BelgianBitcoinEmbassy/frontend/lib/nostr.ts

import { generateSecretKey, getPublicKey as getPubKeyFromSecret } from "nostr-tools/pure";

declare global {
  interface Window {
    nostr?: {
      getPublicKey(): Promise<string>;
      signEvent(event: any): Promise<any>;
      getRelays?(): Promise<Record<string, { read: boolean; write: boolean }>>;
    };
  }
}

export type BunkerSignerInterface = {
  getPublicKey(): Promise<string>;
  signEvent(event: any): Promise<any>;
  close(): Promise<void>;
};

export function hasNostrExtension(): boolean {
  return typeof window !== "undefined" && !!window.nostr;
}

export async function getPublicKey(): Promise<string> {
  if (!window.nostr) throw new Error("No Nostr extension found");
  return window.nostr.getPublicKey();
}

export async function signEvent(event: any): Promise<any> {
  if (!window.nostr) throw new Error("No Nostr extension found");
  return window.nostr.signEvent(event);
}

export function createAuthEvent(pubkey: string, challenge: string) {
  return {
    kind: 22242,
    created_at: Math.floor(Date.now() / 1000),
    tags: [
      ["relay", ""],
      ["challenge", challenge],
    ],
    content: "",
    pubkey,
  };
}

export function shortenPubkey(pubkey: string): string {
  if (!pubkey) return "";
  return `${pubkey.slice(0, 8)}...${pubkey.slice(-8)}`;
}

export interface NostrProfile {
  name?: string;
  picture?: string;
  about?: string;
  nip05?: string;
  displayName?: string;
}

const FALLBACK_RELAYS = [
  "wss://relay.damus.io",
  "wss://nos.lol",
  "wss://relay.nostr.band",
];

let _siteRelaysCache: { relays: string[]; fetchedAt: number } | null = null;
const SITE_RELAY_TTL = 5 * 60 * 1000; // 5 minutes

export async function getSiteRelays(): Promise<string[]> {
  if (_siteRelaysCache && Date.now() - _siteRelaysCache.fetchedAt < SITE_RELAY_TTL) {
    return _siteRelaysCache.relays;
  }
  try {
    const res = await fetch("/api/relays/public");
    if (!res.ok) throw new Error(`HTTP ${res.status}`);
    const data = await res.json();
    if (Array.isArray(data.relays) && data.relays.length > 0) {
      _siteRelaysCache = { relays: data.relays, fetchedAt: Date.now() };
      return data.relays;
    }
  } catch {}
  return FALLBACK_RELAYS;
}

export interface Nip65RelayList {
  write: string[];
  read: string[];
  all: string[];
}

const _nip65Cache = new Map<string, { data: Nip65RelayList; fetchedAt: number }>();
const NIP65_TTL = 10 * 60 * 1000; // 10 minutes

export async function fetchNip65RelayList(pubkey: string): Promise<Nip65RelayList> {
  const cached = _nip65Cache.get(pubkey);
  if (cached && Date.now() - cached.fetchedAt < NIP65_TTL) return cached.data;

  const { SimplePool } = await import("nostr-tools/pool");
  const siteRelays = await getSiteRelays();
  const pool = new SimplePool();

  try {
    const event = await pool.get(siteRelays, {
      kinds: [10002],
      authors: [pubkey],
    });

    const result: Nip65RelayList = { write: [], read: [], all: [] };
    if (!event) {
      _nip65Cache.set(pubkey, { data: result, fetchedAt: Date.now() });
      return result;
    }

    for (const tag of event.tags) {
      if (tag[0] !== "r" || !tag[1]) continue;
      const url = tag[1];
      const marker = tag[2];
      result.all.push(url);
      if (marker === "write") {
        result.write.push(url);
      } else if (marker === "read") {
        result.read.push(url);
      } else {
        result.write.push(url);
        result.read.push(url);
      }
    }

    _nip65Cache.set(pubkey, { data: result, fetchedAt: Date.now() });
    return result;
  } catch {
    return { write: [], read: [], all: [] };
  } finally {
    pool.close(siteRelays);
  }
}

let _userRelaysCache: { relays: { url: string; read: boolean; write: boolean }[]; fetchedAt: number } | null = null;
const USER_RELAY_TTL = 2 * 60 * 1000; // 2 minutes

export async function getUserStoredRelays(): Promise<{ url: string; read: boolean; write: boolean }[]> {
  if (_userRelaysCache && Date.now() - _userRelaysCache.fetchedAt < USER_RELAY_TTL) {
    return _userRelaysCache.relays;
  }
  try {
    const token = typeof window !== "undefined" ? localStorage.getItem("bbe_token") : null;
    if (!token) return [];
    const res = await fetch("/api/user-relays", {
      headers: { Authorization: `Bearer ${token}` },
    });
    if (!res.ok) return [];
    const data = await res.json();
    if (Array.isArray(data)) {
      _userRelaysCache = { relays: data, fetchedAt: Date.now() };
      return data;
    }
  } catch {}
  return [];
}

export function clearUserRelaysCache(): void {
  _userRelaysCache = null;
}

export async function publishEvent(signedEvent: any): Promise<void> {
  const { SimplePool } = await import("nostr-tools/pool");
  const siteRelays = await getSiteRelays();
  const allRelays = new Set<string>(siteRelays);

