rivy / js.os-paths

// # spell-checker:ignore AllUsersProfile HomeDrive HomePath LocalAppData UserProfile WinDir falsey

import { Platform } from '../platform-adapters/_base.js';

/** Determine common OS/platform paths (home, temp, ...) */

type OSPaths = {

	/** @constructor Create an `OSPaths` object. */

	(): OSPaths;

	/** @constructor Create an `OSPaths` object. */

	new (): OSPaths;

	/* eslint-disable functional/no-method-signature */

	/** Returns the path string of the user's home directory (or `undefined` if the user's home directory is not resolvable). */

	home(): string | undefined;

	/** Returns the path string of the system's default directory for temporary files. */

	temp(): string;

	/* eslint-enable functional/no-method-signature */

};

function isEmpty(s: string | null | undefined): boolean {

	return !s; // reminder: JS "falsey" == [undefined, null, NaN, 0, '', false]

}

function Adapt(adapter_: Platform.Adapter): { readonly OSPaths: OSPaths } {

	const { env, os, path } = adapter_;

	const isWinOS = /^win/i.test(adapter_.process.platform);

	function normalizePath(path_: string | undefined): string | undefined {

		return path_ ? adapter_.path.normalize(adapter_.path.join(path_, '.')) : void 0;

	}

	function home() {

		const posix = () =>

			normalizePath((typeof os.homedir === 'function' ? os.homedir() : void 0) || env.get('HOME'));

		const windows = () => {

			const priorityList = [

				typeof os.homedir === 'function' ? os.homedir() : void 0,

				env.get('USERPROFILE'),

				env.get('HOME'),

				env.get('HOMEDRIVE') || env.get('HOMEPATH')

					? path.join(env.get('HOMEDRIVE') || '', env.get('HOMEPATH') || '')

					: void 0,

			];

			return normalizePath(priorityList.find((v) => !isEmpty(v)));

		};

		return isWinOS ? windows() : posix();

	}

	function temp() {

		function joinPathToBase(base: string | undefined, segments: readonly string[]) {

			return base ? path.join(base, ...segments) : void 0;

		}

		function posix() {

			const fallback = '/tmp';

			const priorityList = [

				typeof os.tmpdir === 'function' ? os.tmpdir() : void 0,

				env.get('TMPDIR'),

				env.get('TEMP'),

				env.get('TMP'),

			];

			return normalizePath(priorityList.find((v) => !isEmpty(v))) || fallback;

		}

		function windows() {

			const fallback = 'C:\\Temp';

			const priorityListLazy = [

				os.tmpdir,

				() => env.get('TEMP'),

				() => env.get('TMP'),

				() => joinPathToBase(env.get('LOCALAPPDATA'), ['Temp']),

				() => joinPathToBase(home(), ['AppData', 'Local', 'Temp']),

				() => joinPathToBase(env.get('ALLUSERSPROFILE'), ['Temp']),

				() => joinPathToBase(env.get('SystemRoot'), ['Temp']),

				() => joinPathToBase(env.get('windir'), ['Temp']),

				() => joinPathToBase(env.get('SystemDrive'), ['\\', 'Temp']),

			];

			const v = priorityListLazy.find((v) => v && !isEmpty(v()));

			return (v && normalizePath(v())) || fallback;

		}

		return isWinOS ? windows() : posix();

	}

	// eslint-disable-next-line functional/no-class

	class OSPaths_ {

		constructor() {

			function OSPaths(): OSPaths {

				return new OSPaths_() as OSPaths;

			}

			OSPaths.home = home;

			OSPaths.temp = temp;

			return OSPaths;

		}

	}

	return { OSPaths: new OSPaths_() as OSPaths };

}

export type { OSPaths };

export { Adapt };