o Adding a way to prepend callbacks on the promise's queue. Needed for devices that give you [disconnect, connect] events when connecting. Yay.

o Reading meta data from the Soil Moisture device.

9 files changed, 314 insertions, 75 deletions

diff --git a/app/src/main/java/io/trygvis/android/bt/BtCallback.java b/app/src/main/java/io/trygvis/android/bt/BtCallback.java
index 29ea9e1..8dab149 100644
--- a/app/src/main/java/io/trygvis/android/bt/BtCallback.java
+++ b/app/src/main/java/io/trygvis/android/bt/BtCallback.java
@@ -4,6 +4,8 @@ import android.bluetooth.BluetoothGatt;
 import android.bluetooth.BluetoothGattCharacteristic;
 import android.bluetooth.BluetoothGattDescriptor;
 
+import static io.trygvis.android.bt.BtPromise.*;
+
 public class BtCallback {
     public final String name;
 
@@ -11,39 +13,39 @@ public class BtCallback {
         this.name = name;
     }
 
-    public boolean onConnectionStateChange(BluetoothGatt gatt, int newState) {
+    public PromiseResult onConnectionStateChange(BluetoothGatt gatt, int newState) {
         throw new NotOverriddenException();
     }
 
-    public boolean onServicesDiscovered(BluetoothGatt gatt) {
+    public PromiseResult onServicesDiscovered(BluetoothGatt gatt) {
         throw new NotOverriddenException();
     }
 
-    public boolean onCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
+    public PromiseResult onCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
         throw new NotOverriddenException();
     }
 
-    public boolean onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
+    public PromiseResult onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
         throw new NotOverriddenException();
     }
 
-    public boolean onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
+    public PromiseResult onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
         throw new NotOverriddenException();
     }
 
-    public boolean onDescriptorRead(BluetoothGatt gatt, BluetoothGattDescriptor descriptor) {
+    public PromiseResult onDescriptorRead(BluetoothGatt gatt, BluetoothGattDescriptor descriptor) {
         throw new NotOverriddenException();
     }
 
-    public boolean onDescriptorWrite(BluetoothGatt gatt, BluetoothGattDescriptor descriptor) {
+    public PromiseResult onDescriptorWrite(BluetoothGatt gatt, BluetoothGattDescriptor descriptor) {
         throw new NotOverriddenException();
     }
 
-    public boolean onReliableWriteCompleted(BluetoothGatt gatt) {
+    public PromiseResult onReliableWriteCompleted(BluetoothGatt gatt) {
         throw new NotOverriddenException();
     }
 
-    public boolean onReadRemoteRssi(BluetoothGatt gatt, int rssi) {
+    public PromiseResult onReadRemoteRssi(BluetoothGatt gatt, int rssi) {
         throw new NotOverriddenException();
     }
 
diff --git a/app/src/main/java/io/trygvis/android/bt/BtDevice.java b/app/src/main/java/io/trygvis/android/bt/BtDevice.java
index edad522..1c7666e 100644
--- a/app/src/main/java/io/trygvis/android/bt/BtDevice.java
+++ b/app/src/main/java/io/trygvis/android/bt/BtDevice.java
@@ -1,6 +1,8 @@
 package io.trygvis.android.bt;
 
 import android.bluetooth.BluetoothDevice;
+import android.bluetooth.BluetoothGatt;
+import android.bluetooth.BluetoothGattCallback;
 import android.util.Log;
 
 import java.util.Date;
@@ -10,6 +12,7 @@ public class BtDevice<A extends BtDevice.BtDeviceWrapper<A>> {
 
     private final DefaultBtService btService;
     private final BluetoothDevice bluetoothDevice;
+    private BluetoothGatt gatt;
     private Integer rssi;
     private BtScanResult scanResult;
     private A tag;
@@ -24,8 +27,8 @@ public class BtDevice<A extends BtDevice.BtDeviceWrapper<A>> {
     }
 
