Automatically select added files (#4325)

# Description of Changes
When adding files, the user probably wants to use them straight away in
the next tool that they use, so automatically select any added files (in
addition to whatever they previously had selected).

frontend/src/contexts/FileContext.tsx

@@ -25,7 +25,7 @@ import {
 // Import modular components
 import { fileContextReducer, initialFileContextState } from './file/FileReducer';
 import { createFileSelectors } from './file/fileSelectors';
-import { addFiles, consumeFiles, createFileActions } from './file/fileActions';
+import { AddedFile, addFiles, consumeFiles, createFileActions } from './file/fileActions';
 import { FileLifecycleManager } from './file/lifecycle';
 import { FileStateContext, FileActionsContext } from './file/contexts';
 import { IndexedDBProvider, useIndexedDB } from './IndexedDBContext';
@@ -72,9 +72,21 @@ function FileContextInner({
     dispatch({ type: 'SET_UNSAVED_CHANGES', payload: { hasChanges } });
   }, []);
 
+  const selectFiles = (addedFilesWithIds: AddedFile[]) => {
+    const currentSelection = stateRef.current.ui.selectedFileIds;
+    const newFileIds = addedFilesWithIds.map(({ id }) => id);
+    dispatch({ type: 'SET_SELECTED_FILES', payload: { fileIds: [...currentSelection, ...newFileIds] } });
+  }
+
   // File operations using unified addFiles helper with persistence
-  const addRawFiles = useCallback(async (files: File[], options?: { insertAfterPageId?: string }): Promise<File[]> => {
+  const addRawFiles = useCallback(async (files: File[], options?: { insertAfterPageId?: string; selectFiles?: boolean }): Promise<File[]> => {
     const addedFilesWithIds = await addFiles('raw', { files, ...options }, stateRef, filesRef, dispatch, lifecycleManager);
+
+    // Auto-select the newly added files if requested
+    if (options?.selectFiles && addedFilesWithIds.length > 0) {
+      selectFiles(addedFilesWithIds);
+    }
+
     // Persist to IndexedDB if enabled
     if (indexedDB && enablePersistence && addedFilesWithIds.length > 0) {
       await Promise.all(addedFilesWithIds.map(async ({ file, id, thumbnail }) => {
@@ -94,8 +106,14 @@ function FileContextInner({
     return result.map(({ file }) => file);
   }, []);
 
-  const addStoredFiles = useCallback(async (filesWithMetadata: Array<{ file: File; originalId: FileId; metadata: any }>): Promise<File[]> => {
+  const addStoredFiles = useCallback(async (filesWithMetadata: Array<{ file: File; originalId: FileId; metadata: any }>, options?: { selectFiles?: boolean }): Promise<File[]> => {
     const result = await addFiles('stored', { filesWithMetadata }, stateRef, filesRef, dispatch, lifecycleManager);
+
+    // Auto-select the newly added files if requested
+    if (options?.selectFiles && result.length > 0) {
+      selectFiles(result);
+    }
+
     return result.map(({ file }) => file);
   }, []);
 

frontend/src/contexts/file/fileActions.ts

@@ -88,6 +88,12 @@ interface AddFileOptions {
   insertAfterPageId?: string;
 }
 
+export interface AddedFile {
+  file: File;
+  id: FileId;
+  thumbnail?: string;
+}
+
 /**
  * Unified file addition helper - replaces addFiles/addProcessedFiles/addStoredFiles
  */
@@ -98,13 +104,13 @@ export async function addFiles(
   filesRef: React.MutableRefObject<Map<FileId, File>>,
   dispatch: React.Dispatch<FileContextAction>,
   lifecycleManager: FileLifecycleManager
-): Promise<Array<{ file: File; id: FileId; thumbnail?: string }>> {
+): Promise<AddedFile[]> {
   // Acquire mutex to prevent race conditions
   await addFilesMutex.lock();
 
   try {
   const fileRecords: FileRecord[] = [];
-  const addedFiles: Array<{ file: File; id: FileId; thumbnail?: string }> = [];
+  const addedFiles: AddedFile[] = [];
 
   // Build quickKey lookup from existing files for deduplication
   const existingQuickKeys = buildQuickKeySet(stateRef.current.files.byId);

frontend/src/hooks/useFileHandler.ts

@@ -9,12 +9,12 @@ export const useFileHandler = () => {
 
   const addToActiveFiles = useCallback(async (file: File) => {
     // Let FileContext handle deduplication with quickKey logic
-    await actions.addFiles([file]);
+    await actions.addFiles([file], { selectFiles: true });
   }, [actions.addFiles]);
 
   const addMultipleFiles = useCallback(async (files: File[]) => {
     // Let FileContext handle deduplication with quickKey logic
-    await actions.addFiles(files);
+    await actions.addFiles(files, { selectFiles: true });
   }, [actions.addFiles]);
 
   // Add stored files preserving their original IDs to prevent session duplicates
@@ -25,7 +25,7 @@ export const useFileHandler = () => {
     });
 
     if (newFiles.length > 0) {
-      await actions.addStoredFiles(newFiles);
+      await actions.addStoredFiles(newFiles, { selectFiles: true });
     }
 
     console.log(`📁 Added ${newFiles.length} stored files (${filesWithMetadata.length - newFiles.length} skipped as duplicates)`);

frontend/src/types/fileContext.ts

@@ -214,9 +214,9 @@ export type FileContextAction =
 
 export interface FileContextActions {
   // File management - lightweight actions only
-  addFiles: (files: File[], options?: { insertAfterPageId?: string }) => Promise<File[]>;
+  addFiles: (files: File[], options?: { insertAfterPageId?: string; selectFiles?: boolean }) => Promise<File[]>;
   addProcessedFiles: (filesWithThumbnails: Array<{ file: File; thumbnail?: string; pageCount?: number }>) => Promise<File[]>;
-  addStoredFiles: (filesWithMetadata: Array<{ file: File; originalId: FileId; metadata: FileMetadata }>) => Promise<File[]>;
+  addStoredFiles: (filesWithMetadata: Array<{ file: File; originalId: FileId; metadata: FileMetadata }>, options?: { selectFiles?: boolean }) => Promise<File[]>;
   removeFiles: (fileIds: FileId[], deleteFromStorage?: boolean) => Promise<void>;
   updateFileRecord: (id: FileId, updates: Partial<FileRecord>) => void;
   reorderFiles: (orderedFileIds: FileId[]) => void;