AO3: Autocomplete in Menu Search Field

Turns the general search in the menu bar into an autocomplete for any canonical tags

// ==UserScript==
// @name         AO3: Autocomplete in Menu Search Field
// @namespace    https://greasyfork.org/en/users/906106-escctrl
// @description  Turns the general search in the menu bar into an autocomplete for any canonical tags
// @author       escctrl
// @version      1.0
// @match        *://*.archiveofourown.org/*
// @grant        none
// @require      https://ajax.googleapis.com/ajax/libs/jquery/3.7.0/jquery.min.js
// @require      https://update.greasyfork.org/scripts/491888/1355841/Light%20or%20Dark.js
// @license      MIT
// ==/UserScript==

/* eslint-disable no-multi-spaces */
/* global jQuery, lightOrDark */

(function($) {
    'use strict';

    // styling the autocomplete (because #header has some CSS that interferes we have to set it explicitly)
    let border, bg, text, bgHover, textHover = "";

    // official site skins are <link>'ed, default with various medias, others with media="all"; user site skins are inserted directly with <style>
    var skin = $('link[href^="/stylesheets/skins/"][media="all"]');
    // default site skin means there's no media="all", for others there should be exactly one
    if (skin.length === 1) skin = $(skin).attr("href").match(/skin_(\d+)_/);
    skin = skin[1] || "";

    // In case of non-public site skins, checks if using a dark mode by calculating the 'brightness' of the page background color
    if (skin === "") skin = lightOrDark(window.getComputedStyle(document.body).backgroundColor);

    switch (skin) {
        case "929": // reversi
        case "dark":
            border = "#222";
            bg = "rgb(42, 42, 42)";
            text = "#fff";
            bgHover = "rgb(17, 17, 17)";
            textHover = "#fff";
            break;
        case "932": // snow blue
        case "891": // low vision
        case "light":
        default: // default site skin
            border = "#888";
            bg = "#ddd";
            text = "#2a2a2a";
            bgHover = "rgba(255, 255, 255, 0.25)";
            textHover = "#111";
            break;
    }

    $('header').append(`<style type="text/css">
        #general_search_autocomplete { width: 20em; margin-right: 1em; padding: 0.125em; border-radius: 1em; }
        #header .search li.input { margin: 0; }
        #header .autocomplete.dropdown { display: block; border: 1px solid ${border}; background-color: ${bg}; }
        #header .autocomplete.dropdown ul { box-shadow: none; border: 0; background-color: transparent; }
        #header .autocomplete.dropdown li { display: list-item; float: none; text-align: left; padding: 0.125em 0.25em; color: ${text}; }
        #header .autocomplete.dropdown li:hover { color: ${textHover}; background-color: ${bgHover}; cursor: pointer; }
    </style>`);

    // grab the <li> in which general search sits
    let liSearch = $('#header').find('nav[aria-label="Site"] li.search');

    // replace the general search form with an autocomplete field for any canonical tag
    $(liSearch).html(`<form>
        <input class="autocomplete" data-autocomplete-method="/autocomplete/tag" data-autocomplete-hint-text="Start typing to search for a tag!"
            data-autocomplete-no-results-text="(No suggestions found)" data-autocomplete-min-chars="1" data-autocomplete-searching-text="Searching..." type="text"
            data-autocomplete-token-limit="1" data-autocomplete-value="" id="general_search" style="width: 20em;">
    </form>`);

    // listen to the autocomplete - if a tag is selected, we navigate to its /works page
    $(liSearch).on('blur', '#general_search_autocomplete', function(e) {
        let liAddedTag = $(liSearch).find('li.added.tag').toArray();

        // if there's actually a tag that was selected, we can continue
        if (liAddedTag.length !== 0) {
            let tagName = liAddedTag[0].firstChild.textContent.trim(); // pure tagname without the x delete link
            tagName = tagName.replaceAll("/", "*s*").replaceAll(".", "*d*").replaceAll("?", "*q*").replace("#", "*h*").replace('"', '&quot;'); // replacing the AO3 specific stuff in URLs

            window.location.assign(`${window.location.origin}/tags/${tagName}/works`);
        }
    });


})(jQuery);