Garmin protocol: move field encode/decode interface to the FieldDefinition

This allows for semantic subclassing the FieldDefinition.
A FieldDefinitionTimestamp subclass is introduced as example

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/garmin/GarminSupport.java

@@ -147,8 +147,8 @@ public class GarminSupport extends AbstractBTLEDeviceSupport implements ICommuni
 
             RecordData today = new RecordData(GlobalDefinitionsEnum.TODAY_WEATHER_CONDITIONS.getRecordDefinition());
             today.setFieldByName("weather_report", 0); // 0 = current, 1 = hourly_forecast, 2 = daily_forecast
-            today.setFieldByName("timestamp", GarminTimeUtils.unixTimeToGarminTimestamp(weather.timestamp));
+            today.setFieldByName("timestamp", weather.timestamp);
-            today.setFieldByName("observed_at_time", GarminTimeUtils.unixTimeToGarminTimestamp(weather.timestamp));
+            today.setFieldByName("observed_at_time", weather.timestamp);
             today.setFieldByName("temperature", weather.currentTemp - 273.15);
             today.setFieldByName("low_temperature", weather.todayMinTemp - 273.15);
             today.setFieldByName("high_temperature", weather.todayMaxTemp - 273.15);
@@ -168,7 +168,7 @@ public class GarminSupport extends AbstractBTLEDeviceSupport implements ICommuni
                     WeatherSpec.Hourly hourly = weather.hourly.get(hour);
                     RecordData weatherHourlyForecast = new RecordData(GlobalDefinitionsEnum.HOURLY_WEATHER_FORECAST.getRecordDefinition());
                     weatherHourlyForecast.setFieldByName("weather_report", 1); // 0 = current, 1 = hourly_forecast, 2 = daily_forecast
-                    weatherHourlyForecast.setFieldByName("timestamp", GarminTimeUtils.unixTimeToGarminTimestamp(hourly.timestamp));
+                    weatherHourlyForecast.setFieldByName("timestamp", hourly.timestamp);
                     weatherHourlyForecast.setFieldByName("temperature", hourly.temp - 273.15);
                     weatherHourlyForecast.setFieldByName("condition", FitWeatherConditions.openWeatherCodeToFitWeatherStatus(hourly.conditionCode));
                     weatherHourlyForecast.setFieldByName("wind_direction", hourly.windDirection);
@@ -184,7 +184,7 @@ public class GarminSupport extends AbstractBTLEDeviceSupport implements ICommuni
 //
             RecordData todayDailyForecast = new RecordData(GlobalDefinitionsEnum.DAILY_WEATHER_FORECAST.getRecordDefinition());
             todayDailyForecast.setFieldByName("weather_report", 2); // 0 = current, 1 = hourly_forecast, 2 = daily_forecast
-            todayDailyForecast.setFieldByName("timestamp", GarminTimeUtils.unixTimeToGarminTimestamp(weather.timestamp));
+            todayDailyForecast.setFieldByName("timestamp", weather.timestamp);
             todayDailyForecast.setFieldByName("low_temperature", weather.todayMinTemp - 273.15);
             todayDailyForecast.setFieldByName("high_temperature", weather.todayMaxTemp - 273.15);
             todayDailyForecast.setFieldByName("condition", FitWeatherConditions.openWeatherCodeToFitWeatherStatus(weather.currentConditionCode));
@@ -199,7 +199,7 @@ public class GarminSupport extends AbstractBTLEDeviceSupport implements ICommuni
                     int ts = weather.timestamp + (day + 1) * 24 * 60 * 60; //TODO: is this needed?
                     RecordData weatherDailyForecast = new RecordData(GlobalDefinitionsEnum.DAILY_WEATHER_FORECAST.getRecordDefinition());
                     weatherDailyForecast.setFieldByName("weather_report", 2); // 0 = current, 1 = hourly_forecast, 2 = daily_forecast
-                    weatherDailyForecast.setFieldByName("timestamp", GarminTimeUtils.unixTimeToGarminTimestamp(weather.timestamp));
+                    weatherDailyForecast.setFieldByName("timestamp", weather.timestamp);
                     weatherDailyForecast.setFieldByName("low_temperature", daily.minTemp - 273.15);
                     weatherDailyForecast.setFieldByName("high_temperature", daily.maxTemp - 273.15);
                     weatherDailyForecast.setFieldByName("condition", FitWeatherConditions.openWeatherCodeToFitWeatherStatus(daily.conditionCode));

