Adding in a history buffer (#38)

Up and down arrows traverse the command history.

4 files changed, 164 insertions, 18 deletions

diff --git a/packages/cli/src/ui/App.tsx b/packages/cli/src/ui/App.tsx
index 860663ce..5b4890e3 100644
--- a/packages/cli/src/ui/App.tsx
+++ b/packages/cli/src/ui/App.tsx
@@ -4,11 +4,12 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-import React, { useState } from 'react';
+import React, { useState, useMemo } from 'react';
 import { Box, Text } from 'ink';
 import type { HistoryItem } from './types.js';
 import { useGeminiStream } from './hooks/useGeminiStream.js';
 import { useLoadingIndicator } from './hooks/useLoadingIndicator.js';
+import { useInputHistory } from './hooks/useInputHistory.js';
 import { Header } from './components/Header.js';
 import { Tips } from './components/Tips.js';
 import { HistoryDisplay } from './components/HistoryDisplay.js';
@@ -16,7 +17,6 @@ import { LoadingIndicator } from './components/LoadingIndicator.js';
 import { InputPrompt } from './components/InputPrompt.js';
 import { Footer } from './components/Footer.js';
 import { StreamingState } from '../core/gemini-stream.js';
-import { PartListUnion } from '@google/genai';
 import { ITermDetectionWarning } from './utils/itermDetection.js';
 import {
   useStartupWarnings,
@@ -28,7 +28,6 @@ interface AppProps {
 }
 
 export const App = ({ directory }: AppProps) => {
-  const [query, setQuery] = useState('');
   const [history, setHistory] = useState<HistoryItem[]>([]);
   const [startupWarnings, setStartupWarnings] = useState<string[]>([]);
   const { streamingState, submitQuery, initError } =
@@ -39,22 +38,39 @@ export const App = ({ directory }: AppProps) => {
   useStartupWarnings(setStartupWarnings);
   useInitializationErrorEffect(initError, history, setHistory);
 
-  const handleInputSubmit = (value: PartListUnion) => {
-    submitQuery(value)
-      .then(() => {
-        setQuery('');
-      })
-      .catch(() => {
-        setQuery('');
-      });
-  };
+  const userMessages = useMemo(
+    () =>
+      history
+        .filter(
+          (item): item is HistoryItem & { type: 'user'; text: string } =>
+            item.type === 'user' &&
+            typeof item.text === 'string' &&
+            item.text.trim() !== '',
+        )
+        .map((item) => item.text),
+    [history],
+  );
 
   const isWaitingForToolConfirmation = history.some(
     (item) =>
       item.type === 'tool_group' &&
       item.tools.some((tool) => tool.confirmationDetails !== undefined),
   );
-  const isInputActive = streamingState === StreamingState.Idle && !initError;
+  const isInputActive =
+    streamingState === StreamingState.Idle &&
+    !initError &&
+    !isWaitingForToolConfirmation;
+
+  const {
+    query,
+    setQuery,
+    handleSubmit: handleHistorySubmit,
+    inputKey,
+  } = useInputHistory({
+    userMessages,
+    onSubmit: submitQuery,
+    isActive: isInputActive,
+  });
 
   return (
     <Box flexDirection="column" padding={1} marginBottom={1} width="100%">
@@ -111,7 +127,7 @@ export const App = ({ directory }: AppProps) => {
         )}
 
       <Box flexDirection="column">
-        <HistoryDisplay history={history} onSubmit={handleInputSubmit} />
+        <HistoryDisplay history={history} onSubmit={submitQuery} />
         <LoadingIndicator
           isLoading={streamingState === StreamingState.Responding}
           currentLoadingPhrase={currentLoadingPhrase}
@@ -119,12 +135,13 @@ export const App = ({ directory }: AppProps) => {
         />
       </Box>
 
-      {!isWaitingForToolConfirmation && isInputActive && (
+      {isInputActive && (
         <InputPrompt
           query={query}
           setQuery={setQuery}
-          onSubmit={handleInputSubmit}
+          onSubmit={handleHistorySubmit}
           isActive={isInputActive}
+          forceKey={inputKey}
         />
       )}
 
diff --git a/packages/cli/src/ui/components/InputPrompt.tsx b/packages/cli/src/ui/components/InputPrompt.tsx
index 3b6b10b1..b5d0b2b5 100644
--- a/packages/cli/src/ui/components/InputPrompt.tsx
+++ b/packages/cli/src/ui/components/InputPrompt.tsx
@@ -14,12 +14,15 @@ interface InputPromptProps {
   setQuery: (value: string) => void;
   onSubmit: (value: string) => void;
   isActive: boolean;
+  forceKey?: number;
 }
 
 export const InputPrompt: React.FC<InputPromptProps> = ({
   query,
   setQuery,
   onSubmit,
+  isActive,
+  forceKey,
 }) => {
   const model = globalConfig.getModel();
 
