Implement annotation publisher on Android

This patch introduces an AnnotationPublisher to publish custom
annotations for Android. Fixes #316.

android/core/src/main/java/com/stadiamaps/ferrostar/core/FerrostarCore.kt

@@ -3,6 +3,7 @@ package com.stadiamaps.ferrostar.core
 import com.squareup.moshi.JsonAdapter
 import com.squareup.moshi.Moshi
 import com.squareup.moshi.adapter
+import com.stadiamaps.ferrostar.core.annotation.valhalla.valhallaExtendedOSRMAnnotationPublisher
 import com.stadiamaps.ferrostar.core.service.ForegroundServiceManager
 import java.net.URL
 import java.time.Instant
@@ -248,7 +249,11 @@ class FerrostarCore(
 
     locationProvider.addListener(this, _executor)
 
-    return DefaultNavigationViewModel(this, spokenInstructionObserver, locationProvider)
+    return DefaultNavigationViewModel(
+        this,
+        spokenInstructionObserver,
+        locationProvider,
+        valhallaExtendedOSRMAnnotationPublisher())
   }
 
   /**

android/core/src/main/java/com/stadiamaps/ferrostar/core/NavigationViewModel.kt

@@ -3,6 +3,8 @@ package com.stadiamaps.ferrostar.core
 import android.util.Log
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
+import com.stadiamaps.ferrostar.core.annotation.AnnotationPublisher
+import com.stadiamaps.ferrostar.core.annotation.NoOpAnnotationPublisher
 import com.stadiamaps.ferrostar.core.extensions.deviation
 import com.stadiamaps.ferrostar.core.extensions.progress
 import com.stadiamaps.ferrostar.core.extensions.visualInstruction
@@ -86,14 +88,17 @@ interface NavigationViewModel {
 class DefaultNavigationViewModel(
     private val ferrostarCore: FerrostarCore,
     private val spokenInstructionObserver: SpokenInstructionObserver? = null,
-    private val locationProvider: LocationProvider
+    private val locationProvider: LocationProvider,
+    private val annotationPublisher: AnnotationPublisher<*> = NoOpAnnotationPublisher()
 ) : ViewModel(), NavigationViewModel {
 
   private var userLocation: UserLocation? = locationProvider.lastLocation
 
   override val uiState =
       ferrostarCore.state
-          .map { coreState ->
+          .map { annotationPublisher.map(it) }
+          .map { stateWrapper ->
+            val coreState = stateWrapper.state
             val location = locationProvider.lastLocation
             userLocation =
                 when (coreState.tripState) {

android/core/src/main/java/com/stadiamaps/ferrostar/core/annotation/AnnotationPublisher.kt

@@ -0,0 +1,7 @@
+package com.stadiamaps.ferrostar.core.annotation
+
+import com.stadiamaps.ferrostar.core.NavigationState
+
+interface AnnotationPublisher<T> {
+  fun map(state: NavigationState): AnnotationWrapper<T>
+}

android/core/src/main/java/com/stadiamaps/ferrostar/core/annotation/AnnotationWrapper.kt

@@ -0,0 +1,9 @@
+package com.stadiamaps.ferrostar.core.annotation
+
+import com.stadiamaps.ferrostar.core.NavigationState
+
+data class AnnotationWrapper<T>(
+    val annotation: T? = null,
+    val speed: Speed? = null,
+    val state: NavigationState
+)

android/core/src/main/java/com/stadiamaps/ferrostar/core/annotation/DefaultAnnotationPublisher.kt

@@ -0,0 +1,29 @@
+package com.stadiamaps.ferrostar.core.annotation
+
+import com.squareup.moshi.JsonAdapter
+import com.stadiamaps.ferrostar.core.NavigationState
+import uniffi.ferrostar.TripState
+
+class DefaultAnnotationPublisher<T>(
+    private val adapter: JsonAdapter<T>,
+    private val speedLimitMapper: (T?) -> Speed?,
+) : AnnotationPublisher<T> {
+
+  override fun map(state: NavigationState): AnnotationWrapper<T> {
+    val annotations = decodeAnnotations(state)
+    return AnnotationWrapper(annotations, speedLimitMapper(annotations), state)
+  }
+
+  private fun decodeAnnotations(state: NavigationState): T? {
+    return if (state.tripState is TripState.Navigating) {
+      val json = state.tripState.annotationJson
+      if (json != null) {
+        adapter.fromJson(json)
+      } else {
+        null
+      }
+    } else {
+      null
+    }
+  }
+}

android/core/src/main/java/com/stadiamaps/ferrostar/core/annotation/NoOpAnnotationPublisher.kt

