fix: Replace EPUB Exports Atomically With NativeFile (Closes #1954)

modules/native-file/android/src/main/java/expo/modules/nativefile/NativeFileModule.kt

@@ -1,6 +1,7 @@
 package expo.modules.nativefile
 
 import android.app.Activity
+import android.content.ContentResolver
 import android.content.Intent
 import android.net.Uri
 import android.os.Build
@@ -33,6 +34,7 @@ import java.io.FileWriter
 import java.io.IOException
 import java.io.InputStream
 import java.io.OutputStream
+import java.util.UUID
 import java.io.PushbackInputStream
 import java.util.zip.GZIPInputStream
 import kotlin.coroutines.coroutineContext
@@ -119,9 +121,10 @@ class NativeFileModule : Module() {
         filepath: String,
         destPath: String,
         onDone: (() -> Unit)? = null,
-    ) {
+    ): Long {
         try {
             val inputStream = getInputStream(filepath)
+            var copiedBytes = 0L
             try {
                 val outputStream = getOutputStream(destPath)
                 try {
@@ -130,7 +133,9 @@ class NativeFileModule : Module() {
                     while (inputStream.read(buffer).also { length = it } > 0) {
                         coroutineContext.ensureActive()
                         outputStream.write(buffer, 0, length)
+                        copiedBytes += length
                     }
+                    outputStream.flush()
                 } finally {
                     outputStream.close()
                 }
@@ -140,11 +145,201 @@ class NativeFileModule : Module() {
             if (onDone != null) {
                 onDone()
             }
+            return copiedBytes
         } catch (e: IOException) {
             throw Exception("Failed to copy file from '$filepath' to '$destPath': ${e.message}")
         }
     }
 
