[Site design revamp] Preload MShots when the site creation activity starts

WordPress/src/main/java/org/wordpress/android/ui/layoutpicker/LayoutsRowViewHolder.kt

@@ -56,7 +56,6 @@ class LayoutsItemViewHolder(
                     RecyclerView.HORIZONTAL,
                     false
             ).apply { initialPrefetchItemCount = prefetchItemCount }
-            setRecycledViewPool(RecyclerView.RecycledViewPool())
             adapter = LayoutsAdapter(parent.context, dimensionProvider)
 
             addOnScrollListener(object : OnScrollListener() {

WordPress/src/main/java/org/wordpress/android/ui/sitecreation/SiteCreationActivity.kt

@@ -7,6 +7,7 @@ import android.view.MenuItem
 import androidx.activity.viewModels
 import androidx.fragment.app.Fragment
 import androidx.lifecycle.Observer
+import kotlinx.coroutines.cancel
 import dagger.hilt.android.AndroidEntryPoint
 import org.wordpress.android.R
 import org.wordpress.android.ui.ActivityLauncher
@@ -69,6 +70,7 @@ class SiteCreationActivity : LocaleAwareActivity(),
         setContentView(R.layout.site_creation_activity)
         val siteCreationSource = intent.extras?.getString(ARG_CREATE_SITE_SOURCE)
         mainViewModel.start(savedInstanceState, SiteCreationSource.fromString(siteCreationSource))
+        mainViewModel.preloadThumbnails(this)
 
         observeVMState()
     }
@@ -174,7 +176,15 @@ class SiteCreationActivity : LocaleAwareActivity(),
         val fragment = when (target.wizardStep) {
             INTENTS -> SiteCreationIntentsFragment()
             SITE_NAME -> SiteCreationSiteNameFragment.newInstance(target.wizardState.siteIntent)
-            SITE_DESIGNS -> HomePagePickerFragment.newInstance(target.wizardState.siteIntent)
+            SITE_DESIGNS -> {
+                // Cancel preload job before displaying the theme picker.
+                if (target.wizardStep == SITE_DESIGNS) {
+                    mainViewModel.preloadingJob?.cancel(
+                            "Preload did not complete before theme picker was shown."
+                    )
+                }
+                HomePagePickerFragment.newInstance(target.wizardState.siteIntent)
+            }
             DOMAINS -> SiteCreationDomainsFragment.newInstance(
                     screenTitle
             )

WordPress/src/main/java/org/wordpress/android/ui/sitecreation/SiteCreationMainVM.kt

@@ -1,15 +1,22 @@
 package org.wordpress.android.ui.sitecreation
 
 import android.annotation.SuppressLint
+import android.content.Context
 import android.os.Bundle
 import android.os.Parcelable
 import androidx.annotation.StringRes
 import androidx.lifecycle.LiveData
 import androidx.lifecycle.Transformations
 import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import com.bumptech.glide.Glide
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.launch
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.parcelize.Parcelize
 import org.wordpress.android.R
+import org.wordpress.android.fluxc.Dispatcher
 import org.wordpress.android.ui.sitecreation.SiteCreationMainVM.SiteCreationScreenTitle.ScreenTitleEmpty
 import org.wordpress.android.ui.sitecreation.SiteCreationMainVM.SiteCreationScreenTitle.ScreenTitleGeneral
 import org.wordpress.android.ui.sitecreation.SiteCreationMainVM.SiteCreationScreenTitle.ScreenTitleStepCount
@@ -19,7 +26,9 @@ import org.wordpress.android.ui.sitecreation.SiteCreationStep.SITE_PREVIEW
 import org.wordpress.android.ui.sitecreation.misc.SiteCreationSource
 import org.wordpress.android.ui.sitecreation.misc.SiteCreationTracker
 import org.wordpress.android.ui.sitecreation.previews.SitePreviewViewModel.CreateSiteState
+import org.wordpress.android.ui.sitecreation.usecases.FetchHomePageLayoutsUseCase
 import org.wordpress.android.ui.utils.UiString.UiStringRes
+import org.wordpress.android.util.NetworkUtilsWrapper
 import org.wordpress.android.util.experiments.SiteNameABExperiment
 import org.wordpress.android.util.wizard.WizardManager
 import org.wordpress.android.util.wizard.WizardNavigationTarget
@@ -50,13 +59,28 @@ typealias NavigationTarget = WizardNavigationTarget<SiteCreationStep, SiteCreati
 class SiteCreationMainVM @Inject constructor(
     private val tracker: SiteCreationTracker,
     private val wizardManager: WizardManager<SiteCreationStep>,
-    private val siteNameABExperiment: SiteNameABExperiment
+    private val siteNameABExperiment: SiteNameABExperiment,
+    private val networkUtils: NetworkUtilsWrapper,
+    private val dispatcher: Dispatcher,
+    private val fetchHomePageLayoutsUseCase: FetchHomePageLayoutsUseCase
 ) : ViewModel() {
+    init {
+        // TODO: Remove the duplicate {,un}registration in the picker view model
+        dispatcher.register(fetchHomePageLayoutsUseCase)
+    }
+
+    override fun onCleared() {
+        super.onCleared()
+        dispatcher.unregister(fetchHomePageLayoutsUseCase)
+    }
+
     private var isStarted = false
     private var siteCreationCompleted = false
 