     BtDevice(DefaultBtService btService, BluetoothDevice bluetoothDevice,
-            BtService.BtDbIntegration<A> btDbIntegration, long id, Integer rssi,
-            BtScanResult scanResult, boolean seenBefore, Date firstSeen, Date lastSeen) {
+             BtService.BtDbIntegration<A> btDbIntegration, long id, Integer rssi,
+             BtScanResult scanResult, boolean seenBefore, Date firstSeen, Date lastSeen) {
         this.btService = btService;
         this.bluetoothDevice = bluetoothDevice;
         this.tag = btDbIntegration.createTag(this);
@@ -73,12 +76,20 @@ public class BtDevice<A extends BtDevice.BtDeviceWrapper<A>> {
         this.lastSeen = lastSeen;
     }
 
-    public boolean connect(BtActionExecutor executor) {
-        Log.i(TAG, "connect(), address=" + bluetoothDevice.getAddress() + ", queue=" + executor);
-        bluetoothDevice.connectGatt(btService, false, executor.asCallback());
+    public synchronized boolean connect(BtPromise executor) {
+        Log.i(TAG, "connect(), address=" + bluetoothDevice.getAddress());
+        BluetoothGattCallback callback = executor.asCallback();
+        gatt = bluetoothDevice.connectGatt(btService, false, callback);
         return true;
     }
 
+    public synchronized void disconnect() {
+        if (gatt != null) {
+            gatt.disconnect();
+            gatt = null;
+        }
+    }
+
     public BtScanResult getScanResult() {
         return scanResult;
     }
diff --git a/app/src/main/java/io/trygvis/android/bt/BtActionExecutor.java b/app/src/main/java/io/trygvis/android/bt/BtPromise.java
index 984c738..55b6315 100644
--- a/app/src/main/java/io/trygvis/android/bt/BtActionExecutor.java
+++ b/app/src/main/java/io/trygvis/android/bt/BtPromise.java
@@ -15,114 +15,134 @@ import java.util.Queue;
 import io.trygvis.android.F2;
 import io.trygvis.android.Function;
 
-import static io.trygvis.android.bt.BtActionExecutor.EventType.onCharacteristicChanged;
-import static io.trygvis.android.bt.BtActionExecutor.EventType.onCharacteristicRead;
-import static io.trygvis.android.bt.BtActionExecutor.EventType.onCharacteristicWrite;
-import static io.trygvis.android.bt.BtActionExecutor.EventType.onConnectionStateChange;
-import static io.trygvis.android.bt.BtActionExecutor.EventType.onDescriptorRead;
-import static io.trygvis.android.bt.BtActionExecutor.EventType.onDescriptorWrite;
-import static io.trygvis.android.bt.BtActionExecutor.EventType.onFailure;
-import static io.trygvis.android.bt.BtActionExecutor.EventType.onFinally;
-import static io.trygvis.android.bt.BtActionExecutor.EventType.onReliableWriteCompleted;
-import static io.trygvis.android.bt.BtActionExecutor.EventType.onServicesDiscovered;
-
-public class BtActionExecutor {
-    private final static String TAG = BtActionExecutor.class.getSimpleName();
+import static io.trygvis.android.bt.BtPromise.EventType.onCharacteristicChanged;
+import static io.trygvis.android.bt.BtPromise.EventType.onCharacteristicRead;
+import static io.trygvis.android.bt.BtPromise.EventType.onCharacteristicWrite;
+import static io.trygvis.android.bt.BtPromise.EventType.onConnectionStateChange;
+import static io.trygvis.android.bt.BtPromise.EventType.onDescriptorRead;
+import static io.trygvis.android.bt.BtPromise.EventType.onDescriptorWrite;
+import static io.trygvis.android.bt.BtPromise.EventType.onFailure;
+import static io.trygvis.android.bt.BtPromise.EventType.onFinally;
+import static io.trygvis.android.bt.BtPromise.EventType.onReliableWriteCompleted;
+import static io.trygvis.android.bt.BtPromise.EventType.onServicesDiscovered;
+
+public class BtPromise {
+    private final static String TAG = BtPromise.class.getSimpleName();
     private final Queue<BtCallback> actionQ = new ArrayDeque<>();
     private final Queue<BtCallback> failureQ = new ArrayDeque<>();
     private final Queue<BtCallback> finallyQ = new ArrayDeque<>();
 
