetchStatus.SUCCESS)) {
				report = FetchStatus.SUCCESS;
			} else if (own.containsValue(FetchStatus.SUCCESS_VERIFIED) || remote.containsValue(FetchStatus.SUCCESS_VERIFIED)) {
				report = FetchStatus.SUCCESS_VERIFIED;
			} else if (own.containsValue(FetchStatus.SUCCESS_TRUSTED) || remote.containsValue(FetchStatus.SUCCESS_TRUSTED)) {
				report = FetchStatus.SUCCESS_TRUSTED;
			} else if (own.containsValue(FetchStatus.ERROR) || remote.containsValue(FetchStatus.ERROR)) {
				report = FetchStatus.ERROR;
			}
			mXmppConnectionService.keyStatusUpdated(report);
		}
		if (Config.REMOVE_BROKEN_DEVICES) {
			Set<Integer> ownDeviceIds = new HashSet<>(getOwnDeviceIds());
			boolean publish = false;
			for (Map.Entry<Integer, FetchStatus> entry : own.entrySet()) {
				int id = entry.getKey();
				if (entry.getValue() == FetchStatus.ERROR && PREVIOUSLY_REMOVED_FROM_ANNOUNCEMENT.add(id) && ownDeviceIds.remove(id)) {
					publish = true;
					Log.d(Config.LOGTAG, account.getJid().asBareJid() + ": error fetching own device with id " + id + ". removing from announcement");
				}
			}
			if (publish) {
				publishOwnDeviceId(ownDeviceIds);
			}
		}
	}

	public boolean hasEmptyDeviceList(Jid jid) {
		return !hasAny(jid) && (!deviceIds.containsKey(jid) || deviceIds.get(jid).isEmpty());
	}

	public interface OnDeviceIdsFetched {
		void fetched(Jid jid, Set<Integer> deviceIds);
	}

	public interface OnMultipleDeviceIdFetched {
		void fetched();
	}

	public void fetchDeviceIds(final Jid jid) {
		fetchDeviceIds(jid, null);
	}

	private void fetchDeviceIds(final Jid jid, OnDeviceIdsFetched callback) {
		IqPacket packet;
		synchronized (this.fetchDeviceIdsMap) {
			List<OnDeviceIdsFetched> callbacks = this.fetchDeviceIdsMap.get(jid);
			if (callbacks != null) {
				if (callback != null) {
					callbacks.add(callback);
				}
				Log.d(Config.LOGTAG, account.getJid().asBareJid() + ": fetching device ids for " + jid + " already running. adding callback");
				packet = null;
			} else {
				callbacks = new ArrayList<>();
				if (callback != null) {
					callbacks.add(callback);
				}
				this.fetchDeviceIdsMap.put(jid, callbacks);
				Log.d(Config.LOGTAG, account.getJid().asBareJid() + ": fetching device ids for " + jid);
				packet = mXmppConnectionService.getIqGenerator().retrieveDeviceIds(jid);
			}
		}
		if (packet != null) {
			mXmppConnectionService.sendIqPacket(account, packet, (account, response) -> {
				if (response.getType() == IqPacket.TYPE.RESULT) {
					fetchDeviceListStatus.put(jid, true);
					Element item = mXmppConnectionService.getIqParser().getItem(response);
					Set<Integer> deviceIds = mXmppConnectionService.getIqParser().deviceIds(item);
					registerDevices(jid, deviceIds);
					final List<OnDeviceIdsFetched> callbacks;
					synchronized (fetchDeviceIdsMap) {
						callbacks = fetchDeviceIdsMap.remove(jid);
					}
					if (callbacks != null) {
						for (OnDeviceIdsFetched c : callbacks) {
							c.fetched(jid, deviceIds);
						}
					}
				} else {
					if (response.getType() == IqPacket.TYPE.TIMEOUT) {
						fetchDeviceListStatus.remove(jid);
					} else {
						fetchDeviceListStatus.put(jid, false);
					}
					final List<OnDeviceIdsFetched> callbacks;
					synchronized (fetchDeviceIdsMap) {
						callbacks = fetchDeviceIdsMap.remove(jid);
					}
					if (callbacks != null) {
						for (OnDeviceIdsFetched c : callbacks) {
							c.fetched(jid, null);
						}
					}
				}
			});
		}
	}

