import { getLibraries, getRecentItems } from '../embyApi.js';
import { connectLobby, joinParty, createParty } from '../party.js';
import { navigate } from '../router.js';
import { tileHtml, wireTileButtons, escapeHtml } from '../tiles.js';

export function renderHome(root) {
  root.innerHTML = `
    <div class="pageHeader">
      <h1>Accueil</h1>
    </div>

    <section class="section" id="partiesSection" hidden>
      <h2>Watch parties en cours</h2>
      <div id="partiesCarousel" class="carousel"></div>
    </section>

    <div id="recentSections"></div>`;

  // Live, not a one-shot fetch: the list (and each card's host/member count)
  // updates the moment anything changes anywhere - see
  // server/src/socketHandler.js's "lobby" room. The elapsed-time label is
  // the one piece that ticks purely client-side (from createdUtc) - no
  // point re-pushing from the server once a second just for a clock.
  const lobby = connectLobby((parties) => renderParties(root, parties));
  const elapsedTimer = setInterval(() => updateElapsedLabels(root), 1000);

  loadRecentSections(root);

  // Called by router.js before rendering whatever comes next - stops the
  // lobby socket and the ticking clock from running after you've navigated
  // away (see docs/architecture.md's memory-leak writeup).
  return function cleanup() {
    lobby.disconnect();
    clearInterval(elapsedTimer);
  };
}

function renderParties(root, parties) {
  const section = root.querySelector('#partiesSection');
  const list = root.querySelector('#partiesCarousel');
  if (!section || !list) return; // navigated away mid-flight

  if (!parties.length) {
    section.hidden = true;
    list.innerHTML = '';
    return;
  }

  section.hidden = false;
  list.innerHTML = parties.map((p) => `
    <div class="partyCard">
      <img src="${p.itemImageUrl || ''}" alt="" onerror="this.classList.add('noImage')" />
      <div class="partyCardInfo">
        <strong>${escapeHtml(p.itemName || '')}</strong>
        <span class="hint">
          ${escapeHtml(p.hostUserName || '')} · ${p.memberCount} participant${p.memberCount > 1 ? 's' : ''}
          · <span class="elapsed" data-created="${p.createdUtc}">--:--</span>
        </span>
      </div>
      <button class="joinPartyBtn" data-party-id="${p.partyId}">Rejoindre</button>
    </div>
  `).join('');

  list.querySelectorAll('.joinPartyBtn').forEach((btn) => {
    btn.addEventListener('click', async () => {
      btn.disabled = true;
      try {
        // Actually register as a member before navigating - the player's
        // realtime "join" is rejected server-side otherwise (you'd load the
        // video but never get added to the members list or sync).
        await joinParty(btn.dataset.partyId);
        navigate(`/party/${btn.dataset.partyId}`);
      } catch (err) {
        alert(err.message);
        btn.disabled = false;
      }
    });
  });

  updateElapsedLabels(root);
}

function updateElapsedLabels(root) {
  const now = Date.now();
  root.querySelectorAll('.elapsed').forEach((el) => {
    const created = Number(el.dataset.created);
    if (!created) return;
    el.textContent = formatElapsed(now - created);
  });
}

function formatElapsed(ms) {
  const totalSeconds = Math.max(0, Math.floor(ms / 1000));
  const h = Math.floor(totalSeconds / 3600);
  const m = Math.floor((totalSeconds % 3600) / 60);
  const s = totalSeconds % 60;
  const pad = (n) => String(n).padStart(2, '0');
  return h > 0 ? `${h}:${pad(m)}:${pad(s)}` : `${m}:${pad(s)}`;
}

async function loadRecentSections(root) {
  const container = root.querySelector('#recentSections');
  let libraries;
  try {
    libraries = await getLibraries();
  } catch (err) {
    container.innerHTML = '<p class="error">Impossible de charger les bibliothèques Emby.</p>';
    return;
  }

  for (const lib of libraries) {
    const section = document.createElement('section');
    section.className = 'section';
    section.innerHTML = `<h2>Ajouts récents - ${escapeHtml(lib.name)}</h2><div class="carousel"><p class="hint">Chargement...</p></div>`;
    container.appendChild(section);

    getRecentItems(lib.id)
      .then((items) => {
        if (!items.length) {
          section.remove();
          return;
        }
        const carousel = section.querySelector('.carousel');
        carousel.innerHTML = items.map(tileHtml).join('');
        wireTileButtons(carousel, async (itemId) => {
          const party = await createParty(itemId);
          navigate(`/party/${party.partyId}`);
        });
      })
      .catch(() => section.remove());
  }
}