feat(instruments): add forecast wind, wave, swell and current from Open-Meteo

- Add swell params to MarineApiService request
- Add swell fields to MarineHourly model
- Add MarineConditions snapshot model
- Add WeatherRepository.fetchCurrentConditions() (first forecast hour)
- Add MainViewModel.loadConditions() + marineConditions StateFlow
- Add Forecast section to instrument sheet: Curr / Wave / Swell
- Populate TWS from forecast wind speed on first GPS fix
- Trigger loadConditions() once on first GPS position received

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

8 files changed, 186 insertions, 3 deletions

diff --git a/android-app/app/src/main/kotlin/org/terst/nav/MainActivity.kt b/android-app/app/src/main/kotlin/org/terst/nav/MainActivity.kt
index c48cec2..7c0cd9e 100644
--- a/android-app/app/src/main/kotlin/org/terst/nav/MainActivity.kt
+++ b/android-app/app/src/main/kotlin/org/terst/nav/MainActivity.kt
@@ -182,13 +182,24 @@ class MainActivity : AppCompatActivity(), SafetyFragment.SafetyListener {
             valueBsp = findViewById(R.id.value_bsp),
             valueSog = findViewById(R.id.value_sog),
             valueDepth = findViewById(R.id.value_depth),
-            valueBaro = findViewById(R.id.value_baro)
+            valueBaro = findViewById(R.id.value_baro),
+            valueCurrSpd = findViewById(R.id.value_curr_spd),
+            valueCurrDir = findViewById(R.id.value_curr_dir),
+            valueWaveHt = findViewById(R.id.value_wave_ht),
+            valueWaveDir = findViewById(R.id.value_wave_dir),
+            valueSwellHt = findViewById(R.id.value_swell_ht),
+            valueSwellPer = findViewById(R.id.value_swell_per)
         )
         instrumentHandler?.updateDisplay(
             aws = "—", tws = "—", hdg = "—",
             cog = "—", bsp = "—", sog = "—",
             depth = "—", baro = "—"
         )
+        instrumentHandler?.updateConditions(
+            currSpd = "—", currDir = "—",
+            waveHt = "—", waveDir = "—",
+            swellHt = "—", swellPer = "—"
+        )
     }
 
     // Helper to convert dp to px
@@ -263,6 +274,7 @@ class MainActivity : AppCompatActivity(), SafetyFragment.SafetyListener {
     }
 
