Thumbs-up function 👍

corecomponent/androidcomponent/src/main/java/io/github/droidkaigi/confsched2020/ext/Animators.kt

@@ -0,0 +1,41 @@
+package io.github.droidkaigi.confsched2020.ext
+
+import android.animation.Animator
+import android.animation.AnimatorListenerAdapter
+import kotlinx.coroutines.suspendCancellableCoroutine
+import kotlin.coroutines.resume
+
+// This function is copied from https://medium.com/androiddevelopers/suspending-over-views-19de9ebd7020
+
+suspend fun Animator.awaitEnd() = suspendCancellableCoroutine<Unit> { cont ->
+    // Add an invokeOnCancellation listener. If the coroutine is
+    // cancelled, cancel the animation too that will notify
+    // listener's onAnimationCancel() function
+    cont.invokeOnCancellation { cancel() }
+
+    addListener(object : AnimatorListenerAdapter() {
+        private var endedSuccessfully = true
+
+        override fun onAnimationCancel(animation: Animator) {
+            // Animator has been cancelled, so flip the success flag
+            endedSuccessfully = false
+        }
+
+        override fun onAnimationEnd(animation: Animator) {
+            // Make sure we remove the listener so we don't keep
+            // leak the coroutine continuation
+            animation.removeListener(this)
+
+            if (cont.isActive) {
+                // If the coroutine is still active...
+                if (endedSuccessfully) {
+                    // ...and the Animator ended successfully, resume the coroutine
+                    cont.resume(Unit)
+                } else {
+                    // ...and the Animator was cancelled, cancel the coroutine too
+                    cont.cancel()
+                }
+            }
+        }
+    })
+}

corecomponent/androidcomponent/src/main/java/io/github/droidkaigi/confsched2020/ext/AppErrors.kt

@@ -31,6 +31,7 @@ fun Throwable?.toAppError(): AppError? {
 fun AppError.stringRes() = when (this) {
     is AppError.ApiException.NetworkException -> R.string.error_network
     is AppError.ApiException.ServerException -> R.string.error_server
+    is AppError.ApiException.SessionNotFoundException -> R.string.error_unknown
     is AppError.ApiException.UnknownException -> R.string.error_unknown
     is AppError.ExternalIntegrationError.NoCalendarIntegrationFoundException
         -> R.string.error_no_calendar_integration

corecomponent/androidcomponent/src/main/java/io/github/droidkaigi/confsched2020/ext/LiveDatas.kt

@@ -6,6 +6,8 @@ import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.distinctUntilChanged
 import androidx.lifecycle.map
 import com.hadilq.liveevent.LiveEvent
+import io.github.droidkaigi.confsched2020.model.AppError
+import io.github.droidkaigi.confsched2020.model.ErrorGettable
 
 fun <T : Any> LiveData<T>.requireValue() = requireNotNull(value)
 
@@ -108,6 +110,43 @@ inline fun <T : Any, LIVE1 : Any, LIVE2 : Any, LIVE3 : Any, LIVE4 : Any> combine
     }.distinctUntilChanged()
 }
 
+inline fun <T : Any, LIVE1 : Any, LIVE2 : Any, LIVE3 : Any, LIVE4 : Any, LIVE5 : Any> combine(
+    initialValue: T,
+    liveData1: LiveData<LIVE1>,
+    liveData2: LiveData<LIVE2>,
+    liveData3: LiveData<LIVE3>,
+    liveData4: LiveData<LIVE4>,
+    liveData5: LiveData<LIVE5>,
+    crossinline block: (T, LIVE1, LIVE2, LIVE3, LIVE4, LIVE5) -> T
+): LiveData<T> {
+    return MediatorLiveData<T>().apply {
+        value = initialValue
+        listOf(liveData1, liveData2, liveData3, liveData4, liveData5).forEach { liveData ->
+            addSource(liveData) {
+                val currentValue = value
+                val liveData1Value = liveData1.value
+                val liveData2Value = liveData2.value
+                val liveData3Value = liveData3.value
+                val liveData4Value = liveData4.value
+                val liveData5Value = liveData5.value
+                if (currentValue != null && liveData1Value != null &&
+                    liveData2Value != null && liveData3Value != null &&
+                    liveData4Value != null && liveData5Value != null
+                ) {
+                    value = block(
+                        currentValue,
+                        liveData1Value,
+                        liveData2Value,
+                        liveData3Value,
+                        liveData4Value,
+                        liveData5Value
+                    )
+                }
+            }
+        }
+    }.distinctUntilChanged()
+}
+
 fun <T> LiveData<T>.setOnEach(mutableLiveData: MutableLiveData<T>): LiveData<T> {
     return map {
         mutableLiveData.value = it
@@ -124,3 +163,25 @@ fun <T : Any> LiveData<T?>.toNonNullSingleEvent(): LiveData<T> {
     }
     return result
 }
+
+fun <T> merge(vararg liveDatas: LiveData<T>): LiveData<T> {
+    return MediatorLiveData<T>().apply {
+        liveDatas.forEach { liveData ->
+            addSource(liveData) { value ->
+                this.value = value
+            }
+        }
+    }
+}
+
+fun <T : ErrorGettable> LiveData<T>.toAppError(): LiveData<AppError?> {
+    return map {
+        it.getErrorIfExists().toAppError()
+    }
+}
+
+fun <T, R : Result<T>> LiveData<R>.fromResultToAppError(): LiveData<AppError?> {
+    return map {
+        it.exceptionOrNull()?.toAppError()
+    }
+}

corecomponent/androidcomponent/src/main/java/io/github/droidkaigi/confsched2020/ext/Views.kt

