gsender

const fs = require("fs");
const path = require("path");
const { spawnSync } = require("child_process");

const run = (command, args, cwd) => {
	const result = spawnSync(command, args, {
		cwd,
		stdio: "inherit",
		shell: process.platform === "win32",
	});

	if (result.status !== 0) {
		throw new Error(`Command failed: ${command} ${args.join(" ")}`);
	}
};

const readJson = (filePath) => JSON.parse(fs.readFileSync(filePath, "utf8"));

// Directories that hold generated output or dependencies rather than sources,
// so they never count as an input when timestamping a tree.
const NON_SOURCE_DIRS = new Set([".git", "dist", "node_modules", "ui"]);

/**
 * Greatest mtime (ms) across `targets`, which may be files or directories.
 * Directories are walked recursively, skipping NON_SOURCE_DIRS. Paths that
 * don't exist contribute nothing; returns 0 when none of them do.
 */
const newestMtimeMs = (targets) => {
	let newest = 0;

	const visit = (target) => {
		let stats;
		try {
			stats = fs.statSync(target);
		} catch {
			return;
		}

		if (!stats.isDirectory()) {
			newest = Math.max(newest, stats.mtimeMs);
			return;
		}

		for (const entry of fs.readdirSync(target, { withFileTypes: true })) {
			if (entry.isDirectory() && NON_SOURCE_DIRS.has(entry.name)) {
				continue;
			}
			visit(path.join(target, entry.name));
		}
	};

	targets.forEach(visit);
	return newest;
};

/** True when `outputPath` is missing or older than the newest of `sourcePaths`. */
const isStale = (outputPath, sourcePaths) => {
	let outputStats;
	try {
		outputStats = fs.statSync(outputPath);
	} catch {
		return true;
	}
	return newestMtimeMs(sourcePaths) > outputStats.mtimeMs;
};

module.exports = { run, readJson, newestMtimeMs, isStale };