export interface AnswerMap {
  [index: string]: any;
}

/**
 * Represents a tree of questions that can be used to build up a template context
 */
export interface QuestionTree {
  /**
   * The text that the user is shown before waiting for answer input
   */
  prompt: string;

  /**
   * The name of the question, also used as a variable name in the resulting
   * template context
   */
  name: string;

  /**
   * An optional list of options for multiple-choice questions.
   */
  options?: QuestionOption[];

  /**
   * Transformation and validation function that can be used for both free
   * form and multiple choice question types.
   *
   * @param transformerValidator a function that transforms valid input to
   * the answer data desired and throws on invalid input. Mutates the given
   * AnswerMap as needed. Returns a follow-up question, if necessary. Can be
   * async.
   */
  transformerValidator?: (rawInput: any, answers: AnswerMap) => Promise<QuestionTree | undefined> | QuestionTree | undefined;
}

/**
 * Represents a single option in a list of options for a multiple choice
 * question.
 */
export interface QuestionOption {
  /**
   * The text shown to the user to describe this option.
   */
  label: string;

  /**
   * The value that should be used when this option is selected. If the
   * question also contains a transformerValidator, this data will be
   * passed as rawInput.
   */
  value: any;

  /**
   * The follow-up question that should be given to the user after this one,
   * if applicable.
   */
  nextQuestion?: QuestionTree;

  /**
   * Whether or not this option should be the default if no other option is
   * selected.
   */
  default?: boolean;
}