+    private fun contentResolver(): ContentResolver =
+        reactContext?.contentResolver
+            ?: throw IOException("React context is unavailable")
+
+    private suspend fun copyToOutputStream(sourcePath: String, outputStream: OutputStream): Long {
+        var copiedBytes = 0L
+        getInputStream(sourcePath).use { inputStream ->
+            outputStream.use { output ->
+                val buffer = ByteArray(BUFFER_SIZE)
+                var length: Int
+                while (inputStream.read(buffer).also { length = it } > 0) {
+                    coroutineContext.ensureActive()
+                    output.write(buffer, 0, length)
+                    copiedBytes += length
+                }
+                output.flush()
+            }
+        }
+        return copiedBytes
+    }
+
+    private fun resolveDirectoryFile(directoryUri: String): File {
+        val uri = Uri.parse(directoryUri)
+        val directory = if (uri.scheme == null) {
+            File(directoryUri)
+        } else if (uri.scheme == ContentResolver.SCHEME_FILE) {
+            File(uri.path ?: throw IOException("Invalid directory URI: '$directoryUri'"))
+        } else {
+            throw IOException("Unsupported filesystem directory URI: '$directoryUri'")
+        }
+        if (!directory.isDirectory) {
+            throw IOException("Destination directory does not exist: '$directoryUri'")
+        }
+        return directory
+    }
+
+    private suspend fun copyFileToFilesystemDirectory(
+        sourcePath: String,
+        directoryUri: String,
+        fileName: String,
+        replace: Boolean,
+    ): Map<String, Any> {
+        val directory = resolveDirectoryFile(directoryUri)
+        val destination = File(directory, fileName)
+        if (destination.exists() && !replace) {
+            throw IOException("File already exists: ${destination.absolutePath}")
+        }
+
+        val staging = File(directory, ".$fileName.${UUID.randomUUID()}.tmp")
+        val backup = File(directory, ".$fileName.${UUID.randomUUID()}.bak")
+        try {
+            val copiedBytes = FileOutputStream(staging).use { output ->
+                copyToOutputStream(sourcePath, output)
+            }
+            if (staging.length() != copiedBytes) {
+                throw IOException("Copied file size does not match the source stream")
+            }
+
+            val hadDestination = destination.exists()
+            if (hadDestination && !destination.renameTo(backup)) {
+                throw IOException("Could not stage the existing destination for replacement")
+            }
+            if (!staging.renameTo(destination)) {
+                if (hadDestination) {
+                    backup.renameTo(destination)
+                }
+                throw IOException("Could not move the completed copy into the destination")
+            }
+            if (backup.exists() && !backup.delete()) {
+                throw IOException("Could not remove the replaced destination backup")
+            }
+            return mapOf("uri" to destination.absolutePath, "size" to copiedBytes)
+        } finally {
+            staging.delete()
+            if (backup.exists() && !destination.exists()) {
+                backup.renameTo(destination)
+            }
+        }
+    }
+
+    private fun resolveTreeDirectoryUri(treeUri: Uri): Uri {
+        if (!DocumentsContract.isTreeUri(treeUri)) {
+            throw IOException("Destination is not a Storage Access Framework directory: '$treeUri'")
+        }
+        val documentId = DocumentsContract.getTreeDocumentId(treeUri)
+        return DocumentsContract.buildDocumentUriUsingTree(treeUri, documentId)
+    }
+
+    private fun findChildDocument(treeUri: Uri, directoryUri: Uri, fileName: String): Uri? {
+        val resolver = contentResolver()
+        val documentId = DocumentsContract.getDocumentId(directoryUri)
+        val childrenUri = DocumentsContract.buildChildDocumentsUriUsingTree(treeUri, documentId)
+        val projection = arrayOf(
+            DocumentsContract.Document.COLUMN_DOCUMENT_ID,
+            DocumentsContract.Document.COLUMN_DISPLAY_NAME,
+        )
+        resolver.query(childrenUri, projection, null, null, null)?.use { cursor ->
+            while (cursor.moveToNext()) {
+                if (cursor.getString(1) == fileName) {
+                    return DocumentsContract.buildDocumentUriUsingTree(treeUri, cursor.getString(0))
+                }
+            }
+        }
+        return null
+    }
+
+    private fun renameDocument(documentUri: Uri, displayName: String): Uri =
+        DocumentsContract.renameDocument(contentResolver(), documentUri, displayName)
+            ?: throw IOException("Could not rename destination document to '$displayName'")
+
+    private suspend fun copyFileToSafDirectory(
+        sourcePath: String,
+        directoryUriString: String,
+        fileName: String,
+        mimeType: String,
+        replace: Boolean,
+    ): Map<String, Any> {
+        val resolver = contentResolver()
+        val treeUri = Uri.parse(directoryUriString)
+        val directoryUri = resolveTreeDirectoryUri(treeUri)
+        val existing = findChildDocument(treeUri, directoryUri, fileName)
+        if (existing != null && !replace) {
+            throw IOException("File already exists: $fileName")
+        }
+
+        val token = UUID.randomUUID().toString()
+        val stagingName = "$fileName.lnreader-$token.tmp"
+        val backupName = "$fileName.lnreader-$token.bak"
+        var stagingUri = DocumentsContract.createDocument(
+            resolver,
+            directoryUri,
+            mimeType,
+            stagingName,
+        ) ?: throw IOException("Could not create a temporary destination document")
+        var backupUri: Uri? = null
+        var completedUri: Uri? = null
+
+        try {
+            val copiedBytes = copyToOutputStream(
+                sourcePath,
+                resolver.openOutputStream(stagingUri, writeAccessByAPILevel)
+                    ?: throw IOException("Could not open the temporary destination document"),
+            )
+
+            if (existing != null) {
+                backupUri = renameDocument(existing, backupName)
+            }
+            try {
+                completedUri = renameDocument(stagingUri, fileName)
+                stagingUri = completedUri
+            } catch (error: Exception) {
+                backupUri?.let {
+                    try {
+                        renameDocument(it, fileName)
+                        backupUri = null
+                    } catch (_: Exception) {
+                        // Keep the original replacement error.
+                    }
+                }
+                throw error
+            }
+
+            backupUri?.let {
+                try {
+                    DocumentsContract.deleteDocument(resolver, it)
+                } catch (_: Exception) {
+                    // The completed destination is already in place.
+                }
+                backupUri = null
+            }
+            return mapOf("uri" to completedUri.toString(), "size" to copiedBytes)
+        } finally {
+            if (completedUri == null) {
+                try {
+                    DocumentsContract.deleteDocument(resolver, stagingUri)
+                } catch (_: Exception) {
+                    // Preserve the original copy or replacement error.
+                }
+            }
+            if (completedUri == null) backupUri?.let {
+                try {
+                    renameDocument(it, fileName)
+                } catch (_: Exception) {
+                    // Preserve the original copy or replacement error.
+                }
+            }
+        }
+    }
+
     private suspend fun deleteRecursive(fileOrDirectory: File) {
         coroutineContext.ensureActive()
         if (fileOrDirectory.isDirectory) {
@@ -262,6 +457,25 @@ class NativeFileModule : Module() {
             }
         }
 
