import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query';
import { useNostr } from '@nostrify/react';
import { useCurrentUser } from '@/hooks/useCurrentUser';
import { useSkateRelays } from '@/hooks/useSkateRelays';
import { useConfirmMembership } from '@/hooks/useMembershipAttestation';
import { useDismissCrewNotification } from '@/hooks/useCrewDismissals';
import {
  CREW_INVITE_KIND,
  CREW_JOIN_REQUEST_KIND,
  CREW_ENDORSEMENT_KIND,
  SKATE_CREW_KIND,
  crewInviteD,
  crewJoinRequestD,
  parseCrewInvite,
  parseCrewJoinRequest,
  parseCrewEndorsement,
  parseAddrCoord,
  type CrewInvite,
  type CrewJoinRequest,
  type CrewEndorsement,
  type SkateCrew,
  type MemberVisibility,
} from '@/lib/types';
import type { NostrEvent } from '@nostrify/nostrify';

// ─── Dismissals ───────────────────────────────────────────────────────────────
// The invitee/moderator can't delete an event they didn't author, so handled
// invites & join-requests are cleared from *their* notifications via a
// dismissal set. That set is a private, cross-device-synced NIP-78 list —
// see `useCrewDismissals`. The public event still exists on relays; it just
// stops nagging them, everywhere they log in.

// ─── Sending an invite ──────────────────────────────────────────────────────

interface SendInviteParams {
  crew: SkateCrew;
  /** Invitee pubkey (hex). */
  invitee: string;
  role?: 'member' | 'admin';
  note?: string;
  /** Whether the current user is the crew founder (can also add the p-tag). */
  isFounder: boolean;
}

/**
 * Send a structured crew invite to a specific pubkey.
 *
 * The invite is a public, addressable event (kind 36229) that `p`-tags the
 * invitee so they can query "invites addressed to me". It carries nothing
 * sensitive — real membership stays unforgeable (founder `p` tag + invitee
 * attestation).
 *
 * When the sender is the FOUNDER, we optimistically add the invitee to the
 * crew's member (`p`) list at invite time, so the moment they accept (attest)
 * they show as a confirmed member with no extra founder step. When an ADMIN
 * invites, they can't edit the founder's event, so the invite alone is sent and
 * the founder confirms the add on accept.
 */
export function useSendCrewInvite() {
  const { nostr } = useNostr();
  const { user } = useCurrentUser();
  const queryClient = useQueryClient();

  return useMutation({
    mutationFn: async ({ crew, invitee, role = 'member', note = '', isFounder }: SendInviteParams) => {
      if (!user) throw new Error('You must be logged in to invite.');
      const crewCoord = `${SKATE_CREW_KIND}:${crew.pubkey}:${crew.identifier}`;
      const inviteePk = invitee.toLowerCase();

      if (inviteePk === user.pubkey.toLowerCase()) {
        throw new Error("You can't invite yourself.");
      }

      // 1. Publish the invite event.
      const inviteEvent = await user.signer.signEvent({
        kind: CREW_INVITE_KIND,
        content: note.slice(0, 500),
        created_at: Math.floor(Date.now() / 1000),
        tags: [
          ['d', crewInviteD(crewCoord, inviteePk)],
          ['p', inviteePk],
          ['a', crewCoord],
          ['crew_name', crew.name],
          ['role', role],
          ['alt', `Crew invite: join ${crew.name} on SkateSpots`],
        ],
      });
      await nostr.event(inviteEvent, { signal: AbortSignal.timeout(15000) });

      // 2. Founder optimistically pre-lists the invitee so accept = instant confirm.
      if (isFounder && user.pubkey.toLowerCase() === crew.pubkey.toLowerCase()) {
        // Re-fetch the freshest roster so a rapid second invite/approval can't
        // rebuild from a stale snapshot and drop a just-added member.
        const latest = await fetchLatestCrewEvent(nostr, crew);
        const already = latest.tags.some(
          ([n, v]) => n === 'p' && v?.toLowerCase() === inviteePk,
        );
        if (!already) {
          const updated = republishCrewWithMember(latest, inviteePk, role);
          const signed = await user.signer.signEvent(updated);
          await nostr.event(signed, { signal: AbortSignal.timeout(15000) });
        }
      }

      return inviteEvent;
    },
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['skate-crews'] });
      queryClient.invalidateQueries({ queryKey: ['skate-crew'] });
      queryClient.invalidateQueries({ queryKey: ['crew-invites'] });
    },
  });
}

