Implement Mictrack Low Altitude Flight Decoder (#4546)

* Implement Mictrack Low Altitude Flight Decoder

* Fix headers

* Add MictrackLowAltitudeFlightProtocolDecoderTest test for position

* Merge Mictrack and Mictrack Low Altitude Flight decoders

* Remove empty line

* Minor style changes based on code review

* Cast msg Object to String once in MictrackProtocolDecoder

Co-authored-by: Roeland Boeters <roeland@geodelta.com>

2 files changed, 89 insertions, 2 deletions

diff --git a/src/main/java/org/traccar/protocol/MictrackProtocolDecoder.java b/src/main/java/org/traccar/protocol/MictrackProtocolDecoder.java
index a2fccb707..0f815ca7b 100644
--- a/src/main/java/org/traccar/protocol/MictrackProtocolDecoder.java
+++ b/src/main/java/org/traccar/protocol/MictrackProtocolDecoder.java
@@ -1,5 +1,6 @@
 /*
  * Copyright 2019 Anton Tananaev (anton@traccar.org)
+ * Copyright 2020 Roeland Boeters (roeland@geodelta.com)
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,6 +20,9 @@ import io.netty.channel.Channel;
 import org.traccar.BaseProtocolDecoder;
 import org.traccar.DeviceSession;
 import org.traccar.Protocol;
+import org.traccar.helper.DateBuilder;
+import org.traccar.helper.Parser;
+import org.traccar.helper.PatternBuilder;
 import org.traccar.helper.UnitsConverter;
 import org.traccar.model.CellTower;
 import org.traccar.model.Network;
@@ -30,7 +34,10 @@ import java.text.DateFormat;
 import java.text.ParseException;
 import java.text.SimpleDateFormat;
 import java.util.Date;
+import java.util.LinkedList;
+import java.util.List;
 import java.util.TimeZone;
+import java.util.regex.Pattern;
 
 public class MictrackProtocolDecoder extends BaseProtocolDecoder {
 
@@ -38,6 +45,19 @@ public class MictrackProtocolDecoder extends BaseProtocolDecoder {
         super(protocol);
     }
 
+    private static final Pattern PATTERN_LOW_ALTITUDE = new PatternBuilder()
+            .number("(dd)(dd)(dd).d+,")          // time (hhmmss.sss)
+            .expression("([AV]),")               // validity
+            .number("(d+)(dd.d+),")              // latitude
+            .expression("([NS]),")
+            .number("(d+)(dd.d+),")              // longitude
+            .expression("([EW]),")
+            .number("(d+.?d*)?,")                // speed
+            .number("(d+.?d*)?,")                // course
+            .number("(d+.?d*)?,")                // altitude
+            .number("(dd)(dd)(dd)")              // date (ddmmyy)
+            .compile();
+
     private Date decodeTime(String data) throws ParseException {
         DateFormat dateFormat = new SimpleDateFormat("yyMMddHHmmss");
         dateFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
@@ -142,8 +162,18 @@ public class MictrackProtocolDecoder extends BaseProtocolDecoder {
     @Override
     protected Object decode(
             Channel channel, SocketAddress remoteAddress, Object msg) throws Exception {
+        String sentence = ((String) msg).trim();
+
+        if (sentence.startsWith("MT")) {
+            return decodeStandard(channel, remoteAddress, sentence);
+        } else {
+            return decodeLowAltitude(channel, remoteAddress, sentence);
+        }
+    }
 
-        String[] fragments = ((String) msg).split(";");
+    private Object decodeStandard(
+            Channel channel, SocketAddress remoteAddress, String sentence) throws Exception {
+        String[] fragments = sentence.split(";");
 
         DeviceSession deviceSession = getDeviceSession(channel, remoteAddress, fragments[2]);
         if (deviceSession == null) {
@@ -178,4 +208,46 @@ public class MictrackProtocolDecoder extends BaseProtocolDecoder {
         return position;
     }
 
+    private Object decodeLowAltitude(
+            Channel channel, SocketAddress remoteAddress, String sentence) throws Exception {
+        String deviceId = sentence.substring(0, sentence.indexOf("$"));
+
+        DeviceSession deviceSession = getDeviceSession(channel, remoteAddress, deviceId);
+        if (deviceSession == null) {
+            return null;
+        }
+
+        String[] fragments = sentence.substring(sentence.indexOf("$")).split("\\$");
+
+        List<Position> positions = new LinkedList<>();
+
+        for (String message : fragments) {
+            Parser parser = new Parser(PATTERN_LOW_ALTITUDE, message);
+
+            if (parser.matches()) {
+
+                Position position = new Position(getProtocolName());
+                position.setDeviceId(deviceSession.getDeviceId());
+
+                DateBuilder dateBuilder = new DateBuilder()
+                        .setTime(parser.nextInt(), parser.nextInt(), parser.nextInt());
+
+                position.setValid(parser.next().equals("A"));
+                position.setLatitude(parser.nextCoordinate());
+                position.setLongitude(parser.nextCoordinate());
+
+                position.setSpeed(parser.nextDouble(0));
+                position.setCourse(parser.nextDouble(0));
+                position.setAltitude(parser.nextDouble(0));
+
+                dateBuilder.setDateReverse(parser.nextInt(), parser.nextInt(), parser.nextInt());
+                position.setTime(dateBuilder.getDate());
+
+                positions.add(position);
+            }
+        }
+
+        return positions;
+    }
+
 }
diff --git a/src/test/java/org/traccar/protocol/MictrackProtocolDecoderTest.java b/src/test/java/org/traccar/protocol/MictrackProtocolDecoderTest.java
index 794b2b57e..605a02b92 100644
--- a/src/test/java/org/traccar/protocol/MictrackProtocolDecoderTest.java
+++ b/src/test/java/org/traccar/protocol/MictrackProtocolDecoderTest.java
@@ -6,7 +6,7 @@ import org.traccar.ProtocolTest;
 public class MictrackProtocolDecoderTest extends ProtocolTest {
 
     @Test
-    public void testDecode() throws Exception {
+    public void testDecodeStandard() throws Exception {
 
         MictrackProtocolDecoder decoder = new MictrackProtocolDecoder(null);
 
@@ -31,7 +31,22 @@ public class MictrackProtocolDecoderTest extends ProtocolTest {
 
         verifyAttributes(decoder, text(
                 "MT;5;866425031379169;RH;5+190116112648+0+0+0+0+11+3954+1"));
+    }
+
+    @Test
+    public void testDecodeLowAltitude() throws Exception {
+
+        MictrackProtocolDecoder decoder = new MictrackProtocolDecoder(null);
+
+        verifyPositions(decoder, text(
+                "861108032038761$062232.00,A,2238.2832,N,11401.7381,E,0.01,309.62,95.0,131117"));
+
+        verifyPositions(decoder, text(
+                "861108032038761$062232.00,A,2238.2832,N,11401.7381,E,0.01,309.62,95.0,131117$062332.00,A,2238.2836,N,11401.7386,E,0.06,209.62,95.0,131117"));
 
+        verifyPositions(decoder, text(
+                "861108032038761$062232.00,A,2238.2832,N,11401.7381,E,0.01,309.62,95.0,131117"),
+                position("2017-11-13 06:22:32.000", true, 22.63806, 114.028976));
     }
 
 }