/**
 * Fork https://github.com/egoist/docute/blob/master/src/utils/front-matter.js
 */
/* eslint-disable */
import parser from './yaml.js';

const optionalByteOrderMark = '\\ufeff?';
const pattern =
 '^(' +
 optionalByteOrderMark +
 '(= yaml =|---)' +
 '$([\\s\\S]*?)' +
 '(?:\\2|\\.\\.\\.)' +
 '$' +
 '' +
 '(?:\\n)?)';
// NOTE: If this pattern uses the 'g' flag the `regex` variable definition will
// need to be moved down into the functions that use it.
const regex = new RegExp(pattern, 'm');

function extractor(string) {
 string = string || '';

 const lines = string.split(/(\r?\n)/);
 if (lines[0] && /= yaml =|---/.test(lines[0])) {
 return parse(string);
 } else {
 return { attributes: {}, body: string };
 }
}

function parse(string) {
 const match = regex.exec(string);

 if (!match) {
 return {
 attributes: {},
 body: string,
 };
 }

 const yaml = match[match.length - 1].replace(/^\s+|\s+$/g, '');
 const attributes = parser(yaml) || {};
 const body = string.replace(match[0], '');

 return { attributes: attributes, body: body, frontmatter: yaml };
}

export default extractor;