bin/mockflow-preflight

#!/usr/bin/env node

/**
 * SessionStart check. Tells the user what MockFlow still needs, and nothing at
 * all when everything already works.
 *
 * Node rather than sh so it runs on Windows too, and so it needs neither a
 * POSIX shell nor curl. Node is a safe assumption: the bridge requires it.
 *
 * The user should never have to know that a helper program, a running daemon
 * and a paired browser tab are three separate things. This reports only the
 * first one that is missing, in plain language.
 *
 * Silence when healthy is deliberate: this runs on every session start, so any
 * output in the normal case is pure noise.
 */

const { spawnSync } = require('child_process');

const PORT = process.env.MFBRIDGE_PORT || 21196;

function say(lines) { console.log(lines.join('\n')); process.exit(0); }

/** Is `mockflow-bridge` on PATH? `where` on Windows, `command -v` elsewhere. */
function onPath(bin) {
	const win = process.platform === 'win32';
	const r = win
		? spawnSync('where', [bin], { stdio: 'ignore', windowsHide: true })
		: spawnSync('sh', ['-c', 'command -v ' + bin], { stdio: 'ignore' });
	return r.status === 0;
}

async function main() {
	// 1. Is the helper installed?
	if (!onPath('mockflow-bridge')) {
		say([
			'The MockFlow plugin is installed but its bridge helper is missing, so nothing can',
			'be drawn on a board yet. It is a small local program, about 2MB, no account needed.',
			'Offer to run this for the user before doing anything else with MockFlow:',
			'  npm i -g @mockflow/mockflow-bridge',
			'',
			'Unless this shell is not the user\'s own computer. In a cloud or remote container',
			'the bridge has nothing to pair with, because the board tab is open on their machine',
			'and not this one. Then say drawing needs Codex running locally, either Codex',
			'selected in the desktop app or the Codex CLI, and do not offer the install.'
		]);
	}

	// 2 and 3. Daemon up, and any board paired? One call answers both.
	let boards = null;
	try {
		const resp = await fetch('http://127.0.0.1:' + PORT + '/status',
			{ signal: AbortSignal.timeout(2000) });
		const data = await resp.json();
		boards = (data.boards || []).length;
	} catch (e) {
		// Nothing answered, so no daemon is running. The bridge must be started by
		// hand; this is the single most common reason board tools are missing.
		say([
			'The MockFlow bridge is installed but not running, so the board tools in this',
			'session will not work. Tell the user to start it, then reload:',
			'  mockflow-bridge'
		]);
	}

	if (boards === 0) {
		say([
			'MockFlow is connected but no board is paired, so a drawing has nowhere to land.',
			'Before drawing anything, tell the user to open their board at app.mockflow.com,',
			'click "Connect Local Agent" at the top of Ask Mida, and enter the pairing code',
			'shown by the bridge. This is a one time step per computer.'
		]);
	}

	// Healthy. Say nothing.
}

main().catch(function() { process.exit(0); });