import type { ICalendarCacheEventRepository } from "@calcom/features/calendar-subscription/lib/cache/CalendarCacheEventRepository.interface";
import logger from "@calcom/lib/logger";
import { withSpan } from "@calcom/lib/sentryWrapper";
import type {
  Calendar,
  CalendarEvent,
  CalendarServiceEvent,
  EventBusyDate,
  GetAvailabilityParams,
  IntegrationCalendar,
  NewCalendarEventType,
} from "@calcom/types/Calendar";

const log = logger.getSubLogger({ prefix: ["CachedCalendarWrapper"] });

/**
 * A wrapper to load cache from database and cache it.
 *
 * @see Calendar
 */
export class CalendarCacheWrapper implements Calendar {
  constructor(
    private deps: {
      originalCalendar: Calendar;
      calendarCacheEventRepository: ICalendarCacheEventRepository;
    }
  ) {}

  getCredentialId?(): number {
    return this.deps.originalCalendar.getCredentialId ? this.deps.originalCalendar.getCredentialId() : -1;
  }

  createEvent(
    event: CalendarServiceEvent,
    credentialId: number,
    externalCalendarId?: string
  ): Promise<NewCalendarEventType> {
    return this.deps.originalCalendar.createEvent(event, credentialId, externalCalendarId);
  }

  updateEvent(
    uid: string,
    event: CalendarServiceEvent,
    externalCalendarId?: string | null
  ): Promise<NewCalendarEventType | NewCalendarEventType[]> {
    return this.deps.originalCalendar.updateEvent(uid, event, externalCalendarId);
  }

  deleteEvent(uid: string, event: CalendarEvent, externalCalendarId?: string | null): Promise<unknown> {
    return this.deps.originalCalendar.deleteEvent(uid, event, externalCalendarId);
  }

  /**
   * Retrieves availability combining cache and live sources.
   *
   * - Calendars **with** both `syncToken` and `syncSubscribedAt` → fetched from cache.
   * - Calendars **without** one of them → fetched directly from the original calendar.
   * - Results are merged into a single array.
   */
  async getAvailability(params: GetAvailabilityParams): Promise<EventBusyDate[]> {
    const { dateFrom, dateTo, selectedCalendars } = params;
    return withSpan(
      {
        name: "CalendarCacheWrapper.getAvailability",
        op: "calendar.cache.internal.getAvailability",
        attributes: {
          calendarCount: selectedCalendars?.length ?? 0,
        },
      },
      async (span) => {
        log.debug("getAvailability (mixed cache + original)", {
          dateFrom,
          dateTo,
          calendarIds: selectedCalendars.map((c) => c.id),
          calendarCount: selectedCalendars.length,
        });

        if (!selectedCalendars?.length) return [];

        const withSync = selectedCalendars.filter((c) => c.syncToken && c.syncSubscribedAt);
        const withoutSync = selectedCalendars.filter((c) => !c.syncToken || !c.syncSubscribedAt);

        const results: EventBusyDate[] = [];

        // Fetch from cache for synced calendars
        if (withSync.length) {
          const cacheStartTime = performance.now();
          const ids = withSync.map((c) => c.id).filter((id): id is string => Boolean(id));
          const cached = await this.deps.calendarCacheEventRepository.findAllBySelectedCalendarIdsBetween(
            ids,
            new Date(dateFrom),
            new Date(dateTo)
          );
          const cacheDurationMs = performance.now() - cacheStartTime;
          results.push(
            ...cached.map((event) => ({
              ...event,
              timeZone: event.timeZone ?? undefined,
            }))
          );

          span.setAttribute("cachedCalendarCount", withSync.length);
          span.setAttribute("cacheFetchDurationMs", cacheDurationMs);
          span.setAttribute("cachedEventsCount", cached.length);
          log.info("Calendar cache fetch completed", {
            cachedCalendarCount: withSync.length,
            cacheFetchDurationMs: cacheDurationMs,
            cachedEventsCount: cached.length,
          });
        }