	private void fetchDeviceIds(List<Jid> jids, final OnMultipleDeviceIdFetched callback) {
		final ArrayList<Jid> unfinishedJids = new ArrayList<>(jids);
		synchronized (unfinishedJids) {
			for (Jid jid : unfinishedJids) {
				fetchDeviceIds(jid, (j, deviceIds) -> {
					synchronized (unfinishedJids) {
						unfinishedJids.remove(j);
						if (unfinishedJids.size() == 0 && callback != null) {
							callback.fetched();
						}
					}
				});
			}
		}
	}

	interface OnSessionBuildFromPep {
		void onSessionBuildSuccessful();
		void onSessionBuildFailed();
	}

	private void buildSessionFromPEP(final SignalProtocolAddress address) {
		buildSessionFromPEP(address, null);
	}

	private void buildSessionFromPEP(final SignalProtocolAddress address, OnSessionBuildFromPep callback) {
		Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Building new session for " + address.toString());
		if (address.equals(getOwnAxolotlAddress())) {
			throw new AssertionError("We should NEVER build a session with ourselves. What happened here?!");
		}

		final Jid jid = Jid.of(address.getName());
		final boolean oneOfOurs = jid.asBareJid().equals(account.getJid().asBareJid());
		IqPacket bundlesPacket = mXmppConnectionService.getIqGenerator().retrieveBundlesForDevice(jid, address.getDeviceId());
		mXmppConnectionService.sendIqPacket(account, bundlesPacket, (account, packet) -> {
			if (packet.getType() == IqPacket.TYPE.TIMEOUT) {
				fetchStatusMap.put(address, FetchStatus.TIMEOUT);
			} else if (packet.getType() == IqPacket.TYPE.RESULT) {
				Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Received preKey IQ packet, processing...");
				final IqParser parser = mXmppConnectionService.getIqParser();
				final List<PreKeyBundle> preKeyBundleList = parser.preKeys(packet);
				final PreKeyBundle bundle = parser.bundle(packet);
				if (preKeyBundleList.isEmpty() || bundle == null) {
					Log.e(Config.LOGTAG, AxolotlService.getLogprefix(account) + "preKey IQ packet invalid: " + packet);
					fetchStatusMap.put(address, FetchStatus.ERROR);
					finishBuildingSessionsFromPEP(address);
					if (callback != null) {
						callback.onSessionBuildFailed();
					}
					return;
				}
				Random random = new Random();
				final PreKeyBundle preKey = preKeyBundleList.get(random.nextInt(preKeyBundleList.size()));
				if (preKey == null) {
					//should never happen
					fetchStatusMap.put(address, FetchStatus.ERROR);
					finishBuildingSessionsFromPEP(address);
					if (callback != null) {
						callback.onSessionBuildFailed();
					}
					return;
				}

				final PreKeyBundle preKeyBundle = new PreKeyBundle(0, address.getDeviceId(),
						preKey.getPreKeyId(), preKey.getPreKey(),
						bundle.getSignedPreKeyId(), bundle.getSignedPreKey(),
						bundle.getSignedPreKeySignature(), bundle.getIdentityKey());

