const path = require("path");
const markdownIt = require("markdown-it");
const slugify = require("@sindresorhus/slugify");
const markdownItAnchor = require("markdown-it-anchor");
const markdownItObsidian = require("markdown-it-obsidian");
const markdownItAttrs = require("markdown-it-attrs");
const markdownItEleventyImg = require("markdown-it-eleventy-img");
const pluginRss = require("@11ty/eleventy-plugin-rss");
const embedYouTube = require("eleventy-plugin-youtube-embed");
const sanitizeHtml = require("sanitize-html");
const metadata = require("./src/_data/metadata.json");

const sanitize = (html) => {
  return sanitizeHtml(html, {
    allowedTags: ['b', 'i', 'em', 'strong', 'a'],
    allowedAttributes: { 'a': ['href'] }
  });
};

module.exports = function(eleventyConfig) {
  eleventyConfig.addPlugin(embedYouTube);
  eleventyConfig.addPlugin(pluginRss);

  eleventyConfig.addPassthroughCopy("css");
  eleventyConfig.addPassthroughCopy("fonts");
  eleventyConfig.addPassthroughCopy("images/**/*.{gif,png,jpg,jpeg}");
  eleventyConfig.addPassthroughCopy({ "favicon": "/" });
  eleventyConfig.addPassthroughCopy({
    "node_modules/simpledotcss/simple.css": "css/simple.css",
  });
  eleventyConfig.addPassthroughCopy({ "src/robots.txt": "robots.txt" });

  eleventyConfig.addFilter("buildPageTitle", function(title) {
    if (this.page.url === '/') {
      return title;
    } else {
      return title + ' ⇢ Devon.LoL 😆';
    }
  });
  eleventyConfig.addFilter("stringToDate", function(value) {
    return new Date(value);
  });
  eleventyConfig.addFilter("formatDatetimeForHumans", function(value) {
    const dt = new Date(value);
    const formattedDt = new Intl.DateTimeFormat("en", {
      dateStyle: "medium",
      timeStyle: "medium",
    }).format(dt);
    return formattedDt;
  });
  eleventyConfig.addFilter("formatDateForHumans", function(value) {
    const dt = new Date(value);
    const formattedDt = new Intl.DateTimeFormat("en", {
      dateStyle: "medium",
    }).format(dt);
    return formattedDt;
  });
  eleventyConfig.addFilter("formatDateForRobots", function(value) {
    const dt = new Date(value);
    return dt.toISOString();
  });
  eleventyConfig.addFilter("convertYouTubeURLsToEmbeds", function(value) {
    const youtubeUrlRegex = /<p>\s*(?:https?:\/\/)?(?:www\.)?(?:youtube\.com|youtu\.be)\/(?!channel\/|@)([^\s&<>"']*)\s*<\/p>/gim;
    return value.replace(youtubeUrlRegex, function(match, videoId) {
      return '<iframe width="560" height="315" src="https://www.youtube.com/embed/' + videoId + '" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>';
    });
  });
  eleventyConfig.addFilter('webmentionsByUrl', function(webmentions, url) {
    const allowedTypes = ['in-reply-to', 'like-of', 'repost-of'];
    const hasRequiredFields = mention => {
        const { author, published, content } = mention;
        return author.name && published && content;
    };
    const matchesUrl = mention => {
      return mention['wm-target'] === url;
    };

    const filteredMentions = webmentions
      .filter(mention => {
        const isAllowedType = allowedTypes.includes(mention['wm-property']);
        if (isAllowedType) {
          const isReply = mention['wm-property'] === 'in-reply-to';
          if (isReply) {
            return matchesUrl(mention) && hasRequiredFields(mention);
          }
          return matchesUrl(mention);
        }
      }
    );
    const sanitizedMentions = filteredMentions.map((mention) => {
      if (mention?.content?.html) {
        mention.content.html = sanitize(mention.content.html);
        const mastodonInstance = metadata.author.mastodon.instance;
        const mastodonUsername = metadata.author.mastodon.username;
        const mentionLink = `<a href="https://${mastodonInstance}/@${mastodonUsername}">@${metadata.author.mastodon.username}</a> `;
        if (mention.content.html.startsWith(mentionLink)) {
          mention.content.html = mention.content.html.substring(mentionLink.length)
        }
      }
      return mention;
    });
    const sortedMentions = sanitizedMentions.reduce((accumulator, mention) => {
      const key = mention['wm-property'];
      const curGroup = accumulator[key] ?? [];
      return { ...accumulator, [key]: [...curGroup, mention] };
    }, {});

    return sortedMentions;
  });

  const markdownLibrary = markdownIt({ html: true })
    .use(markdownItAnchor, { slugify })
    .use(
      markdownItObsidian({
        slugifyOnPageLinks: slugify,
      })
    )
    .use(markdownItAttrs)
    .use(markdownItEleventyImg, {
      imgOptions: {
        widths: [75, 150, 300, 600, 900, 1100],
        outputDir: path.join("dist", "img"),
      },
      globalAttributes: {
        loading: "lazy",
        decoding: "async",
        sizes: "100vw",
      },
    });
  eleventyConfig.setLibrary("md", markdownLibrary);

  return {
    dir: {
      input: "src",
      output: "dist",
    },
  };
};