import * as fs from "fs";
import * as path from "path";

import type { NodeCG } from "../../types/nodecg";

export function parseExtension(
	bundleDir: string,
	manifest: NodeCG.Manifest,
): boolean {
	const singleFilePath = path.resolve(bundleDir, "extension.js");
	const directoryPath = path.resolve(bundleDir, "extension");
	const singleFileExists = fs.existsSync(singleFilePath);
	const directoryExists = fs.existsSync(directoryPath);

	// If there is a file named "extension", throw an error. It should be a directory.
	if (directoryExists && !fs.lstatSync(directoryPath).isDirectory()) {
		throw new Error(
			`${manifest.name} has an illegal file named "extension" in its root. ` +
				'Either rename it to "extension.js", or make a directory named "extension"',
		);
	}

	// If both "extension.js" and a directory named "extension" exist, throw an error.
	if (singleFileExists && directoryExists) {
		throw new Error(
			`${manifest.name} has both "extension.js" and a folder named "extension". ` +
				"There can only be one of these, not both.",
		);
	}

	// Return "true" if either "extension.js" or a directory named "extension" exist.
	return singleFileExists || directoryExists;
}