do not use Dialer UI for incoming calls if audio permission is not granted

We cannot request new permissions when Dialer UI is shown. For incoming
calls, if the Dialer UI is displayed over keyguard, then the user may
not even be able to see the permission notifications that we use for
outgoing calls.

If we just do not use the Dialer UI when the permission is not granted,
it is at most a minor annoyance for the first time. After the user has
accepted an incoming call even just once, the permission will be
granted, and the Dialer integration will start to work just fine.

src/cheogram/java/com/cheogram/android/ConnectionService.java

@@ -5,9 +5,12 @@ import java.util.Collections;
 import java.util.HashSet;
 import java.util.Set;
 import java.util.Stack;
+import java.util.Vector;
 
+import com.google.common.base.Joiner;
 import com.google.common.collect.ImmutableSet;
 
+import android.os.Build;
 import android.telecom.CallAudioState;
 import android.telecom.Connection;
 import android.telecom.ConnectionRequest;
@@ -114,9 +117,9 @@ public class ConnectionService extends android.telecom.ConnectionService {
 
 		PermissionManager permissionManager = PermissionManager.getInstance(this);
 		permissionManager.setNotificationSettings(
-			new NotificationSettings.Builder()
-				.withMessage(R.string.microphone_permission_for_call)
-				.withSmallIcon(R.drawable.ic_notification).build()
+				new NotificationSettings.Builder()
+						.withMessage(R.string.microphone_permission_for_call)
+						.withSmallIcon(R.drawable.ic_notification).build()
 		);
 
 		Set<String> permissions = new HashSet<>();
@@ -150,6 +153,29 @@ public class ConnectionService extends android.telecom.ConnectionService {
 		return connection;
 	}
 
+	@Override
+	public Connection onCreateIncomingConnection(PhoneAccountHandle handle, ConnectionRequest request) {
+		Bundle extras = request.getExtras();
+		String accountJid = extras.getString("account");
+		String withJid = extras.getString("with");
+		String sessionId = extras.getString("sessionId");
+
+		Account account = xmppConnectionService.findAccountByJid(Jid.of(accountJid));
+		Jid with = Jid.of(withJid);
+
+		CheogramConnection connection = new CheogramConnection(account, with, null);
+		connection.setSessionId(sessionId);
+		connection.setAddress(
+				Uri.fromParts("tel", with.getLocal(), null),
+				TelecomManager.PRESENTATION_ALLOWED
+		);
+		connection.setRinging();
+
+		xmppConnectionService.setOnRtpConnectionUpdateListener(connection);
+
+		return connection;
+	}
+
 	public class CheogramConnection extends Connection implements XmppConnectionService.OnJingleRtpConnectionUpdate {
 		protected Account account;
 		protected Jid with;
@@ -203,6 +229,8 @@ public class ConnectionService extends android.telecom.ConnectionService {
 				setInitialized();
 			} else if (state == RtpEndUserState.RINGING) {
 				setDialing();
+			} else if (state == RtpEndUserState.INCOMING_CALL) {
+				setRinging();
 			} else if (state == RtpEndUserState.CONNECTED) {
 				xmppConnectionService.setDiallerIntegrationActive(true);
 				setActive();
@@ -221,6 +249,8 @@ public class ConnectionService extends android.telecom.ConnectionService {
 
 		@Override
 		public void onAudioDeviceChanged(AppRTCAudioManager.AudioDevice selectedAudioDevice, Set<AppRTCAudioManager.AudioDevice> availableAudioDevices) {
+			if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.O) return;
+
 			switch(selectedAudioDevice) {
 				case SPEAKER_PHONE:
 					setAudioRoute(CallAudioState.ROUTE_SPEAKER);
@@ -235,6 +265,17 @@ public class ConnectionService extends android.telecom.ConnectionService {
 			}
 		}
 
+		@Override
+		public void onAnswer() {
+			// For incoming calls, a connection update may not have been triggered before answering
+			// so we have to acquire the rtp connection object here
+			this.rtpConnection =
+					xmppConnectionService.getJingleConnectionManager()
+							.findJingleRtpConnection(account, with, sessionId);
+
+			rtpConnection.get().acceptCall();
+		}
+
 		@Override
 		public void onDisconnect() {
 			if (rtpConnection == null || rtpConnection.get() == null) {
@@ -276,9 +317,9 @@ public class ConnectionService extends android.telecom.ConnectionService {
 			while (!postDial.empty()) {
 				String next = postDial.pop();
 				if (next.equals(";")) {
-					Stack v = (Stack) postDial.clone();
+					Vector<String> v = new Vector<>(postDial);
 					Collections.reverse(v);
-					setPostDialWait(String.join("", v));
+					setPostDialWait(Joiner.on("").join(v));
 					return;
 				} else if (next.equals(",")) {
 					sleep(2000);

src/main/java/eu/siacs/conversations/entities/Contact.java

@@ -599,7 +599,7 @@ public class Contact implements ListItem, Blockable {
             "/" + getJid().asBareJid().toString();
     }
 
