Migrate to Flows.

app/src/main/java/com/github/apognu/otter/activities/MainActivity.kt

@@ -32,6 +32,7 @@ import kotlinx.android.synthetic.main.partial_now_playing.*
 import kotlinx.coroutines.Dispatchers.IO
 import kotlinx.coroutines.Dispatchers.Main
 import kotlinx.coroutines.GlobalScope
+import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.launch
 
 class MainActivity : AppCompatActivity() {
@@ -178,7 +179,7 @@ class MainActivity : AppCompatActivity() {
   @SuppressLint("NewApi")
   private fun watchEventBus() {
     GlobalScope.launch(Main) {
-      for (message in EventBus.asChannel<Event>()) {
+      EventBus.get().collect { message ->
         when (message) {
           is Event.LogOut -> {
             PowerPreference.clearAllData()
@@ -315,7 +316,7 @@ class MainActivity : AppCompatActivity() {
     }
 
     GlobalScope.launch(Main) {
-      for ((current, duration, percent) in ProgressBus.asChannel()) {
+      ProgressBus.get().collect { (current, duration, percent) ->
         now_playing_progress.progress = percent
         now_playing_details_progress.progress = percent
 

app/src/main/java/com/github/apognu/otter/fragments/FavoritesFragment.kt

@@ -9,6 +9,7 @@ import com.github.apognu.otter.utils.*
 import kotlinx.android.synthetic.main.fragment_favorites.*
 import kotlinx.coroutines.Dispatchers.Main
 import kotlinx.coroutines.GlobalScope
+import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.launch
 
 class FavoritesFragment : FunkwhaleFragment<Track, FavoritesAdapter>() {
@@ -43,7 +44,7 @@ class FavoritesFragment : FunkwhaleFragment<Track, FavoritesAdapter>() {
 
   private fun watchEventBus() {
     GlobalScope.launch(Main) {
-      for (message in EventBus.asChannel<Event>()) {
+      EventBus.get().collect { message ->
         when (message) {
           is Event.TrackPlayed -> {
             GlobalScope.launch(Main) {

app/src/main/java/com/github/apognu/otter/fragments/FunkwhaleFragment.kt

@@ -10,6 +10,7 @@ import androidx.recyclerview.widget.RecyclerView
 import com.github.apognu.otter.repositories.HttpUpstream
 import com.github.apognu.otter.repositories.Repository
 import com.github.apognu.otter.utils.Cache
+import com.github.apognu.otter.utils.log
 import com.github.apognu.otter.utils.untilNetwork
 import com.google.gson.Gson
 import kotlinx.android.synthetic.main.fragment_artists.*
@@ -44,8 +45,8 @@ abstract class FunkwhaleFragment<D : Any, A : FunkwhaleAdapter<D, *>> : Fragment
 
     (repository.upstream as? HttpUpstream<*, *>)?.let { upstream ->
       if (upstream.behavior == HttpUpstream.Behavior.Progressive) {
-        recycler.setOnScrollChangeListener { _, _, _, _, _ ->
-          if (!recycler.canScrollVertically(1)) {
+        recycler.setOnScrollChangeListener { _, _, y, _, _ ->
+          if (y > 0 && !recycler.canScrollVertically(1)) {
             fetch(Repository.Origin.Network.origin, adapter.data.size)
           }
         }
@@ -66,24 +67,28 @@ abstract class FunkwhaleFragment<D : Any, A : FunkwhaleAdapter<D, *>> : Fragment
   open fun onDataFetched(data: List<D>) {}
 
   private fun fetch(upstreams: Int = (Repository.Origin.Network.origin and Repository.Origin.Cache.origin), size: Int = 0) {
-    var cleared = false
+    var first = true
 
     swiper?.isRefreshing = true
 
-    if (size == 0) {
-      cleared = true
-      adapter.data.clear()
-    }
-
     repository.fetch(upstreams, size).untilNetwork(IO) { data, isCache, hasMore ->
       if (isCache) {
         adapter.data = data.toMutableList()
+        adapter.notifyDataSetChanged()
 
         return@untilNetwork
       }
 
+      if (first) {
+        first = false
+
+        adapter.data.clear()
+      }
+
       onDataFetched(data)
 
+      adapter.data.addAll(data)
+
       if (!hasMore) {
         swiper?.isRefreshing = false
 
