str/src/vm/input.ts

import * as readline from 'node:readline'
import {BehaviorSubject} from "../util/subject.js";
import {Lifecycle, LifecycleAware} from "../util/lifecycle.js";
import {StreamLogger} from "../util/log.js";
import {log} from "../log.js";

export class Input extends BehaviorSubject<string> implements LifecycleAware {
	private rl?: readline.Interface
	private log: StreamLogger = log.getStreamLogger('input')

	public hasPrompt(): boolean {
		return !!this.rl
	}

	public setupPrompt(): void {
		this.log.verbose({
			setupPrompt: { hasExistingPrompt: !!this.rl },
		})

		if ( this.rl ) {
			this.closePrompt()
		}

		this.rl = readline.createInterface({
			input: process.stdin,
			output: process.stdout,
			prompt: 'str %> ',
		})

		this.rl.prompt()

		this.rl.on('line', async (line) => {
			await this.next(line + '\n')
			this.rl?.prompt(true)
		})
	}

	public closePrompt(): void {
		this.log.verbose({
			closePrompt: { hasExistingPrompt: !!this.rl },
		})

		this.rl?.close()
		this.rl = undefined
	}

	adoptLifecycle(lifecycle: Lifecycle): void {
		lifecycle.onClose(() => this.closePrompt())
	}
}