     private lateinit var siteCreationState: SiteCreationState
 
+    internal var preloadingJob: Job? = null
+
     val navigationTargetObservable: SingleEventObservable<NavigationTarget> by lazy {
         SingleEventObservable(
                 Transformations.map(wizardManager.navigatorLiveData) {
@@ -97,6 +121,24 @@ class SiteCreationMainVM @Inject constructor(
         }
     }
 
+    fun preloadThumbnails(context: Context) {
+        if (preloadingJob == null) {
+            preloadingJob = viewModelScope.launch(Dispatchers.IO) {
+                if (networkUtils.isNetworkAvailable()) {
+                    val response = fetchHomePageLayoutsUseCase.fetchStarterDesigns()
+                    for (design in response.designs) {
+                        Glide.with(context)
+                                .downloadOnly()
+                                .load(design.previewMobile)
+                                .submit()
+                                .get() // This makes each call blocking, so subsequent calls can be cancelled if needed.
+                    }
+                }
+                preloadingJob = null
+            }
+        }
+    }
+
     fun writeToBundle(outState: Bundle) {
         outState.putBoolean(KEY_SITE_CREATION_COMPLETED, siteCreationCompleted)
         outState.putInt(KEY_CURRENT_STEP, wizardManager.currentStep)

WordPress/src/test/java/org/wordpress/android/ui/sitecreation/SiteCreationMainVMTest.kt

@@ -21,6 +21,7 @@ import org.mockito.ArgumentCaptor
 import org.mockito.Mock
 import org.mockito.junit.MockitoJUnitRunner
 import org.wordpress.android.R
+import org.wordpress.android.fluxc.Dispatcher
 import org.wordpress.android.fluxc.model.experiments.Variation
 import org.wordpress.android.fluxc.model.experiments.Variation.Control
 import org.wordpress.android.ui.sitecreation.SiteCreationMainVM.SiteCreationScreenTitle.ScreenTitleEmpty
@@ -30,6 +31,8 @@ import org.wordpress.android.ui.sitecreation.misc.SiteCreationSource
 import org.wordpress.android.ui.sitecreation.misc.SiteCreationTracker
 import org.wordpress.android.ui.sitecreation.previews.SitePreviewViewModel.CreateSiteState
 import org.wordpress.android.ui.sitecreation.previews.SitePreviewViewModel.CreateSiteState.SiteCreationCompleted
+import org.wordpress.android.ui.sitecreation.usecases.FetchHomePageLayoutsUseCase
+import org.wordpress.android.util.NetworkUtilsWrapper
 import org.wordpress.android.util.experiments.SiteNameABExperiment
 import org.wordpress.android.util.wizard.WizardManager
 import org.wordpress.android.viewmodel.SingleLiveEvent
@@ -58,6 +61,9 @@ class SiteCreationMainVMTest {
     @Mock lateinit var wizardManager: WizardManager<SiteCreationStep>
     @Mock lateinit var siteCreationStep: SiteCreationStep
     @Mock lateinit var siteNameABExperiment: SiteNameABExperiment
+    @Mock lateinit var networkUtils: NetworkUtilsWrapper
+    @Mock lateinit var dispatcher: Dispatcher
+    @Mock lateinit var fetchHomePageLayoutsUseCase: FetchHomePageLayoutsUseCase
     private val wizardManagerNavigatorLiveData = SingleLiveEvent<SiteCreationStep>()
 