+        AsyncFunction("copyFileToDirectory") { sourcePath: String, directoryUri: String, fileName: String, mimeType: String, replace: Boolean, promise: Promise ->
+            coroutineScope.launch {
+                try {
+                    require(fileName.isNotBlank() && fileName != "." && fileName != ".." && !fileName.contains('/') && !fileName.contains('\\')) {
+                        "Invalid destination file name"
+                    }
+                    val uri = Uri.parse(directoryUri)
+                    val result = if (uri.scheme == ContentResolver.SCHEME_CONTENT) {
+                        copyFileToSafDirectory(sourcePath, directoryUri, fileName, mimeType, replace)
+                    } else {
+                        copyFileToFilesystemDirectory(sourcePath, directoryUri, fileName, replace)
+                    }
+                    promise.resolve(result)
+                } catch (e: Exception) {
+                    rejectFileOperation(promise, "copy into directory", directoryUri, e)
+                }
+            }
+        }
+
         AsyncFunction("moveFile") { filepath: String, destPath: String, promise: Promise ->
             coroutineScope.launch {
                 try {

modules/native-file/ios/NativeFileModule.swift

@@ -17,6 +17,55 @@ public class NativeFileModule: Module {
       try FileManager.default.copyItem(atPath: sourcePath, toPath: destPath)
     }
 
+    AsyncFunction("copyFileToDirectory") { (sourcePath: String, directoryUri: String, fileName: String, mimeType: String, replace: Bool) -> [String: Any] in
+      _ = mimeType
+      guard !fileName.isEmpty,
+            fileName != ".",
+            fileName != "..",
+            !fileName.contains("/"),
+            !fileName.contains("\\") else {
+        throw NSError(
+          domain: "NativeFile",
+          code: 1,
+          userInfo: [NSLocalizedDescriptionKey: "Invalid destination file name"]
+        )
+      }
+
+      let fileManager = FileManager.default
+      let directoryURL: URL
+      if let parsedURL = URL(string: directoryUri), parsedURL.isFileURL {
+        directoryURL = parsedURL
+      } else {
+        directoryURL = URL(fileURLWithPath: directoryUri, isDirectory: true)
+      }
+      let sourceURL = URL(fileURLWithPath: sourcePath)
+      let destinationURL = directoryURL.appendingPathComponent(fileName)
+      let stagingURL = directoryURL.appendingPathComponent(".\(fileName).\(UUID().uuidString).tmp")
+
+      guard fileManager.fileExists(atPath: directoryURL.path) else {
+        throw NSError(
+          domain: "NativeFile",
+          code: 2,
+          userInfo: [NSLocalizedDescriptionKey: "Destination directory does not exist"]
+        )
+      }
+      if fileManager.fileExists(atPath: destinationURL.path) && !replace {
+        throw CocoaError(.fileWriteFileExists)
+      }
+
+      defer { try? fileManager.removeItem(at: stagingURL) }
+      try fileManager.copyItem(at: sourceURL, to: stagingURL)
+      let attributes = try fileManager.attributesOfItem(atPath: stagingURL.path)
+      let copiedSize = (attributes[.size] as? NSNumber)?.int64Value ?? 0
+
+      if fileManager.fileExists(atPath: destinationURL.path) {
+        _ = try fileManager.replaceItemAt(destinationURL, withItemAt: stagingURL)
+      } else {
+        try fileManager.moveItem(at: stagingURL, to: destinationURL)
+      }
+      return ["uri": destinationURL.absoluteString, "size": copiedSize]
+    }
+
     Function("moveFile") { (sourcePath: String, destPath: String) in
       try FileManager.default.moveItem(atPath: sourcePath, toPath: destPath)
     }

