basic implementation of OpenStreetMapApi

#97

app/src/main/java/net/vonforst/evmap/api/ChargepointApi.kt

@@ -6,6 +6,7 @@ import com.car2go.maps.model.LatLngBounds
 import net.vonforst.evmap.R
 import net.vonforst.evmap.api.goingelectric.GoingElectricApiWrapper
 import net.vonforst.evmap.api.openchargemap.OpenChargeMapApiWrapper
+import net.vonforst.evmap.api.openstreetmap.OpenStreetMapApiWrapper
 import net.vonforst.evmap.model.*
 import net.vonforst.evmap.viewmodel.Resource
 import java.time.Duration
@@ -58,6 +59,34 @@ interface ChargepointApi<out T : ReferenceData> {
      * Duration we are limited to if there is a required API local cache time limit.
      */
     val cacheLimit: Duration
+
+    /**
+     * Whether this API supports querying for chargers at the backend
+     *
+     * This determines whether the getChargepoints, getChargepointsRadius and getChargepointDetail functions are supported.
+     */
+    val supportsOnlineQueries: Boolean
+
+    /**
+     * Whether this API supports downloading the whole dataset into local storage
+     *
+     * This determines whether the getAllChargepoints function is supported.
+     */
+    val supportsFullDownload: Boolean
+
+    /**
+     * Fetches all available chargers from this API.
+     *
+     * This may take a long time and should only be used when the user explicitly wants to download all chargers.
+     *
+     * TODO: add an optional callback parameter to this function to be able to receive updates on the download progress?
+     * TODO: Should this also include getting the ReferenceData, instead of taking it as an argument?
+     *       ReferenceData typically includes information that is needed to create the filter options, e.g.
+     *       mappings between IDs and readable names (for operators etc.). So probably for OSM it makes sense
+     *       to generate that within this function (e.g. build the list of available operators using all the
+     *       operators found in the dataset).
+     */
+    suspend fun fullDownload(referenceData: ReferenceData): List<ChargeLocation>
 }
 
 interface StringProvider {
@@ -79,13 +108,19 @@ fun createApi(type: String, ctx: Context): ChargepointApi<ReferenceData> {
                 )
             )
         }
+
         "goingelectric" -> {
             GoingElectricApiWrapper(
                 ctx.getString(
                     R.string.goingelectric_key
                 )
             )
         }
+
+        "openstreetmap" -> {
+            OpenStreetMapApiWrapper()
+        }
+
         else -> throw IllegalArgumentException()
     }
 }

app/src/main/java/net/vonforst/evmap/api/goingelectric/GoingElectricApi.kt

@@ -133,6 +133,12 @@ class GoingElectricApiWrapper(
     override val name = "GoingElectric.de"
     override val id = "goingelectric"
     override val cacheLimit = Duration.ofDays(1)
+    override val supportsOnlineQueries = true
+    override val supportsFullDownload = false
+
+    override suspend fun fullDownload(referenceData: ReferenceData): List<ChargeLocation> {
+        throw NotImplementedError()
+    }
 
     override suspend fun getChargepoints(
         referenceData: ReferenceData,

app/src/main/java/net/vonforst/evmap/api/openchargemap/OpenChargeMapApi.kt

@@ -112,6 +112,12 @@ class OpenChargeMapApiWrapper(
 
     override val name = "OpenChargeMap.org"
     override val id = "openchargemap"
+    override val supportsOnlineQueries = true
+    override val supportsFullDownload = false
+
+    override suspend fun fullDownload(referenceData: ReferenceData): List<ChargeLocation> {
+        throw NotImplementedError()
+    }
 
     private fun formatMultipleChoice(value: MultipleChoiceFilterValue?) =
         if (value == null || value.all) null else value.values.joinToString(",")

app/src/main/java/net/vonforst/evmap/api/openstreetmap/OpenStreetMapAdapters.kt

@@ -0,0 +1,20 @@
+package net.vonforst.evmap.api.openstreetmap
+
+import com.squareup.moshi.FromJson
+import com.squareup.moshi.ToJson
+import java.time.Instant
+import kotlin.math.floor
+
+internal class InstantAdapter {
+    @FromJson
+    fun fromJson(value: Double?): Instant? = value?.let {
+        val seconds = floor(it).toLong()
+        val nanos = ((value - seconds) * 1e9).toLong()
+        Instant.ofEpochSecond(seconds, nanos)
+    }
+
+    @ToJson
+    fun toJson(value: Instant?): Double? = value?.let {
+        it.epochSecond.toDouble() + it.nano / 1e9
+    }
+}