-    public synchronized BtActionExecutor onConnectionStateChange(F2<BluetoothGatt, Integer, Boolean> callback) {
+    public static final PromiseResult continueDownChain = new Continue();
+    public static final PromiseResult doneWithChain = new Done();
+
+    public abstract static class PromiseResult {
+    }
+
+    private static class Continue extends PromiseResult {
+    }
+
+    private static class Done extends PromiseResult {
+    }
+
+    private static class Detour extends PromiseResult {
+        final BtPromise promise;
+
+        private Detour(BtPromise promise) {
+            this.promise = promise;
+        }
+    }
+
+    public synchronized BtPromise onConnectionStateChange(F2<BluetoothGatt, Integer, PromiseResult> callback) {
         actionQ.add(new BtCallback("onConnectionStateChange") {
             @Override
-            public boolean onConnectionStateChange(BluetoothGatt gatt, int newState) {
+            public PromiseResult onConnectionStateChange(BluetoothGatt gatt, int newState) {
                 return callback.apply(gatt, newState);
             }
         });
         return this;
     }
 
-    public synchronized BtActionExecutor onServicesDiscovered(Function<BluetoothGatt, Boolean> callback) {
+    public synchronized BtPromise onServicesDiscovered(Function<BluetoothGatt, PromiseResult> callback) {
         actionQ.add(new BtCallback("onServicesDiscovered") {
             @Override
-            public boolean onServicesDiscovered(BluetoothGatt gatt) {
+            public PromiseResult onServicesDiscovered(BluetoothGatt gatt) {
                 return callback.apply(gatt);
             }
         });
         return this;
     }
 
-    public synchronized BtActionExecutor onCharacteristicRead(F2<BluetoothGatt, BluetoothGattCharacteristic, Boolean> callback) {
+    public synchronized BtPromise onCharacteristicRead(F2<BluetoothGatt, BluetoothGattCharacteristic, PromiseResult> callback) {
         actionQ.add(new BtCallback("onCharacteristicRead") {
             @Override
-            public boolean onCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
+            public PromiseResult onCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
                 return callback.apply(gatt, characteristic);
             }
         });
         return this;
     }
 
-    public synchronized BtActionExecutor onCharacteristicWrite(F2<BluetoothGatt, BluetoothGattCharacteristic, Boolean> callback) {
+    public synchronized BtPromise onCharacteristicWrite(F2<BluetoothGatt, BluetoothGattCharacteristic, PromiseResult> callback) {
         actionQ.add(new BtCallback("onCharacteristicWrite") {
             @Override
-            public boolean onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
+            public PromiseResult onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
                 return callback.apply(gatt, characteristic);
             }
         });
         return this;
     }
 
-    public synchronized BtActionExecutor onCharacteristicChanged(F2<BluetoothGatt, BluetoothGattCharacteristic, Boolean> callback) {
+    public synchronized BtPromise onCharacteristicChanged(F2<BluetoothGatt, BluetoothGattCharacteristic, PromiseResult> callback) {
         actionQ.add(new BtCallback("onCharacteristicChanged") {
             @Override
-            public boolean onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
+            public PromiseResult onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
                 return callback.apply(gatt, characteristic);
             }
         });
         return this;
     }
 
-    public synchronized BtActionExecutor onDescriptorRead(F2<BluetoothGatt, BluetoothGattDescriptor, Boolean> callback) {
+    public synchronized BtPromise onDescriptorRead(F2<BluetoothGatt, BluetoothGattDescriptor, PromiseResult> callback) {
         actionQ.add(new BtCallback("onDescriptorRead") {
             @Override
-            public boolean onDescriptorRead(BluetoothGatt gatt, BluetoothGattDescriptor descriptor) {
+            public PromiseResult onDescriptorRead(BluetoothGatt gatt, BluetoothGattDescriptor descriptor) {
                 return callback.apply(gatt, descriptor);
             }
         });
         return this;
     }
 
-    public synchronized BtActionExecutor onDescriptorWrite(F2<BluetoothGatt, BluetoothGattDescriptor, Boolean> callback) {
+    public synchronized BtPromise onDescriptorWrite(F2<BluetoothGatt, BluetoothGattDescriptor, PromiseResult> callback) {
         actionQ.add(new BtCallback("onDescriptorWrite") {
             @Override
-            public boolean onDescriptorWrite(BluetoothGatt gatt, BluetoothGattDescriptor descriptor) {
+            public PromiseResult onDescriptorWrite(BluetoothGatt gatt, BluetoothGattDescriptor descriptor) {
                 return callback.apply(gatt, descriptor);
             }
         });
         return this;
     }
 
