Split MainViewModel: extract HomeViewModel

app/src/main/java/org/fairscan/app/MainActivity.kt

@@ -53,7 +53,7 @@ import org.fairscan.app.ui.Screen
 import org.fairscan.app.ui.components.rememberCameraPermissionState
 import org.fairscan.app.ui.screens.AboutScreen
 import org.fairscan.app.ui.screens.DocumentScreen
-import org.fairscan.app.ui.screens.HomeScreen
+import org.fairscan.app.ui.screens.home.HomeScreen
 import org.fairscan.app.ui.screens.LibrariesScreen
 import org.fairscan.app.ui.screens.camera.CameraEvent
 import org.fairscan.app.ui.screens.camera.CameraScreen
@@ -61,6 +61,7 @@ import org.fairscan.app.ui.screens.camera.CameraViewModel
 import org.fairscan.app.ui.screens.export.ExportScreenWrapper
 import org.fairscan.app.ui.screens.export.ExportViewModel
 import org.fairscan.app.ui.screens.export.PdfGenerationActions
+import org.fairscan.app.ui.screens.home.HomeViewModel
 import org.fairscan.app.ui.theme.FairScanTheme
 import org.opencv.android.OpenCVLoader
 
@@ -72,6 +73,7 @@ class MainActivity : ComponentActivity() {
         super.onCreate(savedInstanceState)
         initLibraries()
         val viewModel: MainViewModel by viewModels { MainViewModel.getFactory(this) }
+        val homeViewModel: HomeViewModel by viewModels { HomeViewModel.getFactory(this) }
         val cameraViewModel: CameraViewModel by viewModels { CameraViewModel.getFactory(this) }
         val exportViewModel: ExportViewModel by viewModels { ExportViewModel.getFactory(this) }
         lifecycleScope.launch(Dispatchers.IO) {
@@ -91,7 +93,7 @@ class MainActivity : ComponentActivity() {
             val liveAnalysisState by cameraViewModel.liveAnalysisState.collectAsStateWithLifecycle()
             val document by viewModel.documentUiModel.collectAsStateWithLifecycle()
             val cameraPermission = rememberCameraPermissionState()
-            val savePdf = { savePdf(exportViewModel.getFinalPdf(), viewModel, exportViewModel) }
+            val savePdf = { savePdf(exportViewModel.getFinalPdf(), homeViewModel, exportViewModel) }
             val storagePermissionLauncher = rememberLauncherForActivityResult(
                 ActivityResultContracts.RequestPermission()
             ) { isGranted ->
@@ -114,7 +116,7 @@ class MainActivity : ComponentActivity() {
                 )
                 when (val screen = currentScreen) {
                     is Screen.Main.Home -> {
-                        val recentDocs by viewModel.recentDocuments.collectAsStateWithLifecycle()
+                        val recentDocs by homeViewModel.recentDocuments.collectAsStateWithLifecycle()
                         HomeScreen(
                             cameraPermission = cameraPermission,
                             currentDocument = document,
@@ -210,7 +212,7 @@ class MainActivity : ComponentActivity() {
 
     private fun savePdf(
         generatedPdf: GeneratedPdf?,
-        viewModel: MainViewModel,
+        homeViewModel: HomeViewModel,
         exportViewModel: ExportViewModel
     ) {
         if (generatedPdf == null)
@@ -220,7 +222,7 @@ class MainActivity : ComponentActivity() {
         appScope.launch {
             try {
                 val targetFile = exportViewModel.saveFile(generatedPdf.file)
-                viewModel.addRecentDocument(targetFile.absolutePath, generatedPdf.pageCount)
+                homeViewModel.addRecentDocument(targetFile.absolutePath, generatedPdf.pageCount)
 
                 suspendCancellableCoroutine { continuation ->
                     MediaScannerConnection.scanFile(

app/src/main/java/org/fairscan/app/MainViewModel.kt

@@ -17,7 +17,6 @@ package org.fairscan.app
 import android.content.Context
 import android.graphics.Bitmap
 import android.graphics.BitmapFactory
-import androidx.datastore.core.DataStore
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.ViewModelProvider
 import androidx.lifecycle.viewModelScope
@@ -31,16 +30,12 @@ import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.launch
 import org.fairscan.app.data.ImageRepository
-import org.fairscan.app.data.recentDocumentsDataStore
 import org.fairscan.app.ui.NavigationState
 import org.fairscan.app.ui.Screen
 import org.fairscan.app.ui.state.DocumentUiModel
-import org.fairscan.app.ui.state.RecentDocumentUiState
-import java.io.File
 
 class MainViewModel(
-    private val imageRepository: ImageRepository,
+    private val imageRepository: ImageRepository
-    private val recentDocumentsDataStore: DataStore<RecentDocuments>,
 ): ViewModel() {
 
     companion object {
@@ -48,10 +43,7 @@ class MainViewModel(
             @Suppress("UNCHECKED_CAST")
             override fun <T : ViewModel> create(modelClass: Class<T>, extras: CreationExtras): T {
                 val app = context.applicationContext as FairScanApp
-                return MainViewModel(
+                return MainViewModel(app.appContainer.imageRepository) as T
-                    app.appContainer.imageRepository,
-                    context.recentDocumentsDataStore,
-                ) as T
             }
         }
     }
@@ -116,41 +108,6 @@ class MainViewModel(
         return bytes?.let { BitmapFactory.decodeByteArray(it, 0, it.size) }
     }
 
