// Ursprung Sverige - Filtering functionality

(function() {
  'use strict';

  const categoryFilter = document.getElementById('category-filter');
  const regionFilter = document.getElementById('region-filter');
  const tagFilter = document.getElementById('tag-filter');
  const searchInput = document.getElementById('search-input');
  const clearFiltersBtn = document.getElementById('clear-filters');
  const entriesGrid = document.getElementById('entries-grid');
  const visibleCount = document.getElementById('visible-count');
  const noResults = document.getElementById('no-results');

  if (!entriesGrid) return;

  const entries = Array.from(entriesGrid.querySelectorAll('.entry-card'));

  // Update URL with current filter state
  function updateURL() {
    const params = new URLSearchParams();
    
    if (categoryFilter?.value) {
      params.set('category', categoryFilter.value);
    }
    if (regionFilter?.value) {
      params.set('region', regionFilter.value);
    }
    if (tagFilter?.value) {
      params.set('tag', tagFilter.value);
    }
    if (searchInput?.value.trim()) {
      params.set('search', searchInput.value.trim());
    }
    
    const queryString = params.toString();
    const newURL = queryString 
      ? `${window.location.pathname}?${queryString}`
      : window.location.pathname;
    
    window.history.replaceState({}, '', newURL);
  }

  // Apply filters from URL on page load
  function applyFiltersFromURL() {
    const params = new URLSearchParams(window.location.search);
    
    if (params.has('category') && categoryFilter) {
      categoryFilter.value = params.get('category');
    }
    if (params.has('region') && regionFilter) {
      regionFilter.value = params.get('region');
    }
    if (params.has('tag') && tagFilter) {
      tagFilter.value = params.get('tag');
    }
    if (params.has('search') && searchInput) {
      searchInput.value = params.get('search');
    }
    
    filterEntries(false); // Don't update URL on initial load
  }

  function filterEntries(shouldUpdateURL = true) {
    const categoryValue = categoryFilter?.value.toLowerCase() || '';
    const regionValue = regionFilter?.value.toLowerCase() || '';
    const tagValue = tagFilter?.value.toLowerCase() || '';
    const searchValue = searchInput?.value.toLowerCase().trim() || '';

    let visibleEntries = 0;

    entries.forEach(entry => {
      const entryCategory = (entry.dataset.category || '').toLowerCase();
      const entryRegion = (entry.dataset.region || '').toLowerCase();
      const entryTags = (entry.dataset.tags || '').toLowerCase().split(',');
      const entryText = entry.textContent.toLowerCase();

      const matchesCategory = !categoryValue || entryCategory === categoryValue;
      const matchesRegion = !regionValue || entryRegion === regionValue;
      const matchesTag = !tagValue || entryTags.includes(tagValue);
      const matchesSearch = !searchValue || entryText.includes(searchValue);

      const isVisible = matchesCategory && matchesRegion && matchesTag && matchesSearch;

      entry.hidden = !isVisible;
      if (isVisible) visibleEntries++;
    });

    if (visibleCount) {
      visibleCount.textContent = visibleEntries;
    }

    if (noResults) {
      noResults.hidden = visibleEntries > 0;
    }

    if (entriesGrid) {
      entriesGrid.hidden = visibleEntries === 0;
    }

    updateClearButtonVisibility();
    
    if (shouldUpdateURL) {
      updateURL();
    }
  }

  function updateClearButtonVisibility() {
    if (!clearFiltersBtn) return;
    
    const hasFilters = 
      (categoryFilter?.value || '') !== '' ||
      (regionFilter?.value || '') !== '' ||
      (tagFilter?.value || '') !== '' ||
      (searchInput?.value || '') !== '';
    
    clearFiltersBtn.hidden = !hasFilters;
  }

  function clearFilters() {
    if (categoryFilter) categoryFilter.value = '';
    if (regionFilter) regionFilter.value = '';
    if (tagFilter) tagFilter.value = '';
    if (searchInput) searchInput.value = '';
    
    filterEntries(); // This will also clear the URL
  }

  // Handle clicking on filter buttons in cards
  function handleFilterClick(e) {
    const btn = e.target.closest('.filter-btn');
    if (!btn) return;

    const filterType = btn.dataset.filterType;
    const filterValue = btn.dataset.filterValue;

    if (filterType === 'category' && categoryFilter) {
      categoryFilter.value = filterValue;
    } else if (filterType === 'region' && regionFilter) {
      regionFilter.value = filterValue;
    } else if (filterType === 'tag' && tagFilter) {
      tagFilter.value = filterValue;
    }

    filterEntries();
    
    // Scroll to top to see filtered results
    window.scrollTo({ top: 0, behavior: 'smooth' });
  }

  // Handle browser back/forward
  window.addEventListener('popstate', () => {
    applyFiltersFromURL();
  });

  // Debounce for search input
  function debounce(func, wait) {
    let timeout;
    return function(...args) {
      clearTimeout(timeout);
      timeout = setTimeout(() => func.apply(this, args), wait);
    };
  }

  // Event listeners
  if (categoryFilter) {
    categoryFilter.addEventListener('change', () => filterEntries());
  }

  if (regionFilter) {
    regionFilter.addEventListener('change', () => filterEntries());
  }

  if (tagFilter) {
    tagFilter.addEventListener('change', () => filterEntries());
  }

  if (searchInput) {
    searchInput.addEventListener('input', debounce(() => filterEntries(), 300));
  }

  if (clearFiltersBtn) {
    clearFiltersBtn.addEventListener('click', clearFilters);
  }

  // Delegate click events for filter buttons in cards
  if (entriesGrid) {
    entriesGrid.addEventListener('click', handleFilterClick);
  }

  // Apply URL filters on load
  applyFiltersFromURL();
  updateClearButtonVisibility();
})();