import {
  BemItem,
} from '../models';
import { getClassName } from '../core/helpers';

export function useBem (name: string, hyphenate = true) {
  function bem ({ b, e, m }: BemItem): string[] {
    const pascalToKebabCase = (s: string) => s
      .replace(/([A-Z])([A-Z])/g, '$1-$2')
      .replace(/([a-z])([A-Z])/g, '$1-$2')
      .replace(/[\s_]+/g, '-')
      .toLowerCase();
    const n = name;
    const block: string = b || hyphenate ? pascalToKebabCase(n) : n;
    const modifiers: string[] = m ? (typeof m === 'string' ? [m] : (Array.isArray(m) ? m : Object.keys(m).filter(key => m[key]))) : [];
    const elementClass = getClassName(block, e);
    const modifiersClasses = modifiers.map(m => getClassName(block, e, m));
    return [
      elementClass,
      ...modifiersClasses,
    ];
  }
  return bem;
};