-    val recentDocuments: StateFlow<List<RecentDocumentUiState>> =
-        recentDocumentsDataStore.data.map {
-            it.documentsList.map {
-                doc ->
-                    RecentDocumentUiState(
-                        file = File(doc.filePath),
-                        saveTimestamp = doc.createdAt,
-                        pageCount = doc.pageCount,
-                    )
-            }.filter { doc -> doc.file.exists() }
-        }.stateIn(
-            scope = viewModelScope,
-            started = SharingStarted.WhileSubscribed(5_000),
-            initialValue = emptyList(),
-        )
-    fun addRecentDocument(filePath: String, pageCount: Int) {
-        viewModelScope.launch {
-            recentDocumentsDataStore.updateData { current ->
-                val newDoc = RecentDocument.newBuilder()
-                    .setFilePath(filePath)
-                    .setPageCount(pageCount)
-                    .setCreatedAt(System.currentTimeMillis())
-                    .build()
-                current.toBuilder()
-                    .addDocuments(0, newDoc)
-                    .also { builder ->
-                        while (builder.documentsCount > 3) {
-                            builder.removeDocuments(builder.documentsCount - 1)
-                        }
-                    }
-                    .build()
-            }
-        }
-    }
-
     fun handleImageCaptured(jpegBytes: ByteArray) {
         imageRepository.add(jpegBytes)
         _pageIds.value = imageRepository.imageIds()

app/src/main/java/org/fairscan/app/ui/screens/home/HomeScreen.kt

@@ -12,7 +12,7 @@
  * You should have received a copy of the GNU General Public License along with
  * this program. If not, see <https://www.gnu.org/licenses/>.
  */
-package org.fairscan.app.ui.screens
+package org.fairscan.app.ui.screens.home
 
 import androidx.compose.foundation.Image
 import androidx.compose.foundation.clickable

app/src/main/java/org/fairscan/app/ui/screens/home/HomeViewModel.kt

@@ -0,0 +1,80 @@
+/*
+ * Copyright 2025 Pierre-Yves Nicolas
+ *
+ * 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 <https://www.gnu.org/licenses/>.
+ */
+package org.fairscan.app.ui.screens.home
+
+import android.content.Context
+import androidx.datastore.core.DataStore
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+import androidx.lifecycle.viewModelScope
+import androidx.lifecycle.viewmodel.CreationExtras
+import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.stateIn
+import kotlinx.coroutines.launch
+import org.fairscan.app.RecentDocument
+import org.fairscan.app.RecentDocuments
+import org.fairscan.app.data.recentDocumentsDataStore
+import org.fairscan.app.ui.state.RecentDocumentUiState
+import java.io.File
+
+class HomeViewModel(private val recentDocumentsDataStore: DataStore<RecentDocuments>): ViewModel() {
+
+    companion object {
+        fun getFactory(context: Context) = object : ViewModelProvider.Factory {
+            @Suppress("UNCHECKED_CAST")
+            override fun <T : ViewModel> create(modelClass: Class<T>, extras: CreationExtras): T {
+                return HomeViewModel(context.recentDocumentsDataStore) as T
+            }
+        }
+    }
+
+    val recentDocuments: StateFlow<List<RecentDocumentUiState>> =
+        recentDocumentsDataStore.data.map {
+            it.documentsList.map {
+                    doc ->
+                RecentDocumentUiState(
+                    file = File(doc.filePath),
+                    saveTimestamp = doc.createdAt,
+                    pageCount = doc.pageCount,
+                )
+            }.filter { doc -> doc.file.exists() }
+        }.stateIn(
+            scope = viewModelScope,
+            started = SharingStarted.WhileSubscribed(5_000),
+            initialValue = emptyList(),
+        )
+    fun addRecentDocument(filePath: String, pageCount: Int) {
+        viewModelScope.launch {
+            recentDocumentsDataStore.updateData { current ->
+                val newDoc = RecentDocument.newBuilder()
+                    .setFilePath(filePath)
+                    .setPageCount(pageCount)
+                    .setCreatedAt(System.currentTimeMillis())
+                    .build()
+                current.toBuilder()
+                    .addDocuments(0, newDoc)
+                    .also { builder ->
+                        while (builder.documentsCount > 3) {
+                            builder.removeDocuments(builder.documentsCount - 1)
+                        }
+                    }
+                    .build()
+            }
+        }
+    }
+
+}