Implement additional readline-like keybindings, including alt-left arrow and alt-right arrow. (#443)

This change adds keybinding support for:

  - `Ctrl+B`: Moves the cursor backward one character.
  - `Ctrl+F`: Moves the cursor forward one character.
  - `Alt+Left Arrow`: Moves the cursor backward one word.
  - `Alt+Right Arrow`: Moves the cursor forward one word.

Closes b/411469305.

packages/cli/src/ui/App.tsx

@@ -375,7 +375,6 @@ export const App = ({
                   navigateSuggestionUp={completion.navigateUp}
                   navigateSuggestionDown={completion.navigateDown}
                   resetCompletion={completion.resetCompletionState}
-                  setEditorState={setEditorState}
                   onClearScreen={handleClearScreen} // Added onClearScreen prop
                   shellModeActive={shellModeActive}
                   setShellModeActive={setShellModeActive}

packages/cli/src/ui/components/InputPrompt.tsx

@@ -24,7 +24,6 @@ interface InputPromptProps {
   userMessages: readonly string[];
   navigateSuggestionUp: () => void;
   navigateSuggestionDown: () => void;
-  setEditorState: (updater: (prevState: EditorState) => EditorState) => void;
   onClearScreen: () => void;
   shellModeActive: boolean;
   setShellModeActive: (value: boolean) => void;
@@ -48,7 +47,6 @@ export const InputPrompt: React.FC<InputPromptProps> = ({
   navigateSuggestionUp,
   navigateSuggestionDown,
   resetCompletion,
-  setEditorState,
   onClearScreen,
   shellModeActive,
   setShellModeActive,
@@ -114,12 +112,7 @@ export const InputPrompt: React.FC<InputPromptProps> = ({
   );
 
   const inputPreprocessor = useCallback(
-    (
-      input: string,
-      key: Key,
-      _currentText?: string,
-      _cursorOffset?: number,
-    ) => {
+    (input: string, key: Key) => {
       if (input === '!' && query === '' && !showSuggestions) {
         setShellModeActive(!shellModeActive);
         onChangeAndMoveCursor(''); // Clear the '!' from input
@@ -156,17 +149,6 @@ export const InputPrompt: React.FC<InputPromptProps> = ({
         }
       } else {
         // Keybindings when suggestions are not shown
-        if (key.ctrl && input === 'a') {
-          setEditorState((s) => ({ key: s.key + 1, initialCursorOffset: 0 }));
-          return true;
-        }
-        if (key.ctrl && input === 'e') {
-          setEditorState((s) => ({
-            key: s.key + 1,
-            initialCursorOffset: query.length,
-          }));
-          return true;
-        }
         if (key.ctrl && input === 'l') {
           onClearScreen();
           return true;
@@ -193,7 +175,6 @@ export const InputPrompt: React.FC<InputPromptProps> = ({
       activeSuggestionIndex,
       handleSubmit,
       inputHistory,
-      setEditorState,
       onClearScreen,
       shellModeActive,
       setShellModeActive,

packages/cli/src/ui/components/shared/multiline-editor.tsx

@@ -44,12 +44,7 @@ export interface MultilineTextEditorProps {
 
   // Called on all key events to allow the caller. Returns true if the
   // event was handled and should not be passed to the editor.
-  readonly inputPreprocessor?: (
-    input: string,
-    key: Key,
-    currentText: string,
-    cursorOffset: number,
-  ) => boolean;
+  readonly inputPreprocessor?: (input: string, key: Key) => boolean;
 
   // Optional initial cursor position (character offset)
   readonly initialCursorOffset?: number;
@@ -98,14 +93,7 @@ export const MultilineTextEditor = ({
         return;
       }
 
-      // Calculate cursorOffset for inputPreprocessor
-      let charOffset = 0;
-      for (let i = 0; i < buffer.cursor[0]; i++) {
-        charOffset += buffer.lines[i].length + 1; // +1 for newline
-      }
-      charOffset += buffer.cursor[1];
-
-      if (inputPreprocessor?.(input, key, buffer.text, charOffset) === true) {
+      if (inputPreprocessor?.(input, key) === true) {
         return;
       }
 
@@ -121,14 +109,7 @@ export const MultilineTextEditor = ({
 
       const isCtrlX =
         (key.ctrl && (input === 'x' || input === '\x18')) || input === '\x18';
-      const isCtrlE =
-        (key.ctrl && (input === 'e' || input === '\x05')) ||
-        input === '\x05' ||
-        (!key.ctrl &&
-          input === 'e' &&
-          input.length === 1 &&
-          input.charCodeAt(0) === 5);
-      if (isCtrlX || isCtrlE) {
+      if (isCtrlX) {
         buffer.openInExternalEditor();
         return;
       }

packages/cli/src/ui/components/shared/text-buffer.ts

@@ -1104,16 +1104,22 @@ export function useTextBuffer({
       if (key['return'] || input === '\r' || input === '\n') newline();
       else if (key['leftArrow'] && !key['meta'] && !key['ctrl'] && !key['alt'])
         move('left');
+      else if (key['ctrl'] && input === 'b') move('left');
       else if (key['rightArrow'] && !key['meta'] && !key['ctrl'] && !key['alt'])
         move('right');
+      else if (key['ctrl'] && input === 'f') move('right');
       else if (key['upArrow']) move('up');
       else if (key['downArrow']) move('down');
-      else if ((key['meta'] || key['ctrl'] || key['alt']) && key['leftArrow'])
+      else if ((key['ctrl'] || key['alt']) && key['leftArrow'])
         move('wordLeft');
-      else if ((key['meta'] || key['ctrl'] || key['alt']) && key['rightArrow'])
+      else if (key['meta'] && input === 'b') move('wordLeft');
+      else if ((key['ctrl'] || key['alt']) && key['rightArrow'])
         move('wordRight');
+      else if (key['meta'] && input === 'f') move('wordRight');
       else if (key['home']) move('home');
+      else if (key['ctrl'] && input === 'a') move('home');
       else if (key['end']) move('end');
+      else if (key['ctrl'] && input === 'e') move('end');
       else if (
         (key['meta'] || key['ctrl'] || key['alt']) &&
         (key['backspace'] || input === '\x7f')