modules/native-file/src/NativeFileModule.ts

@@ -11,6 +11,11 @@ export type DirectorySelection = {
   name: string;
 };
 
+export type FileCopyResult = {
+  uri: string;
+  size: number;
+};
+
 type NativeFileModule = {
   DocumentDirectoryPath: string;
   ExternalDirectoryPath: string;
@@ -21,6 +26,13 @@ type NativeFileModule = {
   writeFile(path: string, content: string): Promise<void>;
   readFile(path: string): Promise<string>;
   copyFile(filepath: string, destPath: string): Promise<void>;
+  copyFileToDirectory(
+    sourcePath: string,
+    directoryUri: string,
+    fileName: string,
+    mimeType: string,
+    replace: boolean,
+  ): Promise<FileCopyResult>;
   moveFile(filepath: string, destPath: string): Promise<void>;
   exists(filepath: string): Promise<boolean>;
   mkdir(filepath: string): Promise<void>;

package.json

@@ -90,7 +90,6 @@
     "react-native-pager-view": "^8.0.2",
     "react-native-paper": "^5.15.3",
     "react-native-reanimated": "^4.5.0",
-    "react-native-saf-x": "^2.2.3",
     "react-native-safe-area-context": "^5.7.0",
     "react-native-screens": "^4.25.2",
     "react-native-shimmer-placeholder": "^2.0.9",
@@ -151,7 +150,6 @@
           "nitro-epub",
           "native-background-tasks",
           "@react-native-vector-icons/material-design-icons",
-          "react-native-saf-x",
           "lottie-ios"
         ]
       }

pnpm-lock.yaml

@@ -173,9 +173,6 @@ importers:
       react-native-reanimated:
         specifier: ^4.5.0
         version: 4.5.2(react-native-worklets@0.10.2(@babel/core@7.29.7(supports-color@9.4.0))(@react-native/metro-config@0.86.0(@babel/core@7.29.7(supports-color@9.4.0))(supports-color@9.4.0))(react-native@0.86.0(@babel/core@7.29.7(supports-color@9.4.0))(@react-native/jest-preset@0.86.0(@babel/core@7.29.7(supports-color@9.4.0))(react@19.2.3)(supports-color@9.4.0))(@react-native/metro-config@0.86.0(@babel/core@7.29.7(supports-color@9.4.0))(supports-color@9.4.0))(@types/react@19.2.17)(react@19.2.3)(supports-color@9.4.0))(react@19.2.3)(supports-color@9.4.0))(react-native@0.86.0(@babel/core@7.29.7(supports-color@9.4.0))(@react-native/jest-preset@0.86.0(@babel/core@7.29.7(supports-color@9.4.0))(react@19.2.3)(supports-color@9.4.0))(@react-native/metro-config@0.86.0(@babel/core@7.29.7(supports-color@9.4.0))(supports-color@9.4.0))(@types/react@19.2.17)(react@19.2.3)(supports-color@9.4.0))(react@19.2.3)
-      react-native-saf-x:
-        specifier: ^2.2.3
-        version: 2.2.3(react-native@0.86.0(@babel/core@7.29.7(supports-color@9.4.0))(@react-native/jest-preset@0.86.0(@babel/core@7.29.7(supports-color@9.4.0))(react@19.2.3)(supports-color@9.4.0))(@react-native/metro-config@0.86.0(@babel/core@7.29.7(supports-color@9.4.0))(supports-color@9.4.0))(@types/react@19.2.17)(react@19.2.3)(supports-color@9.4.0))(react@19.2.3)
       react-native-safe-area-context:
         specifier: ^5.7.0
         version: 5.8.0(react-native@0.86.0(@babel/core@7.29.7(supports-color@9.4.0))(@react-native/jest-preset@0.86.0(@babel/core@7.29.7(supports-color@9.4.0))(react@19.2.3)(supports-color@9.4.0))(@react-native/metro-config@0.86.0(@babel/core@7.29.7(supports-color@9.4.0))(supports-color@9.4.0))(@types/react@19.2.17)(react@19.2.3)(supports-color@9.4.0))(react@19.2.3)
@@ -5244,12 +5241,6 @@ packages:
       react-native: 0.83 - 0.86
       react-native-worklets: 0.10.x - 0.11.x
 