        // Fetch from original calendar for unsynced ones
        if (withoutSync.length) {
          const originalStartTime = performance.now();
          const original = await this.deps.originalCalendar.getAvailability({
            dateFrom,
            dateTo,
            selectedCalendars: withoutSync,
            mode: params.mode,
            fallbackToPrimary: params.fallbackToPrimary,
          });
          const originalDurationMs = performance.now() - originalStartTime;
          results.push(...original);

          span.setAttribute("originalCalendarCount", withoutSync.length);
          span.setAttribute("originalFetchDurationMs", originalDurationMs);
          span.setAttribute("originalEventsCount", original.length);
          log.info("Original calendar fetch completed", {
            originalCalendarCount: withoutSync.length,
            originalFetchDurationMs: originalDurationMs,
            originalEventsCount: original.length,
          });
        }

        span.setAttribute("cacheUsed", withSync.length > 0);
        span.setAttribute("totalEventsCount", results.length);

        return results;
      }
    );
  }

  /**
   * Retrieves availability with time zones, combining cache and live data.
   *
   * - Calendars **with** both `syncToken` and `syncSubscribedAt` → fetched from cache.
   * - Calendars **without** one of them → fetched directly from the original calendar.
   * - Results are merged into a single array with `{ start, end, timeZone }` format.
   */
  async getAvailabilityWithTimeZones(params: GetAvailabilityParams): Promise<EventBusyDate[]> {
    const { dateFrom, dateTo, selectedCalendars } = params;
    return withSpan(
      {
        name: "CalendarCacheWrapper.getAvailabilityWithTimeZones",
        op: "calendar.cache.internal.getAvailabilityWithTimeZones",
        attributes: {
          calendarCount: selectedCalendars?.length ?? 0,
        },
      },
      async (span) => {
        log.debug("getAvailabilityWithTimeZones (mixed cache + original)", {
          dateFrom,
          dateTo,
          calendarIds: selectedCalendars.map((c) => c.id),
          calendarCount: selectedCalendars.length,
        });

        if (!selectedCalendars?.length) return [];

        const withSync = selectedCalendars.filter((c) => c.syncToken && c.syncSubscribedAt);
        const withoutSync = selectedCalendars.filter((c) => !c.syncToken || !c.syncSubscribedAt);

        const results: EventBusyDate[] = [];

        // Fetch from cache for synced calendars
        if (withSync.length) {
          const cacheStartTime = performance.now();
          const ids = withSync.map((c) => c.id).filter((id): id is string => Boolean(id));
          const cached = await this.deps.calendarCacheEventRepository.findAllBySelectedCalendarIdsBetween(
            ids,
            new Date(dateFrom),
            new Date(dateTo)
          );
          const cacheDurationMs = performance.now() - cacheStartTime;
          results.push(
            ...cached.map(({ start, end, timeZone }) => ({
              start,
              end,
              timeZone: timeZone || "UTC",
            }))
          );

          span.setAttribute("cachedCalendarCount", withSync.length);
          span.setAttribute("cacheFetchDurationMs", cacheDurationMs);
          span.setAttribute("cachedEventsCount", cached.length);
          log.info("Calendar cache fetch with timezones completed", {
            cachedCalendarCount: withSync.length,
            cacheFetchDurationMs: cacheDurationMs,
            cachedEventsCount: cached.length,
          });
        }

        // Fetch from original calendar for unsynced ones
        if (withoutSync.length) {
          const originalStartTime = performance.now();
          const original = await this.deps.originalCalendar.getAvailabilityWithTimeZones?.({
            dateFrom,
            dateTo,
            selectedCalendars: withoutSync,
            mode: params.mode,
            fallbackToPrimary: params.fallbackToPrimary,
          });
          const originalDurationMs = performance.now() - originalStartTime;
          if (original?.length) results.push(...original);

          span.setAttribute("originalCalendarCount", withoutSync.length);
          span.setAttribute("originalFetchDurationMs", originalDurationMs);
          span.setAttribute("originalEventsCount", original?.length ?? 0);
          log.info("Original calendar fetch with timezones completed", {
            originalCalendarCount: withoutSync.length,
            originalFetchDurationMs: originalDurationMs,
            originalEventsCount: original?.length ?? 0,
          });
        }

        span.setAttribute("cacheUsed", withSync.length > 0);
        span.setAttribute("totalEventsCount", results.length);

        return results;
      }
    );
  }

  fetchAvailabilityAndSetCache?(selectedCalendars: IntegrationCalendar[]): Promise<unknown> {
    return this.deps.originalCalendar.fetchAvailabilityAndSetCache?.(selectedCalendars) || Promise.resolve();
  }

  listCalendars(event?: CalendarEvent): Promise<IntegrationCalendar[]> {
    return this.deps.originalCalendar.listCalendars(event);
  }

  testDelegationCredentialSetup?(): Promise<boolean> {
    return this.deps.originalCalendar.testDelegationCredentialSetup?.() || Promise.resolve(false);
  }
}