@@ -97,13 +102,12 @@ abstract class FunkwhaleFragment<D : Any, A : FunkwhaleAdapter<D, *>> : Fragment
       }
 
       GlobalScope.launch(Main) {
-        adapter.data.addAll(data)
-
-        when (cleared) {
+        when (first) {
           true -> {
             adapter.notifyDataSetChanged()
-            cleared = false
+            first = false
           }
+
           false -> adapter.notifyItemRangeInserted(adapter.data.size, data.size)
         }
       }

app/src/main/java/com/github/apognu/otter/fragments/PlaylistTracksFragment.kt

@@ -13,6 +13,7 @@ import com.squareup.picasso.Picasso
 import kotlinx.android.synthetic.main.fragment_tracks.*
 import kotlinx.coroutines.Dispatchers.Main
 import kotlinx.coroutines.GlobalScope
+import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.launch
 
 class PlaylistTracksFragment : FunkwhaleFragment<PlaylistTrack, PlaylistTracksAdapter>() {
@@ -109,7 +110,7 @@ class PlaylistTracksFragment : FunkwhaleFragment<PlaylistTrack, PlaylistTracksAd
 
   private fun watchEventBus() {
     GlobalScope.launch(Main) {
-      for (message in EventBus.asChannel<Event>()) {
+      EventBus.get().collect { message ->
         when (message) {
           is Event.TrackPlayed -> {
             GlobalScope.launch(Main) {

app/src/main/java/com/github/apognu/otter/fragments/QueueFragment.kt

@@ -16,6 +16,7 @@ import kotlinx.android.synthetic.main.fragment_queue.*
 import kotlinx.android.synthetic.main.fragment_queue.view.*
 import kotlinx.coroutines.Dispatchers.Main
 import kotlinx.coroutines.GlobalScope
+import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.launch
 
 class QueueFragment : BottomSheetDialogFragment() {
@@ -78,7 +79,7 @@ class QueueFragment : BottomSheetDialogFragment() {
 
   private fun watchEventBus() {
     GlobalScope.launch(Main) {
-      for (message in EventBus.asChannel<Event>()) {
+      EventBus.get().collect { message ->
         when (message) {
           is Event.TrackPlayed -> refresh()
           is Event.QueueChanged -> refresh()

app/src/main/java/com/github/apognu/otter/fragments/TracksFragment.kt

@@ -13,6 +13,7 @@ import com.squareup.picasso.Picasso
 import kotlinx.android.synthetic.main.fragment_tracks.*
 import kotlinx.coroutines.Dispatchers.Main
 import kotlinx.coroutines.GlobalScope
+import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.launch
 
 class TracksFragment : FunkwhaleFragment<Track, TracksAdapter>() {
@@ -95,7 +96,7 @@ class TracksFragment : FunkwhaleFragment<Track, TracksAdapter>() {
 
   private fun watchEventBus() {
     GlobalScope.launch(Main) {
-      for (message in EventBus.asChannel<Event>()) {
+      EventBus.get().collect { message ->
         when (message) {
           is Event.TrackPlayed -> {
             GlobalScope.launch(Main) {

app/src/main/java/com/github/apognu/otter/playback/PlayerService.kt

@@ -22,6 +22,7 @@ import kotlinx.coroutines.Dispatchers.Main
 import kotlinx.coroutines.GlobalScope
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.delay
+import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.launch
 
 class PlayerService : Service() {
@@ -183,7 +184,7 @@ class PlayerService : Service() {
     })
 
     jobs.add(GlobalScope.launch(Main) {
-      for (request in RequestBus.asChannel<Request>()) {
+      RequestBus.get().collect { request ->
         when (request) {
           is Request.GetCurrentTrack -> request.channel?.offer(
             Response.CurrentTrack(

app/src/main/java/com/github/apognu/otter/repositories/HttpUpstream.kt

@@ -10,10 +10,10 @@ import com.github.kittinunf.fuel.coroutines.awaitObjectResult
 import com.github.kittinunf.result.Result
 import com.google.gson.Gson
 import com.preference.PowerPreference
-import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.GlobalScope
-import kotlinx.coroutines.channels.Channel
-import kotlinx.coroutines.launch
+import kotlinx.coroutines.Dispatchers.IO
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.flow.flowOn
 import java.io.Reader
 import java.lang.reflect.Type
 import kotlin.math.ceil
@@ -23,53 +23,39 @@ class HttpUpstream<D : Any, R : FunkwhaleResponse<D>>(val behavior: Behavior, pr
     Single, AtOnce, Progressive
   }
 
