Fix displayed selected deck in NoteEditorFragment

Properly sets the displayed deck in NoteEditorFragment when starting:
- when adding don't show a filtered deck(even if it's the currently
  selected one) and revert to 'Default'
- show the original deck for the card being edited from the reviewer

Author: lukstbit

AnkiDroid/src/main/java/com/ichi2/anki/NoteEditorFragment.kt

@@ -102,6 +102,7 @@ import com.ichi2.anki.dialogs.tags.TagsDialogFactory
 import com.ichi2.anki.dialogs.tags.TagsDialogListener
 import com.ichi2.anki.libanki.Card
 import com.ichi2.anki.libanki.Collection
+import com.ichi2.anki.libanki.Consts
 import com.ichi2.anki.libanki.DeckId
 import com.ichi2.anki.libanki.Decks.Companion.CURRENT_DECK
 import com.ichi2.anki.libanki.Field
@@ -821,6 +822,33 @@ class NoteEditorFragment :
         }
 
         deckId = requireArguments().getLong(EXTRA_DID, deckId)
+        if (addNote) {
+            // When adding and if we didn't receive a valid deck id or it's the 'Default' deck, look
+            // at what deck is selected and use that(guards against certain scenarios when deleting
+            // a deck and no deck is visually selected in DeckPicker)
+            if (deckId == 0L || deckId == Consts.DEFAULT_DECK_ID) {
+                // check if this is the actual deck selected
+                val currentSelectedDeckId = col.decks.selected()
+                if (currentSelectedDeckId != Consts.DEFAULT_DECK_ID) {
+                    deckId = currentSelectedDeckId
+                }
+            }
+            // Also guard against adding to a filtered deck in which case revert to 'Default'
+            val deck = col.decks.getLegacy(deckId)
+            if (deck == null || deck.isFiltered) {
+                deckId = Consts.DEFAULT_DECK_ID
+            }
+        } else {
+            // When editing we always have a valid currentEditCard. Check to see if it's from a normal
+            // deck or a filtered deck(in which case use it's original did or revert to 'Default')
+            val cardDeckId = currentEditedCard?.did
+            deckId =
+                if (cardDeckId == null || col.decks.isFiltered(cardDeckId)) {
+                    currentEditedCard?.oDid ?: Consts.DEFAULT_DECK_ID
+                } else {
+                    cardDeckId
+                }
+        }
         view?.findViewById<TextView>(R.id.note_deck_name)?.apply {
             text = col.decks.name(deckId)
             setOnClickListener {

AnkiDroid/src/test/java/com/ichi2/anki/NoteEditorTest.kt

@@ -413,6 +413,50 @@ class NoteEditorTest : RobolectricTest() {
         }
     }
 
+    @Test
+    fun `shows 'Default' as selected when attempting to add to a filtered deck`() {
+        val testDeckId = addDeck("TestDeckA")
+        val testFilteredDeckId = addDynamicDeck("TestFiltered")
+        col.decks.select(testFilteredDeckId)
+        val editor = getNoteEditorAdding(NoteType.BASIC).build()
+        val deckNameView = editor.view?.findViewById<TextView>(R.id.note_deck_name)
+        assertNotNull(deckNameView)
+        // we can't add to a filtered deck so this should show the Default deck
+        assertEquals("Default", deckNameView.text.toString())
+    }
+
+    @Test
+    fun `shows the currently selected deck if no deck id is provided`() {
+        val testDeckName = "TestDeckC"
+        addDeck("TestDeckA")
+        addDeck("TestDeckB")
+        val testDeckId3 = addDeck(testDeckName)
+        col.decks.select(testDeckId3)
+        val editor = getNoteEditorAdding(NoteType.BASIC).build()
+        val deckNameView = editor.view?.findViewById<TextView>(R.id.note_deck_name)
+        assertNotNull(deckNameView)
+        // we can't add to a filtered deck so this should show the Default deck
+        assertEquals(testDeckName, deckNameView.text.toString())
+    }
+
+    @Test
+    fun `shows the expected deck if a deck id is provided`() {
+        val testDeckName = "TestDeckA"
+        val testDeckId1 = addDeck(testDeckName)
+        val testDeckId2 = addDeck("TestDeckB")
+        col.decks.select(testDeckId2)
+        val activity =
+            startActivityNormallyOpenCollectionWithIntent(
+                NoteEditorActivity::class.java,
+                NoteEditorLauncher.AddNote(testDeckId1).toIntent(targetContext),
+            )
+        val editor = activity.getNoteEditorFragment()
+        val deckNameView = editor.view?.findViewById<TextView>(R.id.note_deck_name)
+        assertNotNull(deckNameView)
+        // we can't add to a filtered deck so this should show the Default deck
+        assertEquals(testDeckName, deckNameView.text.toString())
+    }
+
     @Test
     fun `edit note in filtered deck from reviewer - 15919`() {
         // TODO: As a future extension, the filtered deck should be displayed