				try {
					SessionBuilder builder = new SessionBuilder(axolotlStore, address);
					builder.process(preKeyBundle);
					XmppAxolotlSession session = new XmppAxolotlSession(account, axolotlStore, address, bundle.getIdentityKey());
					sessions.put(address, session);
					if (Config.X509_VERIFICATION) {
						verifySessionWithPEP(session); //TODO; maybe inject callback in here too
					} else {
						FingerprintStatus status = getFingerprintTrust(CryptoHelper.bytesToHex(bundle.getIdentityKey().getPublicKey().serialize()));
						FetchStatus fetchStatus;
						if (status != null && status.isVerified()) {
							fetchStatus = FetchStatus.SUCCESS_VERIFIED;
						} else if (status != null && status.isTrusted()) {
							fetchStatus = FetchStatus.SUCCESS_TRUSTED;
						} else {
							fetchStatus = FetchStatus.SUCCESS;
						}
						fetchStatusMap.put(address, fetchStatus);
						finishBuildingSessionsFromPEP(address);
						if (callback != null) {
							callback.onSessionBuildSuccessful();
						}
					}
				} catch (UntrustedIdentityException | InvalidKeyException e) {
					Log.e(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Error building session for " + address + ": "
							+ e.getClass().getName() + ", " + e.getMessage());
					fetchStatusMap.put(address, FetchStatus.ERROR);
					finishBuildingSessionsFromPEP(address);
					if (oneOfOurs && cleanedOwnDeviceIds.add(address.getDeviceId())) {
						removeFromDeviceAnnouncement(address.getDeviceId());
					}
					if (callback != null) {
						callback.onSessionBuildFailed();
					}
				}
			} else {
				fetchStatusMap.put(address, FetchStatus.ERROR);
				Element error = packet.findChild("error");
				boolean itemNotFound = error != null && error.hasChild("item-not-found");
				Log.d(Config.LOGTAG, getLogprefix(account) + "Error received while building session:" + packet.findChild("error"));
				finishBuildingSessionsFromPEP(address);
				if (oneOfOurs && itemNotFound && cleanedOwnDeviceIds.add(address.getDeviceId())) {
					removeFromDeviceAnnouncement(address.getDeviceId());
				}
				if (callback != null) {
					callback.onSessionBuildFailed();
				}
			}
		});
	}

	private void removeFromDeviceAnnouncement(Integer id) {
		HashSet<Integer> temp = new HashSet<>(getOwnDeviceIds());
		if (temp.remove(id)) {
			Log.d(Config.LOGTAG,account.getJid().asBareJid()+" remove own device id "+id+" from announcement. devices left:"+temp);
			publishOwnDeviceId(temp);
		}
	}

	public Set<SignalProtocolAddress> findDevicesWithoutSession(final Conversation conversation) {
		Set<SignalProtocolAddress> addresses = new HashSet<>();
		for (Jid jid : getCryptoTargets(conversation)) {
			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Finding devices without session for " + jid);
			final Set<Integer> ids = deviceIds.get(jid);
			if (ids != null && !ids.isEmpty()) {
				for (Integer foreignId : ids) {
					SignalProtocolAddress address = new SignalProtocolAddress(jid.toString(), foreignId);
					if (sessions.get(address) == null) {
						IdentityKey identityKey = axolotlStore.loadSession(address).getSessionState().getRemoteIdentityKey();
						if (identityKey != null) {
							Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Already have session for " + address.toString() + ", adding to cache...");
							XmppAxolotlSession session = new XmppAxolotlSession(account, axolotlStore, address, identityKey);
							sessions.put(address, session);
						} else {
							Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Found device " + jid + ":" + foreignId);
							if (fetchStatusMap.get(address) != FetchStatus.ERROR) {
								addresses.add(address);
							} else {
								Log.d(Config.LOGTAG, getLogprefix(account) + "skipping over " + address + " because it's broken");
							}
						}
					}
				}
			} else {
				mXmppConnectionService.keyStatusUpdated(FetchStatus.ERROR);
				Log.w(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Have no target devices in PEP!");
			}
		}
		Set<Integer> ownIds = this.deviceIds.get(account.getJid().asBareJid());
		for (Integer ownId : (ownIds != null ? ownIds : new HashSet<Integer>())) {
			SignalProtocolAddress address = new SignalProtocolAddress(account.getJid().asBareJid().toString(), ownId);
			if (sessions.get(address) == null) {
				IdentityKey identityKey = axolotlStore.loadSession(address).getSessionState().getRemoteIdentityKey();
				if (identityKey != null) {
					Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Already have session for " + address.toString() + ", adding to cache...");
					XmppAxolotlSession session = new XmppAxolotlSession(account, axolotlStore, address, identityKey);
					sessions.put(address, session);
				} else {
					Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Found device " + account.getJid().asBareJid() + ":" + ownId);
					if (fetchStatusMap.get(address) != FetchStatus.ERROR) {
						addresses.add(address);
					} else {
						Log.d(Config.LOGTAG, getLogprefix(account) + "skipping over " + address + " because it's broken");
					}
				}
			}
		}

