/*
 * section-folds.js -- Parse out sections to hide behind an "unfold" dialog
 * Copyright © 2022 - 2023 Jakob L. Kreuze <zerodaysfordays@sdf.org>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see
 * <http://www.gnu.org/licenses/>.
 */

function handleFolds() {
    function displayFold(fold, foldText, frontMatterText) {
        foldText.innerHTML = `⬇️ ${frontMatterText}`;
        fold.classList.remove("fold-hidden");
        
    }

    function hideFold(fold, foldText, frontMatterText) {
        foldText.innerHTML = `➡️ Folded ${frontMatterText}`;
        fold.classList.add("fold-hidden");
    }

    let folds = document.querySelectorAll(".section-fold");

    for (let fold of folds) {
        // The first thing we'll do is generate the "front matter" for the fold, so
        // that the reader knows what lies beneath the fold.
        let frontMatterText = `Section on "${fold.dataset.name}"`;
        let foldFrontMatter = document.createElement("div");

        // The text will be inside of an anchor, which we'll hook onto using an
        // event listener.
        let foldAnchor = document.createElement("a");
        let foldText = document.createElement("p");
        foldAnchor.appendChild(foldText);
        fold.parentNode.insertBefore(foldAnchor, fold.nextSibling);

        // The fold will start off in the "hidden" state.
        let toggle = false;
        hideFold(fold, foldText, frontMatterText);

        // But clicking on the "front matter" will cause the state of the fold
        // to toggle, first to "visible", and then back to "hidden".
        foldAnchor.addEventListener('click', () => {
            toggle = !toggle;
            if (toggle) {
                displayFold(fold, foldText, frontMatterText);
            } else {
                hideFold(fold, foldText, frontMatterText);
            }
        });
    }

}

// Defer parsing all of the "folds" until the document has completely loaded.
document.addEventListener("DOMContentLoaded", handleFolds);