     private lateinit var viewModel: SiteCreationMainVM
@@ -69,7 +75,7 @@ class SiteCreationMainVMTest {
             wizardManagerNavigatorLiveData.value = siteCreationStep
             Unit
         }
-        viewModel = SiteCreationMainVM(tracker, wizardManager, siteNameABExperiment)
+        viewModel = getNewViewModel()
         viewModel.start(null, SiteCreationSource.UNSPECIFIED)
         viewModel.navigationTargetObservable.observeForever(navigationTargetObserver)
         viewModel.wizardFinishedObservable.observeForever(wizardFinishedObserver)
@@ -84,16 +90,16 @@ class SiteCreationMainVMTest {
     @Test
     fun siteCreationSiteNameExperimentControlTracked() {
         whenever(siteNameABExperiment.getVariation()).thenReturn(Control)
-        viewModel = SiteCreationMainVM(tracker, wizardManager, siteNameABExperiment)
-        viewModel.start(null, SiteCreationSource.UNSPECIFIED)
+        val newViewModel = getNewViewModel()
+        newViewModel.start(null, SiteCreationSource.UNSPECIFIED)
         verify(tracker).trackSiteNameExperimentVariation(Control)
     }
 
     @Test
     fun siteCreationSiteNameExperimentTreatmentTracked() {
         whenever(siteNameABExperiment.getVariation()).thenReturn(Variation.fromName("wpandroid_site_name_v1"))
-        viewModel = SiteCreationMainVM(tracker, wizardManager, siteNameABExperiment)
-        viewModel.start(null, SiteCreationSource.UNSPECIFIED)
+        val newViewModel = getNewViewModel()
+        newViewModel.start(null, SiteCreationSource.UNSPECIFIED)
         verify(tracker).trackSiteNameExperimentVariation(Variation.fromName("wpandroid_site_name_v1"))
     }
 
@@ -220,7 +226,7 @@ class SiteCreationMainVMTest {
                 .thenReturn(expectedState)
 
         // we need to create a new instance of the VM as the `viewModel` has already been started in setUp()
-        val newViewModel = SiteCreationMainVM(tracker, wizardManager, siteNameABExperiment)
+        val newViewModel = getNewViewModel()
         newViewModel.start(savedInstanceState, SiteCreationSource.UNSPECIFIED)
 
         /* we need to simulate navigation to the next step (Domain selection, see comment above) as
@@ -241,15 +247,15 @@ class SiteCreationMainVMTest {
                 .thenReturn(SiteCreationState())
 
         // we need to create a new instance of the VM as the `viewModel` has already been started in setUp()
-        val newViewModel = SiteCreationMainVM(tracker, wizardManager, siteNameABExperiment)
+        val newViewModel = getNewViewModel()
         newViewModel.start(savedInstanceState, SiteCreationSource.UNSPECIFIED)
 
         verify(wizardManager).setCurrentStepIndex(index)
     }
 
     @Test
     fun `given null instance state, when start, then site creation accessed including source is tracked`() {
-        val newViewModel = SiteCreationMainVM(tracker, wizardManager, siteNameABExperiment)
+        val newViewModel = getNewViewModel()
         newViewModel.start(null, SiteCreationSource.UNSPECIFIED)
 
         // Because setup is run before every test, we expect this to be tracked twice
@@ -264,7 +270,7 @@ class SiteCreationMainVMTest {
         whenever(savedInstanceState.getParcelable<SiteCreationState>(KEY_SITE_CREATION_STATE))
                 .thenReturn(expectedState)
 
-        val newViewModel = SiteCreationMainVM(tracker, wizardManager, siteNameABExperiment)
+        val newViewModel = getNewViewModel()
         newViewModel.start(savedInstanceState, SiteCreationSource.UNSPECIFIED)
 
         // Because setup is run before every test, we expect this to be tracked on that first instance only
@@ -273,4 +279,13 @@ class SiteCreationMainVMTest {
 
     private fun currentWizardState(vm: SiteCreationMainVM) =
             vm.navigationTargetObservable.lastEvent!!.wizardState
+
+    private fun getNewViewModel() = SiteCreationMainVM(
+            tracker,
+            wizardManager,
+            siteNameABExperiment,
+            networkUtils,
+            dispatcher,
+            fetchHomePageLayoutsUseCase
+    )
 }