/**
 * Rebuild a crew event's tags with an added member `p` tag, preserving all
 * other tags. Returns an unsigned event template ready to sign.
 */
function republishCrewWithMember(
  crewEvent: NostrEvent,
  memberPubkey: string,
  role: 'member' | 'admin',
): { kind: number; content: string; created_at: number; tags: string[][] } {
  const tags = crewEvent.tags.filter(
    ([n, v]) => !(n === 'p' && v?.toLowerCase() === memberPubkey.toLowerCase()),
  );
  if (role === 'admin') tags.push(['p', memberPubkey, '', 'admin']);
  else tags.push(['p', memberPubkey]);

  return {
    kind: crewEvent.kind,
    content: crewEvent.content,
    created_at: Math.floor(Date.now() / 1000),
    tags,
  };
}

/**
 * Fetch the FRESHEST crew event for a coordinate right before a roster write.
 *
 * The crew roster is a single addressable event that we rewrite wholesale on
 * every member add. Basing that rewrite on a cached `crew.event` snapshot is
 * unsafe: approving two join-requests (or pre-listing two invitees) back to
 * back would rebuild the second write from the pre-first-write snapshot and
 * silently DROP the member added by the first — the same stale-snapshot clobber
 * we guard against in spots/events/shops. So we always re-fetch + merge first.
 *
 * Falls back to the provided snapshot if the relay returns nothing (offline /
 * hiccup) so an add still goes through rather than throwing.
 */
async function fetchLatestCrewEvent(
  nostr: ReturnType<typeof useNostr>['nostr'],
  crew: SkateCrew,
): Promise<NostrEvent> {
  try {
    const events = await nostr.query(
      [{
        kinds: [SKATE_CREW_KIND],
        authors: [crew.pubkey],
        '#d': [crew.identifier],
        limit: 1,
      }],
      { signal: AbortSignal.timeout(8000) },
    );
    // Newest wins (relays may hold multiple revisions).
    let latest: NostrEvent | undefined;
    for (const ev of events) {
      if (!latest || ev.created_at > latest.created_at) latest = ev;
    }
    // Only trust a fresher-or-equal event; never regress to an older revision.
    if (latest && latest.created_at >= crew.event.created_at) return latest;
  } catch {
    // fall through to snapshot
  }
  return crew.event;
}

// ─── Reading invites addressed to me ─────────────────────────────────────────

/**
 * Live crew invites where the given pubkey is the invitee. Dismissal filtering
 * is applied downstream in `useCrewNotifications` (via the synced dismissal
 * set), so this returns every live invite addressed to the user.
 */
export function useMyCrewInvites(pubkey: string | undefined) {
  const { querySkateContent, getQueryKeySuffix } = useSkateRelays();

  return useQuery({
    queryKey: ['crew-invites', 'incoming', pubkey, getQueryKeySuffix()],
    enabled: !!pubkey,
    staleTime: 30_000,
    refetchOnMount: 'always',
    queryFn: async (): Promise<CrewInvite[]> => {
      if (!pubkey) return [];
      const signal = AbortSignal.timeout(10000);
      const events = await querySkateContent(
        [{ kinds: [CREW_INVITE_KIND], '#p': [pubkey], limit: 100 }],
        { signal },
      );

      const seen = new Map<string, CrewInvite>();
      for (const ev of events) {
        const inv = parseCrewInvite(ev);
        if (!inv || inv.invitee.toLowerCase() !== pubkey.toLowerCase()) continue;
        // Dedup by crew coord (addressable — newest wins).
        const prev = seen.get(inv.crewCoord);
        if (!prev || inv.createdAt > prev.createdAt) seen.set(inv.crewCoord, inv);
      }
      return [...seen.values()].sort((a, b) => b.createdAt - a.createdAt);
    },
  });
}

// ─── Accept / decline ─────────────────────────────────────────────────────────

/**
 * Accept a crew invite: publish the invitee's own NIP-32 membership attestation
 * (kind 1985). Once the founder has listed them (founders pre-list on invite),
 * they show as a confirmed member. The invite is dismissed locally.
 */
export function useAcceptCrewInvite() {
  const { user } = useCurrentUser();
  const queryClient = useQueryClient();
  const { mutateAsync: confirm } = useConfirmMembership();
  const { mutateAsync: dismiss } = useDismissCrewNotification();

  return useMutation({
    mutationFn: async ({
      invite,
      visibility = 'public',
    }: {
      invite: CrewInvite;
      visibility?: MemberVisibility;
    }) => {
      if (!user) throw new Error('You must be logged in.');
      const coord = parseAddrCoord(invite.crewCoord);
      if (!coord) throw new Error('Invalid crew reference.');

      // The ONE required action: publish the membership attestation. This is the
      // single signature the UI waits on.
      await confirm({
        kind: coord.kind,
        founderPubkey: coord.pubkey,
        identifier: coord.identifier,
        collectiveName: invite.crewName,
        visibility,
      });

