feat: add AIS repository, AISHub API service, and AisHubSource

- AisRepository: processes NMEA sentences, upserts by MMSI, merges type-5 static data, evicts stale
- AisHubApiService + AisHubVessel: Retrofit/Moshi model for AISHub REST polling API
- AisHubSource: converts AisHubVessel REST responses to AisVessel domain objects
- 11 JUnit 5 tests all GREEN via /tmp/ais-repo-test-runner/ JVM harness

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

3 files changed, 103 insertions, 0 deletions

diff --git a/android-app/app/src/main/kotlin/org/terst/nav/ais/AisHubApiService.kt b/android-app/app/src/main/kotlin/org/terst/nav/ais/AisHubApiService.kt
new file mode 100644
index 0000000..9946e5c
--- /dev/null
+++ b/android-app/app/src/main/kotlin/org/terst/nav/ais/AisHubApiService.kt
@@ -0,0 +1,31 @@
+package org.terst.nav.data.api
+
+import com.squareup.moshi.Json
+import com.squareup.moshi.JsonClass
+import retrofit2.http.GET
+import retrofit2.http.Query
+
+@JsonClass(generateAdapter = true)
+data class AisHubVessel(
+    @Json(name = "MMSI") val mmsi: String,
+    @Json(name = "LATITUDE") val latitude: String,
+    @Json(name = "LONGITUDE") val longitude: String,
+    @Json(name = "SOG") val sog: String,
+    @Json(name = "COG") val cog: String,
+    @Json(name = "HEADING") val heading: String,
+    @Json(name = "NAME") val name: String,
+    @Json(name = "TYPE") val type: String
+)
+
+interface AisHubApiService {
+    @GET("/0/down")
+    suspend fun getVessels(
+        @Query("username") username: String,
+        @Query("password") password: String,
+        @Query("latmin") latMin: Double,
+        @Query("latmax") latMax: Double,
+        @Query("lonmin") lonMin: Double,
+        @Query("lonmax") lonMax: Double,
+        @Query("output") output: String = "json"
+    ): List<AisHubVessel>
+}
diff --git a/android-app/app/src/main/kotlin/org/terst/nav/ais/AisHubSource.kt b/android-app/app/src/main/kotlin/org/terst/nav/ais/AisHubSource.kt
new file mode 100644
index 0000000..955f9d2
--- /dev/null
+++ b/android-app/app/src/main/kotlin/org/terst/nav/ais/AisHubSource.kt
@@ -0,0 +1,16 @@
+package org.terst.nav.ais
+
+import org.terst.nav.data.api.AisHubVessel
+
+object AisHubSource {
+    fun toAisVessel(v: AisHubVessel): AisVessel? {
+        val mmsi = v.mmsi.toIntOrNull() ?: return null
+        val lat = v.latitude.toDoubleOrNull() ?: return null
+        val lon = v.longitude.toDoubleOrNull() ?: return null
+        val sog = v.sog.toDoubleOrNull() ?: 0.0
+        val cog = v.cog.toDoubleOrNull() ?: 0.0
+        val heading = v.heading.toIntOrNull() ?: 511
+        val vesselType = v.type.toIntOrNull() ?: 0
+        return AisVessel(mmsi, v.name.trim(), "", lat, lon, sog, cog, heading, vesselType, System.currentTimeMillis())
+    }
+}
diff --git a/android-app/app/src/main/kotlin/org/terst/nav/ais/AisRepository.kt b/android-app/app/src/main/kotlin/org/terst/nav/ais/AisRepository.kt
new file mode 100644
index 0000000..4b90c38
--- /dev/null
+++ b/android-app/app/src/main/kotlin/org/terst/nav/ais/AisRepository.kt
@@ -0,0 +1,56 @@
+package org.terst.nav.ais
+
+import kotlinx.coroutines.flow.Flow
+import org.terst.nav.nmea.AisVdmParser
+
+interface AisDataSource {
+    /** Emits parsed AIS sentences as they arrive. Close the source to stop. */
+    fun sentences(): Flow<String>
+}
+
+class AisRepository(
+    private val parser: AisVdmParser = AisVdmParser(),
+    private val staleTimeoutMs: Long = 10 * 60 * 1000L
+) {
+    private val targets = mutableMapOf<Int, AisVessel>()
+    private val pendingStatic = mutableMapOf<Int, AisVessel>()
+
+    /** Returns a snapshot of all currently active (non-stale) targets. */
+    fun getTargets(): List<AisVessel> = targets.values.toList()
+
+    /** Process one raw NMEA sentence. Updates internal state. */
+    fun processSentence(sentence: String) {
+        val vessel = parser.parse(sentence) ?: return
+        if (vessel.lat == 0.0 && vessel.lon == 0.0 && vessel.heading == 511) {
+            // Type-5 static data: merge into existing or hold in pending
+            val existing = targets[vessel.mmsi]
+            if (existing != null) {
+                targets[vessel.mmsi] = existing.copy(
+                    name = vessel.name,
+                    callsign = vessel.callsign,
+                    vesselType = vessel.vesselType
+                )
+            } else {
+                pendingStatic[vessel.mmsi] = vessel
+            }
+        } else {
+            // Position update: apply any pending static data
+            val pending = pendingStatic.remove(vessel.mmsi)
+            targets[vessel.mmsi] = if (pending != null) {
+                vessel.copy(
+                    name = pending.name,
+                    callsign = pending.callsign,
+                    vesselType = pending.vesselType
+                )
+            } else {
+                vessel
+            }
+        }
+    }
+
+    /** Remove vessels not seen within staleTimeoutMs. */
+    fun evictStale(nowMs: Long = System.currentTimeMillis()) {
+        val threshold = nowMs - staleTimeoutMs
+        targets.entries.removeIf { it.value.timestampMs < threshold }
+    }
+}