// Shared signer manager for Nostr signers (remote and extension)
import { SimplePool } from 'nostr-tools';
import { BunkerSigner } from 'nostr-tools/nip46';

const REMOTE_SIGNER_KEY = 'amber_remote_signer';

let remoteSigner = null;
let remoteSignerPromise = null;
let remoteSignerPool = null;

export async function getSigner() {
  // If remote signer session is active, use it
  const session = getRemoteSignerSession();
  if (session) {
    if (remoteSigner) return remoteSigner;
    if (remoteSignerPromise) return remoteSignerPromise;

    remoteSignerPromise = createRemoteSigner(session)
      .then(signer => {
        remoteSigner = signer;
        return signer;
      })
      .catch(error => {
        // Reset promise on failure so next call can retry
        remoteSignerPromise = null;
        throw error;
      });
    return remoteSignerPromise;
  }
  // Fallback to browser extension
  if (window.nostr && typeof window.nostr.signEvent === 'function') {
    return window.nostr;
  }
  throw new Error('No signer available');
}

export function setRemoteSignerSession(session) {
  localStorage.setItem(REMOTE_SIGNER_KEY, JSON.stringify(session));
}

export function clearRemoteSignerSession() {
  localStorage.removeItem(REMOTE_SIGNER_KEY);
  remoteSigner = null;
  remoteSignerPromise = null;
  if (remoteSignerPool) {
    try { remoteSignerPool.close?.([]); } catch (_) {}
    remoteSignerPool = null;
  }
}

export function getRemoteSignerSession() {
  const raw = localStorage.getItem(REMOTE_SIGNER_KEY);
  if (!raw) return null;
  try {
    return JSON.parse(raw);
  } catch {
    return null;
  }
}

async function createRemoteSigner(session) {
  remoteSignerPool = new SimplePool();

  // Add timeout to prevent hanging indefinitely
  const timeoutPromise = new Promise((_, reject) => {
    setTimeout(() => reject(new Error('Remote signer connection timeout')), 10000);
  });

  try {
    return await Promise.race([
      BunkerSigner.fromURI(session.privkey, session.uri, { pool: remoteSignerPool }),
      timeoutPromise
    ]);
  } catch (error) {
    // Clean up on error
    if (remoteSignerPool) {
      try { remoteSignerPool.close?.([]); } catch (_) {}
      remoteSignerPool = null;
    }
    remoteSigner = null;
    remoteSignerPromise = null;
    throw error;
  }
}