import markdownIt from "markdown-it";
import markdownItAnchor from "markdown-it-anchor";
import { formatISO9075 } from "date-fns";
import { format } from "date-fns";

export default async function(eleventyConfig) {
  // Options for the `markdown-it` library
  const markdownItOptions = {
    html: true,
  }

  // Options for the `markdown-it-anchor` library
  const markdownItAnchorOptions = {
    permalink: true, permalinkBefore: true, permalinkSymbol: '#'
  }

  const markdownLib = markdownIt(markdownItOptions).use(
    markdownItAnchor,
    markdownItAnchorOptions
  );
  eleventyConfig.addFilter("firstUrlSegment", function(permalink) {
    if (typeof permalink === "string") {
      permalink = permalink.replace(/^\/+|\/+$/g, '');
      const segments = permalink.split('/');
      return segments.length > 0 ? segments[0] : '';
    }
    return '';
  });
  eleventyConfig.addFilter("ISO", (dateObj) => {
    return formatISO9075(dateObj);
  });
  eleventyConfig.addFilter("humanReadable", (dateObj) => {
    return format(dateObj, ("LLLL d, yyyy"));
  });
  eleventyConfig.setLibrary("md", markdownLib);

  // Set directories to pass through to the _site folder
  eleventyConfig.addPassthroughCopy("./_src/assets/");

  // Watch scss folder for changes
  eleventyConfig.addWatchTarget("./_src/assets/");

  // Open a browser window on --watch
  eleventyConfig.setBrowserSyncConfig({
    open: true,
  });
};

// This named export is optional
export const config = {
  dir: {
    input: "_src",
    output: "_site"
  }
};