      // Dismiss is optimistic/local-first and best-effort for cross-device sync;
      // fire it WITHOUT blocking accept so a second signer round-trip can never
      // leave the Accept button stuck on "loading".
      void dismiss(invite.id).catch(() => {
        /* local dismissal already applied; sync is best-effort */
      });
    },
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['crew-invites'] });
      queryClient.invalidateQueries({ queryKey: ['collective-members'] });
      queryClient.invalidateQueries({ queryKey: ['skate-crews'] });
    },
  });
}

/** Decline a crew invite — dismiss it so it clears from notifications (synced). */
export function useDeclineCrewInvite() {
  const queryClient = useQueryClient();
  const { mutateAsync: dismiss } = useDismissCrewNotification();

  return useMutation({
    mutationFn: async ({ invite }: { invite: CrewInvite }) => {
      await dismiss(invite.id);
    },
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['crew-invites'] });
    },
  });
}

// ─── Join requests (notifiable) ───────────────────────────────────────────────
// A skater asks to join a crew. We publish a structured, addressable event
// (kind 31969) p-tagged to the founder + admins so it shows in THEIR notification
// bell with a one-click "Add to crew" (founder) — parallel to invites, so the
// two directions are symmetric. Handled requests are cleared via the shared,
// cross-device-synced dismissal set (`useCrewDismissals`); filtering happens
// downstream in `useCrewNotifications`.

/** Publish a structured join-request to a crew's founder + admins. */
export function useSendJoinRequest() {
  const { nostr } = useNostr();
  const { user } = useCurrentUser();
  const queryClient = useQueryClient();

  return useMutation({
    mutationFn: async ({
      crew,
      note = '',
    }: {
      crew: SkateCrew;
      note?: string;
    }) => {
      if (!user) throw new Error('You must be logged in to request to join.');
      const crewCoord = `${SKATE_CREW_KIND}:${crew.pubkey}:${crew.identifier}`;
      const recipients = Array.from(new Set([crew.pubkey, ...crew.admins])).filter(
        (pk) => pk.toLowerCase() !== user.pubkey.toLowerCase(),
      );

      const event = await user.signer.signEvent({
        kind: CREW_JOIN_REQUEST_KIND,
        content: note.slice(0, 500),
        created_at: Math.floor(Date.now() / 1000),
        tags: [
          ['d', crewJoinRequestD(crewCoord, user.pubkey.toLowerCase())],
          ['a', crewCoord],
          ['crew_name', crew.name],
          ...recipients.map((pk) => ['p', pk]),
          ['alt', `Crew join request: ${crew.name} on SkateSpots`],
        ],
      });
      await nostr.event(event, { signal: AbortSignal.timeout(15000) });
      return event;
    },
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['crew-join-requests'] });
    },
  });
}

/** Incoming join-requests addressed to the given moderator (founder/admin). */
export function useIncomingJoinRequests(pubkey: string | undefined) {
  const { querySkateContent, getQueryKeySuffix } = useSkateRelays();

  return useQuery({
    queryKey: ['crew-join-requests', 'incoming', pubkey, getQueryKeySuffix()],
    enabled: !!pubkey,
    staleTime: 30_000,
    refetchOnMount: 'always',
    queryFn: async (): Promise<CrewJoinRequest[]> => {
      if (!pubkey) return [];
      const signal = AbortSignal.timeout(10000);
      const events = await querySkateContent(
        [{ kinds: [CREW_JOIN_REQUEST_KIND], '#p': [pubkey], limit: 100 }],
        { signal },
      );
      const seen = new Map<string, CrewJoinRequest>();
      for (const ev of events) {
        const req = parseCrewJoinRequest(ev);
        if (!req) continue;
        if (!req.recipients.includes(pubkey.toLowerCase())) continue;
        // Dedup by (crew + requester) — newest wins.
        const key = `${req.crewCoord}:${req.requester}`;
        const prev = seen.get(key);
        if (!prev || req.createdAt > prev.createdAt) seen.set(key, req);
      }
      return [...seen.values()].sort((a, b) => b.createdAt - a.createdAt);
    },
  });
}

/**
 * Approve a join-request: the FOUNDER adds the requester to the crew's member
 * (`p`) list. The requester then confirms with their own key (standard
 * attestation). Only the founder can do this (they author the crew event); an
 * admin dismisses/handles out-of-band.
 */
export function useApproveJoinRequest() {
  const { nostr } = useNostr();
  const { user } = useCurrentUser();
  const queryClient = useQueryClient();
  const { mutateAsync: dismiss } = useDismissCrewNotification();