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/garmin/GarminTimeUtils.java

@@ -5,7 +5,7 @@ import org.threeten.bp.ZoneId;
 
 public class GarminTimeUtils {
 
-    private static final int GARMIN_TIME_EPOCH = 631065600;
+    public static final int GARMIN_TIME_EPOCH = 631065600;
 
     public static int unixTimeToGarminTimestamp(int unixTime) {
         return unixTime - GARMIN_TIME_EPOCH;

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/garmin/fit/FieldDefinition.java

@@ -1,16 +1,18 @@
 package nodomain.freeyourgadget.gadgetbridge.service.devices.garmin.fit;
 
+import java.nio.ByteBuffer;
+
 import nodomain.freeyourgadget.gadgetbridge.service.devices.garmin.fit.baseTypes.BaseType;
 import nodomain.freeyourgadget.gadgetbridge.service.devices.garmin.messages.MessageReader;
 import nodomain.freeyourgadget.gadgetbridge.service.devices.garmin.messages.MessageWriter;
 
-public class FieldDefinition {
+public class FieldDefinition implements FieldInterface {
     private final int localNumber;
     private final int size;
-    private final BaseType baseType;
+    protected final BaseType baseType;
     private final String name;
-    private final int scale;
+    protected final int scale;
-    private final int offset;
+    protected final int offset;
 
     public FieldDefinition(int localNumber, int size, BaseType baseType, String name, int scale, int offset) {
         this.localNumber = localNumber;
@@ -70,4 +72,18 @@ public class FieldDefinition {
         writer.writeByte(baseType.getIdentifier());
     }
 
+    @Override
+    public Object decode(ByteBuffer byteBuffer) {
+        return baseType.decode(byteBuffer, scale, offset);
+    }
+
+    @Override
+    public void encode(ByteBuffer byteBuffer, Object o) {
+        baseType.encode(byteBuffer, o, scale, offset);
+    }
+
+    @Override
+    public void invalidate(ByteBuffer byteBuffer) {
+        baseType.invalidate(byteBuffer);
+    }
 }

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/garmin/fit/FieldInterface.java

@@ -0,0 +1,12 @@
+package nodomain.freeyourgadget.gadgetbridge.service.devices.garmin.fit;
+
+import java.nio.ByteBuffer;
+
+public interface FieldInterface {
+    Object decode(ByteBuffer byteBuffer);
+
+    void encode(ByteBuffer byteBuffer, Object o);
+
+    void invalidate(ByteBuffer byteBuffer);
+
+}

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/garmin/fit/GlobalDefinitionsEnum.java

@@ -6,6 +6,7 @@ import java.nio.ByteOrder;
 import java.util.Arrays;
 
 import nodomain.freeyourgadget.gadgetbridge.service.devices.garmin.fit.baseTypes.BaseType;
+import nodomain.freeyourgadget.gadgetbridge.service.devices.garmin.fit.fieldDefinitions.FieldDefinitionTimestamp;
 