-  private var _channel: Channel<Repository.Response<D>>? = null
-  private val channel: Channel<Repository.Response<D>>
-    get() {
-      if (_channel?.isClosedForSend ?: true) {
-        _channel = Channel()
-      }
-
-      return _channel!!
-    }
-
-  override fun fetch(size: Int): Channel<Repository.Response<D>>? {
-    if (behavior == Behavior.Single && size != 0) return null
+  override fun fetch(size: Int): Flow<Repository.Response<D>> = flow {
+    if (behavior == Behavior.Single && size != 0) return@flow
 
     val page = ceil(size / AppContext.PAGE_SIZE.toDouble()).toInt() + 1
 
-    GlobalScope.launch(Dispatchers.IO) {
-      val offsetUrl =
-        Uri.parse(url)
-          .buildUpon()
-          .appendQueryParameter("page_size", AppContext.PAGE_SIZE.toString())
-          .appendQueryParameter("page", page.toString())
-          .build()
-          .toString()
+    val offsetUrl =
+      Uri.parse(url)
+        .buildUpon()
+        .appendQueryParameter("page_size", AppContext.PAGE_SIZE.toString())
+        .appendQueryParameter("page", page.toString())
+        .build()
+        .toString()
 
-      get(offsetUrl).fold(
-        { response ->
-          val data = response.getData()
+    get(offsetUrl).fold(
+      { response ->
+        val data = response.getData()
 
-          if (behavior == Behavior.Progressive || response.next == null) {
-            channel.offer(Repository.Response(Repository.Origin.Network, data, false))
-          } else {
-            channel.offer(Repository.Response(Repository.Origin.Network, data, true))
+        if (behavior == Behavior.Progressive || response.next == null) {
+          emit(Repository.Response(Repository.Origin.Network, data, false))
+        } else {
+          emit(Repository.Response(Repository.Origin.Network, data, true))
 
-            fetch(size + data.size)
-          }
-        },
-        { error ->
-          when (error.exception) {
-            is RefreshError -> EventBus.send(Event.LogOut)
-            else -> channel.offer(Repository.Response(Repository.Origin.Network, listOf(), false))
-          }
+          fetch(size + data.size)
         }
-      )
-    }
-
-    return channel
-  }
+      },
+      { error ->
+        when (error.exception) {
+          is RefreshError -> EventBus.send(Event.LogOut)
+          else -> emit(Repository.Response(Repository.Origin.Network, listOf(), false))
+        }
+      }
+    )
+  }.flowOn(IO)
 
   class GenericDeserializer<T : FunkwhaleResponse<*>>(val type: Type) : ResponseDeserializable<T> {
     override fun deserialize(reader: Reader): T? {

app/src/main/java/com/github/apognu/otter/repositories/PlaylistTracksRepository.kt

@@ -7,6 +7,8 @@ import com.github.apognu.otter.utils.PlaylistTracksCache
 import com.github.apognu.otter.utils.PlaylistTracksResponse
 import com.github.kittinunf.fuel.gson.gsonDeserializerOf
 import com.google.gson.reflect.TypeToken
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.toList
 import kotlinx.coroutines.runBlocking
 import java.io.BufferedReader
 
@@ -18,7 +20,10 @@ class PlaylistTracksRepository(override val context: Context?, playlistId: Int)
   override fun uncache(reader: BufferedReader) = gsonDeserializerOf(PlaylistTracksCache::class.java).deserialize(reader)
 
   override fun onDataFetched(data: List<PlaylistTrack>): List<PlaylistTrack> = runBlocking {
-    val favorites = FavoritedRepository(context).fetch(Origin.Network.origin).receive().data
+    val favorites = FavoritedRepository(context).fetch(Origin.Network.origin)
+      .map { it.data }
+      .toList()
+      .flatten()
 
     data.map { track ->
       track.track.favorite = favorites.contains(track.track.id)

app/src/main/java/com/github/apognu/otter/repositories/Repository.kt

@@ -3,17 +3,12 @@ package com.github.apognu.otter.repositories
 import android.content.Context
 import com.github.apognu.otter.utils.Cache
 import com.github.apognu.otter.utils.CacheItem
-import com.github.apognu.otter.utils.log
-import com.github.apognu.otter.utils.untilNetwork
-import com.google.gson.Gson
 import kotlinx.coroutines.Dispatchers.IO
-import kotlinx.coroutines.GlobalScope
-import kotlinx.coroutines.channels.Channel
-import kotlinx.coroutines.launch
+import kotlinx.coroutines.flow.*
 import java.io.BufferedReader
 
