import * as _ from 'lodash';
import * as inflection from 'inflection';

function applyHelperToStringWithSeparator(input: any, helper: (str: string) => string): string {
  let str: string;
  if (typeof input === 'string') {
    str = input;
  } else if (typeof input === 'function') {
    str = input();
  } else {
    str = <any>input.toString();
  }

  let separators = _.uniq(str.match(/[^a-z_0-9]+/gi));

  if (separators.length === 1) {
    return str.split(separators[0]).map(s => helper(s)).join(separators[0]);
  } else {
    return helper(str);
  }
}

export function underscore(str: string): string {
  return applyHelperToStringWithSeparator(str, inflection.underscore);
}

export function upperCamelCase(str: string): string {
  return applyHelperToStringWithSeparator(str, inflection.camelize);
}

export function lowerCamelCase(str: string): string {
  return applyHelperToStringWithSeparator(str, s => {
    return inflection.camelize(s, true);
  });
}

export function pluralize(str: string): string {
  return inflection.pluralize(str);
}

export function singularize(str: string): string {
  return inflection.singularize(str);
}