From e53fbe4e984f0f57f3ed73297adf8273bb523808 Mon Sep 17 00:00:00 2001
From: Claudomator Agent <agent@claudomator>
Date: Sat, 14 Mar 2026 02:23:25 +0000
Subject: Add GpsPosition data class and NMEA RMC parser with tests
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- NmeaParser: parses $GPRMC (and any *RMC) sentence → GpsPosition
  - Null for void status (V), malformed input, non-RMC sentence
  - SOG/COG default to 0.0 when empty; S/W give negative lat/lon
  - Timestamp from HHMMSS + DDMMYY fields as Unix epoch millis UTC
  - No Android dependencies
- GpsPositionTest: value holding and data-class equality (2 tests)
- NmeaParserTest: 11 tests covering valid parse, void/malformed/empty,
  hemisphere signs, decimal precision
- All 22 unit tests verified GREEN via kotlinc + JUnitCore

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 SESSION_STATE.md | 27 +++++++++++++++++++++++----
 1 file changed, 23 insertions(+), 4 deletions(-)

(limited to 'SESSION_STATE.md')

diff --git a/SESSION_STATE.md b/SESSION_STATE.md
index fd7f0e1..ef52c00 100644
--- a/SESSION_STATE.md
+++ b/SESSION_STATE.md
@@ -1,7 +1,7 @@
 # SESSION_STATE.md
 
 ## Current Task Goal
-GPS provider abstraction layer — COMPLETE
+GPS navigation implementation: position model, SOG/COG, NMEA RMC parser — COMPLETE
 
 ## Completed Items
 
@@ -45,10 +45,29 @@ GPS provider abstraction layer — COMPLETE
   Full Gradle build requires fixing directory permissions: `chown -R www-data:www-data app/build app/.kotlin`
 - Pre-existing XML layout error in `activity_main.xml:300` (unrelated to GPS work)
 
+### [APPROVED] NmeaParser — RMC parser
+- File: `app/src/main/kotlin/org/terst/nav/nmea/NmeaParser.kt`
+- Parses any `*RMC` sentence (GP, GN, etc.)
+- Returns `null` for void status (V), malformed input, wrong sentence type
+- SOG/COG default to 0.0 when fields are empty
+- Latitude: positive = North, negative = South
+- Longitude: positive = East, negative = West
+- Timestamp: HHMMSS + DDMMYY → Unix epoch millis UTC (YY < 70 → 2000+YY)
+- No Android dependencies — pure JVM
+
+### [APPROVED] GpsPositionTest + NmeaParserTest (22 tests — all GREEN)
+- `app/src/test/kotlin/org/terst/nav/gps/GpsPositionTest.kt` (2 tests)
+- `app/src/test/kotlin/org/terst/nav/nmea/NmeaParserTest.kt` (11 tests)
+- `app/src/test/kotlin/org/terst/nav/gps/GpsProviderTest.kt` (9 tests, pre-existing)
+- All verified via direct `kotlinc` (1.9.22) + `JUnitCore` invocation
+
 ## Next 3 Specific Steps
-1. **UI instrument display** — `MainActivity.kt`: subscribe to `DeviceGpsProvider`, display SOG/COG in instrument panel
-2. **NmeaGpsProvider** — `app/src/main/kotlin/org/terst/nav/gps/NmeaGpsProvider.kt`: implement `GpsProvider` parsing NMEA RMC sentences over TCP/UDP
-3. **Fix build permissions** — `chown -R www-data:www-data /workspace/nav/android-app/app/build /workspace/nav/android-app/app/.kotlin` to enable full Gradle unit test runs
+1. **DeviceGpsProvider** (`app/src/main/kotlin/org/terst/nav/gps/DeviceGpsProvider.kt`)
+   — Implement using FusedLocationProviderClient; SOG = speed × 1.94384 knots
+2. **NmeaGpsProvider** — `GpsProvider` implementation parsing NMEA RMC over TCP/UDP socket
+   using `NmeaParser`
+3. **Fix build permissions** — `chown -R www-data:www-data /workspace/nav/android-app/app/build`
+   to enable full Gradle unit test runs
 
 ## Scripts Added
 - None (tests run via direct JVM invocation)
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