-    public synchronized BtActionExecutor onReliableWriteCompleted(Function<BluetoothGatt, Boolean> callback) {
+    public synchronized BtPromise onReliableWriteCompleted(Function<BluetoothGatt, PromiseResult> callback) {
         actionQ.add(new BtCallback("onReliableWriteCompleted") {
             @Override
-            public boolean onReliableWriteCompleted(BluetoothGatt gatt) {
+            public PromiseResult onReliableWriteCompleted(BluetoothGatt gatt) {
                 return callback.apply(gatt);
             }
         });
         return this;
     }
 
-    public synchronized BtActionExecutor onReadRemoteRssi(F2<BluetoothGatt, Integer, Boolean> callback) {
+    public synchronized BtPromise onReadRemoteRssi(F2<BluetoothGatt, Integer, PromiseResult> callback) {
         actionQ.add(new BtCallback("onReadRemoteRssi") {
             @Override
-            public boolean onReadRemoteRssi(BluetoothGatt gatt, int rssi) {
+            public PromiseResult onReadRemoteRssi(BluetoothGatt gatt, int rssi) {
                 return callback.apply(gatt, rssi);
             }
         });
         return this;
     }
 
-    public synchronized BtActionExecutor onFailure(Runnable callback) {
+    public synchronized BtPromise onFailure(Runnable callback) {
         failureQ.add(new BtCallback("onFailure") {
             @Override
             public void onFailure() {
@@ -132,7 +152,7 @@ public class BtActionExecutor {
         return this;
     }
 
-    public synchronized BtActionExecutor onFinally(Runnable callback) {
+    public synchronized BtPromise onFinally(Runnable callback) {
         finallyQ.add(new BtCallback("finally") {
             @Override
             public void onFinally() {
@@ -160,8 +180,12 @@ public class BtActionExecutor {
         return s.toString();
     }
 
-    public BluetoothGattCallback asCallback() {
-        return new MyBluetoothGattCallback();
+    BtBluetoothGattCallback asCallback() {
+        return new BtBluetoothGattCallback(actionQ, failureQ, finallyQ);
+    }
+
+    public PromiseResult toDetour() {
+        return new Detour(this);
     }
 
     enum EventType {
@@ -180,7 +204,9 @@ public class BtActionExecutor {
         onFinally,
     }
 
-    private static Boolean callCallback(EventType key, BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, BluetoothGattDescriptor descriptor, int newState, BtCallback btCallback) {
+    private static PromiseResult callCallback(EventType key, BluetoothGatt gatt,
+                                              BluetoothGattCharacteristic characteristic,
+                                              BluetoothGattDescriptor descriptor, int newState, BtCallback btCallback) {
         switch (key) {
             case onConnectionStateChange:
                 return btCallback.onConnectionStateChange(gatt, newState);
@@ -211,16 +237,25 @@ public class BtActionExecutor {
         }
     }
 
-    private class MyBluetoothGattCallback extends BluetoothGattCallback {
+    static class BtBluetoothGattCallback extends BluetoothGattCallback {
 
-        private Queue<BtCallback> initialActionQ = new ArrayDeque<>(actionQ);
+        private ArrayDeque<BtCallback> actionQ;
+        private ArrayDeque<BtCallback> failureQ;
+        ArrayDeque<BtCallback> finallyQ;
+//        private ArrayDeque<BtCallback> initialActionQ;
         private List<String> events = new ArrayList<>();
 
+        private BtBluetoothGattCallback(Queue<BtCallback> actionQ, Queue<BtCallback> failureQ, Queue<BtCallback> finallyQ) {
+            this.actionQ = new ArrayDeque<>(actionQ);
+            this.failureQ = new ArrayDeque<>(failureQ);
+            this.finallyQ = new ArrayDeque<>(finallyQ);
+        }
+
         void onEvent(EventType key, String values, BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, BluetoothGattDescriptor descriptor, int status, int newState) {
             boolean success = status == BluetoothGatt.GATT_SUCCESS;
-            events.add(key + ", " + values + ", success=" + success);
+            events.add(key + "(" + values + "), success=" + success);
 