     private fun observeDataSources() {
+        var conditionsLoaded = false
         lifecycleScope.launch {
             LocationService.locationFlow.collect { gpsData ->
                 mapHandler?.centerOnLocation(gpsData.latitude, gpsData.longitude)
@@ -273,6 +285,10 @@ class MainActivity : AppCompatActivity(), SafetyFragment.SafetyListener {
                     sog = "%.1f".format(Locale.getDefault(), sogKnots),
                     cog = "%.0f°".format(Locale.getDefault(), cogDeg)
                 )
+                if (!conditionsLoaded) {
+                    conditionsLoaded = true
+                    viewModel.loadConditions(gpsData.latitude, gpsData.longitude)
+                }
             }
         }
         lifecycleScope.launch {
@@ -283,6 +299,22 @@ class MainActivity : AppCompatActivity(), SafetyFragment.SafetyListener {
             }
         }
         lifecycleScope.launch {
+            viewModel.marineConditions.collect { c ->
+                if (c == null) return@collect
+                instrumentHandler?.updateDisplay(
+                    tws = c.windSpeedKt?.let { "%.1f".format(Locale.getDefault(), it) } ?: "—"
+                )
+                instrumentHandler?.updateConditions(
+                    currSpd = c.currentSpeedKt?.let { "%.1f kn".format(Locale.getDefault(), it) } ?: "—",
+                    currDir = c.currentDirDeg?.let { "%.0f°".format(Locale.getDefault(), it) } ?: "—",
+                    waveHt  = c.waveHeightM?.let { "%.1f m".format(Locale.getDefault(), it) } ?: "—",
+                    waveDir = c.waveDirDeg?.let { "%.0f°".format(Locale.getDefault(), it) } ?: "—",
+                    swellHt = c.swellHeightM?.let { "%.1f m".format(Locale.getDefault(), it) } ?: "—",
+                    swellPer = c.swellPeriodS?.let { "%.0f s".format(Locale.getDefault(), it) } ?: "—"
+                )
+            }
+        }
+        lifecycleScope.launch {
             LocationService.anchorWatchState.collect { state ->
                 safetyFragment.updateAnchorStatus(if (state.isActive) "Active: ${state.watchCircleRadiusMeters}m" else "Inactive")
             }
diff --git a/android-app/app/src/main/kotlin/org/terst/nav/data/api/MarineApiService.kt b/android-app/app/src/main/kotlin/org/terst/nav/data/api/MarineApiService.kt
index 67c14f8..5a7d2e2 100644
--- a/android-app/app/src/main/kotlin/org/terst/nav/data/api/MarineApiService.kt
+++ b/android-app/app/src/main/kotlin/org/terst/nav/data/api/MarineApiService.kt
@@ -11,7 +11,7 @@ interface MarineApiService {
         @Query("latitude")      latitude: Double,
         @Query("longitude")     longitude: Double,
         @Query("hourly")        hourly: String =
-            "wave_height,wave_direction,ocean_current_velocity,ocean_current_direction",
+            "wave_height,wave_direction,swell_wave_height,swell_wave_direction,swell_wave_period,ocean_current_velocity,ocean_current_direction",
         @Query("forecast_days") forecastDays: Int = 7
     ): MarineResponse
 }
diff --git a/android-app/app/src/main/kotlin/org/terst/nav/data/model/MarineConditions.kt b/android-app/app/src/main/kotlin/org/terst/nav/data/model/MarineConditions.kt
new file mode 100644
index 0000000..3cde023
--- /dev/null
+++ b/android-app/app/src/main/kotlin/org/terst/nav/data/model/MarineConditions.kt
@@ -0,0 +1,17 @@
+package org.terst.nav.data.model
+
+/**
+ * Snapshot of current marine conditions derived from the first forecast hour.
+ * All fields are nullable — null means the model returned no data for that parameter.
+ */
+data class MarineConditions(
+    val windSpeedKt: Double?,
+    val windDirDeg: Double?,
+    val waveHeightM: Double?,
+    val waveDirDeg: Double?,
+    val swellHeightM: Double?,
+    val swellDirDeg: Double?,
+    val swellPeriodS: Double?,
+    val currentSpeedKt: Double?,   // ocean_current_velocity converted from m/s to knots
+    val currentDirDeg: Double?
+)
diff --git a/android-app/app/src/main/kotlin/org/terst/nav/data/model/MarineResponse.kt b/android-app/app/src/main/kotlin/org/terst/nav/data/model/MarineResponse.kt
index ab9799b..cf5216d 100644
--- a/android-app/app/src/main/kotlin/org/terst/nav/data/model/MarineResponse.kt
+++ b/android-app/app/src/main/kotlin/org/terst/nav/data/model/MarineResponse.kt
@@ -15,6 +15,9 @@ data class MarineHourly(
     @Json(name = "time")                      val time: List<String>,
     @Json(name = "wave_height")               val waveHeight: List<Double?>,
     @Json(name = "wave_direction")            val waveDirection: List<Double?>,
+    @Json(name = "swell_wave_height")         val swellWaveHeight: List<Double?>,
+    @Json(name = "swell_wave_direction")      val swellWaveDirection: List<Double?>,
+    @Json(name = "swell_wave_period")         val swellWavePeriod: List<Double?>,
     @Json(name = "ocean_current_velocity")    val oceanCurrentVelocity: List<Double?>,
     @Json(name = "ocean_current_direction")   val oceanCurrentDirection: List<Double?>
 )
diff --git a/android-app/app/src/main/kotlin/org/terst/nav/data/repository/WeatherRepository.kt b/android-app/app/src/main/kotlin/org/terst/nav/data/repository/WeatherRepository.kt
index ee586a5..b70ea8c 100644
--- a/android-app/app/src/main/kotlin/org/terst/nav/data/repository/WeatherRepository.kt
+++ b/android-app/app/src/main/kotlin/org/terst/nav/data/repository/WeatherRepository.kt
@@ -3,6 +3,7 @@ package org.terst.nav.data.repository
 import org.terst.nav.data.api.MarineApiService
 import org.terst.nav.data.api.WeatherApiService
 import org.terst.nav.data.model.ForecastItem
+import org.terst.nav.data.model.MarineConditions
 import org.terst.nav.data.model.WindArrow
 
 class WeatherRepository(
@@ -47,6 +48,29 @@ class WeatherRepository(
             )
         }
 
