implement initial UI for predictions

app/src/main/java/net/vonforst/evmap/ui/BarGraphView.kt

@@ -0,0 +1,60 @@
+package net.vonforst.evmap.ui
+
+import android.content.Context
+import android.graphics.Canvas
+import android.graphics.Rect
+import android.util.AttributeSet
+import android.view.View
+import androidx.appcompat.content.res.AppCompatResources
+import net.vonforst.evmap.R
+import java.time.ZonedDateTime
+import kotlin.math.roundToInt
+
+class BarGraphView(context: Context, attrs: AttributeSet) : View(context, attrs) {
+
+    var zeroHeight = 4 * context.resources.displayMetrics.density
+    var barWidth = 16 * context.resources.displayMetrics.density
+    var barMargin = 2 * context.resources.displayMetrics.density
+
+    var barDrawableUnavailable =
+        AppCompatResources.getDrawable(context, R.drawable.bar_graph_unavailable)!!
+    var barDrawableAvailable =
+        AppCompatResources.getDrawable(context, R.drawable.bar_graph_available)!!
+
+    var data: Map<ZonedDateTime, Int>? = null
+        set(value) {
+            field = value
+            invalidate()
+        }
+
+    var activeAlpha = 0.87f
+    var inactiveAlpha = 0.60f
+
+    private lateinit var graphBounds: Rect
+
+    override fun onSizeChanged(w: Int, h: Int, oldw: Int, oldh: Int) {
+        graphBounds = Rect(paddingLeft, paddingTop, w - paddingRight, h - paddingBottom)
+    }
+
+    override fun onDraw(canvas: Canvas) {
+        val data = data ?: return
+        val maxValue = data.maxOf { it.value }
+
+        canvas.apply {
+            data.toSortedMap().entries.forEachIndexed { i, (t, v) ->
+                val drawable = if (v > 0) barDrawableAvailable else barDrawableUnavailable
+
+                val height =
+                    zeroHeight + (graphBounds.height() - zeroHeight) * v.toFloat() / maxValue
+                drawable.setBounds(
+                    graphBounds.left + ((barWidth + barMargin) * i).roundToInt(),
+                    graphBounds.bottom - height.roundToInt(),
+                    graphBounds.left + ((barWidth + barMargin) * i + barWidth).roundToInt(),
+                    graphBounds.bottom
+                )
+                drawable.alpha = (inactiveAlpha * 255).roundToInt()
+                drawable.draw(canvas)
+            }
+        }
+    }
+}

app/src/main/java/net/vonforst/evmap/viewmodel/MapViewModel.kt

@@ -10,9 +10,14 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
 import kotlinx.parcelize.Parcelize
+import net.vonforst.evmap.R
+import net.vonforst.evmap.api.availability.AvailabilityDetectorException
 import net.vonforst.evmap.api.availability.ChargeLocationStatus
 import net.vonforst.evmap.api.availability.getAvailability
 import net.vonforst.evmap.api.createApi
+import net.vonforst.evmap.api.fronyx.FronyxApi
+import net.vonforst.evmap.api.fronyx.FronyxEvseIdResponse
+import net.vonforst.evmap.api.fronyx.FronyxStatus
 import net.vonforst.evmap.api.goingelectric.GEChargepoint
 import net.vonforst.evmap.api.openchargemap.OCMConnection
 import net.vonforst.evmap.api.openchargemap.OCMReferenceData
@@ -25,6 +30,9 @@ import net.vonforst.evmap.storage.FilterProfile
 import net.vonforst.evmap.storage.PreferenceDataSource
 import net.vonforst.evmap.ui.cluster
 import net.vonforst.evmap.utils.distanceBetween
+import retrofit2.HttpException
+import java.io.IOException
+import java.time.ZonedDateTime
 
