(function () {
    'use strict';

    function parseItems() {
        var el = document.getElementById('sk-gallery-lb-json');
        if (!el) return null;
        try {
            var items = JSON.parse(el.textContent.trim());
            return Array.isArray(items) && items.length ? items : null;
        } catch (e) {
            return null;
        }
    }

    function init() {
        var items = parseItems();
        if (!items) return;

        var grid = document.querySelector('.sk-gallery--lb');
        var lb = document.getElementById('sk-lightbox');
        if (!grid || !lb) return;

        var img = lb.querySelector('.sk-lightbox__img');
        var prev = lb.querySelector('.sk-lightbox__prev');
        var next = lb.querySelector('.sk-lightbox__next');
        var closeBtn = lb.querySelector('.sk-lightbox__close');
        var counter = lb.querySelector('.sk-lightbox__counter');
        var inner = lb.querySelector('.sk-lightbox__inner');
        if (!img || !prev || !next || !closeBtn || !counter || !inner) return;

        var idx = 0;
        var single = items.length < 2;

        function show(i) {
            idx = (i + items.length) % items.length;
            var it = items[idx];
            img.src = it.url || '';
            img.alt = it.label || '';
            counter.textContent = (idx + 1) + ' / ' + items.length;
            prev.hidden = single;
            next.hidden = single;
        }

        function open(at) {
            show(at);
            lb.removeAttribute('hidden');
            document.body.classList.add('sk-lightbox-open');
            closeBtn.focus();
        }

        function close() {
            lb.setAttribute('hidden', '');
            document.body.classList.remove('sk-lightbox-open');
            img.removeAttribute('src');
            img.alt = '';
        }

        grid.querySelectorAll('.sk-gallery-item--lb').forEach(function (btn, i) {
            btn.addEventListener('click', function () {
                open(i);
            });
        });

        prev.addEventListener('click', function (e) {
            e.stopPropagation();
            if (!single) show(idx - 1);
        });
        next.addEventListener('click', function (e) {
            e.stopPropagation();
            if (!single) show(idx + 1);
        });
        closeBtn.addEventListener('click', function (e) {
            e.stopPropagation();
            close();
        });
        lb.addEventListener('click', function (e) {
            if (e.target === lb) close();
        });
        inner.addEventListener('click', function (e) {
            e.stopPropagation();
        });

        document.addEventListener('keydown', function (e) {
            if (lb.hasAttribute('hidden')) return;
            if (e.key === 'Escape') {
                close();
            } else if (e.key === 'ArrowLeft' && !single) {
                e.preventDefault();
                show(idx - 1);
            } else if (e.key === 'ArrowRight' && !single) {
                e.preventDefault();
                show(idx + 1);
            }
        });
    }

    if (document.readyState === 'loading') {
        document.addEventListener('DOMContentLoaded', init);
    } else {
        init();
    }
})();