-            Log.i(TAG, "Operation failed: " + key + ", " + values + ", success=" + success);
+            Log.i(TAG, key + "(" + values + "), success=" + success);
 
             if (!success) {
                 doFailure();
@@ -246,11 +281,24 @@ public class BtActionExecutor {
             }
 
             try {
-                boolean ok = callCallback(key, gatt, characteristic, descriptor, newState, btCallback);
+                PromiseResult result = callCallback(key, gatt, characteristic, descriptor, newState, btCallback);
 
-                if (!ok) {
-                    Log.w(TAG, "The callback don't want to continue.");
+                if (result instanceof Done) {
+                    Log.i(TAG, "The chain is done.");
                     doFinally();
+                } else if (result instanceof Detour) {
+                    Log.i(TAG, "Adding detour");
+                    BtPromise promise = ((Detour) result).promise;
+                    if (!promise.failureQ.isEmpty()) {
+                        Log.i(TAG, "Ignoring " + promise.failureQ.size() + " items from the failure Q");
+                    }
+                    if (!promise.finallyQ.isEmpty()) {
+                        Log.i(TAG, "Ignoring " + promise.finallyQ.size() + " items from the finally Q");
+                    }
+
+                    for (BtCallback callback : promise.actionQ) {
+                        actionQ.addFirst(callback);
+                    }
                 }
 
                 if (actionQ.isEmpty()) {
@@ -266,7 +314,7 @@ public class BtActionExecutor {
             StringBuilder msg = new StringBuilder();
 
             msg.append("Expected events: \n");
-            for (BtCallback cb : initialActionQ) {
+            for (BtCallback cb : actionQ) {
                 msg.append("  ").append(cb.name).append("\n");
             }
 
diff --git a/app/src/main/java/io/trygvis/android/bt/DefaultBtService.java b/app/src/main/java/io/trygvis/android/bt/DefaultBtService.java
index 205421b..80a195a 100644
--- a/app/src/main/java/io/trygvis/android/bt/DefaultBtService.java
+++ b/app/src/main/java/io/trygvis/android/bt/DefaultBtService.java
@@ -45,7 +45,7 @@ public class DefaultBtService<A extends BtDevice.BtDeviceWrapper<A>> extends Ser
 
     private BtDbIntegration<A> btDbIntegration;
 
-    private BluetoothManager bluetoothManager;
+    BluetoothManager bluetoothManager;
 
     private BluetoothAdapter bluetoothAdapter;
 
diff --git a/app/src/main/java/io/trygvis/soilmoisture/DefaultSoilMoistureService.java b/app/src/main/java/io/trygvis/soilmoisture/DefaultSoilMoistureService.java
index 0f08076..a2723d5 100644
--- a/app/src/main/java/io/trygvis/soilmoisture/DefaultSoilMoistureService.java
+++ b/app/src/main/java/io/trygvis/soilmoisture/DefaultSoilMoistureService.java
@@ -3,6 +3,7 @@ package io.trygvis.soilmoisture;
 import android.app.Service;
 import android.bluetooth.BluetoothGatt;
 import android.bluetooth.BluetoothGattCharacteristic;
+import android.bluetooth.BluetoothGattDescriptor;
 import android.bluetooth.BluetoothGattService;
 import android.content.ComponentName;
 import android.content.ContentValues;
@@ -18,13 +19,17 @@ import java.util.Set;
 import java.util.TreeSet;
 
 import io.trygvis.android.LocalBinder;
-import io.trygvis.android.bt.BtActionExecutor;
 import io.trygvis.android.bt.BtDevice;
+import io.trygvis.android.bt.BtPromise;
 import io.trygvis.android.bt.BtService;
 import io.trygvis.android.bt.DefaultBtService;
 import io.trygvis.bluetooth.TrygvisIoUuids;
 
+import static io.trygvis.android.bt.BtPromise.continueDownChain;
+import static io.trygvis.android.bt.BtPromise.doneWithChain;
 import static io.trygvis.android.bt.BtService.BtServiceListenerBroadcastReceiver;
+import static io.trygvis.soilmoisture.SmDevice.GetSensorCountRes;
+import static io.trygvis.soilmoisture.SmDevice.SmCmdCode.GET_SENSOR_COUNT;
 
 public class DefaultSoilMoistureService extends Service implements SoilMoistureService {
     private final static String TAG = DefaultSoilMoistureService.class.getSimpleName();
@@ -95,37 +100,73 @@ public class DefaultSoilMoistureService extends Service implements SoilMoistureS
 
