let me = null;
let allSongs = [];
let setlist = null;
let mainRows = [];
let encoreRows = [];
let addSongId = null;

function formatDate(dateStr) {
  const d = new Date(dateStr);
  return d.toLocaleDateString('fr-FR', { weekday: 'long', year: 'numeric', month: 'long', day: 'numeric' });
}

function readOnlyView() {
  const main = setlist.songs.filter((s) => !s.is_encore);
  const encore = setlist.songs.filter((s) => s.is_encore);
  return `
    <div class="card">
      <div class="card-title">${escapeHtml(setlist.name || 'Concert')}</div>
      <div class="card-subtitle">${escapeHtml(setlist.venue || '')} · ${formatDate(setlist.concert_date)}</div>
    </div>
    <div class="setlist-section">
      <h3>Setlist</h3>
      ${main.length
        ? `<ol class="setlist">${main.map((s) => `<li><span class="row-title">${escapeHtml(s.title)}</span> <span class="row-artist">— ${escapeHtml(s.artist)}</span>${s.note ? `<span class="note">${escapeHtml(s.note)}</span>` : ''}</li>`).join('')}</ol>`
        : '<p class="empty">Aucun morceau pour le moment.</p>'}
    </div>
    <div class="setlist-section">
      <h3>Rappel</h3>
      ${encore.length
        ? `<ol class="setlist">${encore.map((s) => `<li><span class="row-title">${escapeHtml(s.title)}</span> <span class="row-artist">— ${escapeHtml(s.artist)}</span>${s.note ? `<span class="note">${escapeHtml(s.note)}</span>` : ''}</li>`).join('')}</ol>`
        : '<p class="empty">Aucun morceau de rappel prévu.</p>'}
    </div>
    ${me.isAdmin ? '<button id="edit-btn" class="secondary" style="margin-top:1rem">Modifier la setlist</button>' : ''}
  `;
}

function renderReadOnly() {
  const container = document.getElementById('content');
  if (!setlist) {
    container.innerHTML = me.isAdmin
      ? `<p class="empty">Aucun concert à venir.</p>${metaFormTemplate()}`
      : '<p class="empty">Aucun concert à venir pour le moment.</p>';
    if (me.isAdmin) attachMetaFormHandler();
    return;
  }
  container.innerHTML = readOnlyView();
  const editBtn = document.getElementById('edit-btn');
  if (editBtn) editBtn.addEventListener('click', enterEditMode);
}

function metaFormTemplate() {
  return `
    <div class="panel">
      <h3>${setlist ? 'Détails du concert' : 'Créer le prochain concert'}</h3>
      <form id="meta-form" class="inline-form">
        <label>Nom <input name="name" value="${escapeHtml(setlist?.name || '')}"></label>
        <label>Lieu <input name="venue" value="${escapeHtml(setlist?.venue || '')}"></label>
        <label>Date <input type="date" name="concertDate" value="${setlist ? setlist.concert_date.slice(0, 10) : ''}" required></label>
        <button type="submit">${setlist ? 'Enregistrer' : 'Créer le concert'}</button>
      </form>
    </div>
  `;
}

function usedSongIds() {
  return new Set([...mainRows, ...encoreRows].map((r) => r.songId));
}

function availableSongOptions() {
  const used = usedSongIds();
  const available = allSongs.filter((s) => !used.has(s.id));
  if (!available.length) return '<option value="">(tous les morceaux sont déjà dans la setlist)</option>';
  return available.map((s) => `<option value="${s.id}">${escapeHtml(s.title)} — ${escapeHtml(s.artist)}</option>`).join('');
}

function rowTemplate(row, index, section, total) {
  return `
    <div class="setlist-row" data-section="${section}" data-index="${index}">
      <div class="row-index">${index + 1}</div>
      <div class="row-main">
        <div class="row-title">${escapeHtml(row.title)}</div>
        <div class="row-artist">${escapeHtml(row.artist)}</div>
      </div>
      <input class="row-note-input" data-field="note" placeholder="Note (optionnel)" value="${escapeHtml(row.note || '')}">
      <div class="row-actions">
        <button type="button" class="secondary icon-btn move-up" ${index === 0 ? 'disabled' : ''} title="Monter">&#8593;</button>
        <button type="button" class="secondary icon-btn move-down" ${index === total - 1 ? 'disabled' : ''} title="Descendre">&#8595;</button>
        <button type="button" class="secondary icon-btn move-section" title="${section === 'main' ? 'Déplacer en rappel' : 'Déplacer au programme'}">${section === 'main' ? '&#8677; Rappel' : '&#8676; Programme'}</button>
        <button type="button" class="danger icon-btn remove-row" title="Retirer">&times;</button>
      </div>
    </div>
  `;
}

function editView() {
  return `
    ${metaFormTemplate()}
    ${setlist ? `
    <div class="panel">
      <h3>Ajouter un morceau du répertoire</h3>
      <form id="add-song-form" class="inline-form">
        <label>Morceau
          <select id="add-song-select">${availableSongOptions()}</select>
        </label>
        <button type="button" id="add-to-main-btn" class="secondary">Ajouter au programme</button>
        <button type="button" id="add-to-encore-btn" class="secondary">Ajouter au rappel</button>
      </form>
    </div>

    <div class="setlist-section">
      <h3>Programme principal</h3>
      <div class="setlist-rows" id="main-rows">
        ${mainRows.length ? mainRows.map((r, i) => rowTemplate(r, i, 'main', mainRows.length)).join('') : '<p class="empty">Aucun morceau. Ajoutez-en depuis le répertoire ci-dessus.</p>'}
      </div>
    </div>

