// Reader vote widget: "which draft would you ship?" per reviewed skill.
// The page itself is static (Gitea Pages), so this talks to a small
// separate API — see /vote-service in the repository root. One vote per
// source is enforced server-side by IP, not here; this module only renders
// state and remembers the local choice so a returning visitor sees it
// without re-voting.
const API_BASE = (window.SKILLS_REVIEW_VOTE_API || '').replace(/\/$/, '');
const escape = (value) => value.replace(/[&<>"']/g, (character) => ({ '&':'&amp;', '<':'&lt;', '>':'&gt;', '"':'&quot;', "'":'&#039;' })[character]);

function voterId() {
  let id = localStorage.getItem('skills-review-voter-id');
  if (!id) { id = crypto.randomUUID(); localStorage.setItem('skills-review-voter-id', id); }
  return id;
}

async function api(path, options = {}) {
  const response = await fetch(`${API_BASE}${path}`, { ...options, headers: { 'Content-Type': 'application/json', 'X-Voter-Id': voterId(), ...options.headers } });
  if (!response.ok) throw new Error(`vote API ${response.status}`);
  return response.json();
}

function widgetMarkup(skillId, tally, you, unavailable, isUpdate = false) {
  const total = (tally.original || 0) + (tally.improved || 0);
  const share = (count) => total ? Math.round((count / total) * 100) : 0;
  if (unavailable) return `<section class="vote-widget" aria-label="Vote unavailable"><span>READER VOTE</span><p>Voting is offline right now — the vote service is not configured or unreachable.</p></section>`;
  return `<section class="vote-widget" aria-label="Vote on this review" data-skill="${escape(skillId)}">
    <span>WHICH DRAFT WOULD YOU SHIP?</span>
    <div class="vote-buttons" role="group" aria-label="Cast your vote">
      <button data-vote="original" aria-pressed="${you === 'original'}">Original<b${isUpdate ? ' class="is-updating"' : ''}>${tally.original || 0} · ${share(tally.original || 0)}%</b></button>
      <button data-vote="improved" aria-pressed="${you === 'improved'}">Improved draft<b${isUpdate ? ' class="is-updating"' : ''}>${tally.improved || 0} · ${share(tally.improved || 0)}%</b></button>
    </div>
    <p class="vote-note">${you ? `You voted ${you === 'original' ? 'original' : 'improved draft'}. Pick the other option to change it.` : 'One vote per visitor, tracked by network source.'}</p>
  </section>`;
}

export async function renderVoteWidget(container, skillId) {
  if (!API_BASE) { container.innerHTML = widgetMarkup(skillId, {}, null, true); return; }
  container.innerHTML = widgetMarkup(skillId, {}, null, false);
  const cast = async (choice) => {
    container.innerHTML = widgetMarkup(skillId, {}, null, false);
    try {
      const result = await api('/api/votes', { method: 'POST', body: JSON.stringify({ skillId, choice }) });
      container.innerHTML = widgetMarkup(skillId, { original: result.original, improved: result.improved }, result.you, false, true);
      bind();
    } catch { container.innerHTML = widgetMarkup(skillId, {}, null, true); }
  };
  function bind() { container.querySelectorAll('[data-vote]').forEach((button) => button.addEventListener('click', () => cast(button.dataset.vote))); }
  try {
    const result = await api(`/api/votes?skillId=${encodeURIComponent(skillId)}`);
    container.innerHTML = widgetMarkup(skillId, result.tallies?.[skillId] || {}, result.you, false);
  } catch { container.innerHTML = widgetMarkup(skillId, {}, null, true); }
  bind();
}