<script>
(function() {

    const targetForums = [1]; // свои ID

    const currentForumId = window.FORUM 
        ? parseInt(FORUM.get('topic.forum_id')) 
        : null;

    if (targetForums.length && (!currentForumId || !targetForums.includes(currentForumId))) {
        return;
    }

    function fixCase(text) {
        text = text.toLowerCase();
        return text.replace(/(^\s*|[.!?]\s+|\n\s*)([a-zа-яё])/gi,
            function(match, sep, letter) {
                return sep + letter.toUpperCase();
            }
        );
    }

    function processTextNodes(container, restore) {
        const walker = document.createTreeWalker(
            container,
            NodeFilter.SHOW_TEXT,
            null,
            false
        );

        let node;
        while (node = walker.nextNode()) {
            if (!node.nodeValue.trim()) continue;

            if (!restore) {
                node._original = node.nodeValue;
                node.nodeValue = fixCase(node.nodeValue);
            } else if (node._original !== undefined) {
                node.nodeValue = node._original;
            }
        }
    }

    $(window).on('load', function() {

        const panel = $('#form-buttons');
        if (!panel.length) return;

        if ($('#btn-caps-fix').length) return;

        const btn = $('<a>', {
            id: 'btn-caps-fix',
            href: '#',
            title: 'Нормализовать регистр',
            html: '<i class="fas fa-font"></i>',
            css: {
                display: 'inline-block',
                marginLeft: '0px',
                verticalAlign: 'middle',
                cursor: 'pointer'
            }
        });

        panel.after(btn);

        btn.on('click', function(e) {
            e.preventDefault();

            const isActive = btn.hasClass('is-fixed');

            $('.post-content').each(function() {
                processTextNodes(this, isActive);
            });

            btn.toggleClass('is-fixed')
               .css('color', isActive ? '' : '#4caf50');
        });

    });

})();
</script>