import { useState, useEffect } from 'react';
import toast from 'react-hot-toast';
import { eventsApi, ticketsApi, emailsApi, doorApi, Event, Ticket, EmailTemplate, DoorSummary, type EventPermission } from '@/lib/api';

/** A 403 means "not for this viewer": render without that data instead of failing the page. */
const forbidden = (error: any) => error?.status === 403;

/**
 * Loads the core data for the event detail page and exposes a reload function
 * used after mutations. The event itself is fetched straight away so the
 * header can render while the rest loads; tickets, active email templates and
 * door takings wait for the viewer's permissions on the event and only request
 * what they may see, so team members get a working page with fewer tabs.
 *
 * `eventLoading` and `detailsLoading` cover the first load only: reloads keep
 * the current data on screen until the new data replaces it.
 */
export function useEventDetailData(eventId: string, permissions: Set<EventPermission> | null) {
  const [eventLoading, setEventLoading] = useState(true);
  const [detailsLoading, setDetailsLoading] = useState(true);
  const [event, setEvent] = useState<Event | null>(null);
  const [tickets, setTickets] = useState<Ticket[]>([]);
  const [templates, setTemplates] = useState<EmailTemplate[]>([]);
  const [doorSummary, setDoorSummary] = useState<DoorSummary | null>(null);

  const loadEvent = async () => {
    try {
      const { event } = await eventsApi.getById(eventId);
      setEvent(event);
    } catch (error) {
      toast.error('Failed to load event data');
    } finally {
      setEventLoading(false);
    }
  };

  const loadDetails = async () => {
    if (!permissions) return;
    const can = (p: EventPermission) => permissions.has(p);
    try {
      const [ticketsRes, templatesRes, doorRes] = await Promise.all([
        can('view_attendees_names')
          ? ticketsApi.getAll({ eventId }).catch((error) => {
            if (forbidden(error)) return { tickets: [] as Ticket[] };
            throw error;
          })
          : { tickets: [] as Ticket[] },
        can('email_attendees')
          ? emailsApi.getTemplates(eventId).catch((error) => {
            if (forbidden(error)) return { templates: [] as EmailTemplate[] };
            throw error;
          })
          : { templates: [] as EmailTemplate[] },
        // Door takings split pre-sale from cash/bitcoin/transfer taken on the
        // night. It is supporting detail, so a failure here must not blank the page.
        can('view_payments') ? doorApi.summary(eventId).catch(() => null) : null,
      ]);
      setTickets(ticketsRes.tickets);
      setTemplates(templatesRes.templates.filter(t => t.isActive));
      setDoorSummary(doorRes);
    } catch (error) {
      toast.error('Failed to load event data');
    } finally {
      setDetailsLoading(false);
    }
  };

  const loadEventData = async () => {
    await Promise.all([loadEvent(), loadDetails()]);
  };

  useEffect(() => {
    loadEvent();
  }, [eventId]);

  useEffect(() => {
    loadDetails();
  }, [eventId, permissions]);

  return { eventLoading, detailsLoading, event, tickets, templates, doorSummary, loadEventData };
}