		return addresses;
	}

	public boolean createSessionsIfNeeded(final Conversation conversation) {
		final List<Jid> jidsWithEmptyDeviceList = getCryptoTargets(conversation);
		for (Iterator<Jid> iterator = jidsWithEmptyDeviceList.iterator(); iterator.hasNext(); ) {
			final Jid jid = iterator.next();
			if (!hasEmptyDeviceList(jid)) {
				iterator.remove();
			}
		}
		Log.d(Config.LOGTAG, account.getJid().asBareJid() + ": createSessionsIfNeeded() - jids with empty device list: " + jidsWithEmptyDeviceList);
		if (jidsWithEmptyDeviceList.size() > 0) {
			fetchDeviceIds(jidsWithEmptyDeviceList, () -> createSessionsIfNeededActual(conversation));
			return true;
		} else {
			return createSessionsIfNeededActual(conversation);
		}
	}

	private boolean createSessionsIfNeededActual(final Conversation conversation) {
		Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Creating axolotl sessions if needed...");
		boolean newSessions = false;
		Set<SignalProtocolAddress> addresses = findDevicesWithoutSession(conversation);
		for (SignalProtocolAddress address : addresses) {
			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Processing device: " + address.toString());
			FetchStatus status = fetchStatusMap.get(address);
			if (status == null || status == FetchStatus.TIMEOUT) {
				fetchStatusMap.put(address, FetchStatus.PENDING);
				this.buildSessionFromPEP(address);
				newSessions = true;
			} else if (status == FetchStatus.PENDING) {
				newSessions = true;
			} else {
				Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Already fetching bundle for " + address.toString());
			}
		}

		return newSessions;
	}

	public boolean trustedSessionVerified(final Conversation conversation) {
		final Set<XmppAxolotlSession> sessions = new HashSet<>();
		sessions.addAll(findSessionsForConversation(conversation));
		sessions.addAll(findOwnSessions());
		boolean verified = false;
		for (XmppAxolotlSession session : sessions) {
			if (session.getTrust().isTrustedAndActive()) {
				if (session.getTrust().getTrust() == FingerprintStatus.Trust.VERIFIED_X509) {
					verified = true;
				} else {
					return false;
				}
			}
		}
		return verified;
	}

	public boolean hasPendingKeyFetches(List<Jid> jids) {
		SignalProtocolAddress ownAddress = new SignalProtocolAddress(account.getJid().asBareJid().toString(), 0);
		if (fetchStatusMap.getAll(ownAddress.getName()).containsValue(FetchStatus.PENDING)) {
			return true;
		}
		synchronized (this.fetchDeviceIdsMap) {
			for (Jid jid : jids) {
				SignalProtocolAddress foreignAddress = new SignalProtocolAddress(jid.asBareJid().toString(), 0);
				if (fetchStatusMap.getAll(foreignAddress.getName()).containsValue(FetchStatus.PENDING) || this.fetchDeviceIdsMap.containsKey(jid)) {
					return true;
				}
			}
		}
		return false;
	}

