import path from 'path';
import { CBFileSystem } from '../node/file-system';

/**
 * True only when `value` is a string and is not empty or whitespace-only after trim.
 * Logically the opposite of `(typeof value !== 'string' || value.trim() === '')`.
 * @param {unknown} value - Value to check
 * @returns {value is string} Whether `value` is a usable non-empty string
 */
export function isNonEmptyString(value: unknown): value is string {
	return typeof value === 'string' && value.trim() !== '';
}

/**
 * Throws if `filePath` does not exist on the given filesystem.
 * Message uses the file basename, e.g. `iparams.json not found`.
 */
export function ensureFileExists(fileSystem: CBFileSystem, filePath: string): void {
	if (!fileSystem.existsSync(filePath)) {
		throw new Error(`${path.basename(filePath)} not found`);
	}
}