app/src/main/java/net/vonforst/evmap/api/openstreetmap/OpenStreetMapApi.kt

@@ -0,0 +1,128 @@
+package net.vonforst.evmap.api.openstreetmap
+
+import com.car2go.maps.model.LatLng
+import com.car2go.maps.model.LatLngBounds
+import com.squareup.moshi.Moshi
+import net.vonforst.evmap.BuildConfig
+import net.vonforst.evmap.addDebugInterceptors
+import net.vonforst.evmap.api.ChargepointApi
+import net.vonforst.evmap.api.ChargepointList
+import net.vonforst.evmap.api.FiltersSQLQuery
+import net.vonforst.evmap.api.StringProvider
+import net.vonforst.evmap.api.openchargemap.ZonedDateTimeAdapter
+import net.vonforst.evmap.model.ChargeLocation
+import net.vonforst.evmap.model.Filter
+import net.vonforst.evmap.model.FilterValue
+import net.vonforst.evmap.model.FilterValues
+import net.vonforst.evmap.model.ReferenceData
+import net.vonforst.evmap.viewmodel.Resource
+import okhttp3.OkHttpClient
+import retrofit2.Response
+import retrofit2.Retrofit
+import retrofit2.converter.moshi.MoshiConverterFactory
+import retrofit2.http.GET
+import java.io.IOException
+import java.time.Duration
+import java.time.Instant
+
+interface OpenStreetMapApi {
+    @GET("charging-stations-osm.json")
+    suspend fun getAllChargingStations(): Response<OSMDocument>
+
+    companion object {
+        private val moshi = Moshi.Builder()
+            .add(ZonedDateTimeAdapter())
+            .add(InstantAdapter())
+            .build()
+
+        fun create(
+            baseurl: String = "https://evmap-dev.vonforst.net"
+        ): OpenStreetMapApi {
+            val client = OkHttpClient.Builder().apply {
+                if (BuildConfig.DEBUG) addDebugInterceptors()
+            }.build()
+
+            val retrofit = Retrofit.Builder()
+                .baseUrl(baseurl)
+                .addConverterFactory(MoshiConverterFactory.create(moshi))
+                .client(client)
+                .build()
+            return retrofit.create(OpenStreetMapApi::class.java)
+        }
+    }
+
+}
+
+class OpenStreetMapApiWrapper(baseurl: String = "https://evmap-dev.vonforst.net") :
+    ChargepointApi<OSMReferenceData> {
+    override val name = "OpenStreetMap"
+    override val id = "openstreetmap"
+    override val cacheLimit = Duration.ofDays(300L)
+    override val supportsOnlineQueries = false
+    override val supportsFullDownload = true
+
+    val api = OpenStreetMapApi.create(baseurl)
+
+    override suspend fun getChargepoints(
+        referenceData: ReferenceData,
+        bounds: LatLngBounds,
+        zoom: Float,
+        useClustering: Boolean,
+        filters: FilterValues?
+    ): Resource<ChargepointList> {
+        throw NotImplementedError()
+    }
+
+    override suspend fun getChargepointsRadius(
+        referenceData: ReferenceData,
+        location: LatLng,
+        radius: Int,
+        zoom: Float,
+        useClustering: Boolean,
+        filters: FilterValues?
+    ): Resource<ChargepointList> {
+        throw NotImplementedError()
+    }
+
+    override suspend fun getChargepointDetail(
+        referenceData: ReferenceData,
+        id: Long
+    ): Resource<ChargeLocation> {
+        throw NotImplementedError()
+    }
+
+    override suspend fun getReferenceData(): Resource<OSMReferenceData> {
+        TODO("Not yet implemented")
+    }
+
+    override fun getFilters(
+        referenceData: ReferenceData,
+        sp: StringProvider
+    ): List<Filter<FilterValue>> {
+        return emptyList()
+    }
+
+    override fun convertFiltersToSQL(
+        filters: FilterValues,
+        referenceData: ReferenceData
+    ): FiltersSQLQuery {
+        TODO("Not yet implemented")
+    }
+
+    override fun filteringInSQLRequiresDetails(filters: FilterValues): Boolean {
+        return true
+    }
+
+    override suspend fun fullDownload(referenceData: ReferenceData): List<ChargeLocation> {
+        val response = api.getAllChargingStations()
+        if (!response.isSuccessful) {
+            throw IOException(response.message())
+        } else {
+            val body = response.body()!!
+            val time = body.timestamp
+            return body.elements.map { it.convert(time) }
+        }
+    }
+}
+
+data class OSMReferenceData(val test: String) : ReferenceData()

app/src/main/java/net/vonforst/evmap/api/openstreetmap/OpenStreetMapModel.kt

@@ -58,6 +58,12 @@ private val SOCKET_TYPES = immutableListOf(
     OsmSocket("sev1011_t25", null),
 )
 
+@JsonClass(generateAdapter = true)
+data class OSMDocument(
+    val timestamp: Instant,
+    val elements: List<OSMChargingStation>
+)
+
 @JsonClass(generateAdapter = true)
 data class OSMChargingStation(
     // Unique numeric ID

app/src/main/java/net/vonforst/evmap/fragment/DataSourceSelectDialog.kt

@@ -54,6 +54,7 @@ class DataSourceSelectDialog : MaterialDialogFragment() {
             when (prefs.dataSource) {
                 "goingelectric" -> binding.rgDataSource.rbGoingElectric.isChecked = true
                 "openchargemap" -> binding.rgDataSource.rbOpenChargeMap.isChecked = true
+                "openstreetmap" -> binding.rgDataSource.rbOpenStreetMap.isChecked = true
             }
         }
 
@@ -65,6 +66,8 @@ class DataSourceSelectDialog : MaterialDialogFragment() {
                 "goingelectric"
             } else if (binding.rgDataSource.rbOpenChargeMap.isChecked) {
                 "openchargemap"
+            } else if (binding.rgDataSource.rbOpenStreetMap.isChecked) {
+                "openstreetmap"
             } else {
                 return@setOnClickListener
             }

app/src/main/java/net/vonforst/evmap/fragment/OnboardingFragment.kt

@@ -254,6 +254,7 @@ class DataSourceSelectFragment : OnboardingPageFragment() {
             when (prefs.dataSource) {
                 "goingelectric" -> binding.rgDataSource.rbGoingElectric.isChecked = true
                 "openchargemap" -> binding.rgDataSource.rbOpenChargeMap.isChecked = true
+                "openstreetmap" -> binding.rgDataSource.rbOpenStreetMap.isChecked = true
             }
         }
 
@@ -272,6 +273,8 @@ class DataSourceSelectFragment : OnboardingPageFragment() {
                 "goingelectric"
             } else if (binding.rgDataSource.rbOpenChargeMap.isChecked) {
                 "openchargemap"
+            } else if (binding.rgDataSource.rbOpenStreetMap.isChecked) {
+                "openstreetmap"
             } else {
                 return@setOnClickListener
             }