oh-my-pi/packages/coding-agent/src/modes/print-mode.ts

/**
 * Print mode (single-shot): Send prompts, output result, exit.
 *
 * Used for:
 * - `omp -p "prompt"` - text output
 * - `omp --mode json "prompt"` - JSON event stream
 */
import type { AssistantMessage, ImageContent } from "@oh-my-pi/pi-ai";
import { sanitizeText } from "@oh-my-pi/pi-natives";
import type { AgentSession } from "../session/agent-session";
import { initializeExtensions } from "./runtime-init";

/**
 * Options for print mode.
 */
export interface PrintModeOptions {
	/** Output mode: "text" for final response only, "json" for all events */
	mode: "text" | "json";
	/** Array of additional prompts to send after initialMessage */
	messages?: string[];
	/** First message to send (may contain @file content) */
	initialMessage?: string;
	/** Images to attach to the initial message */
	initialImages?: ImageContent[];
}

/**
 * Run in print (single-shot) mode.
 * Sends prompts to the agent and outputs the result.
 */
export async function runPrintMode(session: AgentSession, options: PrintModeOptions): Promise<void> {
	const { mode, messages = [], initialMessage, initialImages } = options;

	// Emit session header for JSON mode
	if (mode === "json") {
		const header = session.sessionManager.getHeader();
		if (header) {
			process.stdout.write(`${JSON.stringify(header)}\n`);
		}
	}
	// Set up extensions for print mode (no UI, no command context)
	await initializeExtensions(session, {
		reportSendError: (action, err) => {
			process.stderr.write(
				`Extension ${action === "extension_send" ? "sendMessage" : "sendUserMessage"} failed: ${err.message}\n`,
			);
		},
		reportRuntimeError: err => {
			process.stderr.write(`Extension error (${err.extensionPath}): ${err.error}\n`);
		},
	});

	// Always subscribe to enable session persistence via _handleAgentEvent
	session.subscribe(event => {
		// In JSON mode, output all events
		if (mode === "json") {
			process.stdout.write(`${JSON.stringify(event)}\n`);
		}
	});

	// Send initial message with attachments
	if (initialMessage !== undefined) {
		await session.prompt(initialMessage, { images: initialImages });
	}

	// Send remaining messages
	for (const message of messages) {
		await session.prompt(message);
	}

	// In text mode, output final response
	if (mode === "text") {
		const state = session.state;
		const lastMessage = state.messages[state.messages.length - 1];

		if (lastMessage?.role === "assistant") {
			const assistantMsg = lastMessage as AssistantMessage;

			// Check for error/aborted
			if (assistantMsg.stopReason === "error" || assistantMsg.stopReason === "aborted") {
				const errorLine = sanitizeText(assistantMsg.errorMessage || `Request ${assistantMsg.stopReason}`);
				const flushed = process.stderr.write(`${errorLine}\n`);
				if (flushed) {
					process.exit(1);
				} else {
					process.stderr.once("drain", () => process.exit(1));
				}
			}

			if (
				assistantMsg.errorMessage &&
				assistantMsg.stopReason !== "error" &&
				assistantMsg.stopReason !== "aborted"
			) {
				process.stderr.write(`${sanitizeText(assistantMsg.errorMessage)}\n`);
			}

			// Output text content
			for (const content of assistantMsg.content) {
				if (content.type === "text") {
					process.stdout.write(`${sanitizeText(content.text)}\n`);
				}
			}
		}
	}

	// Ensure stdout is fully flushed before returning
	// This prevents race conditions where the process exits before all output is written
	await new Promise<void>((resolve, reject) => {
		process.stdout.write("", err => {
			if (err) reject(err);
			else resolve();
		});
	});

	await session.dispose();
}