import { checkPath } from '../utils/fs-async';

export const parseNumeric = (value: string) => {
  const out = Number(value);

  if (Number.isNaN(out)) {
    throw new Error(`${value} is not a valid number`);
  }

  return out;
};

export const parseString = (value: string) => {
  if (typeof value !== 'string') {
    throw new Error(`${value} is not a string`);
  }

  return value;
};

export const listMembersParser = <T extends string>(allowedValues: T[]) => (
  values: string[]
) => {
  for (const value of values) {
    if (!allowedValues.includes(value as any)) {
      throw new Error(
        [
          `${value} is not valid`,
          `accepted values are: ${allowedValues.join(', ')}`
        ].join(' - ')
      );
    }
  }

  return values as T[];
};

export const removeUndefined = (object: Object) => {
  for (const key of Object.keys(object)) {
    if (typeof object[key] === 'undefined') {
      delete object[key];
    }
  }

  return object;
};

export const parseBoolean = (val: any) => {
  if (typeof val === 'string' && ['1', '0', 'true', 'false'].includes(val)) {
    return val === 'true' || val === '1';
  } else if (typeof val === 'number' && [0, 1].includes(val)) {
    return val === 1;
  } else if (typeof val === 'boolean') {
    return val;
  }

  throw new Error(`must be a boolean value`);
};

const skipIfMatching = (match: any) => (fn: (value: any, cur?: any) => any) => (
  val: any
) => (val === match ? match : fn(val));

export const parseDir = async (dirname: string) => {
  if ((await checkPath(dirname, 'directory')) === false) {
    throw new Error(`${dirname} is not a directory`);
  }

  return dirname;
};

export const nullable = skipIfMatching(null);

export const optional = skipIfMatching(undefined);