  // Merge user's stored write relays
  try {
    const stored = await getUserStoredRelays();
    stored
      .filter((r) => r.write)
      .forEach((r) => allRelays.add(r.url));
  } catch {}

  // Merge NIP-65 write relays for the event author
  if (signedEvent.pubkey) {
    try {
      const nip65 = await fetchNip65RelayList(signedEvent.pubkey);
      nip65.write.forEach((url) => allRelays.add(url));
    } catch {}
  }

  // Merge extension relays
  try {
    if (window.nostr?.getRelays) {
      const ext = await window.nostr.getRelays();
      Object.entries(ext)
        .filter(([, p]) => (p as any).write)
        .forEach(([url]) => allRelays.add(url));
    }
  } catch {}

  const relayUrls = [...allRelays];
  const pool = new SimplePool();
  try {
    await Promise.allSettled(pool.publish(relayUrls, signedEvent));
  } finally {
    pool.close(relayUrls);
  }
}

export async function fetchNostrProfile(
  pubkey: string,
  relayUrls?: string[]
): Promise<NostrProfile> {
  const { SimplePool } = await import("nostr-tools/pool");
  const allRelays = new Set<string>(relayUrls || await getSiteRelays());

  try {
    const nip65 = await fetchNip65RelayList(pubkey);
    nip65.write.forEach((url) => allRelays.add(url));
  } catch {}

  const urls = [...allRelays];
  const pool = new SimplePool();

  try {
    const event = await pool.get(urls, {
      kinds: [0],
      authors: [pubkey],
    });

    if (!event?.content) return {};

    const meta = JSON.parse(event.content);
    return {
      name: meta.name || meta.display_name,
      displayName: meta.display_name,
      picture: meta.picture,
      about: meta.about,
      nip05: meta.nip05,
    };
  } catch {
    return {};
  } finally {
    pool.close(urls);
  }
}

export async function fetchEventFromRelays(eventId: string): Promise<any | null> {
  const { SimplePool } = await import("nostr-tools/pool");
  const siteRelays = await getSiteRelays();
  const pool = new SimplePool();

  try {
    const event = await pool.get(siteRelays, { ids: [eventId] });
    return event || null;
  } catch {
    return null;
  } finally {
    pool.close(siteRelays);
  }
}

export async function fetchLongformFromRelays(naddrStr: string): Promise<any | null> {
  const { SimplePool } = await import("nostr-tools/pool");
  const { nip19 } = await import("nostr-tools");

  let decoded: { kind: number; pubkey: string; identifier: string; relays?: string[] };
  try {
    const result = nip19.decode(naddrStr);
    if (result.type !== "naddr") return null;
    decoded = result.data;
  } catch {
    return null;
  }

  const siteRelays = await getSiteRelays();
  const naddrRelays = decoded.relays || [];
  const allRelays = new Set<string>([...naddrRelays, ...siteRelays]);

  try {
    const nip65 = await fetchNip65RelayList(decoded.pubkey);
    nip65.write.forEach((url) => allRelays.add(url));
  } catch {}

  const relayUrls = [...allRelays];
  const filter = {
    kinds: [decoded.kind],
    authors: [decoded.pubkey],
    "#d": [decoded.identifier],
  };

  const pool = new SimplePool();
  try {
    const event = await pool.get(relayUrls, filter);
    return event || null;
  } catch {
    return null;
  } finally {
    pool.close(relayUrls);
  }
}

// NIP-46: External signer (bunker:// URI)
export async function createBunkerSigner(
  input: string
): Promise<{ signer: BunkerSignerInterface; pubkey: string }> {
  const { BunkerSigner, parseBunkerInput } = await import("nostr-tools/nip46");
  const bp = await parseBunkerInput(input);
  if (!bp) throw new Error("Invalid bunker URI or NIP-05 identifier");
  const clientSecretKey = generateSecretKey();
  const signer = BunkerSigner.fromBunker(clientSecretKey, bp);
  await signer.connect();
  const pubkey = await signer.getPublicKey();
  return { signer, pubkey };
}

// NIP-46: Generate a nostrconnect:// URI for QR display
export async function generateNostrConnectSetup(
  relayUrls?: string[]
): Promise<{ uri: string; clientSecretKey: Uint8Array }> {
  if (!relayUrls) relayUrls = (await getSiteRelays()).slice(0, 2);
  const { createNostrConnectURI } = await import("nostr-tools/nip46");
  const clientSecretKey = generateSecretKey();
  const clientPubkey = getPubKeyFromSecret(clientSecretKey);
  const secretBytes = crypto.getRandomValues(new Uint8Array(8));
  const secret = Array.from(secretBytes)
    .map((b) => b.toString(16).padStart(2, "0"))
    .join("");
  const uri = createNostrConnectURI({
    clientPubkey,
    relays: relayUrls,
    secret,
    name: "Belgian Bitcoin Embassy",
  });
  return { uri, clientSecretKey };
}

// NIP-46: Wait for a remote signer to connect via nostrconnect:// URI
export async function waitForNostrConnectSigner(
  clientSecretKey: Uint8Array,
  uri: string,
  signal?: AbortSignal
): Promise<{ signer: BunkerSignerInterface; pubkey: string }> {
  const { BunkerSigner } = await import("nostr-tools/nip46");
  const signer = await BunkerSigner.fromURI(clientSecretKey, uri, {}, signal);
  const pubkey = await signer.getPublicKey();
  return { signer, pubkey };
}