namespace _heimdall.helpers.misc
{
	
	/**
	 */
	export function get_env_language(
	) : (null | string)
	{
		const env_lang : (undefined | string) = process.env["LANG"];
		if (env_lang === undefined) {
			return null;
		}
		else {
			const locale : string = env_lang.split(".")[0];
			const language : string = locale.split("_")[0];
			return language;
		}
	}
	
	/**
	 */
	export function format_bytes(
		bytes : int
	) : string
	{
		const units : Array<{label : string; digits : int;}> = [
			{"label": "B", "digits": 0},
			{"label": "KB", "digits": 1},
			{"label": "MB", "digits": 1},
			{"label": "GB", "digits": 1},
			{"label": "TB", "digits": 1},
			{"label": "PB", "digits": 1},
		]
		let number_ : int = bytes;
		let index : int = 0;
		while ((number_ >= 1000) && (index < (units.length - 1))) {
			number_ /= 1000;
			index += 1;
		}
		return lib_plankton.string.coin(
			"{{number}} {{label}}",
			{
				"number": number_.toFixed(units[index].digits),
				"label": units[index].label,
			}
		);
	}
	
	
	/**
	 */
	export type type_shell_exec_result = {return_code : int; stdout : string; stderr : string;};
	
	
	/**
	 * @see https://nodejs.org/api/child_process.html#child_processspawncommand-args-options
	 */
	export function shell_exec(
		head : string,
		args : Array<string>
	) : Promise<type_shell_exec_result>
	{
		const nm_child_process = require("child_process");
		
		return new Promise<type_shell_exec_result>(
			(resolve, reject) => {
				let stdout : string = "";
				let stderr : string = "";
				const proc = nm_child_process.spawn(
					head,
					args,
					{
					},
				);
				proc.stdout.on(
					"data",
					(data) => {
						stdout += data;
					}
				);
				proc.stderr.on(
					"data",
					(data) => {
						stderr += data;
					}
				);
				proc.on(
					"close",
					(return_code) => {
						resolve(
							{
								"return_code": return_code,
								"stdout": stdout,
								"stderr": stderr,
							}
						);
					}
				);
			}
		);
	}

}