	@Nullable
	private boolean buildHeader(XmppAxolotlMessage axolotlMessage, Conversation c) {
		Set<XmppAxolotlSession> remoteSessions = findSessionsForConversation(c);
		final boolean acceptEmpty = (c.getMode() == Conversation.MODE_MULTI && c.getMucOptions().getUserCount() == 0) || c.getContact().isSelf();
		Collection<XmppAxolotlSession> ownSessions = findOwnSessions();
		if (remoteSessions.isEmpty() && !acceptEmpty) {
			return false;
		}
		for (XmppAxolotlSession session : remoteSessions) {
			axolotlMessage.addDevice(session);
		}
		for (XmppAxolotlSession session : ownSessions) {
			axolotlMessage.addDevice(session);
		}

		return true;
	}

	//this is being used for private muc messages only
	private boolean buildHeader(XmppAxolotlMessage axolotlMessage, Jid jid) {
		if (jid == null) {
			return false;
		}
		HashSet<XmppAxolotlSession> sessions = new HashSet<>();
		sessions.addAll(this.sessions.getAll(getAddressForJid(jid).getName()).values());
		if (sessions.isEmpty()) {
			return false;
		}
		sessions.addAll(findOwnSessions());
		for(XmppAxolotlSession session : sessions) {
			axolotlMessage.addDevice(session);
		}
		return true;
	}

	@Nullable
	public XmppAxolotlMessage encrypt(Message message) {
		final XmppAxolotlMessage axolotlMessage = new XmppAxolotlMessage(account.getJid().asBareJid(), getOwnDeviceId());
		final String content;
		if (message.hasFileOnRemoteHost()) {
			content = message.getFileParams().url.toString();
		} else {
			content = message.getBody();
		}
		try {
			axolotlMessage.encrypt(content);
		} catch (CryptoFailedException e) {
			Log.w(Config.LOGTAG, getLogprefix(account) + "Failed to encrypt message: " + e.getMessage());
			return null;
		}

		final boolean success;
		if (message.isPrivateMessage()) {
			success = buildHeader(axolotlMessage, message.getTrueCounterpart());
		} else {
			success = buildHeader(axolotlMessage, (Conversation) message.getConversation());
		}
		return success ? axolotlMessage : null;
	}

	public void preparePayloadMessage(final Message message, final boolean delay) {
		executor.execute(new Runnable() {
			@Override
			public void run() {
				XmppAxolotlMessage axolotlMessage = encrypt(message);
				if (axolotlMessage == null) {
					mXmppConnectionService.markMessage(message, Message.STATUS_SEND_FAILED);
					//mXmppConnectionService.updateConversationUi();
				} else {
					Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Generated message, caching: " + message.getUuid());
					messageCache.put(message.getUuid(), axolotlMessage);
					mXmppConnectionService.resendMessage(message, delay);
				}
			}
		});
	}

	public void prepareKeyTransportMessage(final Conversation conversation, final OnMessageCreatedCallback onMessageCreatedCallback) {
		executor.execute(new Runnable() {
			@Override
			public void run() {
				final XmppAxolotlMessage axolotlMessage = new XmppAxolotlMessage(account.getJid().asBareJid(), getOwnDeviceId());
				if (buildHeader(axolotlMessage, conversation)) {
					onMessageCreatedCallback.run(axolotlMessage);
				} else {
					onMessageCreatedCallback.run(null);
				}
			}
		});
	}

	public XmppAxolotlMessage fetchAxolotlMessageFromCache(Message message) {
		XmppAxolotlMessage axolotlMessage = messageCache.get(message.getUuid());
		if (axolotlMessage != null) {
			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Cache hit: " + message.getUuid());
			messageCache.remove(message.getUuid());
		} else {
			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Cache miss: " + message.getUuid());
		}
		return axolotlMessage;
	}

