function PleromaModFavicon () {
  this.instances = {};
  this.config = {
    favicon: "favicon.png",
    fallback: "favicon.ico"
  };
  this.loadConfig();
}

[
  function loadConfig () {
    window.fetch(PleromaModLoader.getModDir() + "pleroma-mod-favicon/config.json").then((response) => {
      if (response.ok) {
        response.json().then((json) => {
          // TODO (puniko): do config stuff
        }).catch((error) => {
          console.error("can't parse favicon config");
          console.error(error);
        });
      }
    }).catch((error) => {
      console.error("can't load favicon config");
      console.error(error);
    });
  },

  function onMutation (mutation, observer) {
    this.addFavicon();
  },

  function onReady () {
    this.addFavicon();
  },

  function run () {
    PleromaModLoader.includeModCss("pleroma-mod-favicon/style.css");
  },

  function addFavicon () {
    const statusHeadingRights = document.querySelectorAll(".status>.status-body");
    for (let statusHeadingRight of statusHeadingRights) {
      this.addFaviconByStatus(statusHeadingRight);
    }
  },

  function addFaviconByStatus (statusHeadingRight) {
    if (statusHeadingRight.querySelector(".instance-favicon")) {
      return;
    }
    const sourceElements = statusHeadingRight.querySelector(".source_url");
    let instance = "default";
    if (sourceElements) {
      const urlMatches = sourceElements.href.match(/https?:\/\/[^/]*/);
      if (urlMatches.length > 0) {
        instance = urlMatches[0];
      }
    }
    instance = instance.replace(/^https?:\/\//, "");

    const faviconElement = document.createElement("img");
    faviconElement.src = PleromaModLoader.getModDir() + "pleroma-mod-favicon/cache/" + instance + ".png";
    faviconElement.className = "instance-favicon";
    statusHeadingRight.appendChild(faviconElement);
  }
].forEach((func) => { PleromaModFavicon.prototype[func.name] = func; });

PleromaModLoader.registerMod(PleromaModFavicon);