import { colors } from 'utils/theme';

import { ColourOptions } from 'types/theme';

interface ColourConfig {
  key: ColourOptions;
}

const setColour = (config?: ColourConfig, defaultOption: string = 'white'): string =>
  !config || config.key === 'default' ? colors[defaultOption] : colors[config.key];

const buildThemeConfig = (defaultConfig: any, siteConfig: any): any => Object.keys(defaultConfig)
  .reduce((acc, curr) => {
    if (siteConfig[curr]) {
      return {
        ...acc,
        [curr]: setColour(siteConfig[curr], defaultConfig[curr])
      };
    }

    throw new Error(`An error occured when building theme config: ${curr} does not exist. Have you incorrectly spelled a constant value?`);
  }, {});

export {
  setColour,
  buildThemeConfig
};