scroll/src/common/runtime.ts

import process from 'node:process';
import { IRuntime, ITestBase } from './types.ts';
import { noop } from './fns.ts';
import { SCROLL_ERR_FILE, SCROLL_LOG_FILE } from './config.ts';

export type { IFileIO, IRuntime, ITerminal } from './types.ts';

/**
 * Which Typescript runtime is currently being used
 */
export enum RunTimeType {
	Bun = 'bun',
	Deno = 'deno',
	Unknown = 'common',
}

export enum LogLevel {
	Debug = 'Debug',
	Info = 'Info',
	Notice = 'Notice',
	Warning = 'Warning',
	Error = 'Error',
}

let scrollRuntime: IRuntime | null = null;

// ----------------------------------------------------------------------------
// Misc runtime functions
// ----------------------------------------------------------------------------

export function log(s: unknown, level: LogLevel = LogLevel.Notice): void {
	getRuntime().then(({ file }) => {
		const raw = JSON.stringify(s, null, 2);
		const output = `${level}: ${raw}\n`;

		const outputFile = (level === LogLevel.Error)
			? SCROLL_ERR_FILE
			: SCROLL_LOG_FILE;
		file.appendFile(outputFile, output).then(noop);
	});
}

/**
 * Append information to the scroll.err logfile
 */
export function logError(s: unknown): void {
	log(s, LogLevel.Error);
}

/**
 * Kill program, displaying an error message
 * @param s
 */
export function die(s: string | Error): void {
	logError(s);
	process.stdin.setRawMode(false);
	console.error(s);
	getRuntime().then((r) => r.exit());
}

/**
 * Determine which Typescript runtime we are operating under
 */
export function runtimeType(): RunTimeType {
	let runtime = RunTimeType.Unknown;

	if ('Deno' in globalThis) {
		runtime = RunTimeType.Deno;
	}
	if ('Bun' in globalThis) {
		runtime = RunTimeType.Bun;
	}

	return runtime;
}

/**
 * Get the adapter object for the current Runtime
 */
export async function getRuntime(): Promise<IRuntime> {
	if (scrollRuntime === null) {
		const runtime = runtimeType();
		const path = `../${runtime}/mod.ts`;

		const pkg = await import(path);
		if ('default' in pkg) {
			scrollRuntime = pkg.default;
		}

		if (scrollRuntime !== null) {
			return Promise.resolve(scrollRuntime);
		}

		return Promise.reject('Missing default import');
	}

	return Promise.resolve(scrollRuntime);
}

/**
 * Get the common test interface object
 */
export async function getTestRunner(): Promise<ITestBase> {
	const runtime = runtimeType();
	const path = `../${runtime}/test_base.ts`;
	const pkg = await import(path);
	if ('default' in pkg) {
		return pkg.default;
	}

	return pkg;
}

/**
 * Import a runtime-specific module
 *
 * e.g. to load "src/bun/mod.ts", if the runtime is bun,
 * you can use like so `await importForRuntime('index')`;
 *
 * @param path - the path within the runtime module
 */
export const importForRuntime = async (path: string) => {
	const runtime = runtimeType();
	const suffix = '.ts';
	const base = `../${runtime}/`;

	const pathParts = path
		.split('/')
		.filter((part) => part !== '' && part !== '.' && part !== suffix)
		.map((part) => part.replace(suffix, ''));

	const cleanedPath = pathParts.join('/');
	const importPath = base + cleanedPath + suffix;

	const pkg = await import(importPath);
	if ('default' in pkg) {
		return pkg.default;
	}

	return pkg;
};