/* =========================================================================
   models.js — live catalog: search + provider filter + sort + render
   Loads data/models-catalog.json once, then filters entirely client-side.
   Renders incrementally; caps visible cards for snappy scroll on 374 items.
   ========================================================================= */

(function () {
  'use strict';

  const GRID = document.getElementById('model-grid');
  const RAIL = document.getElementById('filter-rail');
  const SEARCH = document.getElementById('model-search');
  const COUNT = document.getElementById('model-count');
  const SORT = document.getElementById('model-sort');
  if (!GRID) return;

  let DATA = null;                 // { total_models, total_targets, providers, models }
  let view = [];                   // current filtered+sorted slice
  let state = { q: '', provider: 'all', sort: 'targets' };
  const PAGE = 60;                 // render in pages for scroll perf
  let shown = PAGE;

  /* ---- load the catalog ---- */
  async function load() {
    try {
      const res = await fetch('data/models-catalog.json', { cache: 'force-cache' });
      DATA = await res.json();
    } catch (e) {
      GRID.innerHTML = '<div class="model-empty"><p>Could not load the catalog. Try again in a moment.</p></div>';
      return;
    }
    buildFilters();
    apply();
  }

  /* ---- build the provider filter rail ---- */
  function buildFilters() {
    const frag = document.createDocumentFragment();
    const all = document.createElement('button');
    all.type = 'button';
    all.dataset.provider = 'all';
    all.setAttribute('aria-pressed', 'true');
    all.innerHTML = `All <span class="n">${DATA.total_models}</span>`;
    frag.appendChild(all);
    DATA.providers.forEach((p) => {
      const b = document.createElement('button');
      b.type = 'button';
      b.dataset.provider = p.name;
      b.setAttribute('aria-pressed', 'false');
      b.innerHTML = `${p.name} <span class="n">${p.count}</span>`;
      frag.appendChild(b);
    });
    RAIL.innerHTML = '';
    RAIL.appendChild(frag);
    RAIL.addEventListener('click', (e) => {
      const btn = e.target.closest('button[data-provider]');
      if (!btn) return;
      state.provider = btn.dataset.provider;
      RAIL.querySelectorAll('button').forEach((b) =>
        b.setAttribute('aria-pressed', String(b === btn)));
      shown = PAGE;
      apply();
    });
  }

  /* ---- filter + sort ---- */
  function apply() {
    const q = state.q.trim().toLowerCase();
    view = DATA.models.filter((m) => {
      if (state.provider !== 'all' && m.provider !== state.provider) return false;
      if (!q) return true;
      return (
        m.name.toLowerCase().includes(q) ||
        m.provider.toLowerCase().includes(q) ||
        m.upstream.some((u) => u.toLowerCase().includes(q))
      );
    });
    if (state.sort === 'targets') view.sort((a, b) => b.targets - a.targets);
    else if (state.sort === 'name') view.sort((a, b) => a.name.localeCompare(b.name));
    shown = PAGE;
    render();
  }

  /* ---- render the visible page ---- */
  function render() {
    COUNT.innerHTML = `showing <strong>${view.length}</strong> of <strong>${DATA.total_models}</strong> models`;
    if (!view.length) {
      GRID.innerHTML = '<div class="model-empty"><p>No models match. Try a different search.</p></div>';
      return;
    }
    const slice = view.slice(0, shown);
    const html = slice.map((m) => `
      <article class="model-card">
        <div class="name">${escapeHtml(m.name)}</div>
        <div class="meta">
          <span class="tag">${escapeHtml(m.provider)}</span>
          <span class="tag targets">${m.targets.toLocaleString()} targets</span>
          ${m.stream ? '<span class="tag stream">stream</span>' : ''}
        </div>
      </article>`).join('');
    const more = view.length > shown
      ? `<button class="btn btn-ghost model-more" type="button" style="grid-column:1/-1;justify-self:center;margin-top:1rem;">Show more (${view.length - shown} left)</button>`
      : '';
    GRID.innerHTML = html + more;
    const moreBtn = GRID.querySelector('.model-more');
    if (moreBtn) moreBtn.addEventListener('click', () => { shown += PAGE; render(); });
  }

  function escapeHtml(s) {
    return s.replace(/[&<>"']/g, (c) => (
      { '&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;', "'": '&#39;' }[c]
    ));
  }

  /* ---- wire controls ---- */
  let debounce;
  SEARCH.addEventListener('input', (e) => {
    clearTimeout(debounce);
    debounce = setTimeout(() => { state.q = e.target.value; apply(); }, 120);
  });
  SORT.addEventListener('change', (e) => { state.sort = e.target.value; apply(); });

  load();
})();