import readline from 'node:readline';

const { stdout } = process;

export interface CliProgressBarOptions {
  /** @default 20 */
  barWidth?: number;
  /** @default '\u2591' (faded square) */
  pending?: string;
  /** @default '\u2588' (opaque square) */
  complete?: string;
  /** @default '[' */
  prefix?: string;
  /** @default ']' */
  postfix?: string;
  /** @default `${percent}%` */
  message?: (current: number) => string | undefined;
}

export function createCliProgressBar({
  barWidth = 20,
  pending = '\u2591', // faded square
  complete = '\u2588', // opaque square
  prefix = '[',
  postfix = ']',
  message = numberAsPercent,
}: CliProgressBarOptions = {}): {
  update: (current: number, messageText?: string) => void;
  done: (messageText?: string) => void;
} {
  update(0);

  /**
   * @param current a number between 0 and 1 representing the progress
   * @param messageText custom message to show for this specific update
   */
  function update(current: number, messageText = message(current)) {
    const completeWidth = Math.round(current * barWidth);
    readline.cursorTo(stdout, 0);
    stdout.write(prefix);
    for (let pos = 0; pos < barWidth; ++pos) {
      stdout.write(pos < completeWidth ? complete : pending);
    }
    stdout.write(`${postfix} `);
    if (messageText) {
      stdout.write(`${messageText} `);
    }
    if (stdout.isTTY) {
      readline.clearLine(stdout, 1);
    } else {
      stdout.write('\n');
    }
  }

  function done(messageText = message(1)) {
    update(1, messageText);
    if (stdout.isTTY) {
      stdout.write('\n');
    }
  }

  return {
    update,
    done,
  };
}

function numberAsPercent(value: number) {
  return `${Math.round(Math.min(value * 100, 100))}%`;
}