import type { Payload } from "payload";
import { EVENT_CATEGORIES } from "@/collections/Events";
import type { ICSEvent } from "./ics";
import type { BookingRequest, Customer, Event, Offer } from "@/payload-types";

// A rolling window rather than "everything ever": calendar apps refetch a
// subscribed feed periodically on their own, so this just needs to cover a
// sensible range each time, not paginate an entire history.
const WINDOW_PAST_MS = 30 * 24 * 60 * 60 * 1000;
const WINDOW_FUTURE_MS = 400 * 24 * 60 * 60 * 1000;

/**
 * Builds the calendar entries for Anna's personal ICS feed: confirmed
 * bookings (never pending ones) plus standalone public events — onsite and
 * online alike. Deliberately never includes the meeting password anywhere
 * in the output, only a link to the protected join page.
 *
 * Local API is used with the default overrideAccess: true because this is
 * only ever reached after the caller already verified the feed's secret
 * token (see app/(frontend)/calendar/[tokenFile]/route.ts) — equivalent
 * trust to the existing admin calendar view.
 */
export async function getAdminFeedICSEvents(payload: Payload): Promise<ICSEvent[]> {
  const from = new Date(Date.now() - WINDOW_PAST_MS);
  const to = new Date(Date.now() + WINDOW_FUTURE_MS);
  const serverUrl = process.env.NEXT_PUBLIC_SERVER_URL || "http://localhost:3000";
  const domainHost = new URL(serverUrl).host;

  const [{ docs: bookings }, { docs: events }, settings] = await Promise.all([
    payload.find({
      collection: "booking-requests",
      where: {
        and: [
          { status: { equals: "confirmed" } },
          { date: { greater_than_equal: from.toISOString() } },
          { date: { less_than_equal: to.toISOString() } },
        ],
      },
      depth: 2,
      limit: 1000,
    }),
    payload.find({
      collection: "events",
      where: {
        and: [
          { date: { greater_than_equal: from.toISOString() } },
          { date: { less_than_equal: to.toISOString() } },
          { isPrivateBooking: { not_equals: true } },
        ],
      },
      depth: 0,
      limit: 1000,
    }),
    payload.findGlobal({ slug: "booking-settings" }),
  ]);

  const addressParts = [settings.locationName, settings.street, [settings.postalCode, settings.city].filter(Boolean).join(" ")].filter(Boolean);
  const fullAddress = addressParts.join(", ");

  const bookingEvents: ICSEvent[] = (bookings as BookingRequest[]).map((b) => {
    const offer = typeof b.offer === "object" ? (b.offer as Offer) : null;
    const customer = typeof b.user === "object" ? (b.user as Customer) : null;
    const isOnline = b.appointmentType === "online";

    const description = [
      customer?.name ? `Mit: ${customer.name}` : null,
      isOnline ? "Online-Termin" : "Vor-Ort-Termin",
      b.userMessage ? `Nachricht: ${b.userMessage}` : null,
    ]
      .filter(Boolean)
      .join("\n");

    let url: string | undefined;
    if (isOnline && b.linkedEvent && typeof b.linkedEvent === "object") {
      url = `${serverUrl}/termine/${(b.linkedEvent as Event).slug}/beitreten`;
    } else if (!isOnline && fullAddress) {
      url = `https://www.google.com/maps/search/?api=1&query=${encodeURIComponent(fullAddress)}`;
    }

    return {
      uid: `booking-${b.id}@${domainHost}`,
      start: new Date(b.startTime),
      end: new Date(b.endTime),
      summary: offer?.title ?? "Termin",
      description: description || undefined,
      // Vor Ort: vollständige Adresse. Online: literal "Online" — never the
      // meeting password, which is intentionally not part of this feed.
      location: isOnline ? "Online" : fullAddress || undefined,
      url,
    };
  });

  const eventEvents: ICSEvent[] = (events as Event[]).map((e) => {
    const isOnline = Boolean(e.isOnline);
    const start = new Date(e.startTime || e.date);
    const end = new Date(e.endTime || e.startTime || e.date);
    return {
      uid: `event-${e.id}@${domainHost}`,
      start,
      end,
      summary: e.title,
      description: EVENT_CATEGORIES.find((c) => c.value === e.category)?.label,
      location: isOnline ? "Online" : e.location || fullAddress || undefined,
      url: e.slug ? `${serverUrl}/termine/${e.slug}` : undefined,
    };
  });

  return [...bookingEvents, ...eventEvents];
}