 public enum GlobalDefinitionsEnum {
     TODAY_WEATHER_CONDITIONS(MesgType.TODAY_WEATHER_CONDITIONS, new RecordDefinition(
@@ -13,8 +14,8 @@ public enum GlobalDefinitionsEnum {
             ByteOrder.BIG_ENDIAN,
             MesgType.TODAY_WEATHER_CONDITIONS,
             Arrays.asList(new FieldDefinition(0, 1, BaseType.ENUM, "weather_report"),
-                    new FieldDefinition(253, 4, BaseType.UINT32, "timestamp"),
+                    new FieldDefinitionTimestamp(253, 4, BaseType.UINT32, "timestamp"),
-                    new FieldDefinition(9, 4, BaseType.UINT32, "observed_at_time"),
+                    new FieldDefinitionTimestamp(9, 4, BaseType.UINT32, "observed_at_time"),
                     new FieldDefinition(1, 1, BaseType.SINT8, "temperature"),
                     new FieldDefinition(14, 1, BaseType.SINT8, "low_temperature"),
                     new FieldDefinition(13, 1, BaseType.SINT8, "high_temperature"),
@@ -33,7 +34,7 @@ public enum GlobalDefinitionsEnum {
             ByteOrder.BIG_ENDIAN,
             MesgType.HOURLY_WEATHER_FORECAST,
             Arrays.asList(new FieldDefinition(0, 1, BaseType.ENUM, "weather_report"),
-                    new FieldDefinition(253, 4, BaseType.UINT32, "timestamp"),
+                    new FieldDefinitionTimestamp(253, 4, BaseType.UINT32, "timestamp"),
                     new FieldDefinition(1, 1, BaseType.SINT8, "temperature"),
                     new FieldDefinition(2, 1, BaseType.ENUM, "condition"),
                     new FieldDefinition(3, 2, BaseType.UINT16, "wind_direction"),
@@ -49,7 +50,7 @@ public enum GlobalDefinitionsEnum {
             ByteOrder.BIG_ENDIAN,
             MesgType.DAILY_WEATHER_FORECAST,
             Arrays.asList(new FieldDefinition(0, 1, BaseType.ENUM, "weather_report"),
-                    new FieldDefinition(253, 4, BaseType.UINT32, "timestamp"),
+                    new FieldDefinitionTimestamp(253, 4, BaseType.UINT32, "timestamp"),
                     new FieldDefinition(14, 1, BaseType.SINT8, "low_temperature"),
                     new FieldDefinition(13, 1, BaseType.SINT8, "high_temperature"),
                     new FieldDefinition(2, 1, BaseType.ENUM, "condition"),

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/garmin/fit/RecordData.java

@@ -29,7 +29,7 @@ public class RecordData {
 
         for (FieldDefinition fieldDef :
                 recordDefinition.getFieldDefinitions()) {
-            fieldDataList.add(new FieldData(fieldDef.getBaseType(), totalSize, fieldDef.getSize(), fieldDef.getName(), fieldDef.getLocalNumber(), fieldDef.getScale(), fieldDef.getOffset()));
+            fieldDataList.add(new FieldData(fieldDef, totalSize));
             totalSize += fieldDef.getSize();
 
         }
@@ -90,10 +90,10 @@ public class RecordData {
         StringBuilder oBuilder = new StringBuilder();
         for (FieldData fieldData :
                 fieldDataList) {
-            if (fieldData.getName() != null) {
+            if (fieldData.getName() != null && !fieldData.getName().equals("")) {
                 oBuilder.append(fieldData.getName());
             } else {
-                oBuilder.append(fieldData.getNumber());
+                oBuilder.append("unknown_" + fieldData.getNumber());
             }
             oBuilder.append(": ");
             oBuilder.append(fieldData.decode());
@@ -104,45 +104,46 @@ public class RecordData {
     }
 
 
-    private class FieldData {
+    public FieldData getFieldByNumber(int number) {
-        private final BaseType baseType;
+        for (FieldData fieldData :
+                fieldDataList) {
+            if (number == fieldData.getNumber()) {
+                return fieldData;
+            }
+        }
+        return null;
+    }
+
+
+    public class FieldData {
+        private FieldDefinition fieldDefinition;
         private final int position;
         private final int size;
-        private final String name;
+
-        private final int scale;
+        public FieldData(FieldDefinition fieldDefinition, int position) {
-        private final int offset;
+            this.fieldDefinition = fieldDefinition;
-        private final int number;
-        public FieldData(BaseType baseType, int position, int size, String name, int number, int scale, int offset) {
-            this.baseType = baseType;
             this.position = position;
-            this.size = size;
+            this.size = fieldDefinition.getSize();
-            this.name = name;
-            this.number = number;
-            this.scale = scale;
-            this.offset = offset;
         }
 
