refactor(image-occlusion): move deck name to ViewModel

I want to make the deck selection conditional on 'ADD' mode

Author: david-allison

AnkiDroid/src/main/java/com/ichi2/anki/pages/ImageOcclusion.kt

@@ -25,23 +25,25 @@ import android.widget.TextView
 import androidx.activity.addCallback
 import androidx.core.os.bundleOf
 import androidx.fragment.app.viewModels
+import androidx.lifecycle.Lifecycle
 import androidx.lifecycle.lifecycleScope
+import androidx.lifecycle.repeatOnLifecycle
 import com.google.android.material.appbar.MaterialToolbar
-import com.ichi2.anki.CollectionManager.withCol
 import com.ichi2.anki.R
 import com.ichi2.anki.SingleFragmentActivity
 import com.ichi2.anki.common.annotations.NeedsTest
+import com.ichi2.anki.common.utils.android.isRobolectric
 import com.ichi2.anki.dialogs.DeckSelectionDialog
 import com.ichi2.anki.dialogs.DiscardChangesDialog
-import com.ichi2.anki.launchCatchingTask
 import com.ichi2.anki.model.SelectableDeck
 import com.ichi2.anki.pages.viewmodel.ImageOcclusionArgs
 import com.ichi2.anki.pages.viewmodel.ImageOcclusionViewModel
 import com.ichi2.anki.pages.viewmodel.ImageOcclusionViewModel.Companion.IO_ARGS_KEY
-import com.ichi2.anki.requireAnkiActivity
-import com.ichi2.anki.selectedDeckIfNotFiltered
 import com.ichi2.anki.startDeckSelection
+import com.ichi2.utils.HandlerUtils
+import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.launch
+import kotlinx.coroutines.runBlocking
 import timber.log.Timber
 
 /**
@@ -80,11 +82,6 @@ class ImageOcclusion :
         deckNameView = view.findViewById(R.id.deck_name)
         deckNameView.setOnClickListener { startDeckSelection(all = false, filtered = false, skipEmptyDefault = false) }
 
-        requireAnkiActivity().launchCatchingTask {
-            val selectedDeck = withCol { selectedDeckIfNotFiltered() }
-            deckNameView.text = selectedDeck.name
-        }
-
         @NeedsTest("#17393 verify that the added image occlusion cards are put in the correct deck")
         view.findViewById<MaterialToolbar>(R.id.toolbar).setOnMenuItemClickListener {
             if (it.itemId == R.id.action_save) {
@@ -93,6 +90,8 @@ class ImageOcclusion :
             }
             return@setOnMenuItemClickListener true
         }
+
+        setupFlows()
     }
 
     override fun onCreateWebViewClient(savedInstanceState: Bundle?): PageWebViewClient =
@@ -113,13 +112,7 @@ class ImageOcclusion :
     override fun onDeckSelected(deck: SelectableDeck?) {
         if (deck == null) return
         require(deck is SelectableDeck.Deck)
-        deckNameView.text = deck.name
-        val deckDidChange = viewModel.handleDeckSelection(deck.deckId)
-        if (deckDidChange) {
-            viewLifecycleOwner.lifecycleScope.launch {
-                withCol { decks.select(viewModel.selectedDeckId) }
-            }
-        }
+        viewModel.handleDeckSelection(deck.deckId)
     }
 
     // HACK: detect a successful save; #19443 will provide a better method
@@ -134,6 +127,29 @@ class ImageOcclusion :
             }
         }
 
+    private fun setupFlows() {
+        fun onDeckNameChanged(name: String) {
+            deckNameView.text = name
+        }
+
+        viewModel.deckNameFlow.launchCollectionInLifecycleScope(::onDeckNameChanged)
+    }
+
+    // TODO: Move this to an extension method once we have context parameters
+    private fun <T> Flow<T>.launchCollectionInLifecycleScope(block: suspend (T) -> Unit) {
+        lifecycleScope.launch {
+            lifecycle.repeatOnLifecycle(Lifecycle.State.RESUMED) {
+                this@launchCollectionInLifecycleScope.collect {
+                    if (isRobolectric) {
+                        HandlerUtils.postOnNewHandler { runBlocking { block(it) } }
+                    } else {
+                        block(it)
+                    }
+                }
+            }
+        }
+    }
+
     companion object {
         /**
          * @param args arguments for either adding or editing a note

AnkiDroid/src/main/java/com/ichi2/anki/pages/viewmodel/ImageOcclusionViewModel.kt

@@ -21,11 +21,15 @@ import android.os.Parcelable
 import androidx.lifecycle.SavedStateHandle
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
-import com.ichi2.anki.CollectionManager
+import com.ichi2.anki.CollectionManager.withCol
 import com.ichi2.anki.libanki.DeckId
 import com.ichi2.anki.libanki.NoteId
 import com.ichi2.anki.libanki.NoteTypeId
 import com.ichi2.anki.pages.ImageOcclusion
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.launchIn
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.onEach
 import kotlinx.coroutines.launch
 import kotlinx.parcelize.Parcelize
 import org.json.JSONObject
@@ -94,31 +98,41 @@ class ImageOcclusionViewModel(
     val args: ImageOcclusionArgs =
         checkNotNull(savedStateHandle[IO_ARGS_KEY]) { "$IO_ARGS_KEY required" }
 
-    var selectedDeckId: DeckId = args.originalDeckId
+    var selectedDeckIdFlow = MutableStateFlow(args.originalDeckId)
+
+    val deckNameFlow =
+        selectedDeckIdFlow
+            .map { did -> withCol { decks.name(did) } }
+
+    init {
+        // if we are in 'add' mode, thr current deck is used to add the note.
+        // This is reverted in 'onSaveOperationCompleted'
+        selectedDeckIdFlow
+            .onEach { withCol { decks.select(it) } }
+            .launchIn(viewModelScope)
+    }
 
     /**
      * Handles the selection of a new deck.
      *
      * @param deckId The [DeckId] object representing the selected deck. Can be null if no deck is selected.
      */
-    fun handleDeckSelection(deckId: DeckId): Boolean {
-        if (deckId == selectedDeckId) return false
-        selectedDeckId = deckId
-        return true
+    fun handleDeckSelection(deckId: DeckId) {
+        selectedDeckIdFlow.value = deckId
     }
 
     /**
      * Executed when the 'save' operation is completed, before the UI receives the response
      */
     fun onSaveOperationCompleted() {
         Timber.i("save operation completed")
-        if (args.originalDeckId == selectedDeckId) return
+        if (args.originalDeckId == selectedDeckIdFlow.value) return
         // reset to the previous deck that the backend "saw" as selected, this
         // avoids other screens unexpectedly having their working decks modified(
         // most important being the Reviewer where the user would find itself
         // studying another deck after editing a note with changing the deck)
         viewModelScope.launch {
-            CollectionManager.withCol { backend.setCurrentDeck(args.originalDeckId) }
+            withCol { backend.setCurrentDeck(args.originalDeckId) }
         }
     }