@@ -0,0 +1,40 @@
+package io.github.droidkaigi.confsched2020.ext
+
+import android.view.View
+import kotlinx.coroutines.suspendCancellableCoroutine
+import kotlin.coroutines.resume
+
+// This function is copied from https://medium.com/androiddevelopers/suspending-over-views-19de9ebd7020
+
+suspend fun View.awaitNextLayout() = suspendCancellableCoroutine<Unit> { cont ->
+    // This lambda is invoked immediately, allowing us to create
+    // a callback/listener
+
+    val listener = object : View.OnLayoutChangeListener {
+        override fun onLayoutChange(
+            v: View?,
+            left: Int,
+            top: Int,
+            right: Int,
+            bottom: Int,
+            oldLeft: Int,
+            oldTop: Int,
+            oldRight: Int,
+            oldBottom: Int
+        ) {
+            // The next layout has happened!
+            // First remove the listener to not leak the coroutine
+            v?.removeOnLayoutChangeListener(this)
+            // Finally resume the continuation, and
+            // wake the coroutine up
+            cont.resume(Unit)
+        }
+    }
+    // If the coroutine is cancelled, remove the listener
+    cont.invokeOnCancellation { removeOnLayoutChangeListener(listener) }
+    // And finally add the listener to view
+    addOnLayoutChangeListener(listener)
+
+    // The coroutine will now be suspended. It will only be resumed
+    // when calling cont.resume() in the listener above
+}

corecomponent/androidcomponent/src/main/res/values/themes.xml

@@ -10,6 +10,7 @@
         <item name="textAppearanceBody1">@style/TextAppearance.DroidKaigi.Body1</item>
         <item name="textAppearanceBody2">@style/TextAppearance.DroidKaigi.Body2</item>
         <item name="textAppearanceCaption">@style/TextAppearance.DroidKaigi.Caption</item>
+        <item name="textAppearanceButton">@style/TextAppearance.DroidKaigi.Button</item>
 
         <!-- Widget styles -->
         <item name="filterChipStyle">@style/Widget.DroidKaigi.FilterChip</item>

corecomponent/androidcomponent/src/main/res/values/type.xml

@@ -50,4 +50,10 @@
         <item name="android:textColor">?colorOnBackground</item>
     </style>
 
+    <!-- Notosans Medium 14sp -->
+    <style name="TextAppearance.DroidKaigi.Button" parent="TextAppearance.MaterialComponents.Button">
+        <item name="android:fontFamily">@font/notosans_medium</item>
+        <item name="fontFamily">@font/notosans_medium</item>
+        <item name="android:textColor">?colorOnBackground</item>
+    </style>
 </resources>

data/firestore/build.gradle

@@ -52,6 +52,14 @@ kotlin {
             implementation Dep.Test.KotlinMultiPlatform.commonModuleTestAnnotations
             implementation Dep.MockK.common
         }
+        test {
+            dependsOn commonMain
+            dependencies {
+                implementation Dep.Test.KotlinMultiPlatform.jvmModuleTest
+                implementation Dep.Test.KotlinMultiPlatform.jvmModuleTestJunit
+                implementation Dep.MockK.jvm
+            }
+        }
         androidTest {
             dependsOn commonMain
             dependencies {

data/firestore/src/commonMain/kotlin/io/github/droidkaigi/confsched2020/data/firestore/Firestore.kt

@@ -6,4 +6,6 @@ import kotlinx.coroutines.flow.Flow
 interface Firestore {
     fun getFavoriteSessionIds(): Flow<List<String>>
     suspend fun toggleFavorite(sessionId: SessionId)
+    fun getThumbsUpCount(sessionId: SessionId): Flow<Int>
+    suspend fun incrementThumbsUpCount(sessionId: SessionId, count: Int)
 }

data/firestore/src/main/java/io/github/droidkaigi/confsched2020/data/firestore/internal/FirestoreImpl.kt

@@ -1,25 +1,30 @@
 package io.github.droidkaigi.confsched2020.data.firestore.internal
 