	private XmppAxolotlSession recreateUncachedSession(SignalProtocolAddress address) {
		IdentityKey identityKey = axolotlStore.loadSession(address).getSessionState().getRemoteIdentityKey();
		return (identityKey != null)
				? new XmppAxolotlSession(account, axolotlStore, address, identityKey)
				: null;
	}

	private XmppAxolotlSession getReceivingSession(XmppAxolotlMessage message) {
		SignalProtocolAddress senderAddress = new SignalProtocolAddress(message.getFrom().toString(), message.getSenderDeviceId());
		return getReceivingSession(senderAddress);

	}

	private XmppAxolotlSession getReceivingSession(SignalProtocolAddress senderAddress) {
		XmppAxolotlSession session = sessions.get(senderAddress);
		if (session == null) {
			//Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Account: " + account.getJid() + " No axolotl session found while parsing received message " + message);
			session = recreateUncachedSession(senderAddress);
			if (session == null) {
				session = new XmppAxolotlSession(account, axolotlStore, senderAddress);
			}
		}
		return session;
	}

	public XmppAxolotlMessage.XmppAxolotlPlaintextMessage processReceivingPayloadMessage(XmppAxolotlMessage message, boolean postponePreKeyMessageHandling) throws NotEncryptedForThisDeviceException, BrokenSessionException {
		XmppAxolotlMessage.XmppAxolotlPlaintextMessage plaintextMessage = null;

		XmppAxolotlSession session = getReceivingSession(message);
		int ownDeviceId = getOwnDeviceId();
		try {
			plaintextMessage = message.decrypt(session, ownDeviceId);
			Integer preKeyId = session.getPreKeyIdAndReset();
			if (preKeyId != null) {
				postPreKeyMessageHandling(session, postponePreKeyMessageHandling);
			}
		} catch (NotEncryptedForThisDeviceException e) {
			if (account.getJid().asBareJid().equals(message.getFrom().asBareJid()) && message.getSenderDeviceId() == ownDeviceId) {
				Log.w(Config.LOGTAG, getLogprefix(account) + "Reflected omemo message received");
			} else {
				throw e;
			}
		} catch (final BrokenSessionException e) {
			throw e;
		} catch (CryptoFailedException e) {
			Log.w(Config.LOGTAG, getLogprefix(account) + "Failed to decrypt message from " + message.getFrom(), e);
		}

		if (session.isFresh() && plaintextMessage != null) {
			putFreshSession(session);
		}

		return plaintextMessage;
	}

	public void reportBrokenSessionException(BrokenSessionException e, boolean postpone) {
		Log.e(Config.LOGTAG,account.getJid().asBareJid()+": broken session with "+e.getSignalProtocolAddress().toString()+" detected", e);
		if (postpone) {
			postponedHealing.add(e.getSignalProtocolAddress());
		} else {
			notifyRequiresHealing(e.getSignalProtocolAddress());
		}
	}

	private void notifyRequiresHealing(final SignalProtocolAddress signalProtocolAddress) {
		if (healingAttempts.add(signalProtocolAddress)) {
			Log.d(Config.LOGTAG,account.getJid().asBareJid()+": attempt to heal "+signalProtocolAddress);
			buildSessionFromPEP(signalProtocolAddress, new OnSessionBuildFromPep() {
				@Override
				public void onSessionBuildSuccessful() {
					Log.d(Config.LOGTAG, "successfully build new session from pep after detecting broken session");
					completeSession(getReceivingSession(signalProtocolAddress));
				}

