Export: avoid silencing issues in applyRenaming

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

@@ -187,7 +187,7 @@ class MainActivity : ComponentActivity() {
                             pdfActions = ExportActions(
                                 prepareExportIfNeeded = exportViewModel::prepareExportIfNeeded,
                                 setFilename = exportViewModel::setFilename,
-                                share = { share(exportViewModel.applyRenaming(), exportViewModel) },
+                                share = { exportViewModel.onShareClicked() },
                                 save = { exportViewModel.onSaveClicked() },
                                 open = { item -> openUri(item.uri, item.format.mimeType) },
                             ),
@@ -324,6 +324,9 @@ class MainActivity : ComponentActivity() {
                             exportViewModel.onRequestSave(context)
                         }
                     }
+                    is ExportEvent.Share -> {
+                        share(event.result)
+                    }
                 }
             }
         }
@@ -343,10 +346,8 @@ class MainActivity : ComponentActivity() {
         }
     }
 
-    private fun share(result: ExportResult?, viewModel: ExportViewModel) {
+    private fun share(result: ExportResult) {
-        if (result == null || result.files.isEmpty()) return
+        if (result.files.isEmpty()) return
-
-        viewModel.setAsShared()
 
         val uris = result.files.map(::uriForFile)
         val intent = Intent().apply {

app/src/main/java/org/fairscan/app/ui/screens/export/ExportScreen.kt

@@ -584,7 +584,7 @@ private fun ErrorBar(error: ExportError) {
 @Composable
 private fun ExportError.toDisplayText(): Pair<String, String?> {
     return when (this) {
-        is ExportError.OnPrepare -> {
+        is ExportError.OnPrepareOrShare -> {
             val summary = message
             val details = throwable.message
             summary to details
@@ -684,7 +684,7 @@ fun PreviewExportScreenAfterSave() {
 fun ExportScreenPreviewWithError() {
     ExportPreviewToCustomize(
         ExportUiState(error =
-            ExportError.OnPrepare("PDF generation failed", IOException("Boom")))
+            ExportError.OnPrepareOrShare("PDF generation failed", IOException("Boom")))
     )
 }
 

app/src/main/java/org/fairscan/app/ui/screens/export/ExportUiState.kt

@@ -48,7 +48,7 @@ data class SaveDir(
 
 sealed class ExportError {
 
-    data class OnPrepare(
+    data class OnPrepareOrShare(
         val message: String,
         val throwable: Throwable,
     ) : ExportError()

app/src/main/java/org/fairscan/app/ui/screens/export/ExportViewModel.kt

@@ -61,6 +61,7 @@ import kotlin.coroutines.suspendCoroutine
 
 sealed interface ExportEvent {
     data object RequestSave : ExportEvent
+    data class Share(val result: ExportResult) : ExportEvent
 }
 
 class ExportViewModel(container: AppContainer, val imageRepository: ImageRepository): ViewModel() {
@@ -160,7 +161,7 @@ class ExportViewModel(container: AppContainer, val imageRepository: ImageReposit
                     val message = "Failed to prepare $exportFormat export"
                     logger.e("FairScan", message, e)
                     _uiState.update {
-                        it.copy(error = ExportError.OnPrepare(message, e))
+                        it.copy(error = ExportError.OnPrepareOrShare(message, e))
                     }
                 } finally {
                     _uiState.update { it.copy(isGenerating = false) }
@@ -184,29 +185,27 @@ class ExportViewModel(container: AppContainer, val imageRepository: ImageReposit
         ExportResult.Jpeg(files, sizeInBytes)
     }
 
-    fun setAsShared() {
+    private fun renameFile(source: File, target: File) {
-        _uiState.update { it.copy(hasShared = true) }
+        if (source.absolutePath == target.absolutePath) return
+        if (target.exists() && !target.delete()) {
+            throw IOException("Cannot delete existing file ${target.absolutePath}")
+        }
+        if (!source.renameTo(target)) {
+            throw IOException("Failed to rename ${source.name} to ${target.name}")
+        }
     }
 
-    fun applyRenaming(): ExportResult? {
+    private fun applyRenaming(): ExportResult {
-        val result = _uiState.value.result ?: return null
+        val result = _uiState.value.result
+            ?: throw IllegalStateException("Export result missing")
         ensureValidFilename()
         val filename = _uiState.value.filename
-        when (result) {
+        val updated = when (result) {
             is ExportResult.Pdf -> {
                 val fileName = FileManager.addPdfExtensionIfMissing(filename)
                 val newFile = File(result.file.parentFile, fileName)
-                val tempFile = result.file
+                renameFile(result.file, newFile)
-                if (tempFile.absolutePath != newFile.absolutePath) {
+                ExportResult.Pdf(newFile, result.sizeInBytes, result.pageCount)
-                    if (newFile.exists()) newFile.delete()
-                    val success = tempFile.renameTo(newFile)
-                    if (!success) return null
-                    _uiState.update {
-                        it.copy(result = ExportResult.Pdf(
-                            newFile, result.sizeInBytes, result.pageCount)
-                        )
-                    }
-                }
             }
             is ExportResult.Jpeg -> {
                 val base = filename.removeSuffix(".jpg")
@@ -214,17 +213,28 @@ class ExportViewModel(container: AppContainer, val imageRepository: ImageReposit
                 val renamedFiles = files.mapIndexed { index, file ->
                     val indexSuffix = if (files.size == 1) "" else "_${index + 1}"
                     val newFile = File(file.parentFile, "${base}${indexSuffix}.jpg")
-                    if (file.absolutePath != newFile.absolutePath) {
+                    renameFile(file, newFile)
-                        if (newFile.exists()) newFile.delete()
-                        file.renameTo(newFile)
-                    }
                     newFile
                 }
-                val updated = result.copy(jpegFiles = renamedFiles)
+                result.copy(jpegFiles = renamedFiles)
+            }
+        }
         _uiState.update { it.copy(result = updated) }
+        return updated
+    }
+
+    fun onShareClicked() {
+        viewModelScope.launch {
+            try {
+                val result = applyRenaming()
+                _events.emit(ExportEvent.Share(result))
+                _uiState.update { it.copy(hasShared = true) }
+            } catch (e: Exception) {
+                val message = "Failed to prepare share"
+                logger.e("FairScan", message, e)
+                _uiState.update { it.copy(error = ExportError.OnPrepareOrShare(message, e)) }
             }
         }
-        return _uiState.value.result
     }
 
     fun onSaveClicked() {