POC: Retain streambundle across fragment navigations

app/src/main/java/com/aurora/store/data/model/State.kt

@@ -21,20 +21,20 @@ package com.aurora.store.data.model
 
 
 sealed class ViewState {
-    object Loading : ViewState()
-    object Empty : ViewState()
+    data object Loading : ViewState()
+    data object Empty : ViewState()
     data class Error(val error: String?) : ViewState()
     data class Status(val status: String?) : ViewState()
     data class Success<T>(val data: T) : ViewState()
 }
 
 sealed class AuthState {
-    object Available : AuthState()
-    object Unavailable : AuthState()
-    object SignedIn : AuthState()
-    object SignedOut : AuthState()
-    object Valid : AuthState()
-    object Fetching: AuthState()
-    object Verifying: AuthState()
+    data object Available : AuthState()
+    data object Unavailable : AuthState()
+    data object SignedIn : AuthState()
+    data object SignedOut : AuthState()
+    data object Valid : AuthState()
+    data object Fetching: AuthState()
+    data object Verifying: AuthState()
     data class Failed(val status: String) : AuthState()
 }

app/src/main/java/com/aurora/store/view/ui/commons/ForYouFragment.kt

@@ -21,7 +21,7 @@ package com.aurora.store.view.ui.commons
 
 import android.os.Bundle
 import android.view.View
-import androidx.fragment.app.viewModels
+import androidx.fragment.app.activityViewModels
 import com.aurora.Constants
 import com.aurora.gplayapi.data.models.App
 import com.aurora.gplayapi.data.models.StreamBundle
@@ -33,7 +33,7 @@ import com.aurora.store.data.model.ViewState
 import com.aurora.store.databinding.FragmentForYouBinding
 import com.aurora.store.view.custom.recycler.EndlessRecyclerOnScrollListener
 import com.aurora.store.view.epoxy.controller.GenericCarouselController
-import com.aurora.store.viewmodel.homestream.BaseClusterViewModel
+import com.aurora.store.viewmodel.homestream.StreamViewModel
 import dagger.hilt.android.AndroidEntryPoint
 
 @AndroidEntryPoint
@@ -43,7 +43,8 @@ class ForYouFragment : BaseFragment(R.layout.fragment_for_you),
     private var _binding: FragmentForYouBinding? = null
     private val binding get() = _binding!!
 
-    private val viewModel: BaseClusterViewModel by viewModels()
+    private var category: Category = Category.APPLICATION
+    private val viewModel: StreamViewModel by activityViewModels()
 
     private lateinit var streamBundle: StreamBundle
 
@@ -71,35 +72,31 @@ class ForYouFragment : BaseFragment(R.layout.fragment_for_you),
         }
 
         when (pageType) {
-            0 -> viewModel.getStreamBundle(Category.APPLICATION, Type.HOME)
-            1 -> viewModel.getStreamBundle(Category.GAME, Type.HOME)
+            0 -> {
+                category = Category.APPLICATION
+                viewModel.getStreamBundle(category, Type.HOME)
+            }
+
+            1 -> {
+                category = Category.GAME
+                viewModel.getStreamBundle(category, Type.HOME)
+            }
         }
 
         binding.recycler.setController(genericCarouselController)
 
         viewModel.liveData.observe(viewLifecycleOwner) {
             when (it) {
-                is ViewState.Empty -> {
-                }
-
                 is ViewState.Loading -> {
                     genericCarouselController.setData(null)
                 }
 
-                is ViewState.Error -> {
-
-                }
-
-                is ViewState.Status -> {
-
-                }
-
                 is ViewState.Success<*> -> {
                     if (!::streamBundle.isInitialized) {
                         binding.recycler.addOnScrollListener(
                             object : EndlessRecyclerOnScrollListener() {
                                 override fun onLoadMore(currentPage: Int) {
-                                    viewModel.observe()
+                                    viewModel.observe(category, Type.HOME)
                                 }
                             }
                         )
@@ -108,6 +105,8 @@ class ForYouFragment : BaseFragment(R.layout.fragment_for_you),
                     streamBundle = it.data as StreamBundle
                     genericCarouselController.setData(streamBundle)
                 }
+
+                else -> {}
             }
         }
     }
@@ -123,7 +122,7 @@ class ForYouFragment : BaseFragment(R.layout.fragment_for_you),
     }
 
     override fun onClusterScrolled(streamCluster: StreamCluster) {
-        viewModel.observeCluster(streamCluster)
+        viewModel.observeCluster(category, streamCluster)
     }
 