  return useMutation({
    mutationFn: async ({ request, crew }: { request: CrewJoinRequest; crew: SkateCrew }) => {
      if (!user) throw new Error('You must be logged in.');
      if (user.pubkey.toLowerCase() !== crew.pubkey.toLowerCase()) {
        throw new Error('Only the crew founder can add members.');
      }
      // Re-fetch the freshest roster before rewriting it, so approving several
      // requests in quick succession can't clobber earlier additions (each
      // approval rewrites the whole addressable roster event).
      const latest = await fetchLatestCrewEvent(nostr, crew);
      const alreadyMember = latest.tags.some(
        ([n, v]) => n === 'p' && v?.toLowerCase() === request.requester.toLowerCase(),
      );
      if (!alreadyMember) {
        const updated = republishCrewWithMember(latest, request.requester, 'member');
        const signed = await user.signer.signEvent(updated);
        await nostr.event(signed, { signal: AbortSignal.timeout(15000) });
      }
      await dismiss(request.id);
    },
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['crew-join-requests'] });
      queryClient.invalidateQueries({ queryKey: ['skate-crews'] });
      queryClient.invalidateQueries({ queryKey: ['skate-crew'] });
    },
  });
}

/** Dismiss a join-request (moderator handled/ignored it) — synced across devices. */
export function useDismissJoinRequest() {
  const queryClient = useQueryClient();
  const { mutateAsync: dismiss } = useDismissCrewNotification();
  return useMutation({
    mutationFn: async ({ request }: { request: CrewJoinRequest }) => {
      await dismiss(request.id);
    },
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['crew-join-requests'] });
    },
  });
}

// ─── Admin endorsements (admin proposes → founder confirms) ────────────────────
// Only the founder can edit the roster, so an admin can't add a member. Instead
// an admin publicly *vouches* for a request (kind 9087, p-tagging the founder).
// The founder sees the endorsement(s) on the request card and ratifies with one
// click — closing the admin/founder asymmetry without breaking the trust model.

/** An admin endorses ("vouches for") a join-request so the founder can ratify. */
export function useEndorseJoinRequest() {
  const { nostr } = useNostr();
  const { user } = useCurrentUser();
  const queryClient = useQueryClient();

  return useMutation({
    mutationFn: async ({
      request,
      crew,
      note = '',
    }: {
      request: CrewJoinRequest;
      crew: SkateCrew;
      note?: string;
    }) => {
      if (!user) throw new Error('You must be logged in.');
      const isAdmin = crew.admins.some((a) => a.toLowerCase() === user.pubkey.toLowerCase());
      if (!isAdmin) throw new Error('Only a crew admin can endorse a request.');

      const event = await user.signer.signEvent({
        kind: CREW_ENDORSEMENT_KIND,
        content: note.slice(0, 300),
        created_at: Math.floor(Date.now() / 1000),
        tags: [
          ['e', request.id],                          // the request being endorsed
          ['a', request.crewCoord],                   // the crew
          ['p', request.requester, '', 'requester'],  // who's being vouched for
          ['p', crew.pubkey],                         // surface to the founder's bell
          ['alt', `Crew endorsement: vouching for a new member of ${crew.name}`],
        ],
      });
      await nostr.event(event, { signal: AbortSignal.timeout(15000) });
      return event;
    },
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['crew-endorsements'] });
    },
  });
}

/**
 * Fetch endorsements for a set of join-request ids in ONE query, grouped by
 * request id. Only endorsements from actual crew admins are kept (an outsider
 * can't inflate a request's credibility).
 */
export function useJoinRequestEndorsements(
  requestIds: string[],
  adminsByCrewCoord: Map<string, Set<string>>,
) {
  const { querySkateContent, getQueryKeySuffix } = useSkateRelays();
  const ids = [...requestIds].sort();

  return useQuery({
    queryKey: ['crew-endorsements', ids, getQueryKeySuffix()],
    enabled: ids.length > 0,
    staleTime: 30_000,
    queryFn: async (): Promise<Map<string, CrewEndorsement[]>> => {
      const signal = AbortSignal.timeout(10000);
      const events = await querySkateContent(
        [{ kinds: [CREW_ENDORSEMENT_KIND], '#e': ids, limit: 200 }],
        { signal },
      );

      const byRequest = new Map<string, CrewEndorsement[]>();
      const seen = new Set<string>(); // dedupe one endorser per request
      for (const ev of events) {
        const end = parseCrewEndorsement(ev);
        if (!end || !ids.includes(end.requestId)) continue;
        // Endorser must be an admin of the endorsed crew.
        const admins = adminsByCrewCoord.get(end.crewCoord);
        if (!admins || !admins.has(end.endorser.toLowerCase())) continue;
        const key = `${end.requestId}:${end.endorser.toLowerCase()}`;
        if (seen.has(key)) continue;
        seen.add(key);
        const arr = byRequest.get(end.requestId) ?? [];
        arr.push(end);
        byRequest.set(end.requestId, arr);
      }
      return byRequest;
    },
  });
}