-  react-native-saf-x@2.2.3:
-    resolution: {integrity: sha512-aPQbUfuHy8txZ/+t8Daoy8G3aRZ5H+0/SH9mJdb6quvxvt48jeIjq2n82anV77tSCXyX0du955PrtWpRzYliPQ==}
-    peerDependencies:
-      react: '*'
-      react-native: '*'
-
   react-native-safe-area-context@5.8.0:
     resolution: {integrity: sha512-t+ZsAVzY/wWzzx34vqGbo3/as9EEESJdbyZNL7Yg5EYX+toYMtMqFoDDCvqZUi35eeGVsXc6pAaEk4edMwbuCQ==}
     peerDependencies:
@@ -12196,11 +12187,6 @@ snapshots:
       react-native-worklets: 0.10.2(@babel/core@7.29.7(supports-color@9.4.0))(@react-native/metro-config@0.86.0(@babel/core@7.29.7(supports-color@9.4.0))(supports-color@9.4.0))(react-native@0.86.0(@babel/core@7.29.7(supports-color@9.4.0))(@react-native/jest-preset@0.86.0(@babel/core@7.29.7(supports-color@9.4.0))(react@19.2.3)(supports-color@9.4.0))(@react-native/metro-config@0.86.0(@babel/core@7.29.7(supports-color@9.4.0))(supports-color@9.4.0))(@types/react@19.2.17)(react@19.2.3)(supports-color@9.4.0))(react@19.2.3)(supports-color@9.4.0)
       semver: 7.8.5
 
-  react-native-saf-x@2.2.3(react-native@0.86.0(@babel/core@7.29.7(supports-color@9.4.0))(@react-native/jest-preset@0.86.0(@babel/core@7.29.7(supports-color@9.4.0))(react@19.2.3)(supports-color@9.4.0))(@react-native/metro-config@0.86.0(@babel/core@7.29.7(supports-color@9.4.0))(supports-color@9.4.0))(@types/react@19.2.17)(react@19.2.3)(supports-color@9.4.0))(react@19.2.3):
-    dependencies:
-      react: 19.2.3
-      react-native: 0.86.0(@babel/core@7.29.7(supports-color@9.4.0))(@react-native/jest-preset@0.86.0(@babel/core@7.29.7(supports-color@9.4.0))(react@19.2.3)(supports-color@9.4.0))(@react-native/metro-config@0.86.0(@babel/core@7.29.7(supports-color@9.4.0))(supports-color@9.4.0))(@types/react@19.2.17)(react@19.2.3)(supports-color@9.4.0)
-
   react-native-safe-area-context@5.8.0(react-native@0.86.0(@babel/core@7.29.7(supports-color@9.4.0))(@react-native/jest-preset@0.86.0(@babel/core@7.29.7(supports-color@9.4.0))(react@19.2.3)(supports-color@9.4.0))(@react-native/metro-config@0.86.0(@babel/core@7.29.7(supports-color@9.4.0))(supports-color@9.4.0))(@types/react@19.2.17)(react@19.2.3)(supports-color@9.4.0))(react@19.2.3):
     dependencies:
       react: 19.2.3

