import { Transaction, Connection } from '@solana/web3.js';
import type { WalletAdapter } from '../wallet/types';

/**
 * Deserialize a base64-encoded transaction, sign via wallet adapter, send to Solana.
 * Prefers signAndSendTransaction if available (MWA), otherwise falls back to
 * signTransaction + sendRawTransaction via RPC (Phantom deeplinks).
 * Returns the transaction signature.
 */
export async function signAndSendBase64Transaction(
  base64Tx: string,
  wallet: WalletAdapter,
  connection: Connection,
): Promise<string> {
  if (!wallet.publicKey) throw new Error('Wallet not connected');

  const binaryStr = atob(base64Tx);
  const bytes = new Uint8Array(binaryStr.length);
  for (let i = 0; i < binaryStr.length; i++) {
    bytes[i] = binaryStr.charCodeAt(i);
  }
  const transaction = Transaction.from(bytes);

  // Prefer signAndSendTransaction if wallet supports it (e.g. MWA)
  if (wallet.signAndSendTransaction) {
    return wallet.signAndSendTransaction(transaction);
  }

  // Fallback: sign via wallet, then send via RPC
  const signed = await wallet.signTransaction(transaction);
  const signature = await connection.sendRawTransaction(signed.serialize());
  return signature;
}