 interface Upstream<D> {
-  fun fetch(size: Int = 0): Channel<Repository.Response<D>>?
+  fun fetch(size: Int = 0): Flow<Repository.Response<D>>
 }
 
 abstract class Repository<D : Any, C : CacheItem<D>> {
@@ -28,44 +23,29 @@ abstract class Repository<D : Any, C : CacheItem<D>> {
   abstract val cacheId: String?
   abstract val upstream: Upstream<D>
 
-  private var _channel: Channel<Response<D>>? = null
-  private val channel: Channel<Response<D>>
-    get() {
-      if (_channel?.isClosedForSend ?: true) {
-        _channel = Channel(10)
-      }
-
-      return _channel!!
-    }
-
   open fun cache(data: List<D>): C? = null
   protected open fun uncache(reader: BufferedReader): C? = null
 
-  fun fetch(upstreams: Int = Origin.Cache.origin and Origin.Network.origin, size: Int = 0): Channel<Response<D>> {
-    if (Origin.Cache.origin and upstreams == upstreams) fromCache()
-    if (Origin.Network.origin and upstreams == upstreams) fromNetwork(size)
-
-    return channel
+  fun fetch(upstreams: Int = Origin.Cache.origin and Origin.Network.origin, size: Int = 0): Flow<Response<D>> = flow {
+    if (Origin.Cache.origin and upstreams == upstreams) fromCache().collect { emit(it) }
+    if (Origin.Network.origin and upstreams == upstreams) fromNetwork(size).collect { emit(it) }
   }
 
-  private fun fromCache() {
-    GlobalScope.launch(IO) {
-      cacheId?.let { cacheId ->
-        Cache.get(context, cacheId)?.let { reader ->
-          uncache(reader)?.let { cache ->
-            channel.offer(Response(Origin.Cache, cache.data, false))
-          }
+  private fun fromCache() = flow {
+    cacheId?.let { cacheId ->
+      Cache.get(context, cacheId)?.let { reader ->
+        uncache(reader)?.let { cache ->
+          emit(Response(Origin.Cache, cache.data, false))
         }
       }
     }
-  }
+  }.flowOn(IO)
 
-  private fun fromNetwork(size: Int) {
-    upstream.fetch(size)?.untilNetwork(IO) { data, _, hasMore ->
-      val data = onDataFetched(data)
-
-      channel.offer(Response(Origin.Network, data, hasMore))
-    }
+  private fun fromNetwork(size: Int) = flow {
+    upstream
+      .fetch(size)
+      .map { response -> Response(Origin.Network, onDataFetched(response.data), response.hasMore) }
+      .collect { response -> emit(Response(Origin.Network, response.data, response.hasMore)) }
   }
 
   protected open fun onDataFetched(data: List<D>) = data

app/src/main/java/com/github/apognu/otter/repositories/SearchRepository.kt

@@ -7,6 +7,8 @@ import com.github.apognu.otter.utils.TracksCache
 import com.github.apognu.otter.utils.TracksResponse
 import com.github.kittinunf.fuel.gson.gsonDeserializerOf
 import com.google.gson.reflect.TypeToken
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.toList
 import kotlinx.coroutines.runBlocking
 import java.io.BufferedReader
 
@@ -18,7 +20,10 @@ class SearchRepository(override val context: Context?, query: String) : Reposito
   override fun uncache(reader: BufferedReader) = gsonDeserializerOf(TracksCache::class.java).deserialize(reader)
 
   override fun onDataFetched(data: List<Track>): List<Track> = runBlocking {
-    val favorites = FavoritedRepository(context).fetch(Origin.Network.origin).receive().data
+    val favorites = FavoritedRepository(context).fetch(Origin.Network.origin)
+      .map { it.data }
+      .toList()
+      .flatten()
 
     data.map { track ->
       track.favorite = favorites.contains(track.id)

app/src/main/java/com/github/apognu/otter/repositories/TracksRepository.kt

@@ -7,6 +7,8 @@ import com.github.apognu.otter.utils.TracksCache
 import com.github.apognu.otter.utils.TracksResponse
 import com.github.kittinunf.fuel.gson.gsonDeserializerOf
 import com.google.gson.reflect.TypeToken
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.toList
 import kotlinx.coroutines.runBlocking
 import java.io.BufferedReader
 
