/* ============================================
   GrubFlip — Feed & Meal Cards
   Renders the meal feed with filtering,
   pagination, and card interactions.
   ============================================ */

const Feed = (() => {
  'use strict';

  const { api, $, $$, el, timeUntil, timeAgo, starsHTML, debounce, toast } = GrubFlip;

  // --- State ---
  let meals = [];
  let pagination = { page: 1, per_page: 20, total: 0, has_more: false };
  let loading = false;
  let filters = {
    dietary: [],
    cuisine: '',
    trade_type: '',
    sort: 'newest',
  };

  const DIETARY_OPTIONS = [
    'vegan', 'vegetarian', 'gluten-free', 'dairy', 'dairy-free',
    'nut-free', 'halal', 'kosher', 'high-protein', 'low-carb', 'spicy'
  ];

  // --- Meal Card Rendering ---
  function renderMealCard(meal) {
    const card = el('article', { className: 'meal-card', dataset: { mealId: meal.id } });

    // Image
    const imageWrap = el('div', { className: 'meal-card__image-wrap' });
    const img = el('img', {
      className: 'meal-card__image',
      src: meal.image_thumb_url || meal.image_url,
      alt: meal.title,
      loading: 'lazy',
    });
    imageWrap.appendChild(img);

    // Trade type badge
    const tradeLabel = meal.trade_type === 'swap' ? 'Swap' : meal.trade_type;
    imageWrap.appendChild(el('span', {
      className: 'meal-card__trade-type',
      textContent: tradeLabel,
    }));

    // Expiry countdown
    if (meal.expires_at) {
      const remaining = timeUntil(meal.expires_at);
      if (remaining !== 'expired') {
        imageWrap.appendChild(el('span', {
          className: 'meal-card__expiry',
          innerHTML: `<svg width="12" height="12" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><circle cx="12" cy="12" r="10"/><path d="M12 6v6l4 2"/></svg> ${remaining}`,
        }));
      }
    }

    card.appendChild(imageWrap);

    // Body
    const body = el('div', { className: 'meal-card__body' });

    body.appendChild(el('h3', { className: 'meal-card__title', textContent: meal.title }));
    body.appendChild(el('p', { className: 'meal-card__desc', textContent: meal.description }));

    // Tags
    const tagsWrap = el('div', { className: 'meal-card__tags' });
    if (meal.cuisine) {
      tagsWrap.appendChild(el('span', {
        className: 'meal-card__tag meal-card__tag--cuisine',
        textContent: meal.cuisine,
      }));
    }
    for (const tag of (meal.dietary_tags || []).slice(0, 3)) {
      tagsWrap.appendChild(el('span', {
        className: 'meal-card__tag',
        textContent: tag,
      }));
    }
    body.appendChild(tagsWrap);

    // Footer — user + distance
    const footer = el('div', { className: 'meal-card__footer' });

    const userSection = el('div', { className: 'meal-card__user' });
    userSection.appendChild(el('img', {
      className: 'meal-card__avatar',
      src: meal.user.avatar_url,
      alt: meal.user.display_name,
      loading: 'lazy',
    }));

    const userInfo = el('div', { className: 'meal-card__user-info' });
    userInfo.appendChild(el('span', {
      className: 'meal-card__user-name',
      textContent: meal.user.display_name,
    }));
    const metaHTML = `${starsHTML(meal.user.rating)} · ${meal.user.trade_count} trades`;
    userInfo.appendChild(el('span', {
      className: 'meal-card__user-meta',
      innerHTML: metaHTML,
    }));
    userSection.appendChild(userInfo);
    footer.appendChild(userSection);

    if (meal.distance_km != null) {
      footer.appendChild(el('span', {
        className: 'meal-card__distance',
        innerHTML: `<svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><path d="M21 10c0 7-9 13-9 13s-9-6-9-13a9 9 0 0118 0z"/><circle cx="12" cy="10" r="3"/></svg> ${meal.distance_km} km`,
      }));
    }

    body.appendChild(footer);
    card.appendChild(body);

    // Click handler — open detail modal
    card.addEventListener('click', () => {
      if (typeof MealDetail !== 'undefined') {
        MealDetail.open(meal);
      } else {
        toast(`Opening ${meal.title}...`);
      }
    });

    return card;
  }

  // --- Skeleton Card ---
  function renderSkeleton() {
    const card = el('div', { className: 'meal-card' });
    card.innerHTML = `
      <div class="meal-card__image-wrap skeleton" style="aspect-ratio:4/3"></div>
      <div class="meal-card__body">
        <div class="skeleton" style="height:1rem;width:70%;margin-bottom:0.5rem"></div>
        <div class="skeleton" style="height:0.75rem;width:90%;margin-bottom:0.75rem"></div>
        <div style="display:flex;gap:0.375rem;margin-bottom:0.75rem">
          <div class="skeleton" style="height:1.25rem;width:4rem;border-radius:9999px"></div>
          <div class="skeleton" style="height:1.25rem;width:5rem;border-radius:9999px"></div>
        </div>
        <div style="display:flex;align-items:center;gap:0.5rem;padding-top:0.75rem;border-top:1px solid var(--gf-neutral-100)">
          <div class="skeleton" style="width:32px;height:32px;border-radius:50%"></div>
          <div class="skeleton" style="height:0.75rem;width:5rem"></div>
        </div>
      </div>`;
    return card;
  }

