refactor(image-occlusion): use discriminated union for args

david-allison · mikehardy · commit 14741bdc244f · 2025-11-30T13:52:00.000Z
* Removes nullable properties
* Strongly types 'id' + 'deckId'
* Properties are only available if the mode ('Add'/'Edit') is checked

For issue 19605, we will want to know whether the page is adding
 or editing a note, this will read better if we are not
 assuming existence of properties
diff --git a/AnkiDroid/src/main/java/com/ichi2/anki/NoteEditorFragment.kt b/AnkiDroid/src/main/java/com/ichi2/anki/NoteEditorFragment.kt
@@ -141,6 +141,7 @@ import com.ichi2.anki.noteeditor.Toolbar.TextFormatListener
 import com.ichi2.anki.noteeditor.Toolbar.TextWrapper
 import com.ichi2.anki.observability.undoableOp
 import com.ichi2.anki.pages.ImageOcclusion
+import com.ichi2.anki.pages.viewmodel.ImageOcclusionArgs
 import com.ichi2.anki.preferences.sharedPrefs
 import com.ichi2.anki.previewer.TemplatePreviewerArguments
 import com.ichi2.anki.previewer.TemplatePreviewerPage
@@ -2751,22 +2752,28 @@ class NoteEditorFragment :
     private fun currentNotetypeIsImageOcclusion() = currentlySelectedNotetype?.isImageOcclusion == true
 
     private fun setupImageOcclusionEditor(imagePath: String = "") {
-        val kind: String
-        val id: Long
-        if (addNote) {
-            kind = "add"
-            // if opened from an intent, the selected note type may not be suitable for IO
-            id =
-                if (currentNotetypeIsImageOcclusion()) {
-                    currentlySelectedNotetype!!.id
-                } else {
-                    0
-                }
-        } else {
-            kind = "edit"
-            id = editorNote?.id!!
-        }
-        val intent = ImageOcclusion.getIntent(requireContext(), kind, id, imagePath, deckId)
+        val args =
+            if (addNote) {
+                // if opened from an intent, the selected note type may not be suitable for IO
+                val noteTypeId =
+                    if (currentNotetypeIsImageOcclusion()) {
+                        currentlySelectedNotetype!!.id
+                    } else {
+                        0
+                    }
+                ImageOcclusionArgs.Add(
+                    noteTypeId = noteTypeId,
+                    imagePath = imagePath,
+                    deckId = deckId,
+                )
+            } else {
+                ImageOcclusionArgs.Edit(
+                    noteId = editorNote!!.id,
+                    deckId = deckId,
+                )
+            }
+
+        val intent = ImageOcclusion.getIntent(requireContext(), args)
         requestIOEditorCloser.launch(intent)
     }
 
diff --git a/AnkiDroid/src/main/java/com/ichi2/anki/pages/ImageOcclusion.kt b/AnkiDroid/src/main/java/com/ichi2/anki/pages/ImageOcclusion.kt
@@ -34,7 +34,6 @@ import com.ichi2.anki.common.annotations.NeedsTest
 import com.ichi2.anki.dialogs.DeckSelectionDialog
 import com.ichi2.anki.dialogs.DiscardChangesDialog
 import com.ichi2.anki.launchCatchingTask
-import com.ichi2.anki.libanki.DeckId
 import com.ichi2.anki.model.SelectableDeck
 import com.ichi2.anki.pages.viewmodel.ImageOcclusionArgs
 import com.ichi2.anki.pages.viewmodel.ImageOcclusionViewModel
@@ -103,7 +102,7 @@ class ImageOcclusion :
                 url: String?,
             ) {
                 super.onPageFinished(view, url)
-                viewModel.webViewOptions.let { options ->
+                viewModel.args.toImageOcclusionMode().let { options ->
                     view?.evaluateJavascript("globalThis.anki.imageOcclusion.mode = $options") {
                         super.onPageFinished(view, url)
                     }
@@ -137,24 +136,17 @@ class ImageOcclusion :
 
     companion object {
         /**
-         * @param editorWorkingDeckId the current deck id that [com.ichi2.anki.NoteEditorFragment] is using
+         * @param args arguments for either adding or editing a note
          */
         fun getIntent(
             context: Context,
-            kind: String,
-            noteOrNotetypeId: Long,
-            imagePath: String?,
-            editorWorkingDeckId: DeckId,
+            args: ImageOcclusionArgs,
         ): Intent {
-            val suffix = if (kind == "edit") noteOrNotetypeId else Uri.encode(imagePath)
-
-            val args =
-                ImageOcclusionArgs(
-                    kind = kind,
-                    id = noteOrNotetypeId,
-                    imagePath = imagePath,
-                    editorDeckId = editorWorkingDeckId,
-                )
+            val suffix =
+                when (args) {
+                    is ImageOcclusionArgs.Add -> Uri.encode(args.imagePath)
+                    is ImageOcclusionArgs.Edit -> args.noteId
+                }
 
