refactor(coding-agent): extracted external editor handling into shared utility module

- Extracted external editor handling logic into shared utility module to reduce code duplication across hook-editor and input-controller components.
- Created new external-editor utility module with getEditorCommand() and openInEditor() functions for centralizing editor process management and temporary file handling.
- Simplified hook-editor component by replacing manual editor spawning and file operations with openInEditor() utility function call.
- Simplified input-controller component by replacing manual editor spawning and file operations with openInEditor() utility function call.

packages/coding-agent/CHANGELOG.md

@@ -1,6 +1,14 @@
 # Changelog
 
 ## [Unreleased]
+### Added
+
+- Added `openInEditor()` utility function to centralize external editor handling with support for custom file extensions and stdio configuration
+- Added `getEditorCommand()` utility function to retrieve the user's preferred editor from $VISUAL or $EDITOR environment variables
+
+### Changed
+
+- Refactored hook editor and input controller to use shared external editor utilities, reducing code duplication
 
 ## [11.0.3] - 2026-02-05
 ### Added

packages/coding-agent/src/modes/components/hook-editor.ts

@@ -2,12 +2,9 @@
  * Multi-line editor component for hooks.
  * Supports Ctrl+G for external editor.
  */
-import * as fs from "node:fs/promises";
-import * as os from "node:os";
-import * as path from "node:path";
 import { Container, Editor, matchesKey, Spacer, Text, type TUI } from "@oh-my-pi/pi-tui";
-import { $env, Snowflake } from "@oh-my-pi/pi-utils";
 import { getEditorTheme, theme } from "../../modes/theme/theme";
+import { getEditorCommand, openInEditor } from "../../utils/external-editor";
 import { DynamicBorder } from "./dynamic-border";
 
 export class HookEditorComponent extends Container {
@@ -47,10 +44,7 @@ export class HookEditorComponent extends Container {
 		this.addChild(new Spacer(1));
 
 		// Add hint
-		const hasExternalEditor = !!($env.VISUAL || $env.EDITOR);
-		const hint = hasExternalEditor
-			? "ctrl+enter submit  esc cancel  ctrl+g external editor"
-			: "ctrl+enter submit  esc cancel";
+		const hint = "ctrl+enter submit  esc cancel  ctrl+g external editor";
 		this.addChild(new Text(theme.fg("dim", hint), 1, 0));
 
 		this.addChild(new Spacer(1));
@@ -83,36 +77,17 @@ export class HookEditorComponent extends Container {
 	}
 
 	private async openExternalEditor(): Promise<void> {
-		const editorCmd = $env.VISUAL || $env.EDITOR;
-		if (!editorCmd) {
-			return;
-		}
+		const editorCmd = getEditorCommand();
+		if (!editorCmd) return;
 
 		const currentText = this.editor.getText();
-		const tmpFile = path.join(os.tmpdir(), `omp-hook-editor-${Snowflake.next()}.md`);
-
 		try {
-			await Bun.write(tmpFile, currentText);
 			this.tui.stop();
-
-			const [editor, ...editorArgs] = editorCmd.split(" ");
-			const child = Bun.spawn([editor, ...editorArgs, tmpFile], {
-				stdin: "inherit",
-				stdout: "inherit",
-				stderr: "inherit",
-			});
-			const exitCode = await child.exited;
-
-			if (exitCode === 0) {
-				const newContent = (await Bun.file(tmpFile).text()).replace(/\n$/, "");
-				this.editor.setText(newContent);
+			const result = await openInEditor(editorCmd, currentText);
+			if (result !== null) {
+				this.editor.setText(result);
 			}
 		} finally {
-			try {
-				await fs.rm(tmpFile, { force: true });
-			} catch {
-				// Ignore cleanup errors
-			}
 			this.tui.start();
 			this.tui.requestRender(true);
 		}

packages/coding-agent/src/modes/controllers/input-controller.ts

@@ -1,16 +1,14 @@
-import { spawn } from "node:child_process";
 import * as fs from "node:fs/promises";
-import * as os from "node:os";
-import * as path from "node:path";
 import type { AgentMessage } from "@oh-my-pi/pi-agent-core";
 import { readImageFromClipboard } from "@oh-my-pi/pi-natives";
-import { $env, Snowflake } from "@oh-my-pi/pi-utils";
+import { $env } from "@oh-my-pi/pi-utils";
 import type { SettingPath, SettingValue } from "../../config/settings";
 import { settings } from "../../config/settings";
 import { theme } from "../../modes/theme/theme";
 import type { InteractiveModeContext } from "../../modes/types";
 import type { AgentSessionEvent } from "../../session/agent-session";
 import { SKILL_PROMPT_MESSAGE_TYPE, type SkillPromptDetails } from "../../session/messages";
+import { getEditorCommand, openInEditor } from "../../utils/external-editor";
 import { resizeImage } from "../../utils/image-resize";
 import { generateSessionTitle, setTerminalTitle } from "../../utils/title-generator";
 