-        public BaseType getBaseType() {
-            return baseType;
-        }
 
         public String getName() {
-            return name;
+            return fieldDefinition.getName();
         }
 
         public int getNumber() {
-            return number;
+            return fieldDefinition.getLocalNumber();
         }
 
         public void invalidate() {
             goToPosition();
-            if (STRING.equals(getBaseType())) {
+            if (STRING.equals(fieldDefinition.getBaseType())) {
                 for (int i = 0; i < size; i++) {
                     valueHolder.put((byte) 0);
                 }
                 return;
             }
-            baseType.invalidate(valueHolder);
+            fieldDefinition.invalidate(valueHolder);
         }
 
         private void goToPosition() {
@@ -159,18 +160,18 @@ public class RecordData {
                 throw new IllegalArgumentException("Array of values not supported yet"); //TODO: handle arrays
             Object o = objects[0];
             goToPosition();
-            if (STRING.equals(getBaseType())) {
+            if (STRING.equals(fieldDefinition.getBaseType())) {
                 final byte[] bytes = ((String) o).getBytes(StandardCharsets.UTF_8);
                 valueHolder.put(Arrays.copyOf(bytes, Math.min(this.size - 1, bytes.length)));
                 valueHolder.put((byte) 0);
                 return;
             }
-            getBaseType().encode(valueHolder, o, scale, offset);
+            fieldDefinition.encode(valueHolder, o);
         }
 
         public Object decode() {
             goToPosition();
-            if (STRING.equals(getBaseType())) {
+            if (STRING.equals(fieldDefinition.getBaseType())) {
                 final byte[] bytes = new byte[size];
                 valueHolder.get(bytes);
                 final int zero = ArrayUtils.indexOf((byte) 0, bytes);
@@ -180,7 +181,8 @@ public class RecordData {
                 return new String(bytes, 0, zero, StandardCharsets.UTF_8);
             }
             //TODO: handle arrays
-            return getBaseType().decode(valueHolder, scale, offset);
+            return fieldDefinition.decode(valueHolder);
+
         }
     }
 }

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/garmin/fit/fieldDefinitions/FieldDefinitionTimestamp.java

@@ -0,0 +1,26 @@
+package nodomain.freeyourgadget.gadgetbridge.service.devices.garmin.fit.fieldDefinitions;
+
+import nodomain.freeyourgadget.gadgetbridge.service.devices.garmin.fit.FieldDefinition;
+import nodomain.freeyourgadget.gadgetbridge.service.devices.garmin.fit.baseTypes.BaseType;
+
+import static nodomain.freeyourgadget.gadgetbridge.service.devices.garmin.GarminTimeUtils.GARMIN_TIME_EPOCH;
+
+public class FieldDefinitionTimestamp extends FieldDefinition {
+    public FieldDefinitionTimestamp(int localNumber, int size, BaseType baseType, String name) {
+        super(localNumber, size, baseType, name, 1, GARMIN_TIME_EPOCH);
+    }
+
+//    @Override
+//    public Object decode(ByteBuffer byteBuffer) {
+//        return new Timestamp((long) baseType.decode(byteBuffer, scale, offset) * 1000L);
+//    }
+//
+//    @Override
+//    public void encode(ByteBuffer byteBuffer, Object o) {
+//        if(o instanceof Timestamp) {
+//            baseType.encode(byteBuffer, (int) (((Timestamp) o).getTime() / 1000L), scale, offset);
+//            return;
+//        }
+//        baseType.encode(byteBuffer, o, scale, offset);
+//    }
+}