+    /**
+     * Fetches current marine conditions (first forecast hour) for [lat]/[lon].
+     * Ocean current velocity is converted from m/s to knots.
+     */
+    suspend fun fetchCurrentConditions(lat: Double, lon: Double): Result<MarineConditions> =
+        runCatching {
+            val weather = weatherApi.getWeatherForecast(lat, lon, forecastDays = 1)
+            val marine = marineApi.getMarineForecast(lat, lon)
+            val w = weather.hourly
+            val m = marine.hourly
+            MarineConditions(
+                windSpeedKt    = w.windspeed10m.firstOrNull(),
+                windDirDeg     = w.winddirection10m.firstOrNull(),
+                waveHeightM    = m.waveHeight.firstOrNull(),
+                waveDirDeg     = m.waveDirection.firstOrNull(),
+                swellHeightM   = m.swellWaveHeight.firstOrNull(),
+                swellDirDeg    = m.swellWaveDirection.firstOrNull(),
+                swellPeriodS   = m.swellWavePeriod.firstOrNull(),
+                currentSpeedKt = m.oceanCurrentVelocity.firstOrNull()?.let { it * 1.94384 },
+                currentDirDeg  = m.oceanCurrentDirection.firstOrNull()
+            )
+        }
+
     companion object {
         /** Factory using the shared ApiClient singletons. */
         fun create(): WeatherRepository {
diff --git a/android-app/app/src/main/kotlin/org/terst/nav/ui/InstrumentHandler.kt b/android-app/app/src/main/kotlin/org/terst/nav/ui/InstrumentHandler.kt
index 7e09756..91582c0 100644
--- a/android-app/app/src/main/kotlin/org/terst/nav/ui/InstrumentHandler.kt
+++ b/android-app/app/src/main/kotlin/org/terst/nav/ui/InstrumentHandler.kt
@@ -13,7 +13,13 @@ class InstrumentHandler(
     private val valueBsp: TextView,
     private val valueSog: TextView,
     private val valueDepth: TextView,
-    private val valueBaro: TextView
+    private val valueBaro: TextView,
+    private val valueCurrSpd: TextView,
+    private val valueCurrDir: TextView,
+    private val valueWaveHt: TextView,
+    private val valueWaveDir: TextView,
+    private val valueSwellHt: TextView,
+    private val valueSwellPer: TextView
 ) {
     /**
      * Updates the text displays for the given instruments. Null arguments leave the current value unchanged.
@@ -37,4 +43,24 @@ class InstrumentHandler(
         depth?.let { valueDepth.text = it }
         baro?.let { valueBaro.text = it }
     }
+
+    /**
+     * Updates the forecast conditions section (Curr, Wave, Swell).
+     * Null arguments leave the current value unchanged.
+     */
+    fun updateConditions(
+        currSpd: String? = null,
+        currDir: String? = null,
+        waveHt: String? = null,
+        waveDir: String? = null,
+        swellHt: String? = null,
+        swellPer: String? = null
+    ) {
+        currSpd?.let { valueCurrSpd.text = it }
+        currDir?.let { valueCurrDir.text = it }
+        waveHt?.let { valueWaveHt.text = it }
+        waveDir?.let { valueWaveDir.text = it }
+        swellHt?.let { valueSwellHt.text = it }
+        swellPer?.let { valueSwellPer.text = it }
+    }
 }
diff --git a/android-app/app/src/main/kotlin/org/terst/nav/ui/MainViewModel.kt b/android-app/app/src/main/kotlin/org/terst/nav/ui/MainViewModel.kt
index 0efff52..0431f31 100644
--- a/android-app/app/src/main/kotlin/org/terst/nav/ui/MainViewModel.kt
+++ b/android-app/app/src/main/kotlin/org/terst/nav/ui/MainViewModel.kt
@@ -9,6 +9,7 @@ import org.terst.nav.data.api.AisHubApiService
 import org.terst.nav.track.TrackPoint
 import org.terst.nav.track.TrackRepository
 import org.terst.nav.data.model.ForecastItem
+import org.terst.nav.data.model.MarineConditions
 import org.terst.nav.data.model.WindArrow
 import org.terst.nav.data.repository.WeatherRepository
 import com.squareup.moshi.Moshi
@@ -40,6 +41,9 @@ class MainViewModel(
     private val _forecast = MutableStateFlow<List<ForecastItem>>(emptyList())
     val forecast: StateFlow<List<ForecastItem>> = _forecast
 