@@ -730,61 +728,36 @@ export class InputController {
 	}
 
 	async openExternalEditor(): Promise<void> {
-		// Determine editor (respect $VISUAL, then $EDITOR)
-		const editorCmd = $env.VISUAL || $env.EDITOR;
+		const editorCmd = getEditorCommand();
 		if (!editorCmd) {
 			this.ctx.showWarning("No editor configured. Set $VISUAL or $EDITOR environment variable.");
 			return;
 		}
 
 		const currentText = this.ctx.editor.getText();
-		const tmpFile = path.join(os.tmpdir(), `omp-editor-${Snowflake.next()}.omp.md`);
 
 		let ttyHandle: fs.FileHandle | null = null;
 		try {
-			// Write current content to temp file
-			await Bun.write(tmpFile, currentText);
-
-			// Stop TUI to release terminal
 			ttyHandle = await this.openEditorTerminalHandle();
 			this.ctx.ui.stop();
 
-			// Split by space to support editor arguments (e.g., "code --wait")
-			const [editor, ...editorArgs] = editorCmd.split(" ");
-
 			const stdio: [number | "inherit", number | "inherit", number | "inherit"] = ttyHandle
 				? [ttyHandle.fd, ttyHandle.fd, ttyHandle.fd]
 				: ["inherit", "inherit", "inherit"];
 
-			const child = spawn(editor, [...editorArgs, tmpFile], { stdio });
-			const exitCode = await new Promise<number>((resolve, reject) => {
-				child.once("exit", (code, signal) => resolve(code ?? (signal ? -1 : 0)));
-				child.once("error", error => reject(error));
-			});
-
-			// On successful exit (exitCode 0), replace editor content
-			if (exitCode === 0) {
-				const newContent = (await Bun.file(tmpFile).text()).replace(/\n$/, "");
-				this.ctx.editor.setText(newContent);
+			const result = await openInEditor(editorCmd, currentText, { extension: ".omp.md", stdio });
+			if (result !== null) {
+				this.ctx.editor.setText(result);
 			}
-			// On non-zero exit, keep original text (no action needed)
 		} catch (error) {
 			this.ctx.showWarning(
 				`Failed to open external editor: ${error instanceof Error ? error.message : String(error)}`,
 			);
 		} finally {
-			// Clean up temp file
-			try {
-				await fs.rm(tmpFile, { force: true });
-			} catch {
-				// Ignore cleanup errors
-			}
-
 			if (ttyHandle) {
 				await ttyHandle.close();
 			}
 
-			// Restart TUI
 			this.ctx.ui.start();
 			this.ctx.ui.requestRender();
 		}

packages/coding-agent/src/utils/external-editor.ts

@@ -0,0 +1,59 @@
+/**
+ * Utilities for launching an external text editor ($VISUAL / $EDITOR).
+ */
+import { spawn } from "node:child_process";
+import * as fs from "node:fs/promises";
+import * as os from "node:os";
+import * as path from "node:path";
+import { $env, Snowflake } from "@oh-my-pi/pi-utils";
+
+/** Returns the user's preferred editor command, or undefined if not configured. */
+export function getEditorCommand(): string | undefined {
+	return $env.VISUAL || $env.EDITOR || undefined;
+}
+
+export interface OpenInEditorOptions {
+	/** File extension for the temp file (default: ".md"). */
+	extension?: string;
+	/** Custom stdio configuration (default: all "inherit"). */
+	stdio?: [number | "inherit", number | "inherit", number | "inherit"];
+}
+
+/**
+ * Opens `content` in the user's external editor and returns the edited text.
+ * Returns `null` if the editor exits with a non-zero code.
+ *
+ * The caller is responsible for stopping/starting the TUI around this call.
+ */
+export async function openInEditor(
+	editorCmd: string,
+	content: string,
+	options?: OpenInEditorOptions,
+): Promise<string | null> {
+	const ext = options?.extension ?? ".md";
+	const tmpFile = path.join(os.tmpdir(), `omp-editor-${Snowflake.next()}${ext}`);
+
+	try {
+		await Bun.write(tmpFile, content);
+
+		const [editor, ...editorArgs] = editorCmd.split(" ");
+		const stdio = options?.stdio ?? ["inherit", "inherit", "inherit"];
+
+		const child = spawn(editor, [...editorArgs, tmpFile], { stdio });
+		const exitCode = await new Promise<number>((resolve, reject) => {
+			child.once("exit", (code, signal) => resolve(code ?? (signal ? -1 : 0)));
+			child.once("error", error => reject(error));
+		});
+
+		if (exitCode === 0) {
+			return (await Bun.file(tmpFile).text()).replace(/\n$/, "");
+		}
+		return null;
+	} finally {
+		try {
+			await fs.rm(tmpFile, { force: true });
+		} catch {
+			// Ignore cleanup errors
+		}
+	}
+}