+import com.google.android.gms.tasks.Task
+import com.google.android.gms.tasks.Tasks
 import com.google.firebase.auth.FirebaseAuth
 import com.google.firebase.firestore.CollectionReference
 import com.google.firebase.firestore.DocumentReference
 import com.google.firebase.firestore.DocumentSnapshot
+import com.google.firebase.firestore.FieldValue
 import com.google.firebase.firestore.FirebaseFirestore
 import com.google.firebase.firestore.Query
 import com.google.firebase.firestore.QuerySnapshot
 import com.google.firebase.firestore.Source
 import io.github.droidkaigi.confsched2020.data.firestore.Firestore
 import io.github.droidkaigi.confsched2020.model.SessionId
-import javax.inject.Inject
 import kotlinx.coroutines.channels.awaitClose
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.callbackFlow
 import kotlinx.coroutines.flow.flatMapLatest
 import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.mapLatest
 import kotlinx.coroutines.tasks.await
 import timber.log.Timber
 import timber.log.debug
+import javax.inject.Inject
+import kotlin.math.floor
 
 internal class FirestoreImpl @Inject constructor() : Firestore {
 
@@ -35,7 +40,7 @@ internal class FirestoreImpl @Inject constructor() : Firestore {
             emit(favoritesRef)
         }
         val favoritesSnapshotFlow = setupFavorites.flatMapLatest {
-            it.whereEqualTo("favorite", true).toFlow()
+            it.whereEqualTo(FAVORITE_VALUE_KEY, true).toFlow()
         }
         return favoritesSnapshotFlow.mapLatest { favorites ->
             Timber.debug { "favoritesSnapshotFlow onNext" }
@@ -57,12 +62,47 @@ internal class FirestoreImpl @Inject constructor() : Firestore {
         } else {
             Timber.debug { "toggleFavorite: $sessionId document not exits" }
             document.reference
-                .set(mapOf("favorite" to newFavorite))
+                .set(mapOf(FAVORITE_VALUE_KEY to newFavorite))
                 .await()
         }
         Timber.debug { "toggleFavorite: end" }
     }
 
+    override fun getThumbsUpCount(sessionId: SessionId): Flow<Int> {
+        val setupThumbsUp = flow {
+            signInIfNeeded()
+            val counterRef = getThumbsUpCounterRef(sessionId)
+            createShardsIfNeeded(counterRef)
+            emit(counterRef)
+        }
+
+        val thumbsUpSnapshot = setupThumbsUp.flatMapLatest {
+            it.toFlow()
+        }
+
+        return thumbsUpSnapshot.map { shards ->
+            var count = 0
+            shards.forEach { snap ->
+                count += snap.get(SHARDS_COUNT_KEY, Int::class.java) ?: 0
+            }
+            count
+        }
+    }
+
+    override suspend fun incrementThumbsUpCount(
+        sessionId: SessionId,
+        count: Int
+    ) {
+        signInIfNeeded()
+        val counterRef = getThumbsUpCounterRef(sessionId)
+        createShardsIfNeeded(counterRef)
+        val shardId = floor(Math.random() * NUM_SHARDS).toInt()
+        counterRef
+            .document(shardId.toString())
+            .update(SHARDS_COUNT_KEY, FieldValue.increment(count.toLong()))
+            .await()
+    }
+
     private fun getFavoritesRef(): CollectionReference {
         val firebaseAuth = FirebaseAuth.getInstance()
         val firebaseUserId = firebaseAuth.currentUser?.uid ?: throw RuntimeException(
@@ -83,6 +123,42 @@ internal class FirestoreImpl @Inject constructor() : Firestore {
         firebaseAuth.signInAnonymously().await()
         Timber.debug { "signInIfNeeded end" }
     }
+
+    private fun getThumbsUpCounterRef(sessionId: SessionId): CollectionReference {
+        return FirebaseFirestore
+            .getInstance()
+            .collection("confsched/2020/sessions/${sessionId.id}/thumbsup_counters")
+    }
+
+    private suspend fun createShardsIfNeeded(counterRef: CollectionReference) {
+        val lastShardId = NUM_SHARDS - 1
+        val lastShard = counterRef
+            .document(lastShardId.toString())
+            .get(Source.SERVER)
+            .await()
+
+        if (lastShard.exists()) {
+            Timber.debug { "createShardsIfNeeded shards already exist" }
+            return
+        }
+
+        val tasks = arrayListOf<Task<Void>>()
+        (0 until NUM_SHARDS).forEach {
+            val makeShard = counterRef
+                .document(it.toString())
+                .set(mapOf(SHARDS_COUNT_KEY to 0))
+            tasks.add(makeShard)
+        }
+
+        Tasks.whenAll(tasks).await()
+        Timber.debug { "createShardsIfNeeded creating shards completed" }
+    }
+
+    companion object {
+        const val NUM_SHARDS = 5
+        const val SHARDS_COUNT_KEY = "shards"
+        const val FAVORITE_VALUE_KEY = "favorite"
+    }
 }
 
 private suspend fun DocumentReference.fastGet(): DocumentSnapshot {