				@Override
				public void onSessionBuildFailed() {
					Log.d(Config.LOGTAG, account.getJid().asBareJid() + ": unable to build new session from pep after detecting broken session");
				}
			});
		} else {
			Log.d(Config.LOGTAG,account.getJid().asBareJid()+": do not attempt to heal "+signalProtocolAddress+" again");
		}
	}

	private void postPreKeyMessageHandling(final XmppAxolotlSession session, final boolean postpone) {
		if (postpone) {
			postponedSessions.add(session);
		} else {
			if (axolotlStore.flushPreKeys()) {
				publishBundlesIfNeeded(false, false);
			} else {
				Log.d(Config.LOGTAG,account.getJid().asBareJid()+": nothing to flush. Not republishing key");
			}
			if (trustedOrPreviouslyResponded(session)) {
				completeSession(session);
			}
		}
	}

	public void processPostponed() {
		if (postponedSessions.size() > 0) {
			if (axolotlStore.flushPreKeys()) {
				publishBundlesIfNeeded(false, false);
			}
		}
		final Iterator<XmppAxolotlSession> iterator = postponedSessions.iterator();
		while (iterator.hasNext()) {
			final XmppAxolotlSession session = iterator.next();
			if (trustedOrPreviouslyResponded(session)) {
				completeSession(session);
			}
			iterator.remove();
		}
		final Iterator<SignalProtocolAddress> postponedHealingAttemptsIterator = postponedHealing.iterator();
		while (postponedHealingAttemptsIterator.hasNext()) {
			notifyRequiresHealing(postponedHealingAttemptsIterator.next());
			postponedHealingAttemptsIterator.remove();
		}
	}


	private boolean trustedOrPreviouslyResponded(XmppAxolotlSession session) {
		try {
			return trustedOrPreviouslyResponded(Jid.of(session.getRemoteAddress().getName()));
		} catch (IllegalArgumentException e) {
			return false;
		}
	}

	public boolean trustedOrPreviouslyResponded(Jid jid) {
		final Contact contact = account.getRoster().getContact(jid);
		if (contact.showInRoster() || contact.isSelf()) {
			return true;
		}
		final Conversation conversation = mXmppConnectionService.find(account, jid);
		return conversation != null && conversation.sentMessagesCount() > 0;
	}

	private void completeSession(XmppAxolotlSession session) {
		final XmppAxolotlMessage axolotlMessage = new XmppAxolotlMessage(account.getJid().asBareJid(), getOwnDeviceId());
		axolotlMessage.addDevice(session, true);
		try {
			final Jid jid = Jid.of(session.getRemoteAddress().getName());
			MessagePacket packet = mXmppConnectionService.getMessageGenerator().generateKeyTransportMessage(jid, axolotlMessage);
			mXmppConnectionService.sendMessagePacket(account, packet);
		} catch (IllegalArgumentException e) {
			throw new Error("Remote addresses are created from jid and should convert back to jid", e);
		}
	}


	public XmppAxolotlMessage.XmppAxolotlKeyTransportMessage processReceivingKeyTransportMessage(XmppAxolotlMessage message, final boolean postponePreKeyMessageHandling) {
		final XmppAxolotlMessage.XmppAxolotlKeyTransportMessage keyTransportMessage;
		final XmppAxolotlSession session = getReceivingSession(message);
		try {
			keyTransportMessage = message.getParameters(session, getOwnDeviceId());
			Integer preKeyId = session.getPreKeyIdAndReset();
			if (preKeyId != null) {
				postPreKeyMessageHandling(session, postponePreKeyMessageHandling);
			}
		} catch (CryptoFailedException e) {
			Log.d(Config.LOGTAG, "could not decrypt keyTransport message " + e.getMessage());
			return null;
		}

		if (session.isFresh() && keyTransportMessage != null) {
			putFreshSession(session);
		}

		return keyTransportMessage;
	}

	private void putFreshSession(XmppAxolotlSession session) {
		sessions.put(session);
		if (Config.X509_VERIFICATION) {
			if (session.getIdentityKey() != null) {
				verifySessionWithPEP(session);
			} else {
				Log.e(Config.LOGTAG, account.getJid().asBareJid() + ": identity key was empty after reloading for x509 verification");
			}
		}
	}
}