Add demo project

src/demo/project.ts

@@ -0,0 +1,152 @@
+// File: index.ts
+
+import bitcoin from 'bitcoinjs-lib';
+import axios from 'axios';
+import { NativeModules, Platform } from 'react-native';
+
+// Define types for UTXO and PayJoin response
+interface Utxo {
+  txid: string;
+  vout: number;
+  hex: string;
+  timelock: number;
+  amount: number;
+  address: string;
+  preimage: string;
+  scriptPubKey: string;
+  confirmations: number;
+  is_coinbase: boolean;
+}
+
+interface Payjoin {
+  psbt: string;
+}
+
+interface PayJoinRequest {
+  psbt: string;
+}
+
+interface PayJoinResponse {
+  psbt: string;
+}
+
+// Create initial PSBT
+async function createInitialPayJoinTx(
+  senderAddress: string,
+  receiverAddress: string,
+  amountToSend: number
+): Promise<bitcoin.Psbt> {
+  const psbt = new bitcoin.Psbt();
+
+  // Fetch UTXOs for sender (placeholder logic)
+  const utxos: Utxo[] = await fetchUtxos(senderAddress);
+
+  // Add UTXOs as inputs
+  utxos.forEach((utxo) => {
+    psbt.addInput({
+      hash: utxo.txid,
+      index: utxo.vout,
+      nonWitnessUtxo: Buffer.from(utxo.hex, 'hex'),
+    });
+  });
+
+  // Add receiver address as output
+  psbt.addOutput({
+    address: receiverAddress,
+    value: BigInt(amountToSend),
+  });
+
+  return psbt;
+}
+
+// Send PSBT to receiver's PayJoin endpoint
+async function sendPayJoinRequest(psbt: bitcoin.Psbt): Promise<bitcoin.Psbt> {
+  const url = 'https://receiver.payjoin.endpoint/payjoin';
+
+  const response = await axios.post<PayJoinResponse>(url, { psbt: psbt.toBase64() });
+
+  // Get the modified PSBT from receiver
+  const modifiedPsbt = bitcoin.Psbt.fromBase64(response.data.psbt);
+
+  return modifiedPsbt;
+}
+
+// Finalize, sign, and broadcast PayJoin transaction
+async function finalizeAndBroadcast(
+  modifiedPsbt: bitcoin.Psbt,
+  senderPrivateKey: string
+): Promise<void> {
+  const keyPair = bitcoin.payments.p2pkh({ wif: senderPrivateKey }).keys[0];
+
+  // Sign the transaction
+  modifiedPsbt.signAllInputs(keyPair);
+
+  // Validate and finalize
+
+  modifiedPsbt.validateSignaturesOfAllInputs((pubkey, msghash, signature) => {
+    return bitcoin.verify(msghash, pubkey, signature);
+  });
+  modifiedPsbt.finalizeAllInputs();
+
+  const txHex = modifiedPsbt.extractTransaction().toHex();
+
+  // Broadcast transaction (placeholder logic)
+  await broadcastTransaction(txHex);
+
+}// Fetch UTXOs for a given address (placeholder implementation)
+async function fetchUtxos(senderAddress: string): Promise<Utxo[]> {
+  // Replace with actual API call to fetch UTXOs
+  return [
+    {
+      txid: 'dummy-txid',
+      vout: 0,
+      hex: 'dummy-hex',
+      timelock: 0,
+      amount: 1000000,
+      address: senderAddress,
+      preimage: '',
+      scriptPubKey: '',
+      confirmations: 10,
+      is_coinbase: false,
+    },
+  ];
+}
+
+async function broadcastTransaction(txHex: string): Promise<void> {
+  console.log(`Broadcasting transaction: ${txHex}`);
+  // Implement actual broadcasting logic using a Bitcoin node or API
+}
+
+const { YourLibrary } = NativeModules;
+
+const sampleMethod = async (input: string): Promise<string> => {
+  return await YourLibrary.sampleMethod(input);
+};
+
+export default {
+  sampleMethod,
+  createInitialPayJoinTx,
+  sendPayJoinRequest,
+  finalizeAndBroadcast,
+};
+
+// Run a demo
+(async () => {
+  const senderAddress = 'sender-test-address';
+  const receiverAddress = 'receiver-test-address';
+  const amountToSend = 100000; // Satoshis
+
+  try {
+    const initialPsbt = await createInitialPayJoinTx(senderAddress, receiverAddress, amountToSend);
+    console.log('Initial PSBT created:', initialPsbt.toBase64());
+
+    const modifiedPsbt = await sendPayJoinRequest(initialPsbt);
+    console.log('Modified PSBT received:', modifiedPsbt.toBase64());
+
+    const senderPrivateKey = 'dummy-private-key';
+    await finalizeAndBroadcast(modifiedPsbt, senderPrivateKey);
+    console.log('Transaction finalized and broadcasted.');
+  } catch (error) {
+    console.error('Error in PayJoin process:', error);
+  }
+})();