/* PCO Plan — which service type THIS dashboard is looking at.

   The module's server follows one service type at a time: whichever the
   admin's priority order lands on. A dashboard may want a different one on
   screen — the other campus, the youth plan — without changing what the
   server follows or what any other screen sees.

   That choice belongs to the browser, so it lives here: one value for the
   whole page, kept in localStorage and shared between every PCO Plan tile on
   it, so switching from one tile moves them all together. */

const KEY = 'pco-plan:viewed-service-type';

/** One bus per page, however many tiles import this. */
function bus() {
  if (!window.__pcoPlanViewed) {
    let value = '';
    try {
      value = String(localStorage.getItem(KEY) || '');
    } catch {
      value = ''; // private window, storage off: the choice just won't persist
    }
    window.__pcoPlanViewed = { value, listeners: new Set() };
  }
  return window.__pcoPlanViewed;
}

/** '' means "whatever the server is following" — the normal case. */
export function viewedType() {
  return bus().value;
}

export function setViewedType(id) {
  const b = bus();
  const next = String(id || '');
  if (next === b.value) return;
  b.value = next;
  try {
    if (next) localStorage.setItem(KEY, next);
    else localStorage.removeItem(KEY);
  } catch { /* not persisted, still shared for this page */ }
  for (const fn of [...b.listeners]) {
    try {
      fn(next);
    } catch (err) {
      console.error('[pco-plan] viewed-type listener failed:', err);
    }
  }
}

/** Returns an unsubscribe — call it from the tile's stop(). */
export function onViewedType(fn) {
  const b = bus();
  b.listeners.add(fn);
  return () => b.listeners.delete(fn);
}

/**
 * The plan a tile should draw, given the whole state and this page's choice:
 * the one the server follows, or one of the others it also reads.
 *
 * `live` is false for anything but the followed one — the ProPresenter match,
 * the service clock and the timers belong to the service actually running, so
 * a tile looking elsewhere must not pretend to have them.
 */
export function viewOf(state) {
  const empty = { id: '', name: '', plan: null, items: [], teams: [], teamsError: '', live: true, lastError: '' };
  if (!state) return empty;
  const wanted = viewedType();
  const activeId = state.serviceType?.id || '';
  if (!wanted || wanted === activeId) {
    return {
      id: activeId,
      name: state.serviceType?.name || '',
      plan: state.plan,
      items: state.items || [],
      teams: state.teams || [],
      teamsError: state.teamsError || '',
      live: true,
      lastError: '',
    };
  }
  const other = (state.others || {})[wanted];
  if (!other) {
    // Ticked off in admin since this dashboard chose it, or not read yet.
    return { ...empty, id: wanted, live: false, lastError: 'That service type is no longer selected' };
  }
  return {
    id: other.id,
    name: other.name,
    plan: other.plan,
    items: other.items || [],
    teams: other.teams || [],
    teamsError: other.teamsError || '',
    live: false,
    lastError: other.lastError || '',
  };
}

/** Every service type a dashboard may switch to, in the admin's priority order. */
export function choices(state) {
  const out = [];
  const activeId = state?.serviceType?.id || '';
  for (const id of state?.serviceTypes || []) {
    if (id === activeId) out.push({ id, name: state.serviceType?.name || id, following: true });
    else out.push({ id, name: (state.others || {})[id]?.name || id, following: false });
  }
  return out;
}

const SWITCH_SVG = '<svg viewBox="0 0 24 24" width="14" height="14" fill="none" stroke="currentColor" stroke-width="2.1" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><path d="M4 8h13l-3-3"/><path d="M20 16H7l3 3"/></svg>';

/**
 * The title-bar control that switches this dashboard between the selected
 * service types. Added by every PCO Plan tile, because switching from any of
 * them moves all of them; it hides itself whenever there is only one service
 * type to choose from, which is the usual case.
 *
 * Returns { sync } — call it when the state arrives so the control appears,
 * disappears or re-labels itself.
 */
export function addServiceTypeSwitch({ moduleApi, getState }) {
  const menu = moduleApi.header.addMenu({
    icon: SWITCH_SVG,
    title: 'Service type shown on this dashboard',
    build(el) {
      el.classList.add('pp-menu');
      const state = getState();
      const wanted = viewedType();
      const rows = [
        { id: '', name: 'Whatever is live', following: false, auto: true },
        ...choices(state),
      ];
      for (const row of rows) {
        const item = document.createElement('button');
        item.type = 'button';
        item.className = 'pp-menu-item' + (row.id === wanted ? ' is-on' : '');
        const tick = document.createElement('span');
        tick.className = 'pp-menu-tick';
        tick.textContent = '✓';
        const name = document.createElement('span');
        name.className = 'pp-menu-name';
        name.textContent = row.name;
        item.append(tick, name);
        if (row.following) {
          const note = document.createElement('span');
          note.className = 'pp-menu-note';
          note.textContent = 'live';
          item.appendChild(note);
        }
        item.addEventListener('click', () => {
          setViewedType(row.id);
          menu.close();
        });
        el.appendChild(item);
      }
    },
  });

  return {
    sync() {
      const state = getState();
      // One service type is no choice at all — rule 11, nothing in the bar
      // that has nothing to do.
      const many = (state?.serviceTypes || []).length > 1;
      menu.button.hidden = !many;
      const wanted = viewedType();
      menu.button.classList.toggle('active', Boolean(wanted) && wanted !== (state?.serviceType?.id || ''));
    },
  };
}