import { createInterface } from 'node:readline';
import { Cancelled, type Io } from '../src/cli/userWizard';

export function makeIo(): { io: Io; close: () => void } {
  const rl = createInterface({ input: process.stdin, output: process.stdout });
  const queue: string[] = [];
  let waiting: ((line: string | null) => void) | null = null;
  let ended = false;

  rl.on('line', (line) => {
    if (waiting) {
      const w = waiting;
      waiting = null;
      w(line);
    } else {
      queue.push(line);
    }
  });
  rl.on('close', () => {
    ended = true;
    if (waiting) {
      const w = waiting;
      waiting = null;
      w(null);
    }
  });

  const io: Io = {
    async ask(question) {
      rl.setPrompt(question);
      rl.prompt();
      const line = queue.length > 0 ? queue.shift()! : ended ? null : await new Promise<string | null>((r) => (waiting = r));
      if (line === null) throw new Cancelled();
      return line.trim();
    },
    say(line = '') {
      console.log(line);
    },
  };
  return { io, close: () => rl.close() };
}