//
// Thin promise wrappers around Nova's Process API.
//

// Runs a command to completion and resolves with its captured output.
// Rejects with an Error carrying the exit status and stderr when the
// command fails, so callers can surface a useful message.
function exec(path, args, options = {}) {
	return new Promise((resolve, reject) => {
		let stdout = "";
		let stderr = "";
		let process;

		try {
			process = new Process(path, {
				args: args,
				cwd: options.cwd,
				env: options.env,
				stdio: ["ignore", "pipe", "pipe"]
			});
		} catch (error) {
			reject(error);
			return;
		}

		process.onStdout((line) => {
			stdout += line;
		});

		process.onStderr((line) => {
			stderr += line;
		});

		process.onDidExit((status) => {
			if (status === 0 || options.ignoreStatus) {
				resolve({ status: status, stdout: stdout, stderr: stderr });
				return;
			}

			let error = new Error(cleanMessage(stderr) || `${path} exited with status ${status}.`);
			error.status = status;
			error.stdout = stdout;
			error.stderr = stderr;
			reject(error);
		});

		try {
			process.start();
		} catch (error) {
			reject(error);
		}
	});
}

// Runs a command and parses its stdout as JSON.
async function execJSON(path, args, options = {}) {
	let result = await exec(path, args, options);

	if (!result.stdout.trim()) {
		return [];
	}

	try {
		return JSON.parse(result.stdout);
	} catch (error) {
		throw new Error(`Unable to parse output of ${path}: ${error.message}`);
	}
}

// Apple Container prefixes failures with "Error: " and appends a hint about
// starting the system services. Keep the first meaningful line only.
function cleanMessage(stderr) {
	if (!stderr) {
		return "";
	}

	let line = stderr
		.split("\n")
		.map((entry) => entry.trim())
		.filter((entry) => entry.length > 0)[0];

	if (!line) {
		return "";
	}

	return line.replace(/^Error:\s*/, "");
}

module.exports = { exec, execJSON, cleanMessage };