     override fun onAppClick(app: App) {

app/src/main/java/com/aurora/store/viewmodel/homestream/StreamViewModel.kt

@@ -42,7 +42,7 @@ import javax.inject.Inject
 
 @HiltViewModel
 @SuppressLint("StaticFieldLeak") // false positive, see https://github.com/google/dagger/issues/3253
-class BaseClusterViewModel @Inject constructor(
+class StreamViewModel @Inject constructor(
     @ApplicationContext private val context: Context,
     private val authProvider: AuthProvider
 ) : ViewModel() {
@@ -54,10 +54,11 @@ class BaseClusterViewModel @Inject constructor(
         .using(HttpClient.getPreferredClient(context))
 
     val liveData: MutableLiveData<ViewState> = MutableLiveData()
-    var streamBundle: StreamBundle = StreamBundle()
 
-    lateinit var type: StreamContract.Type
-    lateinit var category: StreamContract.Category
+    private var streamBundleMap: MutableMap<StreamContract.Category, StreamBundle> = mutableMapOf(
+        StreamContract.Category.APPLICATION to StreamBundle(),
+        StreamContract.Category.GAME to StreamBundle()
+    )
 
     fun contract(): StreamContract {
         return if (authProvider.isAnonymous) {
@@ -68,33 +69,38 @@ class BaseClusterViewModel @Inject constructor(
     }
 
     fun getStreamBundle(category: StreamContract.Category, type: StreamContract.Type) {
-        this.type = type
-        this.category = category
         liveData.postValue(ViewState.Loading)
-        observe()
+        observe(category, type)
     }
 
-    fun observe() {
+    fun observe(category: StreamContract.Category, type: StreamContract.Type) {
         viewModelScope.launch(Dispatchers.IO) {
             supervisorScope {
+                if (targetBundle(category).streamClusters.isNotEmpty()) {
+                    liveData.postValue(ViewState.Success(targetBundle(category)))
+                }
+
                 try {
-                    if (!streamBundle.hasCluster() || streamBundle.hasNext()) {
+                    if (!targetBundle(category).hasCluster() || targetBundle(category).hasNext()) {
 
                         //Fetch new stream bundle
-                        val newBundle = if (streamBundle.streamClusters.isEmpty()) {
+                        val newBundle = if (targetBundle(category).streamClusters.isEmpty()) {
                             contract().fetch(type, category)
                         } else {
-                            contract().nextStreamBundle(category, streamBundle.streamNextPageUrl)
+                            contract().nextStreamBundle(
+                                category,
+                                targetBundle((category)).streamNextPageUrl
+                            )
                         }
 
                         //Update old bundle
-                        streamBundle.apply {
+                        targetBundle(category).apply {
                             streamClusters.putAll(newBundle.streamClusters)
                             streamNextPageUrl = newBundle.streamNextPageUrl
                         }
 
                         //Post updated to UI
-                        liveData.postValue(ViewState.Success(streamBundle))
+                        liveData.postValue(ViewState.Success(targetBundle(category)))
                     } else {
                         Log.i("End of Bundle")
                     }
@@ -105,15 +111,15 @@ class BaseClusterViewModel @Inject constructor(
         }
     }
 
-    fun observeCluster(streamCluster: StreamCluster) {
+    fun observeCluster(category: StreamContract.Category, streamCluster: StreamCluster) {
         viewModelScope.launch(Dispatchers.IO) {
             supervisorScope {
                 try {
                     if (streamCluster.hasNext()) {
                         val newCluster =
                             contract().nextStreamCluster(streamCluster.clusterNextPageUrl)
-                        updateCluster(streamCluster.id, newCluster)
-                        liveData.postValue(ViewState.Success(streamBundle))
+                        updateCluster(category, streamCluster.id, newCluster)
+                        liveData.postValue(ViewState.Success(targetBundle(category)))
                     } else {
                         Log.i("End of cluster")
                         streamCluster.clusterNextPageUrl = String()
@@ -125,10 +131,20 @@ class BaseClusterViewModel @Inject constructor(
         }
     }
 
-    private fun updateCluster(clusterID: Int, newCluster: StreamCluster) {
-        streamBundle.streamClusters[clusterID]?.apply {
+    private fun updateCluster(
+        category: StreamContract.Category,
+        clusterID: Int,
+        newCluster: StreamCluster
+    ) {
+        targetBundle(category).streamClusters[clusterID]?.apply {
             clusterAppList.addAll(newCluster.clusterAppList)
             clusterNextPageUrl = newCluster.clusterNextPageUrl
         }
     }
+
+    private fun targetBundle(category: StreamContract.Category): StreamBundle {
+        val streamBundle = streamBundleMap[category]
+
+        return streamBundle!!
+    }
 }