src/screens/novel/components/ExportEpubModal.tsx

@@ -1,9 +1,9 @@
 import React, { useState } from 'react';
 import { Pressable, ScrollView, StyleSheet, View } from 'react-native';
 import { HelperText, TextInput } from 'react-native-paper';
-import { openDocumentTree } from 'react-native-saf-x';
 
 import { Dialog, SwitchItem } from '@components';
+import NativeFile from '@modules/native-file';
 
 import { useBoolean } from '@hooks';
 import { getString } from '@i18n/translations';
@@ -138,10 +138,8 @@ const ExportEpubModal: React.FC<ExportEpubModalProps> = ({
 
   const openFolderPicker = async () => {
     try {
-      const resultUri = await openDocumentTree(true);
-      if (resultUri) {
-        setUri(resultUri.uri);
-      }
+      const result = await NativeFile.pickDirectory();
+      setUri(result.uri);
     } catch (error) {
       showToast(error instanceof Error ? error.message : String(error));
     }

src/screens/novel/components/ExportNovelAsEpubButton.tsx

@@ -1,9 +1,9 @@
 import React, { useMemo } from 'react';
 import { Portal } from 'react-native-paper';
 import { StatusBar } from 'react-native';
-import { openDocumentTree } from 'react-native-saf-x';
 
 import { type EpubExportChapter } from '@modules/nitro-epub';
+import NativeFile from '@modules/native-file';
 
 import { NovelInfo } from '@database/types';
 import { useChapterReaderSettings, useTheme } from '@hooks/persisted';
@@ -125,10 +125,7 @@ const ExportNovelAsEpubButton: React.FC<ExportNovelAsEpubButtonProps> = ({
 
       let resolvedDestinationUri = destinationUri;
       if (!resolvedDestinationUri) {
-        const selectedFolder = await openDocumentTree(true);
-        if (!selectedFolder) {
-          return;
-        }
+        const selectedFolder = await NativeFile.pickDirectory();
         resolvedDestinationUri = selectedFolder.uri;
       }
 

src/screens/novel/components/__tests__/NovelScreenList.test.tsx

@@ -167,9 +167,14 @@ jest.mock('@utils/showToast', () => ({
 }));
 
 jest.mock('@modules/native-file', () => ({
-  ExternalCachesDirectoryPath: '/tmp',
-  copyFile: jest.fn(),
-  unlink: jest.fn(),
+  __esModule: true,
+  default: {
+    ExternalCachesDirectoryPath: '/tmp',
+    copyFile: jest.fn(),
+    copyFileToDirectory: jest.fn(),
+    pickDirectory: jest.fn(),
+    unlink: jest.fn(),
+  },
 }));
 
