import { useCallback } from 'react';

import { useCurrentUser } from '@/hooks/useCurrentUser';
import {
  SKATE_NIP05_DOMAIN,
  buildSkateNip05,
  normalizeSkateNip05Name,
  skateApiBase,
} from '@/lib/skateNip05';

export interface SkateNip05Availability {
  available: boolean;
  reason: string | null;
}

export type SkateNip05ClaimResult =
  | { ok: true; nip05: string }
  | { ok: false; error: string };

/** UTF-8 safe base64 (the NIP-98 event travels as base64 JSON in a header). */
function b64(value: string): string {
  const bytes = new TextEncoder().encode(value);
  let binary = '';
  for (const byte of bytes) binary += String.fromCharCode(byte);
  return btoa(binary);
}

/**
 * Claim a free `name@skate-spots.org` handle.
 *
 * The claim is proven with a NIP-98 (kind 27235) event signed by the account
 * that will own the name, so only the owner can claim a name for themselves.
 * Nothing here blocks the app: callers treat a failure as "no handle yet".
 */
export function useSkateNip05() {
  const { user } = useCurrentUser();

  const checkAvailability = useCallback(
    async (name: string, signal?: AbortSignal): Promise<SkateNip05Availability> => {
      const clean = normalizeSkateNip05Name(name);
      if (!clean) return { available: false, reason: null };
      try {
        const res = await fetch(
          `${skateApiBase()}/api/nip05/check?name=${encodeURIComponent(clean)}`,
          { signal },
        );
        if (!res.ok) return { available: false, reason: 'Could not check right now.' };
        const data = (await res.json()) as { available?: boolean; reason?: string | null };
        return { available: !!data.available, reason: data.reason ?? null };
      } catch {
        return { available: false, reason: 'Could not check right now.' };
      }
    },
    [],
  );

  const claim = useCallback(
    async (name: string): Promise<SkateNip05ClaimResult> => {
      const clean = normalizeSkateNip05Name(name);
      if (!user) return { ok: false, error: 'Log in first.' };
      if (!clean) return { ok: false, error: 'Enter a name.' };
      try {
        const auth = await user.signer.signEvent({
          kind: 27235,
          content: '',
          created_at: Math.floor(Date.now() / 1000),
          tags: [
            ['u', `https://${SKATE_NIP05_DOMAIN}/api/nip05/claim`],
            ['method', 'POST'],
            ['action', 'claim'],
            ['name', clean],
          ],
        });
        const res = await fetch(`${skateApiBase()}/api/nip05/claim`, {
          method: 'POST',
          headers: { 'x-nip05-auth': b64(JSON.stringify(auth)) },
        });
        const data = (await res.json().catch(() => ({}))) as { ok?: boolean; nip05?: string; error?: string };
        if (res.ok && data.ok) return { ok: true, nip05: data.nip05 ?? buildSkateNip05(clean) };
        return { ok: false, error: data.error || 'Could not claim that name.' };
      } catch {
        return { ok: false, error: 'Could not reach the name service.' };
      }
    },
    [user],
  );

  /** Hand a name back (owner, or a platform admin). Rarely used from the UI. */
  const release = useCallback(
    async (name: string): Promise<{ ok: true } | { ok: false; error: string }> => {
      const clean = normalizeSkateNip05Name(name);
      if (!user) return { ok: false, error: 'Log in first.' };
      try {
        const auth = await user.signer.signEvent({
          kind: 27235,
          content: '',
          created_at: Math.floor(Date.now() / 1000),
          tags: [
            ['u', `https://${SKATE_NIP05_DOMAIN}/api/nip05/release`],
            ['method', 'POST'],
            ['action', 'release'],
            ['name', clean],
          ],
        });
        const res = await fetch(`${skateApiBase()}/api/nip05/release`, {
          method: 'POST',
          headers: { 'x-nip05-auth': b64(JSON.stringify(auth)) },
        });
        const data = (await res.json().catch(() => ({}))) as { ok?: boolean; error?: string };
        if (res.ok && data.ok) return { ok: true };
        return { ok: false, error: data.error || 'Could not release that name.' };
      } catch {
        return { ok: false, error: 'Could not reach the name service.' };
      }
    },
    [user],
  );

  return { domain: SKATE_NIP05_DOMAIN, checkAvailability, claim, release, canClaim: !!user };
}