+    private val _marineConditions = MutableStateFlow<MarineConditions?>(null)
+    val marineConditions: StateFlow<MarineConditions?> = _marineConditions.asStateFlow()
+
     private val _aisTargets = MutableStateFlow<List<AisVessel>>(emptyList())
     val aisTargets: StateFlow<List<AisVessel>> = _aisTargets.asStateFlow()
 
@@ -89,6 +93,17 @@ class MainViewModel(
     }
 
     /**
+     * Fetches current conditions snapshot for [lat]/[lon] and exposes it via [marineConditions].
+     * Silently ignored on network failure — the UI keeps showing dashes.
+     */
+    fun loadConditions(lat: Double, lon: Double) {
+        viewModelScope.launch {
+            repository.fetchCurrentConditions(lat, lon)
+                .onSuccess { _marineConditions.value = it }
+        }
+    }
+
+    /**
      * Fetch weather and marine data for [lat]/[lon] in parallel.
      * Called once the device location is known.
      */
diff --git a/android-app/app/src/main/res/layout/layout_instruments_sheet.xml b/android-app/app/src/main/res/layout/layout_instruments_sheet.xml
index c651ba2..a6b74b0 100644
--- a/android-app/app/src/main/res/layout/layout_instruments_sheet.xml
+++ b/android-app/app/src/main/res/layout/layout_instruments_sheet.xml
@@ -131,4 +131,70 @@
 
     </LinearLayout>
 
+    <!-- Divider -->
+    <View
+        android:id="@+id/conditions_divider"
+        android:layout_width="match_parent"
+        android:layout_height="1dp"
+        android:background="@color/md_theme_outline"
+        android:layout_marginTop="20dp"
+        app:layout_constraintTop_toBottomOf="@id/expanded_instruments"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintEnd_toEndOf="parent" />
+
+    <TextView
+        android:id="@+id/label_conditions"
+        style="@style/InstrumentLabel"
+        android:text="FORECAST"
+        android:layout_marginTop="12dp"
+        app:layout_constraintTop_toBottomOf="@id/conditions_divider"
+        app:layout_constraintStart_toStartOf="parent" />
+
+    <!-- Conditions: Curr | Wave | Swell (3 columns, value + sub-label) -->
+    <LinearLayout
+        android:id="@+id/conditions_row"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:orientation="horizontal"
+        android:layout_marginTop="8dp"
+        app:layout_constraintTop_toBottomOf="@id/label_conditions"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintBottom_toBottomOf="parent">
+
+        <LinearLayout
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:orientation="vertical"
+            android:gravity="center">
+            <TextView style="@style/InstrumentLabel" android:text="Curr" />
+            <TextView android:id="@+id/value_curr_spd" style="@style/InstrumentPrimaryValue" tools:text="—" />
+            <TextView android:id="@+id/value_curr_dir" style="@style/InstrumentLabel" tools:text="—" />
+        </LinearLayout>
+
+        <LinearLayout
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:orientation="vertical"
+            android:gravity="center">
+            <TextView style="@style/InstrumentLabel" android:text="Wave" />
+            <TextView android:id="@+id/value_wave_ht" style="@style/InstrumentPrimaryValue" tools:text="—" />
+            <TextView android:id="@+id/value_wave_dir" style="@style/InstrumentLabel" tools:text="—" />
+        </LinearLayout>
+
+        <LinearLayout
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:orientation="vertical"
+            android:gravity="center">
+            <TextView style="@style/InstrumentLabel" android:text="Swell" />
+            <TextView android:id="@+id/value_swell_ht" style="@style/InstrumentPrimaryValue" tools:text="—" />
+            <TextView android:id="@+id/value_swell_per" style="@style/InstrumentLabel" tools:text="—" />
+        </LinearLayout>
+
+    </LinearLayout>
+
 </androidx.constraintlayout.widget.ConstraintLayout>