@@ -28,11 +31,12 @@ export const InputPrompt: React.FC<InputPromptProps> = ({
       <Text color={'white'}>&gt; </Text>
       <Box flexGrow={1}>
         <TextInput
+          key={forceKey?.toString()}
           value={query}
           onChange={setQuery}
           onSubmit={onSubmit}
           showCursor={true}
-          focus={true}
+          focus={isActive}
           placeholder={`Ask Gemini (${model})... (try "/init" or "/help")`}
         />
       </Box>
diff --git a/packages/cli/src/ui/hooks/useGeminiStream.ts b/packages/cli/src/ui/hooks/useGeminiStream.ts
index dc108701..8cbb5f51 100644
--- a/packages/cli/src/ui/hooks/useGeminiStream.ts
+++ b/packages/cli/src/ui/hooks/useGeminiStream.ts
@@ -112,7 +112,7 @@ export const useGeminiStream = (
 
           const maybeCommand = trimmedQuery.split(/\s+/)[0];
           if (allowlistedCommands.includes(maybeCommand)) {
-            exec(trimmedQuery, (error, stdout, stderr) => {
+            exec(trimmedQuery, (error, stdout) => {
               const timestamp = getNextMessageId(userMessageTimestamp);
               // TODO: handle stderr, error
               addHistoryItem(
diff --git a/packages/cli/src/ui/hooks/useInputHistory.ts b/packages/cli/src/ui/hooks/useInputHistory.ts
new file mode 100644
index 00000000..9a6aaacb
--- /dev/null
+++ b/packages/cli/src/ui/hooks/useInputHistory.ts
@@ -0,0 +1,125 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { useState, useCallback } from 'react';
+import { useInput } from 'ink';
+
+// Props for the hook
+interface UseInputHistoryProps {
+  userMessages: readonly string[]; // History of user messages
+  onSubmit: (value: string) => void; // Original submit function from App
+  isActive: boolean; // To enable/disable the useInput hook
+}
+
+// Return type of the hook
+interface UseInputHistoryReturn {
+  query: string; // The current input query managed by the hook
+  setQuery: React.Dispatch<React.SetStateAction<string>>; // Setter for the query
+  handleSubmit: (value: string) => void; // Wrapped submit handler
+  inputKey: number; // Key to force input reset
+}
+
+export function useInputHistory({
+  userMessages,
+  onSubmit,
+  isActive,
+}: UseInputHistoryProps): UseInputHistoryReturn {
+  const [query, setQuery] = useState(''); // Hook manages its own query state
+  const [historyIndex, setHistoryIndex] = useState<number>(-1); // -1 means current query
+  const [originalQueryBeforeNav, setOriginalQueryBeforeNav] =
+    useState<string>('');
+  const [inputKey, setInputKey] = useState<number>(0); // Key for forcing input reset
+
+  // Function to reset navigation state, called on submit or manual reset
+  const resetHistoryNav = useCallback(() => {
+    setHistoryIndex(-1);
+    setOriginalQueryBeforeNav('');
+  }, []);
+
+  // Wrapper for the onSubmit prop to include resetting history navigation
+  const handleSubmit = useCallback(
+    (value: string) => {
+      const trimmedValue = value.trim();
+      if (trimmedValue) {
+        // Only submit non-empty values
+        onSubmit(trimmedValue); // Call the original submit function
+      }
+      setQuery(''); // Clear the input field managed by this hook
+      resetHistoryNav(); // Reset history state
+      // Don't increment inputKey here, only on nav changes
+    },
+    [onSubmit, resetHistoryNav],
+  );
+
+  useInput(
+    (input, key) => {
+      // Do nothing if the hook is not active
+      if (!isActive) {
+        return;
+      }
+
+      let didNavigate = false;
+
+      if (key.upArrow) {
+        if (userMessages.length === 0) return;
+
+        let nextIndex = historyIndex;
+        if (historyIndex === -1) {
+          // Starting navigation UP, save current input
+          setOriginalQueryBeforeNav(query);
+          nextIndex = 0; // Go to the most recent item (index 0 in reversed view)
+        } else if (historyIndex < userMessages.length - 1) {
+          // Continue navigating UP (towards older items)
+          nextIndex = historyIndex + 1;
+        } else {
+          return; // Already at the oldest item
+        }
+
+        if (nextIndex !== historyIndex) {
+          setHistoryIndex(nextIndex);
+          // History is ordered newest to oldest, so access from the end
+          const newValue = userMessages[userMessages.length - 1 - nextIndex];
+          setQuery(newValue);
+          setInputKey((k) => k + 1); // Increment key on navigation change
+          didNavigate = true;
+        }
+      } else if (key.downArrow) {
+        if (historyIndex === -1) return; // Already at the bottom (current input)
+
+        const nextIndex = historyIndex - 1; // Move towards more recent items / current input
+        setHistoryIndex(nextIndex);
+
+        if (nextIndex === -1) {
+          // Restore original query
+          setQuery(originalQueryBeforeNav);
+        } else {
+          // Set query based on reversed index
+          const newValue = userMessages[userMessages.length - 1 - nextIndex];
+          setQuery(newValue);
+        }
+        setInputKey((k) => k + 1); // Increment key on navigation change
+        didNavigate = true;
+      } else {
+        // If user types anything other than arrows while navigating, reset history navigation state
+        if (historyIndex !== -1 && !didNavigate) {
+          // Check if it's a key that modifies input content
+          if (input || key.backspace || key.delete) {
+            resetHistoryNav();
+            // The actual query state update for typing is handled by the component's onChange calling setQuery
+          }
+        }
+      }
+    },
+    { isActive }, // Pass isActive to useInput
+  );
+
+  return {
+    query,
+    setQuery, // Return the hook's setQuery
+    handleSubmit, // Return the wrapped submit handler
+    inputKey, // Return the key
+  };
+}