1 files changed, 183 insertions, 0 deletions
diff --git a/packages/cli/src/ui/hooks/atCommandProcessor.ts b/packages/cli/src/ui/hooks/atCommandProcessor.ts
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+++ b/packages/cli/src/ui/hooks/atCommandProcessor.ts
@@ -0,0 +1,183 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { PartListUnion } from '@google/genai';
+import { Config, getErrorMessage } from '@gemini-code/server';
+import {
+  HistoryItem,
+  IndividualToolCallDisplay,
+  ToolCallStatus,
+} from '../types.js';
+
+// Helper function to add history items (could be moved to a shared util if needed elsewhere)
+const addHistoryItem = (
+  setHistory: React.Dispatch<React.SetStateAction<HistoryItem[]>>,
+  itemData: Omit<HistoryItem, 'id'>,
+  id: number,
+) => {
+  setHistory((prevHistory) => [
+    ...prevHistory,
+    { ...itemData, id } as HistoryItem,
+  ]);
+};
+
+interface HandleAtCommandParams {
+  query: string; // Raw user input
+  config: Config;
+  setHistory: React.Dispatch<React.SetStateAction<HistoryItem[]>>;
+  setDebugMessage: React.Dispatch<React.SetStateAction<string>>;
+  getNextMessageId: (baseTimestamp: number) => number;
+  userMessageTimestamp: number;
+}
+
+interface HandleAtCommandResult {
+  processedQuery: PartListUnion; // Query to potentially send to Gemini
+  shouldProceed: boolean; // Whether the main hook should continue processing
+}
+
+/**
+ * Processes user input that might start with the '@' command to read files/directories.
+ * If it's an '@' command, it attempts to read the specified path, updates the UI
+ * with the tool call status, and prepares the query to be sent to the LLM.
+ *
+ * @returns An object containing the potentially modified query and a flag
+ *          indicating if the main hook should proceed with the Gemini API call.
+ */
+export async function handleAtCommand({
+  query,
+  config,
+  setHistory,
+  setDebugMessage,
+  getNextMessageId,
+  userMessageTimestamp,
+}: HandleAtCommandParams): Promise<HandleAtCommandResult> {
+  const trimmedQuery = query.trim();
+
+  if (!trimmedQuery.startsWith('@')) {
+    // Not an '@' command, proceed as normal
+    // Add the user message here before returning
+    addHistoryItem(
+      setHistory,
+      { type: 'user', text: query },
+      userMessageTimestamp,
+    );
+    // Use property shorthand for processedQuery
+    return { processedQuery: query, shouldProceed: true };
+  }
+
+  // --- It is an '@' command ---
+  const filePath = trimmedQuery.substring(1);
+
+  if (!filePath) {
+    // Handle case where it's just "@" - treat as normal input
+    addHistoryItem(
+      setHistory,
+      { type: 'user', text: query },
+      userMessageTimestamp,
+    );
+    // Use property shorthand for processedQuery
+    return { processedQuery: query, shouldProceed: true }; // Send the "@" to the model
+  }
+
+  const toolRegistry = config.getToolRegistry();
+  const readManyFilesTool = toolRegistry.getTool('read_many_files');
+
+  // Add user message first, so it appears before potential errors/tool UI
+  addHistoryItem(
+    setHistory,
+    { type: 'user', text: query },
+    userMessageTimestamp,
+  );
+
+  if (!readManyFilesTool) {
+    const errorTimestamp = getNextMessageId(userMessageTimestamp);
+    addHistoryItem(
+      setHistory,
+      { type: 'error', text: 'Error: read_many_files tool not found.' },
+      errorTimestamp,
+    );
+    // Use property shorthand for processedQuery
+    return { processedQuery: query, shouldProceed: false }; // Don't proceed if tool is missing
+  }
+
+  // --- Path Handling for @ command ---
+  let pathSpec = filePath;
+  // Basic check: If no extension or ends with '/', assume directory and add globstar.
+  if (!filePath.includes('.') || filePath.endsWith('/')) {
+    pathSpec = filePath.endsWith('/') ? `${filePath}**` : `${filePath}/**`;
+  }
+  const toolArgs = { paths: [pathSpec] };
+  const contentLabel =
+    pathSpec === filePath ? filePath : `directory ${filePath}`; // Adjust label
+  // --- End Path Handling ---
+
+  let toolCallDisplay: IndividualToolCallDisplay;
+  let processedQuery: PartListUnion = query; // Default to original query
+
+  try {
+    setDebugMessage(`Reading via @ command: ${pathSpec}`);
+    const result = await readManyFilesTool.execute(toolArgs);
+    const fileContent = result.llmContent || '';
+
+    // Construct success UI
+    toolCallDisplay = {
+      callId: `client-read-${userMessageTimestamp}`,
+      name: readManyFilesTool.displayName,
+      description: readManyFilesTool.getDescription(toolArgs),
+      status: ToolCallStatus.Success,
+      resultDisplay: result.returnDisplay,
+      confirmationDetails: undefined,
+    };
+
+    // Prepend file content to the query sent to the model
+    processedQuery = [
+      {
+        text: `--- Content from: ${contentLabel} ---
+${fileContent}
+--- End Content ---`,
+      },
+      // TODO: Handle cases like "@README.md explain this" by appending the rest of the query
+    ];
+
+    // Add the tool group UI
+    const toolGroupId = getNextMessageId(userMessageTimestamp);
+    addHistoryItem(
+      setHistory,
+      { type: 'tool_group', tools: [toolCallDisplay] } as Omit<
+        HistoryItem,
+        'id'
+      >,
+      toolGroupId,
+    );
+
+    // Use property shorthand for processedQuery
+    return { processedQuery, shouldProceed: true }; // Proceed to Gemini
+  } catch (error) {
+    // Construct error UI
+    toolCallDisplay = {
+      callId: `client-read-${userMessageTimestamp}`,
+      name: readManyFilesTool.displayName,
+      description: readManyFilesTool.getDescription(toolArgs),
+      status: ToolCallStatus.Error,
+      resultDisplay: `Error reading ${contentLabel}: ${getErrorMessage(error)}`,
+      confirmationDetails: undefined,
+    };
+
+    // Add the tool group UI and signal not to proceed
+    const toolGroupId = getNextMessageId(userMessageTimestamp);
+    addHistoryItem(
+      setHistory,
+      { type: 'tool_group', tools: [toolCallDisplay] } as Omit<
+        HistoryItem,
+        'id'
+      >,
+      toolGroupId,
+    );
+
+    // Use property shorthand for processedQuery
+    return { processedQuery: query, shouldProceed: false }; // Don't proceed on error
+  }
+}