import type { Plugin } from 'postcss';
import selectorParser from 'postcss-selector-parser';

const prependNestingTypeToSelector = (selector: selectorParser.Node) => {
  const { parent } = selector;

  if (parent) {
    const nesting = selectorParser.nesting();
    parent.insertBefore(selector, nesting);
  }
};

/**
 * Parent orphened pseudos PostCSS plugin.
 * This plugin will move child nested orphened pseudos to the parent declaration.
 *
 * E.g: `.class { &:hover {} }` will become `.class:hover {}`
 *
 * Requires the use of Once over Rule else it runs into conflicts with the postcss-nested plugin
 */
export const parentOrphanedPseudos = (): Plugin => {
  return {
    postcssPlugin: 'parent-orphened-pseudos',
    Once(root) {
      root.walkRules((rule) => {
        const { selectors } = rule;

        rule.selectors = selectors.map((selector) => {
          if (!selector.startsWith(':')) {
            return selector;
          }

          const parser = selectorParser((root) => {
            root.walkPseudos((pseudoSelector) => {
              prependNestingTypeToSelector(pseudoSelector);
            });
          }).astSync(selector, { lossless: false });

          return parser.toString();
        });
      });
    },
  };
};

export const postcss = true;