import { existsSync } from 'fs';
import { resolve, isAbsolute } from 'path';

export default function(theme, opts = {}) {
  const { cwd = process.cwd() } = opts;
  if (!theme) return {};
  if (typeof theme === 'string') {
    const themePath = isAbsolute(theme) ? theme : resolve(cwd, theme);
    if (existsSync(themePath)) {
      const themeConfig = require(themePath); // eslint-disable-line
      if (typeof themeConfig === 'function') {
        return themeConfig();
      } else {
        return themeConfig;
      }
    } else {
      throw new Error(`theme file don't exists`);
    }
  }
  return theme;
}