import { type INestApplicationContext, Logger, type LoggerService, type LogLevel } from '@nestjs/common';
import { NestFactory } from '@nestjs/core';
import type { MaybePromise } from '@wener/utils';
import { setAppContext } from './AppContext';

export interface NestApplicationContextOptions {
	/**
	 * Specifies the logger to use.  Pass `false` to turn off logging.
	 */
	logger?: LoggerService | LogLevel[] | false;
	/**
	 * Whether to abort the process on Error. By default, the process is exited.
	 * Pass `false` to override the default behavior. If `false` is passed, Nest will not exit
	 * the application and instead will rethrow the exception.
	 * @default true
	 */
	abortOnError?: boolean | undefined;
	/**
	 * If enabled, logs will be buffered until the "Logger#flush" method is called.
	 * @default false
	 */
	bufferLogs?: boolean;
	/**
	 * If enabled, logs will be automatically flushed and buffer detached when
	 * application initialization process either completes or fails.
	 * @default true
	 */
	autoFlushLogs?: boolean;
	/**
	 * Whether to run application in the preview mode.
	 * In the preview mode, providers/controllers are not instantiated & resolved.
	 *
	 * @default false
	 */
	preview?: boolean;
	/**
	 * Whether to generate a serialized graph snapshot.
	 *
	 * @default false
	 */
	snapshot?: boolean;
}

/**
 * create a bootstrap function for createApplicationContext, allowed to call multiple times
 */
export function createBootstrap({
	module,
	options,
	onBootstrap,
}: {
	module: any;
	options?: NestApplicationContextOptions;
	onBootstrap?: (ctx: INestApplicationContext) => MaybePromise<void>;
}) {
	let _context: INestApplicationContext;
	let _$context: Promise<INestApplicationContext> | undefined;
	const log = new Logger('Bootstrap');

	function bootstrap() {
		// avoid race
		if (_$context) {
			return _$context;
		}
		let start = Date.now();
		return (_$context = Promise.resolve().then(async () => {
			_context = await NestFactory.createApplicationContext(module, options);
			setAppContext(_context);
			await _context.init();
			await onBootstrap?.(_context);
			log.log(`started in ${Date.now() - start}ms`);
			return _context;
		}));
	}

	return bootstrap;
}