// ==UserScript==
// @name         Batoto Quick Links
// @namespace    Doomcat55
// @version      0.2
// @description  Add convenient links to Batoto series pages.
// @author       Doomcat55
// @match        *://bato.to/reader
// @match        *://bato.to/comic/_/comics/*
// @grant        GM_setValue
// @grant        GM_getValue
// @downloadURL none
// ==/UserScript==

(function matchURL(path) {
    switch (true) {
        case /\/reader/.test(path):
            setBookmarks();
            break;
        case /\/comic\/_\/comics/.test(path):
            showBookmarks();
            break;
    }
})(window.location.pathname);


function parseSeriesID(link) {
    const text = link.match(/-r(\d+)/)[1];
    return parseInt(text);
}

function setBookmarks() {
    const reader = document.getElementById('reader');

    const observer = new MutationObserver(() => {
        const seriesID = parseSeriesID(document.querySelector('a[href*="/comic/"]').pathname);
        const pageID = window.location.hash;
        GM_setValue(seriesID, pageID);
    });

    observer.observe(reader, {childList: true});
}

function showBookmarks() {
    const seriesID = parseSeriesID(window.location.pathname);
    const bookmarkedPage = GM_getValue(seriesID);
    const linkedPage = bookmarkedPage || document.querySelector('.chapter_row:nth-last-child(2) td:first-child a').hash;
    if (linkedPage) {
        const quickLink = document.createElement('a');
        quickLink.href = `/reader${linkedPage}`;
        quickLink.className = 'ipsButton_secondary';
        quickLink.innerHTML = bookmarkedPage ? 'Resume reading' : 'First chapter';
        const linkParent = document.querySelector('.__like.right');
        linkParent.insertBefore(quickLink, linkParent.firstChild);
    }
}