             if (!smDevice.isProbed()) {
                 Log.i(TAG, "Probing " + address + ", name=" + btDevice.getName());
-                BtActionExecutor executor = new BtActionExecutor().
+                BtPromise executor = new BtPromise().
                         onConnectionStateChange((gatt, newState) -> {
                             //noinspection SimplifiableIfStatement
                             if (newState == BluetoothGatt.STATE_CONNECTED) {
                                 Log.i(TAG, "Connected to " + address + ", getting services");
-                                return gatt.discoverServices();
-                            }
+                                return gatt.discoverServices() ? continueDownChain : doneWithChain;
+                            } else {
+                                Log.i(TAG, "Disconnected from " + address + ", trying again");
+
+                                return new BtPromise().onConnectionStateChange((gatt2, newState2) -> {
+                                    if (newState2 == BluetoothGatt.STATE_CONNECTED) {
+                                        Log.i(TAG, "Connected to " + address + ", getting services");
+                                        return continueDownChain;
+                                    }
 
-                            Log.i(TAG, "Could not connect to to " + address);
-                            smDevice.setIsUseful(false);
-                            return false;
+                                    Log.i(TAG, "Could still not connect to " + address + ", failing.");
+
+                                    return doneWithChain;
+                                }).toDetour();
+                            }
                         }).
                         onServicesDiscovered(gatt -> {
                             Log.i(TAG, "Services discovered");
 
                             BluetoothGattService service = gatt.getService(TrygvisIoUuids.Services.SOIL_MOISTURE_SERVICE);
 
-                            boolean useful = false;
-                            if (service != null) {
-                                BluetoothGattCharacteristic characteristic = service.getCharacteristic(TrygvisIoUuids.Characteristics.SOIL_MOISTURE);
+                            if (service == null) {
+                                return doneWithChain;
+                            }
 
-                                useful = characteristic != null;
+                            BluetoothGattCharacteristic soilMoisture = service.getCharacteristic(TrygvisIoUuids.Characteristics.SOIL_MOISTURE);
 
-                                smDevice.setIsUseful(useful);
+                            if (soilMoisture == null) {
+                                return doneWithChain;
                             }
 
-                            gatt.disconnect();
+                            BluetoothGattDescriptor ccg = soilMoisture.getDescriptor(TrygvisIoUuids.CLIENT_CHARACTERISTIC_CONFIG);
+                            ccg.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
+                            gatt.setCharacteristicNotification(soilMoisture, true);
 
-                            return false;
+                            return gatt.writeDescriptor(ccg) ? continueDownChain : doneWithChain;
+                        }).
+                        onDescriptorWrite((gatt, descriptor) -> {
+                            Log.i(TAG, "Notifications enabled, getting sensor count");
+                            BluetoothGattCharacteristic c = descriptor.getCharacteristic();
+                            c.setValue(SmDevice.createGetSensorCountReq());
+                            return gatt.writeCharacteristic(c) ? continueDownChain : doneWithChain;
+                        }).
+                        onCharacteristicWrite((gatt, characteristic) -> continueDownChain).
+                        onCharacteristicChanged((gatt, characteristic) -> {
+                            GetSensorCountRes getSensorCountRes = SmDevice.parseResponse(characteristic.getValue(),
+                                    GET_SENSOR_COUNT, GetSensorCountRes.class);
+
+                            Log.i(TAG, "The device has " + getSensorCountRes.count + " sensors.");
+
+                            smDevice.setIsUseful(true);
+                            smDevice.setSensorCount(getSensorCountRes.count);
+
+                            return doneWithChain;
                         }).
                         onFinally(() -> {
+                            btDevice.disconnect();
+
+                            if (smDevice.getIsUseful() == null) {
+                                smDevice.setIsUseful(false);
+                            }
+
                             btService.runTx(db -> {
                                 if (!btDevice.isSeenBefore() && smDevice.isUseful()) {
                                     for (SmSensor soilMonitor : smDevice.getSensors()) {
diff --git a/app/src/main/java/io/trygvis/soilmoisture/MainActivity.java b/app/src/main/java/io/trygvis/soilmoisture/MainActivity.java
index 2e6df76..7aa3534 100644
--- a/app/src/main/java/io/trygvis/soilmoisture/MainActivity.java
+++ b/app/src/main/java/io/trygvis/soilmoisture/MainActivity.java
@@ -222,6 +222,7 @@ public class MainActivity extends ListActivity {
         final TextView deviceName;
         final TextView deviceAddress;
         final TextView rssi;
+        final TextView info;
         final ProgressBar spinner;
         final Button connect;
 