 jest.mock('@plugins/helpers/fetch', () => ({

src/screens/updates/__tests__/UpdatesScreen.test.tsx

@@ -0,0 +1,93 @@
+import { render } from '@testing-library/react-native';
+import { useFocusEffect } from '@react-navigation/native';
+
+import UpdatesScreen from '../UpdatesScreen';
+
+const mockGetUpdates = jest.fn();
+
+jest.mock('@components', () => {
+  const ReactModule = require('react');
+
+  return {
+    EmptyView: () => null,
+    ErrorScreenV2: () => null,
+    SearchbarV2: () => null,
+    SafeAreaView: ({ children }: { children: React.ReactNode }) =>
+      ReactModule.createElement(ReactModule.Fragment, null, children),
+  };
+});
+
+jest.mock('@components/Context/UpdateContext', () => ({
+  useUpdateContext: () => ({
+    updatesOverview: [],
+    getUpdates: mockGetUpdates,
+    lastUpdateTime: undefined,
+    showLastUpdateTime: true,
+    error: '',
+  }),
+}));
+
+jest.mock('@hooks', () => ({
+  useSearch: () => ({
+    searchText: '',
+    setSearchText: jest.fn(),
+    clearSearchbar: jest.fn(),
+  }),
+}));
+
+jest.mock('@hooks/persisted', () => ({
+  useAppSettings: () => ({}),
+  useTheme: () => ({
+    background: '#000000',
+    onPrimary: '#ffffff',
+    onSurface: '#ffffff',
+    primary: '#000000',
+  }),
+}));
+
+jest.mock('@i18n/translations', () => ({
+  getString: (key: string) => key,
+}));
+
+jest.mock('@database/queries/ChapterQueries', () => ({
+  deleteChapter: jest.fn(),
+}));
+
+jest.mock('@services/backgroundTasks', () => ({
+  backgroundTasks: { enqueue: jest.fn() },
+}));
+
+jest.mock('@utils/dateFormat', () => ({
+  formatDate: (date: string) => date,
+}));
+
+jest.mock('../components/UpdateNovelChapterGroup', () => () => null);
+
+const mockUseFocusEffect = useFocusEffect as jest.MockedFunction<
+  typeof useFocusEffect
+>;
+
+describe('UpdatesScreen', () => {
+  beforeEach(() => {
+    mockGetUpdates.mockReset();
+  });
+
+  it('reloads the update overview when the Updates screen gains focus', () => {
+    const navigation = {
+      addListener: jest.fn(() => jest.fn()),
+      isFocused: jest.fn(() => false),
+      navigate: jest.fn(),
+    };
+
+    render(
+      <UpdatesScreen navigation={navigation as never} route={{} as never} />,
+    );
+
+    const focusCallback = mockUseFocusEffect.mock.calls.at(-1)?.[0];
+    expect(focusCallback).toBeDefined();
+
+    focusCallback?.();
+
+    expect(mockGetUpdates).toHaveBeenCalledTimes(1);
+  });
+});