             val arguments =
                 bundleOf(
diff --git a/AnkiDroid/src/main/java/com/ichi2/anki/pages/viewmodel/ImageOcclusionViewModel.kt b/AnkiDroid/src/main/java/com/ichi2/anki/pages/viewmodel/ImageOcclusionViewModel.kt
@@ -23,52 +23,78 @@ import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import com.ichi2.anki.CollectionManager
 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.launch
 import kotlinx.parcelize.Parcelize
 import org.json.JSONObject
 import timber.log.Timber
 
-@Parcelize
-data class ImageOcclusionArgs(
-    val kind: String,
-    val id: Long,
-    val imagePath: String?,
-    val editorDeckId: Long,
-) : Parcelable
-
 /**
- * ViewModel for the Image Occlusion fragment.
+ * Arguments for either adding or editing an image occlusion note
+ *
+ * @see ImageOcclusionArgs.Add
+ * @see ImageOcclusionArgs.Edit
  */
-class ImageOcclusionViewModel(
-    savedStateHandle: SavedStateHandle,
-) : ViewModel() {
-    private val args: ImageOcclusionArgs =
-        checkNotNull(savedStateHandle[IO_ARGS_KEY]) { "$IO_ARGS_KEY required" }
+@Parcelize
+sealed class ImageOcclusionArgs : Parcelable {
+    @Parcelize
+    data class Add(
+        val imagePath: String,
+        val noteTypeId: NoteTypeId,
+        val deckId: DeckId,
+    ) : ImageOcclusionArgs()
 
-    var selectedDeckId: Long = args.editorDeckId
+    @Parcelize
+    data class Edit(
+        val noteId: NoteId,
+        val deckId: DeckId,
+    ) : ImageOcclusionArgs()
 
     /**
-     * The ID of the deck that was originally selected when the editor was opened.
-     * This is used to restore the deck after saving a note to prevent unexpected deck changes.
+     * The ID of the deck that was selected when the editor was opened.
+     * Used to restore the deck after saving a note to prevent unexpected deck changes.
      */
-    val oldDeckId: Long = args.editorDeckId
+    val originalDeckId: DeckId
+        get() =
+            when (this) {
+                is Add -> this.deckId
+                is Edit -> this.deckId
+            }
 
     /**
      * A [JSONObject] containing options for loading the [image occlusion page][ImageOcclusion].
      * This includes the type of operation ("add" or "edit"), and relevant IDs and paths.
      *
-     * Defined in https://github.com/ankitects/anki/blob/main/ts/routes/image-occlusion/lib.ts
+     * See 'IOMode' in https://github.com/ankitects/anki/blob/main/ts/routes/image-occlusion/lib.ts
      */
-    val webViewOptions: JSONObject =
-        JSONObject().apply {
-            put("kind", args.kind)
-            if (args.kind == "add") {
-                put("imagePath", args.imagePath)
-                put("notetypeId", args.id)
-            } else {
-                put("noteId", args.id)
-            }
+    fun toImageOcclusionMode() =
+        when (this) {
+            is Add ->
+                JSONObject().also {
+                    it.put("kind", "add")
+                    it.put("imagePath", this.imagePath)
+                    it.put("notetypeId", this.noteTypeId)
+                }
+            is Edit ->
+                JSONObject().also {
+                    it.put("kind", "edit")
+                    it.put("noteId", this.noteId)
+                }
         }
+}
+
+/**
+ * ViewModel for the Image Occlusion fragment.
+ */
+class ImageOcclusionViewModel(
+    savedStateHandle: SavedStateHandle,
+) : ViewModel() {
+    val args: ImageOcclusionArgs =
+        checkNotNull(savedStateHandle[IO_ARGS_KEY]) { "$IO_ARGS_KEY required" }
+
+    var selectedDeckId: DeckId = args.originalDeckId
 
     /**
      * Handles the selection of a new deck.
@@ -86,13 +112,13 @@ class ImageOcclusionViewModel(
      */
     fun onSaveOperationCompleted() {
         Timber.i("save operation completed")
-        if (oldDeckId == selectedDeckId) return
+        if (args.originalDeckId == selectedDeckId) 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(oldDeckId) }
+            CollectionManager.withCol { backend.setCurrentDeck(args.originalDeckId) }
         }
     }
 