    <div class="setlist-section">
      <h3>Rappel</h3>
      <div class="setlist-rows" id="encore-rows">
        ${encoreRows.length ? encoreRows.map((r, i) => rowTemplate(r, i, 'encore', encoreRows.length)).join('') : '<p class="empty">Aucun morceau de rappel prévu.</p>'}
      </div>
    </div>

    <div class="inline-form" style="margin-top:1.25rem">
      <button type="button" id="save-songs-btn">Enregistrer la setlist</button>
      <button type="button" id="cancel-edit-btn" class="secondary">Retour</button>
    </div>` : ''}
  `;
}

function enterEditMode() {
  mainRows = setlist.songs
    .filter((s) => !s.is_encore)
    .map((s) => ({ setlistSongId: s.id, songId: s.song_id, title: s.title, artist: s.artist, note: s.note }));
  encoreRows = setlist.songs
    .filter((s) => s.is_encore)
    .map((s) => ({ setlistSongId: s.id, songId: s.song_id, title: s.title, artist: s.artist, note: s.note }));
  renderEdit();
}

function renderEdit() {
  const container = document.getElementById('content');
  container.innerHTML = editView();
  attachMetaFormHandler();
  attachEditHandlers();
}

function attachMetaFormHandler() {
  const form = document.getElementById('meta-form');
  if (!form) return;
  form.addEventListener('submit', async (e) => {
    e.preventDefault();
    const name = form.name.value.trim();
    const venue = form.venue.value.trim();
    const concertDate = form.concertDate.value;
    try {
      if (setlist) {
        setlist = await api.patch(`/api/setlists/${setlist.id}`, { name, venue, concertDate });
        setlist.songs = (await api.get(`/api/setlists/${setlist.id}`)).songs;
      } else {
        setlist = await api.post('/api/setlists', { name, venue, concertDate });
        setlist.songs = [];
      }
      enterEditMode();
    } catch (err) {
      showError(err.message);
    }
  });
}

function rowsForSection(section) {
  return section === 'main' ? mainRows : encoreRows;
}

function attachEditHandlers() {
  const addSelect = document.getElementById('add-song-select');
  const addToMain = document.getElementById('add-to-main-btn');
  const addToEncore = document.getElementById('add-to-encore-btn');
  if (addSelect) {
    if (!addSelect.value) addSongId = null;
    addSelect.addEventListener('change', () => { addSongId = addSelect.value ? parseInt(addSelect.value, 10) : null; });
  }
  if (addToMain) addToMain.addEventListener('click', () => addSongToSection('main', addSelect));
  if (addToEncore) addToEncore.addEventListener('click', () => addSongToSection('encore', addSelect));

  document.querySelectorAll('.setlist-row').forEach((rowEl) => {
    const section = rowEl.dataset.section;
    const index = parseInt(rowEl.dataset.index, 10);
    const rows = rowsForSection(section);

    rowEl.querySelector('.row-note-input').addEventListener('change', (e) => {
      rows[index].note = e.target.value;
    });
    rowEl.querySelector('.move-up')?.addEventListener('click', () => {
      if (index === 0) return;
      [rows[index - 1], rows[index]] = [rows[index], rows[index - 1]];
      renderEdit();
    });
    rowEl.querySelector('.move-down')?.addEventListener('click', () => {
      if (index === rows.length - 1) return;
      [rows[index + 1], rows[index]] = [rows[index], rows[index + 1]];
      renderEdit();
    });
    rowEl.querySelector('.move-section').addEventListener('click', () => {
      const [row] = rows.splice(index, 1);
      if (section === 'main') encoreRows.push(row);
      else mainRows.push(row);
      renderEdit();
    });
    rowEl.querySelector('.remove-row').addEventListener('click', () => {
      rows.splice(index, 1);
      renderEdit();
    });
  });

  const saveBtn = document.getElementById('save-songs-btn');
  if (saveBtn) saveBtn.addEventListener('click', onSaveSongs);
  const cancelBtn = document.getElementById('cancel-edit-btn');
  if (cancelBtn) cancelBtn.addEventListener('click', renderReadOnly);
}

function addSongToSection(section, selectEl) {
  const songId = selectEl.value ? parseInt(selectEl.value, 10) : null;
  if (!songId) return;
  const song = allSongs.find((s) => s.id === songId);
  if (!song) return;
  const row = { setlistSongId: null, songId: song.id, title: song.title, artist: song.artist, note: '' };
  if (section === 'main') mainRows.push(row);
  else encoreRows.push(row);
  renderEdit();
}

async function onSaveSongs() {
  try {
    const payload = [
      ...mainRows.map((r, i) => ({ songId: r.songId, position: i + 1, note: r.note, isEncore: false })),
      ...encoreRows.map((r, i) => ({ songId: r.songId, position: i + 1, note: r.note, isEncore: true })),
    ];
    setlist = await api.put(`/api/setlists/${setlist.id}/songs`, { songs: payload });
    renderReadOnly();
  } catch (err) {
    showError(err.message);
  }
}

function showError(message) {
  document.getElementById('error').innerHTML = `<div class="error-banner">${escapeHtml(message)}</div>`;
}

(async function init() {
  me = await initNav('setlist');
  if (me.isAdmin) {
    allSongs = await api.get('/api/songs');
  }
  setlist = await api.get('/api/setlists/next');
  renderReadOnly();
})();