 @Parcelize
 data class MapPosition(val bounds: LatLngBounds, val zoom: Float) : Parcelable
@@ -202,6 +210,60 @@ class MapViewModel(application: Application, private val state: SavedStateHandle
             addSource(filteredMinPower, callback)
         }
     }
+
+    val predictionApi = FronyxApi.create(application.getString(R.string.fronyx_key))
+
+    val prediction: LiveData<Resource<List<FronyxEvseIdResponse>>> by lazy {
+        availability.switchMap { av ->
+            av?.data?.evseIds?.let { evseIds ->
+                liveData {
+                    emit(Resource.loading(null))
+
+                    val allEvseIds = evseIds.flatMap { it.value }
+
+                    try {
+                        val result = allEvseIds.map {
+                            predictionApi.getPredictionsForEvseId(it)
+                        }
+
+                        emit(Resource.success(result))
+                        println(result)
+                    } catch (e: IOException) {
+                        emit(Resource.error(e.message, null))
+                        e.printStackTrace()
+                    } catch (e: HttpException) {
+                        emit(Resource.error(e.message, null))
+                        e.printStackTrace()
+                    } catch (e: AvailabilityDetectorException) {
+                        emit(Resource.error(e.message, null))
+                        e.printStackTrace()
+                    }
+                }
+            } ?: liveData { emit(Resource.success(null)) }
+        }
+    }
+
+    val predictionGraph: LiveData<Map<ZonedDateTime, Int>?> by lazy {
+        prediction.map {
+            it.data?.let { responses ->
+                if (responses.isEmpty()) {
+                    null
+                } else {
+                    val timestamps = responses[0].predictions.map { it.timestamp }
+                    // TODO: implement this in a more elegant way: first ensure that all timestamps are the same, then take them in order
+                    timestamps.associateWith { ts ->
+                        responses.sumOf {
+                            val av =
+                                it.predictions.find { it.timestamp == ts }?.status == FronyxStatus.AVAILABLE
+                            val count = if (av) 1 else 0
+                            count
+                        }
+                    }
+                }
+            }
+        }
+    }
+
     val myLocationEnabled: MutableLiveData<Boolean> by lazy {
         MutableLiveData<Boolean>()
     }

app/src/main/res/drawable/bar_graph_available.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="utf-8"?>
+<shape xmlns:android="http://schemas.android.com/apk/res/android"
+    android:shape="rectangle">
+    <solid android:color="@color/available" />
+    <corners
+        android:topLeftRadius="2dp"
+        android:topRightRadius="2dp" />
+</shape>

app/src/main/res/drawable/bar_graph_unavailable.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="utf-8"?>
+<shape xmlns:android="http://schemas.android.com/apk/res/android"
+    android:shape="rectangle">
+    <solid android:color="@color/unavailable" />
+    <corners
+        android:topLeftRadius="2dp"
+        android:topRightRadius="2dp" />
+</shape>

app/src/main/res/layout/detail_view.xml

@@ -5,6 +5,10 @@
 
     <data>
 
+        <import type="java.util.Map" />
+
+        <import type="java.time.ZonedDateTime" />
+
         <import type="net.vonforst.evmap.model.ChargeLocation" />
 
         <import type="net.vonforst.evmap.model.Chargepoint" />
@@ -39,6 +43,10 @@
             name="availability"
             type="Resource&lt;ChargeLocationStatus&gt;" />
 
+        <variable
+            name="predictionGraph"
+            type="Map&lt;ZonedDateTime, Integer&gt;" />
+
         <variable
             name="filteredAvailability"
             type="Resource&lt;ChargeLocationStatus&gt;" />
@@ -325,7 +333,22 @@
                 app:icon="@drawable/ic_chargeprice"
                 app:layout_constraintEnd_toStartOf="@+id/guideline2"
                 app:layout_constraintStart_toStartOf="@+id/guideline"
-                app:layout_constraintTop_toBottomOf="@+id/textView13" />
+                app:layout_constraintTop_toBottomOf="@+id/prediction" />
+
+            <net.vonforst.evmap.ui.BarGraphView
+                android:id="@+id/prediction"
+                android:layout_width="0dp"
+                android:layout_height="80dp"
+                android:layout_marginTop="16dp"
+                app:goneUnless="@{predictionGraph != null}"
+                app:data="@{predictionGraph}"
+                app:layout_constraintEnd_toStartOf="@+id/guideline2"
+                app:layout_constraintStart_toStartOf="@+id/guideline"
+                app:layout_constraintTop_toBottomOf="@+id/textView13"
+                tools:itemCount="3"
+                tools:layoutManager="LinearLayoutManager"
+                tools:listitem="@layout/item_connector"
+                tools:orientation="horizontal" />
 
             <ImageView
                 android:id="@+id/imgVerified"

app/src/main/res/layout/fragment_map.xml

@@ -195,6 +195,7 @@
                 app:charger="@{vm.charger}"
                 app:availability="@{vm.availability}"
                 app:filteredAvailability="@{vm.filteredAvailability}"
+                app:predictionGraph="@{vm.predictionGraph}"
                 app:chargeCards="@{vm.chargeCardMap}"
                 app:filteredChargeCards="@{vm.filteredChargeCards}"
                 app:distance="@{vm.chargerDistance}"