src/services/epub/__tests__/export.test.ts

@@ -0,0 +1,123 @@
+import NativeFile from '@modules/native-file';
+import { epub } from '@modules/nitro-epub';
+import type {
+  BackgroundTaskMetadata,
+  EpubExportData,
+} from '@services/backgroundTasks/contracts';
+import { exportEpub } from '../export';
+
+jest.mock('@modules/nitro-epub', () => ({
+  epub: {
+    exportEpub: jest.fn(),
+  },
+}));
+
+jest.mock('@i18n/translations', () => ({
+  getString: (key: string) => key,
+}));
+
+const data: EpubExportData = {
+  novelName: 'Example Novel',
+  destinationUri: '/storage/emulated/0/Download',
+  fileName: 'Example Novel.epub',
+  chapters: [
+    {
+      title: 'Chapter 1',
+      htmlPath: '/novels/1/1/index.html',
+      novelId: '1',
+      chapterId: '1',
+    },
+  ],
+  metadata: {
+    title: 'Example Novel',
+    language: 'en',
+    coverPath: '',
+    description: '',
+    author: '',
+    bookId: 'urn:lnreader:test',
+    stylesheet: '',
+    javascript: '',
+  },
+};
+
+const createProgressUpdater = () => {
+  let metadata: BackgroundTaskMetadata = {
+    name: 'Exporting EPUB',
+    isRunning: false,
+    progress: 0,
+    progressText: '',
+  };
+  return {
+    getMetadata: () => metadata,
+    updateProgress: jest.fn(transformer => {
+      metadata = transformer(metadata);
+    }),
+  };
+};
+
+describe('exportEpub', () => {
+  beforeEach(() => {
+    jest.spyOn(Date, 'now').mockReturnValue(1234);
+    jest.mocked(epub.exportEpub).mockResolvedValue({
+      outputPath: '/mock/caches/epub-export-1234.epub',
+      chapterCount: 1,
+    });
+    jest.mocked(NativeFile.copyFileToDirectory).mockResolvedValue({
+      uri: '/storage/emulated/0/Download/Example Novel.epub',
+      size: 4096,
+    });
+    jest.mocked(NativeFile.exists).mockResolvedValue(true);
+    jest.mocked(NativeFile.unlink).mockResolvedValue(undefined);
+  });
+
+  it('replaces the named destination through NativeFile', async () => {
+    const progress = createProgressUpdater();
+
+    await exportEpub(data, progress.updateProgress);
+
+    expect(NativeFile.copyFileToDirectory).toHaveBeenCalledWith(
+      '/mock/caches/epub-export-1234.epub',
+      '/storage/emulated/0/Download',
+      'Example Novel.epub',
+      'application/epub+zip',
+      true,
+    );
+    expect(progress.getMetadata()).toMatchObject({
+      isRunning: false,
+      progress: 1,
+      completionText: 'novelScreen.epub.exportSuccess',
+    });
+  });
+
+  it('rejects an empty destination copy instead of reporting success', async () => {
+    jest.mocked(NativeFile.copyFileToDirectory).mockResolvedValue({
+      uri: '/storage/emulated/0/Download/Example Novel.epub',
+      size: 0,
+    });
+    const progress = createProgressUpdater();
+
+    await expect(exportEpub(data, progress.updateProgress)).rejects.toThrow(
+      'Exported EPUB is empty',
+    );
+
+    expect(progress.getMetadata().completionText).toBeUndefined();
+    expect(NativeFile.unlink).toHaveBeenCalledWith(
+      '/mock/caches/epub-export-1234.epub',
+    );
+  });
+
+  it('cleans up the generated cache file when destination replacement fails', async () => {
+    jest
+      .mocked(NativeFile.copyFileToDirectory)
+      .mockRejectedValue(new Error('Destination replacement failed'));
+    const progress = createProgressUpdater();
+
+    await expect(exportEpub(data, progress.updateProgress)).rejects.toThrow(
+      'Destination replacement failed',
+    );
+
+    expect(NativeFile.unlink).toHaveBeenCalledWith(
+      '/mock/caches/epub-export-1234.epub',
+    );
+  });
+});

src/services/epub/export.ts

@@ -1,5 +1,3 @@
-import { copyFile } from 'react-native-saf-x';
-
 import NativeFile from '@modules/native-file';
 import { epub } from '@modules/nitro-epub';
 
@@ -77,11 +75,16 @@ export const exportEpub = async (
     }));
 
     const epubFileName = `${sanitizeEpubFileName(fileName)}.epub`;
-    await copyFile(
-      `file://${result.outputPath}`,
-      `${destinationUri}/${epubFileName}`,
-      { replaceIfDestinationExists: true },
+    const copyResult = await NativeFile.copyFileToDirectory(
+      result.outputPath,
+      destinationUri,
+      epubFileName,
+      'application/epub+zip',
+      true,
     );
+    if (copyResult.size <= 0) {
+      throw new Error('Exported EPUB is empty');
+    }
 
     const completionText = getString('novelScreen.epub.exportSuccess', {
       chapters: result.chapterCount.toString(),

test/mocks/nativeModules.js

@@ -10,6 +10,12 @@ jest.mock('@modules/native-file', () => ({
     writeFile: jest.fn(),
     readFile: jest.fn(() => ''),
     copyFile: jest.fn(),
+    copyFileToDirectory: jest.fn(() =>
+      Promise.resolve({ uri: '/mock/export.epub', size: 1 }),
+    ),
+    pickDirectory: jest.fn(() =>
+      Promise.resolve({ uri: '/mock/export', name: 'export' }),
+    ),
     moveFile: jest.fn(),
     exists: jest.fn(() => true),
     mkdir: jest.fn(),