- add code to send the confirmation of the activity data transfer after a timeout.

==> This is currently commented out because it was done to solve #141 but while doing this #143 popped out.
- send a stop_sync message to the band if the data doesn't fit the buffer. This way the data remains on the band.

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/miband/operations/FetchActivityOperation.java

@@ -15,6 +15,9 @@ import java.text.DateFormat;
 import java.util.Calendar;
 import java.util.GregorianCalendar;
 import java.util.UUID;
+//import java.util.concurrent.Executors;
+//import java.util.concurrent.ScheduledExecutorService;
+//import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.TimeUnit;
 
 import nodomain.freeyourgadget.gadgetbridge.GBApplication;
@@ -39,6 +42,12 @@ public class FetchActivityOperation extends AbstractBTLEOperation<MiBandSupport>
     private static final Logger LOG = LoggerFactory.getLogger(FetchActivityOperation.class);
     private static final byte[] fetch = new byte[]{MiBandService.COMMAND_FETCH_DATA};
 
+    //sometimes the Mi Band stops sending data, we confirm the part of the data transfer after some time
+    //private ScheduledExecutorService scheduleTaskExecutor;
+    //private ScheduledFuture scheduledTask;
+
+    private int activityMetadataLength = 11;
+
     //temporary buffer, size is a multiple of 60 because we want to store complete minutes (1 minute = 3 bytes)
     private static final int activityDataHolderSize = 3 * 60 * 4; // 4h
 
@@ -122,6 +131,8 @@ public class FetchActivityOperation extends AbstractBTLEOperation<MiBandSupport>
 
     @Override
     public void perform() throws IOException {
+//        scheduleTaskExecutor = Executors.newScheduledThreadPool(1);
+
         TransactionBuilder builder = performInitialized("fetch activity data");
 //            builder.write(getCharacteristic(MiBandService.UUID_CHARACTERISTIC_LE_PARAMS), getLowLatency());
 
@@ -169,7 +180,27 @@ public class FetchActivityOperation extends AbstractBTLEOperation<MiBandSupport>
      * @see #bufferActivityData(byte[])
      */
     private void handleActivityNotif(byte[] value) {
-        if (value.length == 11) {
+        if (value.length == activityMetadataLength) {
+            handleActivityMetadata(value);
+        } else {
+            bufferActivityData(value);
+        }
+        LOG.debug("activity data: length: " + value.length + ", remaining bytes: " + activityStruct.activityDataRemainingBytes);
+
+        GB.updateTransferNotification(getContext().getString(R.string.busy_task_fetch_activity_data), true, (int) (((float) (activityStruct.activityDataUntilNextHeader - activityStruct.activityDataRemainingBytes)) / activityStruct.activityDataUntilNextHeader * 100), getContext());
+
+        if (activityStruct.isBlockFinished()) {
+            sendAckDataTransfer(activityStruct.activityDataTimestampToAck, activityStruct.activityDataUntilNextHeader);
+            GB.updateTransferNotification("", false, 100, getContext());
+        }
+    }
+
+    private void handleActivityMetadata(byte[] value) {
+
+        if (value.length != activityMetadataLength) {
+            return;
+        }
+
         // byte 0 is the data type: 1 means that each minute is represented by a triplet of bytes
         int dataType = value[0];
         // byte 1 to 6 represent a timestamp
@@ -199,18 +230,6 @@ public class FetchActivityOperation extends AbstractBTLEOperation<MiBandSupport>
         LOG.info("TIMESTAMP: " + DateFormat.getDateTimeInstance().format(timestamp.getTime()).toString() + " magic byte: " + dataUntilNextHeader);
 
         activityStruct.startNewBlock(timestamp, dataUntilNextHeader);
-
-        } else {
-            bufferActivityData(value);
-        }
-        LOG.debug("activity data: length: " + value.length + ", remaining bytes: " + activityStruct.activityDataRemainingBytes);
-
-        GB.updateTransferNotification(getContext().getString(R.string.busy_task_fetch_activity_data), true, (int)(((float) (activityStruct.activityDataUntilNextHeader - activityStruct.activityDataRemainingBytes)) / activityStruct.activityDataUntilNextHeader * 100), getContext());
-
-        if (activityStruct.isBlockFinished()) {
-            sendAckDataTransfer(activityStruct.activityDataTimestampToAck, activityStruct.activityDataUntilNextHeader);
-            GB.updateTransferNotification("", false, 100, getContext());
-        }
     }
 
     /**
@@ -221,10 +240,24 @@ public class FetchActivityOperation extends AbstractBTLEOperation<MiBandSupport>
      * @param value
      */
     private void bufferActivityData(byte[] value) {
+/*
+        if (scheduledTask != null) {
+            scheduledTask.cancel(true);
+        }
+*/
         if (activityStruct.hasRoomFor(value)) {
             if (activityStruct.isValidData(value)) {
                 activityStruct.buffer(value);
 
+/*                scheduledTask = scheduleTaskExecutor.schedule(new Runnable() {
+                    @Override
+                    public void run() {
+                        GB.toast(getContext(), "chiederei " + activityStruct.activityDataTimestampToAck + "   "+ activityStruct.activityDataUntilNextHeader, Toast.LENGTH_LONG, GB.ERROR);
+                        //sendAckDataTransfer(activityStruct.activityDataTimestampToAck, activityStruct.activityDataUntilNextHeader);
+                        LOG.debug("runnable called");
+                    }
+                }, 10l, TimeUnit.SECONDS);
+*/
                 if (activityStruct.isBufferFull()) {
                     flushActivityDataHolder();
                 }
@@ -234,6 +267,17 @@ public class FetchActivityOperation extends AbstractBTLEOperation<MiBandSupport>
                 getSupport().logMessageContent(value);
             }
         } else {
+            try {
+                TransactionBuilder builder = performInitialized("send stop sync data");
+                builder.write(getCharacteristic(MiBandService.UUID_CHARACTERISTIC_CONTROL_POINT), new byte[]{MiBandService.COMMAND_STOP_SYNC_DATA});
+                builder.queue(getQueue());
+                GB.updateTransferNotification("Data transfer failed", false, 0, getContext());
+                handleActivityFetchFinish();
+
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+            GB.toast(getContext(), "error buffering activity data: remaining bytes: " + activityStruct.activityDataRemainingBytes + ", received: " + value.length, Toast.LENGTH_LONG, GB.ERROR);
             LOG.error("error buffering activity data: remaining bytes: " + activityStruct.activityDataRemainingBytes + ", received: " + value.length);
         }
     }