document.addEventListener('DOMContentLoaded', function () {
    var sentinel = document.getElementById('scroll-sentinel');
    var grid = document.getElementById('post-grid');
    var spinner = document.getElementById('scroll-spinner');

    if (!sentinel || !grid) return;

    var page = 1;
    var loading = false;
    var done = false;

    // Read filter params from sentinel data attributes (set server-side)
    var categoryId = sentinel.dataset.category || '';
    var axe = sentinel.dataset.axe || '';
    var dateFrom = sentinel.dataset.dateFrom || '';
    var dateTo = sentinel.dataset.dateTo || '';
    var taxonomy = sentinel.dataset.taxonomy || '';
    var termId = sentinel.dataset.term || '';
    var catFilter    = sentinel.dataset.filterCat || '';
    var filterAutres = sentinel.dataset.filterAutres || '';
    var excludeCats  = sentinel.dataset.excludeCats || '';
    var searchQuery  = sentinel.dataset.search || '';

    function fetchPosts() {
        if (loading || done) return;
        loading = true;
        page++;
        spinner.style.display = 'flex';

        var data = new FormData();
        data.append('action', 'load_more_posts');
        data.append('page', page);
        data.append('nonce', infiniteScrollData.nonce);
        data.append('lang', infiniteScrollData.lang || 'fr');
        if (categoryId) data.append('category', categoryId);
        if (axe) data.append('axe', axe);
        if (dateFrom) data.append('date_from', dateFrom);
        if (dateTo) data.append('date_to', dateTo);
        if (taxonomy) data.append('taxonomy', taxonomy);
        if (termId) data.append('term', termId);
        if (catFilter) data.append('filter_cat', catFilter);
        if (filterAutres) data.append('filter_autres', filterAutres);
        if (excludeCats) data.append('exclude_cats', excludeCats);
        if (searchQuery) data.append('search', searchQuery);

        fetch(infiniteScrollData.ajaxUrl, { method: 'POST', body: data })
            .then(function (response) { return response.json(); })
            .then(function (result) {
                spinner.style.display = 'none';
                if (result.success && result.data.html) {
                    grid.insertAdjacentHTML('beforeend', result.data.html);
                    loading = false;
                } else {
                    done = true;
                    observer.disconnect();
                }
            })
            .catch(function () {
                spinner.style.display = 'none';
                loading = false;
            });
    }

    var observer = new IntersectionObserver(function (entries) {
        if (entries[0].isIntersecting) {
            fetchPosts();
        }
    }, { rootMargin: '200px' });

    observer.observe(sentinel);
});