@@ -229,6 +230,7 @@ public class MainActivity extends ListActivity {
             this.deviceName = (TextView) view.findViewById(R.id.device_name);
             this.deviceAddress = (TextView) view.findViewById(R.id.device_address);
             this.rssi = (TextView) view.findViewById(R.id.device_rssi);
+            this.info = (TextView) view.findViewById(R.id.device_info);
             this.spinner = (ProgressBar) view.findViewById(R.id.device_spinner);
             this.connect = (Button) view.findViewById(R.id.button_connect);
         }
@@ -241,7 +243,7 @@ public class MainActivity extends ListActivity {
         private LayoutInflater inflater = MainActivity.this.getLayoutInflater();
 
         private boolean groupByDevice = true;
-        private boolean showAll = false;
+        private boolean showAll = true;
 
         public void sort() {
             Log.i(TAG, "sort(), groupByDevice=" + groupByDevice + ", showAll=" + showAll);
@@ -400,6 +402,12 @@ public class MainActivity extends ListActivity {
             item.rssi.setText(getText(R.string.rssi) + ": " +
                     (smDevice.getBtDevice().getRssi() != 0 ? valueOf(smDevice.getBtDevice().getRssi()) : getText(R.string.unknown)));
 
+            if (smDevice.isUseful()) {
+                item.info.setText("number of sensors: " + smDevice.getSensors().size());
+            } else {
+                item.info.setText("");
+            }
+
             boolean useful = smDevice.isUseful();
             item.spinner.setVisibility(useful ? View.GONE : View.VISIBLE);
             item.connect.setVisibility(useful ? View.VISIBLE : View.GONE);
diff --git a/app/src/main/java/io/trygvis/soilmoisture/SmDevice.java b/app/src/main/java/io/trygvis/soilmoisture/SmDevice.java
index e24416c..b51b3fa 100644
--- a/app/src/main/java/io/trygvis/soilmoisture/SmDevice.java
+++ b/app/src/main/java/io/trygvis/soilmoisture/SmDevice.java
@@ -2,11 +2,19 @@ package io.trygvis.soilmoisture;
 
 import android.util.Log;
 
+import java.nio.charset.Charset;
 import java.util.ArrayList;
 import java.util.List;
 
 import io.trygvis.android.bt.BtDevice;
 
+import static io.trygvis.soilmoisture.SmDevice.SmCmdCode.GET_SENSOR_COUNT;
+import static io.trygvis.soilmoisture.SmDevice.SmCmdCode.GET_SENSOR_NAME;
+import static io.trygvis.soilmoisture.SmDevice.SmCmdCode.GET_VALUE;
+import static io.trygvis.soilmoisture.SmDevice.SmCmdCode.GET_WARNING_VALUE;
+import static io.trygvis.soilmoisture.SmDevice.SmCmdCode.SET_SENSOR_NAME;
+import static io.trygvis.soilmoisture.SmDevice.SmCmdCode.SET_WARNING_VALUE;
+
 class SmDevice implements BtDevice.BtDeviceWrapper<SmDevice> {
     private final static String TAG = SmDevice.class.getSimpleName();
 
