// ABOUTME: Transaction building and submission module
// ABOUTME: Uses kaspa-wasm Generator for KIP-9 compliant transaction creation
import * as kaspa from 'kaspa-wasm';
import { getApi } from './api.js';
import { getWallet } from './wallet.js';
const {
Generator,
RpcClient,
Resolver,
Encoding,
sompiToKaspaString,
Address,
} = kaspa;
export interface SendResult {
txId: string;
fee: string;
}
export async function sendKaspa(
to: string,
amountSompi: bigint,
priorityFee: bigint = 0n
): Promise<SendResult> {
const wallet = getWallet();
const senderAddress = wallet.getAddress();
const api = getApi(wallet.getNetworkId());
const rpc = new RpcClient({
resolver: new Resolver(),
encoding: Encoding.Borsh,
networkId: wallet.getNetworkId(),
});
await rpc.connect({});
try {
const { isSynced } = await rpc.getServerInfo();
if (!isSynced) {
throw new Error('RPC node is not synced');
}
// Fetch UTXOs via RPC - returns properly formatted UtxoEntry objects
const { entries } = await rpc.getUtxosByAddresses([new Address(senderAddress)]);
if (!entries || entries.length === 0) {
throw new Error('No UTXOs available');
}
// Check balance
const feeEstimate = await api.getFeeEstimate();
const totalBalance = entries.reduce((sum: bigint, e: { amount: bigint }) => sum + e.amount, 0n);
const estimatedFee = BigInt(Math.ceil(feeEstimate.priorityBucket.feerate * 3000));
const totalRequired = amountSompi + estimatedFee + priorityFee;
if (totalBalance < totalRequired) {
throw new Error(
`Insufficient balance: have ${sompiToKaspaString(totalBalance)} KAS, need ~${sompiToKaspaString(totalRequired)} KAS (including estimated fees)`
);
}
// Sort UTXOs by amount (smallest first for efficient UTXO consolidation)
entries.sort((a: { amount: bigint }, b: { amount: bigint }) => (a.amount > b.amount ? 1 : -1));
// Create generator with RPC-provided UTXOs
const generator = new Generator({
entries,
outputs: [{ address: to, amount: amountSompi }],
priorityFee,
changeAddress: senderAddress,
networkId: wallet.getNetworkId(),
});
let pending: kaspa.PendingTransaction | undefined;
let lastTxId = '';
while ((pending = await generator.next())) {
await pending.sign([wallet.getPrivateKey()]);
lastTxId = await pending.submit(rpc);
}
const summary = generator.summary();
return {
txId: lastTxId,
fee: sompiToKaspaString(summary.fees).toString(),
};
} finally {
await rpc.disconnect();
}
}