@@ -0,0 +1,9 @@
+package com.stadiamaps.ferrostar.core.annotation
+
+import com.stadiamaps.ferrostar.core.NavigationState
+
+class NoOpAnnotationPublisher : AnnotationPublisher<Any> {
+  override fun map(state: NavigationState): AnnotationWrapper<Any> {
+    return AnnotationWrapper(state = state)
+  }
+}

android/core/src/main/java/com/stadiamaps/ferrostar/core/annotation/Speed.kt

@@ -0,0 +1,9 @@
+package com.stadiamaps.ferrostar.core.annotation
+
+sealed class Speed {
+  data object NoLimit : Speed()
+
+  data object Unknown : Speed()
+
+  data class Value(val value: Double, val unit: SpeedUnit) : Speed()
+}

android/core/src/main/java/com/stadiamaps/ferrostar/core/annotation/SpeedSerializationAdapter.kt

@@ -0,0 +1,61 @@
+package com.stadiamaps.ferrostar.core.annotation
+
+import com.squareup.moshi.FromJson
+import com.squareup.moshi.JsonAdapter
+import com.squareup.moshi.JsonReader
+import com.squareup.moshi.JsonWriter
+import com.squareup.moshi.ToJson
+
+class SpeedSerializationAdapter : JsonAdapter<Speed>() {
+
+  @ToJson
+  override fun toJson(writer: JsonWriter, speed: Speed?) {
+    if (speed == null) {
+      writer.nullValue()
+    } else {
+      writer.beginObject()
+      when (speed) {
+        is Speed.NoLimit -> writer.name("none").value(true)
+        is Speed.Unknown -> writer.name("unknown").value(true)
+        is Speed.Value ->
+            writer.name("value").value(speed.value).name("unit").value(speed.unit.text)
+      }
+      writer.endObject()
+    }
+  }
+
+  @FromJson
+  override fun fromJson(reader: JsonReader): Speed {
+    reader.beginObject()
+    var unknown: Boolean? = null
+    var none: Boolean? = null
+    var value: Double? = null
+    var unit: String? = null
+
+    while (reader.hasNext()) {
+      when (reader.selectName(JsonReader.Options.of("none", "unknown", "value", "unit"))) {
+        0 -> none = reader.nextBoolean()
+        1 -> unknown = reader.nextBoolean()
+        2 -> value = reader.nextDouble()
+        3 -> unit = reader.nextString()
+        else -> reader.skipName()
+      }
+    }
+    reader.endObject()
+
+    return if (none == true) {
+      Speed.NoLimit
+    } else if (unknown == true) {
+      Speed.Unknown
+    } else if (value != null && unit != null) {
+      val speed = SpeedUnit.fromString(unit)
+      if (speed != null) {
+        Speed.Value(value, speed)
+      } else {
+        throw IllegalArgumentException("Invalid speed unit: $unit")
+      }
+    } else {
+      throw IllegalArgumentException("Invalid max speed")
+    }
+  }
+}

android/core/src/main/java/com/stadiamaps/ferrostar/core/annotation/SpeedUnit.kt

@@ -0,0 +1,13 @@
+package com.stadiamaps.ferrostar.core.annotation
+
+enum class SpeedUnit(val text: String) {
+  KILOMETERS_PER_HOUR("km/h"),
+  MILES_PER_HOUR("mph"),
+  KNOTS("knots");
+
+  companion object {
+    fun fromString(text: String): SpeedUnit? {
+      return SpeedUnit.entries.firstOrNull { it.text == text }
+    }
+  }
+}

android/core/src/main/java/com/stadiamaps/ferrostar/core/annotation/valhalla/ValhallaOSRMAnnotationPublisher.kt

@@ -0,0 +1,14 @@
+package com.stadiamaps.ferrostar.core.annotation.valhalla
+
+import com.squareup.moshi.Moshi
+import com.squareup.moshi.kotlin.reflect.KotlinJsonAdapterFactory
+import com.stadiamaps.ferrostar.core.annotation.AnnotationPublisher
+import com.stadiamaps.ferrostar.core.annotation.DefaultAnnotationPublisher
+import com.stadiamaps.ferrostar.core.annotation.SpeedSerializationAdapter
+
+fun valhallaExtendedOSRMAnnotationPublisher(): AnnotationPublisher<ValhallaOSRMExtendedAnnotation> {
+  val moshi =
+      Moshi.Builder().add(SpeedSerializationAdapter()).add(KotlinJsonAdapterFactory()).build()
+  val adapter = moshi.adapter(ValhallaOSRMExtendedAnnotation::class.java)
+  return DefaultAnnotationPublisher<ValhallaOSRMExtendedAnnotation>(adapter) { it?.speedLimit }
+}

android/core/src/main/java/com/stadiamaps/ferrostar/core/annotation/valhalla/ValhallaOSRMExtendedAnnotation.kt

@@ -0,0 +1,11 @@
+package com.stadiamaps.ferrostar.core.annotation.valhalla
+
+import com.squareup.moshi.Json
+import com.stadiamaps.ferrostar.core.annotation.Speed
+
+data class ValhallaOSRMExtendedAnnotation(
+    @Json(name = "maxspeed") val speedLimit: Speed?,
+    val speed: Double?,
+    val distance: Double?,
+    val duration: Double?
+)