-    protected PhoneAccountHandle phoneAccountHandle() {
+    public PhoneAccountHandle phoneAccountHandle() {
         ComponentName componentName = new ComponentName(
             "com.cheogram.android",
             "com.cheogram.android.ConnectionService"

src/main/java/eu/siacs/conversations/services/NotificationService.java

@@ -1,5 +1,6 @@
 package eu.siacs.conversations.services;
 
+import android.Manifest;
 import android.app.Notification;
 import android.app.NotificationChannel;
 import android.app.NotificationChannelGroup;
@@ -8,6 +9,7 @@ import android.app.PendingIntent;
 import android.content.Context;
 import android.content.Intent;
 import android.content.SharedPreferences;
+import android.content.pm.PackageManager;
 import android.content.res.Resources;
 import android.graphics.Bitmap;
 import android.graphics.Typeface;
@@ -16,9 +18,12 @@ import android.media.Ringtone;
 import android.media.RingtoneManager;
 import android.net.Uri;
 import android.os.Build;
+import android.os.Bundle;
 import android.os.SystemClock;
 import android.os.Vibrator;
 import android.preference.PreferenceManager;
+import android.telecom.PhoneAccountHandle;
+import android.telecom.TelecomManager;
 import android.text.SpannableString;
 import android.text.style.StyleSpan;
 import android.util.DisplayMetrics;
@@ -423,7 +428,59 @@ public class NotificationService {
         notify(DELIVERY_FAILED_NOTIFICATION_ID, summaryNotification);
     }
 
+    private synchronized boolean tryRingingWithDialerUI(final AbstractJingleConnection.Id id, final Set<Media> media) {
+        if (mXmppConnectionService.checkSelfPermission(Manifest.permission.RECORD_AUDIO) != PackageManager.PERMISSION_GRANTED) {
+            // We cannot request audio permission in Dialer UI
+            // when Dialer is shown over keyguard, the user cannot even necessarily
+            // see notifications.
+            return false;
+        }
+
+        if (media.size() != 1 || !media.contains(Media.AUDIO)) {
+            // Currently our ConnectionService only handles single audio calls
+            Log.w(Config.LOGTAG, "only audio calls can be handled by cheogram connection service");
+            return false;
+        }
+
+        PhoneAccountHandle handle = null;
+        for (Contact contact : id.account.getRoster().getContacts()) {
+            if (!contact.getJid().getDomain().equals(id.with.getDomain()))
+                continue;
+            if (!contact.getPresences().anyIdentity("gateway", "pstn"))
+                continue;
+            handle = contact.phoneAccountHandle();
+            break;
+        }
+
+        if (handle == null) {
+            Log.w(Config.LOGTAG, "Could not find phone account handle for " + id.account.getJid().toString());
+            return false;
+        }
+
+        Bundle callInfo = new Bundle();
+        callInfo.putString("account", id.account.getJid().toString());
+        callInfo.putString("with", id.with.toString());
+        callInfo.putString("sessionId", id.sessionId);
+
+        TelecomManager telecomManager = mXmppConnectionService.getSystemService(TelecomManager.class);
+
+        try {
+            telecomManager.addNewIncomingCall(handle, callInfo);
+        } catch (SecurityException e) {
+            // If the account is not registered or enabled, it could result in a security exception
+            // Just fall back to the built-in UI in this case.
+            Log.w(Config.LOGTAG, e);
+            return false;
+        }
+
+        return true;
+    }
+
     public synchronized void startRinging(final AbstractJingleConnection.Id id, final Set<Media> media) {
+        if (tryRingingWithDialerUI(id, media)) {
+            return;
+        }
+
         showIncomingCallNotification(id, media);
         final NotificationManager notificationManager = (NotificationManager) mXmppConnectionService.getSystemService(Context.NOTIFICATION_SERVICE);
         final int currentInterruptionFilter;