  // --- Filter Bar ---
  function renderFilterBar(container) {
    const bar = el('div', { className: 'filter-bar', role: 'toolbar', 'aria-label': 'Filter meals' });

    // Sort chip
    const sortChip = el('button', {
      className: 'filter-chip active',
      textContent: '✨ Newest',
      onClick: () => {
        filters.sort = filters.sort === 'newest' ? 'nearest' : 'newest';
        sortChip.textContent = filters.sort === 'newest' ? '✨ Newest' : '📍 Nearest';
        loadMeals(true);
      },
    });
    bar.appendChild(sortChip);

    // Dietary filters
    for (const tag of DIETARY_OPTIONS) {
      const chip = el('button', {
        className: 'filter-chip',
        textContent: tag,
        onClick: () => {
          const idx = filters.dietary.indexOf(tag);
          if (idx >= 0) {
            filters.dietary.splice(idx, 1);
            chip.classList.remove('active');
          } else {
            filters.dietary.push(tag);
            chip.classList.add('active');
          }
          loadMeals(true);
        },
      });
      bar.appendChild(chip);
    }

    container.appendChild(bar);
  }

  // --- Load Meals ---
  async function loadMeals(reset = false) {
    if (loading) return;
    loading = true;

    const listEl = $('#feed-list');
    if (!listEl) return;

    if (reset) {
      pagination.page = 1;
      meals = [];
      listEl.innerHTML = '';
      // Show skeletons
      for (let i = 0; i < 6; i++) {
        listEl.appendChild(renderSkeleton());
      }
    }

    try {
      const params = {
        page: pagination.page,
        sort: filters.sort,
      };
      if (filters.dietary.length) params.dietary = filters.dietary.join(',');
      if (filters.cuisine) params.cuisine = filters.cuisine;
      if (filters.trade_type) params.trade_type = filters.trade_type;

      const data = await api.get('/meals', params);

      if (reset) listEl.innerHTML = '';

      meals = reset ? data.meals : [...meals, ...data.meals];
      pagination = data.pagination;

      for (const meal of data.meals) {
        listEl.appendChild(renderMealCard(meal));
      }

      // Load more button
      const existingMore = $('#load-more-btn');
      if (existingMore) existingMore.remove();

      if (pagination.has_more) {
        const moreBtn = el('button', {
          className: 'btn btn--outline btn--block',
          id: 'load-more-btn',
          textContent: 'Load more meals',
          onClick: () => {
            pagination.page++;
            loadMeals(false);
          },
        });
        listEl.parentElement.appendChild(moreBtn);
      }

      // Empty state
      if (meals.length === 0) {
        listEl.innerHTML = `
          <div class="feed__empty">
            <svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.5">
              <path d="M12 2C6.48 2 2 6.48 2 12s4.48 10 10 10 10-4.48 10-10S17.52 2 12 2zm-2 15l-5-5 1.41-1.41L10 14.17l7.59-7.59L19 8l-9 9z"/>
            </svg>
            <h3>No meals found</h3>
            <p>Try adjusting your filters or check back later</p>
          </div>`;
      }
    } catch (err) {
      toast(err.message, 'error');
      if (reset) listEl.innerHTML = '';
    } finally {
      loading = false;
    }
  }

  // --- Infinite Scroll ---
  function setupInfiniteScroll() {
    const scrollHandler = debounce(() => {
      if (loading || !pagination.has_more) return;
      const scrollBottom = window.innerHeight + window.scrollY;
      const pageBottom = document.documentElement.offsetHeight - 200;
      if (scrollBottom >= pageBottom) {
        pagination.page++;
        loadMeals(false);
      }
    }, 100);

    window.addEventListener('scroll', scrollHandler, { passive: true });
  }

  // --- Init ---
  function init() {
    const feedContainer = $('#feed-container');
    if (!feedContainer) return;

    renderFilterBar(feedContainer);

    const list = el('div', { className: 'feed__list', id: 'feed-list', role: 'feed', 'aria-label': 'Meal listings' });
    feedContainer.appendChild(list);

    loadMeals(true);
    setupInfiniteScroll();
  }

  return { init, loadMeals, renderMealCard };
})();

document.addEventListener('DOMContentLoaded', Feed.init);