import { useMemo } from 'react';
import { useCurrentUser } from '@/hooks/useCurrentUser';
import { useMyCrewInvites, useIncomingJoinRequests, useJoinRequestEndorsements } from '@/hooks/useCrewInvites';
import { useCrewDismissals } from '@/hooks/useCrewDismissals';
import { useCrews } from '@/hooks/useCrews';
import { useCollectiveMembers } from '@/hooks/useCollectiveMembers';
import { SKATE_CREW_KIND, type CrewEndorsement, type CrewInvite, type CrewJoinRequest, type SkateCrew } from '@/lib/types';

export interface CrewNotification {
  /** Stable id for the notification (invite id or crew coord). */
  id: string;
  type: 'invite' | 'pending-confirm';
  crew?: SkateCrew;
  invite?: CrewInvite;
  createdAt: number;
}

/**
 * The logged-in user's actionable crew notifications:
 *
 *  - `invite`:          a structured crew invite addressed to them (kind 36229).
 *  - `pending-confirm`: a crew that has LISTED them as a member but which they
 *                       haven't confirmed yet (they were added directly, e.g.
 *                       via the founder editor before invites existed).
 *
 * Both resolve to the same "join this crew" action, so the notification center
 * can render them uniformly.
 */
export function useCrewNotifications() {
  const { user } = useCurrentUser();
  const { data: invites, isLoading: invitesLoading } = useMyCrewInvites(user?.pubkey);
  const { data: joinRequests, isLoading: joinLoading } = useIncomingJoinRequests(user?.pubkey);
  const { data: crews, isLoading: crewsLoading } = useCrews(200);
  // Cross-device-synced set of dismissed invite/request ids.
  const { data: dismissed } = useCrewDismissals();

  // Invites addressed to me, minus anything I've dismissed (accepted/declined),
  // synced across all my devices.
  const visibleInvites = useMemo(() => {
    const list = invites ?? [];
    if (!dismissed || dismissed.size === 0) return list;
    return list.filter((inv) => !dismissed.has(inv.id));
  }, [invites, dismissed]);

  // Crews that list me as a member (candidates for "pending confirmation").
  const listedCrews = useMemo(() => {
    if (!user || !crews) return [];
    return crews.filter(
      (c) =>
        c.pubkey.toLowerCase() !== user.pubkey.toLowerCase() &&
        c.members.some((m) => m.toLowerCase() === user.pubkey.toLowerCase()),
    );
  }, [user, crews]);

  // Resolve each incoming join-request to its crew (for approval + display).
  const requestsWithCrew = useMemo(() => {
    if (!user || !joinRequests?.length || !crews) return [];
    return joinRequests
      // Drop dismissed requests (synced across the moderator's devices).
      .filter((req) => !dismissed?.has(req.id))
      .map((req) => {
        const crew = crews.find(
          (c) => `${SKATE_CREW_KIND}:${c.pubkey}:${c.identifier}` === req.crewCoord,
        );
        return crew ? { request: req, crew } : null;
      })
      .filter((x): x is { request: CrewJoinRequest; crew: SkateCrew } => !!x)
      // Only show requests for crews I actually lead or help run.
      .filter(
        ({ crew }) =>
          crew.pubkey.toLowerCase() === user.pubkey.toLowerCase() ||
          crew.admins.some((a) => a.toLowerCase() === user.pubkey.toLowerCase()),
      );
  }, [user, joinRequests, crews, dismissed]);

  // Batch-fetch admin endorsements for the visible requests (one query), keyed
  // per crew so only real admins of THAT crew can vouch.
  const requestIds = useMemo(
    () => requestsWithCrew.map(({ request }) => request.id),
    [requestsWithCrew],
  );
  const adminsByCrewCoord = useMemo(() => {
    const map = new Map<string, Set<string>>();
    for (const { request, crew } of requestsWithCrew) {
      map.set(request.crewCoord, new Set(crew.admins.map((a) => a.toLowerCase())));
    }
    return map;
  }, [requestsWithCrew]);
  const { data: endorsements } = useJoinRequestEndorsements(requestIds, adminsByCrewCoord);

  // Attach each request's endorsements for the card to render.
  const requestsWithEndorsements = useMemo(
    () =>
      requestsWithCrew.map((entry) => ({
        ...entry,
        endorsements: (endorsements?.get(entry.request.id) ?? []) as CrewEndorsement[],
      })),
    [requestsWithCrew, endorsements],
  );

  return {
    user,
    invites: visibleInvites,
    listedCrews,
    joinRequests: requestsWithEndorsements,
    isLoading: invitesLoading || joinLoading || crewsLoading,
  };
}

/**
 * Resolve whether the logged-in user has CONFIRMED membership in a listed crew.
 * Used per-crew to decide if a "pending confirm" notification is still relevant.
 */
export function useIsPendingMember(crew: SkateCrew | undefined) {
  const { user } = useCurrentUser();
  const { data: members } = useCollectiveMembers({
    kind: SKATE_CREW_KIND,
    founderPubkey: crew?.pubkey ?? '',
    identifier: crew?.identifier ?? '',
    claimedMembers: crew?.members ?? [],
    enabled: !!crew && (crew.members.length ?? 0) > 0,
  });

  if (!user || !crew) return false;
  const me = members?.find((m) => m.pubkey.toLowerCase() === user.pubkey.toLowerCase());
  return me?.status === 'pending';
}