@@ -18,7 +20,10 @@ class TracksRepository(override val context: Context?, albumId: Int) : Repositor
   override fun uncache(reader: BufferedReader) = gsonDeserializerOf(TracksCache::class.java).deserialize(reader)
 
   override fun onDataFetched(data: List<Track>): List<Track> = runBlocking {
-    val favorites = FavoritedRepository(context).fetch(Origin.Network.origin).receive().data
+    val favorites = FavoritedRepository(context).fetch(Origin.Network.origin)
+      .map { it.data }
+      .toList()
+      .flatten()
 
     data.map { track ->
       track.favorite = favorites.contains(track.id)

app/src/main/java/com/github/apognu/otter/utils/EventBus.kt

@@ -7,6 +7,8 @@ import kotlinx.coroutines.channels.Channel
 import kotlinx.coroutines.channels.ReceiveChannel
 import kotlinx.coroutines.channels.filter
 import kotlinx.coroutines.channels.map
+import kotlinx.coroutines.flow.asFlow
+import kotlinx.coroutines.flow.conflate
 import kotlinx.coroutines.launch
 
 sealed class Command {
@@ -55,15 +57,11 @@ sealed class Response {
 object EventBus {
   fun send(event: Event) {
     GlobalScope.launch {
-      get().offer(event)
+      Otter.get().eventBus.send(event)
     }
   }
 
-  fun get() = Otter.get().eventBus
-
-  inline fun <reified T : Event> asChannel(): ReceiveChannel<T> {
-    return get().openSubscription().filter { it is T }.map { it as T }
-  }
+  fun get() = Otter.get().eventBus.asFlow()
 }
 
 object CommandBus {
@@ -82,16 +80,12 @@ object RequestBus {
       GlobalScope.launch(Main) {
         request.channel = it
 
-        get().offer(request)
+        Otter.get().requestBus.offer(request)
       }
     }
   }
 
-  fun get() = Otter.get().requestBus
-
-  inline fun <reified T> asChannel(): ReceiveChannel<T> {
-    return get().openSubscription().filter { it is T }.map { it as T }
-  }
+  fun get() = Otter.get().requestBus.asFlow()
 }
 
 object ProgressBus {
@@ -101,9 +95,7 @@ object ProgressBus {
     }
   }
 
-  fun asChannel(): ReceiveChannel<Triple<Int, Int, Int>> {
-    return Otter.get().progressBus.openSubscription()
-  }
+  fun get() = Otter.get().progressBus.asFlow().conflate()
 }
 
 suspend inline fun <reified T> Channel<Response>.wait(): T? {

app/src/main/java/com/github/apognu/otter/utils/Extensions.kt

@@ -11,7 +11,8 @@ import com.squareup.picasso.Picasso
 import com.squareup.picasso.RequestCreator
 import kotlinx.coroutines.Dispatchers.Main
 import kotlinx.coroutines.GlobalScope
-import kotlinx.coroutines.channels.Channel
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.launch
 import kotlin.coroutines.CoroutineContext
 
@@ -19,23 +20,10 @@ fun Context.getColor(colorRes: Int): Int {
   return ContextCompat.getColor(this, colorRes)
 }
 
-inline fun <D> Channel<Repository.Response<D>>.await(context: CoroutineContext = Main, crossinline callback: (data: List<D>) -> Unit) {
+inline fun <D> Flow<Repository.Response<D>>.untilNetwork(context: CoroutineContext = Main, crossinline callback: (data: List<D>, isCache: Boolean, hasMore: Boolean) -> Unit) {
   GlobalScope.launch(context) {
-    this@await.receive().also {
-      callback(it.data)
-      close()
-    }
-  }
-}
-
-inline fun <D> Channel<Repository.Response<D>>.untilNetwork(context: CoroutineContext = Main, crossinline callback: (data: List<D>, isCache: Boolean, hasMore: Boolean) -> Unit) {
-  GlobalScope.launch(context) {
-    for (data in this@untilNetwork) {
+    collect { data ->
       callback(data.data, data.origin == Repository.Origin.Cache, data.hasMore)
-
-      if (data.origin == Repository.Origin.Network && !data.hasMore) {
-        close()
-      }
     }
   }
 }