const seperator = {
  start: "<!-- excerpt start -->",
  end: "<!-- excerpt end -->",
  total: "<!-- excerpt -->",
};

module.exports = function (eleventyConfig) {
  // excerpt shortcode for feed layouts
  // taken from https://github.com/brob/eleventy-plugin-blog-tools
  eleventyConfig.addShortcode("excerpt", function (article) {
    let excerpt = article.data.excerpt ? `<p>${article.data.excerpt}</p>` : "";
    const articleContent = article.templateContent;

    let startPosition = articleContent.toLowerCase().indexOf(seperator.start);
    let endPosition = articleContent.toLowerCase().indexOf(seperator.end);
    let totalPosition = articleContent.toLowerCase().indexOf(seperator.total);

    if (totalPosition !== -1) {
      excerpt = articleContent.substring(0, totalPosition);
    } else if (startPosition !== -1 && endPosition !== -1) {
      excerpt = articleContent.substring(
        startPosition + seperator.start.length,
        endPosition,
      );
    } else if (!article.data.excerpt) {
      let startPosition = articleContent.toLowerCase().indexOf("<p>");
      let endPosition = articleContent.toLowerCase().indexOf("</p>");

      excerpt = articleContent.substring(startPosition + 3, endPosition);
    }
    return excerpt;
  });
};