feat: introduce a view model in ManageNotetypes

AnkiDroid/src/main/java/com/ichi2/anki/notetype/AddNewNotesType.kt

@@ -45,6 +45,7 @@ import com.ichi2.utils.positiveButton
 
 class AddNewNotesType(
     private val activity: ManageNotetypes,
+    private val viewModel: ManageNotetypeViewModel,
 ) {
     private lateinit var dialogView: View
 
@@ -152,14 +153,15 @@ class AddNewNotesType(
         selectedOption: AddNotetypeUiModel,
     ) {
         activity.launchCatchingTask {
-            activity.runAndRefreshAfter {
+            withCol {
                 val kind = StockNotetype.Kind.forNumber(selectedOption.id.toInt())
                 val updatedStandardNotetype =
                     BackendUtils.fromJsonBytes(getStockNotetypeLegacy(kind)).apply {
                         set("name", newName)
                     }
                 addNotetypeLegacy(BackendUtils.toJsonBytes(updatedStandardNotetype))
             }
+            viewModel.refresh()
         }
     }
 
@@ -168,7 +170,7 @@ class AddNewNotesType(
         model: AddNotetypeUiModel,
     ) {
         activity.launchCatchingTask {
-            activity.runAndRefreshAfter {
+            withCol {
                 val targetNotetype = getNotetype(model.id)
                 val newNotetype =
                     targetNotetype.copy {
@@ -177,6 +179,7 @@ class AddNewNotesType(
                     }
                 addNotetype(newNotetype)
             }
+            viewModel.refresh()
         }
     }
 

AnkiDroid/src/main/java/com/ichi2/anki/notetype/ManageNotetypeViewModel.kt

@@ -0,0 +1,130 @@
+/****************************************************************************************
+ * This program is free software; you can redistribute it and/or modify it under        *
+ * the terms of the GNU General Public License as published by the Free Software        *
+ * Foundation; either version 3 of the License, or (at your option) any later           *
+ * version.                                                                             *
+ *                                                                                      *
+ * This program is distributed in the hope that it will be useful, but WITHOUT ANY      *
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A      *
+ * PARTICULAR PURPOSE. See the GNU General Public License for more details.             *
+ *                                                                                      *
+ * You should have received a copy of the GNU General Public License along with         *
+ * this program.  If not, see <http://www.gnu.org/licenses/>.                           *
+ ****************************************************************************************/
+package com.ichi2.anki.notetype
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import anki.notetypes.copy
+import com.ichi2.anki.CollectionManager.withCol
+import com.ichi2.libanki.NoteTypeId
+import com.ichi2.libanki.getNotetype
+import com.ichi2.libanki.getNotetypeNameIdUseCount
+import com.ichi2.libanki.removeNotetype
+import com.ichi2.libanki.updateNotetype
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.update
+import kotlinx.coroutines.launch
+
+/**
+ * @see ManageNotetypes
+ */
+class ManageNotetypeViewModel : ViewModel() {
+    private val _uiState = MutableStateFlow(NotetypesUiState())
+    val uiState: StateFlow<NotetypesUiState> = _uiState.asStateFlow()
+
+    /**
+     * Reference to the coroutine started in response to a filter request. As every change in the
+     * query makes a request, this job can be used to cancel previous coroutines to avoid useless
+     * work.
+     */
+    private var filterJob: Job? = null
+
+    fun refresh() {
+        viewModelScope.launch {
+            _uiState.update { state -> state.copy(isProcessing = true) }
+            refreshNotetypes()
+        }
+    }
+
+    /**
+     * Refreshes the list of notetypes, additionally filtering the list. Also calls to emit the new
+     * state.
+     * @param query the option query string to use to filter the list of notetypes
+     */
+    private suspend fun refreshNotetypes(query: String = "") {
+        val notetypes =
+            withCol {
+                getNotetypeNameIdUseCount()
+                    .filter { backendNotetype ->
+                        if (query.isEmpty()) {
+                            true
+                        } else {
+                            backendNotetype.name.lowercase().contains(query.lowercase())
+                        }
+                    }.map { backendNotetype ->
+                        NotetypeItemUiState(
+                            id = backendNotetype.id,
+                            name = backendNotetype.name,
+                            useCount = backendNotetype.useCount,
+                            onNavigateTo = { destination ->
+                                _uiState.update { state ->
+                                    state.copy(destination = destination)
+                                }
+                            },
+                        )
+                    }
+            }
+        _uiState.update { state ->
+            state.copy(
+                notetypes = notetypes,
+                isProcessing = false,
+            )
+        }
+    }
+
+    fun rename(
+        noteTypeId: NoteTypeId,
+        newName: String,
+    ) {
+        viewModelScope.launch {
+            _uiState.update { state -> state.copy(isProcessing = true) }
+            withCol {
+                val initialNotetype = getNotetype(noteTypeId)
+                val renamedNotetype = initialNotetype.copy { this.name = newName }
+                updateNotetype(renamedNotetype)
+            }
+            refreshNotetypes()
+        }
+    }
+
+    fun delete(noteTypeId: NoteTypeId) {
+        viewModelScope.launch {
+            _uiState.update { state -> state.copy(isProcessing = true) }
+            withCol {
+                removeNotetype(noteTypeId)
+            }
+            refreshNotetypes()
+        }
+    }
+
+    fun filter(query: String) {
+        filterJob?.cancel()
+        filterJob =
+            viewModelScope.launch {
+                refreshNotetypes(query)
+            }
+    }
+
+    /**
+     * Mark the previously sent [NotetypesDestination] as consumed by the ui. Done to prevent
+     * situations when we would come back to the screen and the navigation requests is again seen
+     * and we would enter in a loop.
+     */
+    fun markNavigationRequestAsDone() {
+        _uiState.update { state -> state.copy(destination = null) }
+    }
+}