const isQuestion = (message: string): boolean => message.trim().endsWith("?");
const hasUpperCase = (message: string): boolean =>
  Boolean(message.match(/[A-Z]/));
const hasLowerCase = (message: string): boolean =>
  Boolean(message.match(/[a-z]/));
const isOnlyUpperCase = (message: string): boolean =>
  hasUpperCase(message) && !hasLowerCase(message);
const isEmpty = (message: string): boolean => message.trim() === "";

export function hey(message: string): string {
  if (isQuestion(message)) {
    if (isOnlyUpperCase(message)) {
      return "Calm down, I know what I'm doing!";
    }
    return "Sure.";
  }
  if (isOnlyUpperCase(message)) {
    return "Whoa, chill out!";
  }
  if (isEmpty(message)) {
    return "Fine. Be that way!";
  }
  return "Whatever.";
}