@@ -57,4 +65,109 @@ class SmDevice implements BtDevice.BtDeviceWrapper<SmDevice> {
     public List<SmSensor> getSensors() {
         return sensors;
     }
+
+    // -----------------------------------------------------------------------
+    //
+    // -----------------------------------------------------------------------
+
+    @SuppressWarnings("unchecked")
+    public static <T> T parseResponse(byte[] bytes, SmCmdCode code, Class<T> klass) {
+        byte c = bytes[0];
+
+        if (c != code.code) {
+            throw new RuntimeException("Expected response of type " + code + ", got " + c);
+        }
+
+        Object value = null;
+        if (c == GET_SENSOR_COUNT.code) {
+            return (T) new GetSensorCountRes(bytes[1]);
+        } else if (c == GET_VALUE.code) {
+        } else if (c == SET_WARNING_VALUE.code) {
+        } else if (c == GET_WARNING_VALUE.code) {
+        } else if (c == SET_SENSOR_NAME.code) {
+        } else if (c == GET_SENSOR_NAME.code) {
+        }
+
+        throw new RuntimeException("Unknown code: " + c);
+    }
+
+    public void setSensorCount(int count) {
+        sensors = new ArrayList<>();
+        for (int index = 0; index < count; index++) {
+            sensors.add(new SmSensor(this, index));
+        }
+    }
+
+    public static class GetSensorCountRes {
+        public final int count;
+
+        public GetSensorCountRes(int count) {
+            this.count = count;
+        }
+    }
+
+    public static byte[] createGetSensorCountReq() {
+        return new byte[]{
+                GET_SENSOR_COUNT.code
+        };
+    }
+
+    public static byte[] createGetValueReq(byte sensor) {
+        return new byte[]{
+                GET_VALUE.code,
+                sensor
+        };
+    }
+
+    public static byte[] createSetWarningValueReq(byte sensor, short warningValue) {
+        return new byte[]{
+                SET_WARNING_VALUE.code,
+                sensor,
+                (byte) (warningValue & 0xff),
+                (byte) ((warningValue >> 8) & 0xff)
+        };
+    }
+
+    public static byte[] createGetWarningValueReq(byte sensor) {
+        return new byte[]{
+                GET_WARNING_VALUE.code,
+                sensor
+        };
+    }
+
+    public static byte[] createSetSensorNameReq(byte sensor, String name) {
+        byte[] tmp = name.getBytes(Charset.defaultCharset());
+
+        byte[] bytes = new byte[3 + tmp.length];
+        bytes[0] = GET_WARNING_VALUE.code;
+        bytes[1] = sensor;
+        bytes[2] = (byte) tmp.length;
+        System.arraycopy(tmp, 0, bytes, 1, tmp.length);
+        return bytes;
+    }
+
+    public static byte[] createGetSensorNameReq(byte sensor) {
+        return new byte[]{
+                GET_SENSOR_NAME.code,
+                sensor
+        };
+    }
+
+    public static final int SENSOR_NAME_LEN = 10;
+
+    public enum SmCmdCode {
+        GET_SENSOR_COUNT(1),
+        GET_VALUE(2),
+        SET_WARNING_VALUE(3),
+        GET_WARNING_VALUE(4),
+        SET_SENSOR_NAME(5),
+        GET_SENSOR_NAME(6),
+        FAIL(255);
+
+        public final byte code;
+
+        SmCmdCode(int value) {
+            this.code = (byte) value;
+        }
+    }
 }
diff --git a/app/src/main/java/io/trygvis/soilmoisture/SmSensor.java b/app/src/main/java/io/trygvis/soilmoisture/SmSensor.java
index f27c364..ec4b423 100644
--- a/app/src/main/java/io/trygvis/soilmoisture/SmSensor.java
+++ b/app/src/main/java/io/trygvis/soilmoisture/SmSensor.java
@@ -5,18 +5,25 @@ import java.util.Date;
 class SmSensor {
     private final SmDevice device;
 
+    private final int index;
+
     private Date timestamp;
 
     private int lastValue;
 
-    SmSensor(SmDevice device) {
+    SmSensor(SmDevice device, int index) {
         this.device = device;
+        this.index = index;
     }
 
     public SmDevice getDevice() {
         return device;
     }
 
+    public int getIndex() {
+        return index;
+    }
+
     public int getLastValue() {
         return lastValue;
     }
diff --git a/app/src/main/res/layout/listitem_device.xml b/app/src/main/res/layout/listitem_device.xml
index 0904d94..44021d9 100644
--- a/app/src/main/res/layout/listitem_device.xml
+++ b/app/src/main/res/layout/listitem_device.xml
@@ -31,6 +31,15 @@
         android:layout_alignParentStart="true"
         android:layout_toStartOf="@+id/spacer"/>
 
+    <TextView
+        android:id="@+id/device_info"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:textSize="12sp"
+        android:layout_below="@+id/device_rssi"
+        android:layout_alignParentStart="true"
+        android:layout_toStartOf="@+id/spacer"/>
+
     <LinearLayout
         android:layout_width="wrap_content"
         android:layout_height="match_parent"