chore(utxo-coredao): op_return

TICKET: BTC-1578

modules/utxo-coredao/src/index.ts

@@ -1 +1,2 @@
 export * from './descriptor';
+export * from './transaction';

modules/utxo-coredao/src/transaction.ts

@@ -0,0 +1,96 @@
+// Source: https://docs.coredao.org/docs/Learn/products/btc-staking/design
+export const CORE_DAO_TESTNET_CHAIN_ID = Buffer.from([0x1115]);
+export const CORE_DAO_MAINNET_CHAIN_ID = Buffer.from([0x1116]);
+export const CORE_DAO_SATOSHI_PLUS_IDENTIFIER = Buffer.from([0x5341542b]);
+
+/** As of v2, this is the construction of the OP_RETURN:
+ * Source: https://docs.coredao.org/docs/Learn/products/btc-staking/design#op_return-output
+ *
+ * The OP_RETURN output should contain all staking information in order, and be composed in the following format:
+ *
+ * OP_RETURN: identifier 0x6a
+ * LENGTH: which represents the total byte length after the OP_RETURN opcode. Note that all data has to be pushed with its appropriate size byte(s).
+ * Satoshi Plus Identifier: (SAT+) 4 bytes
+ * Version: (0x01) 1 byte
+ * Chain ID: (0x1115 for Core Testnet and 0x1116 for Core Mainnet) 2 bytes
+ * Delegator: The Core address to receive rewards, 20 bytes
+ * Validator: The Core validator address to stake to, 20 bytes
+ * Fee: Fee for relayer, 1 byte, range [0,255], measured in CORE
+ * (Optional) RedeemScript
+ * (Optional) Timelock: 4 bytes
+ *
+ * Either RedeemScript or Timelock must be available, the purpose is to allow relayer to
+ * obtain the RedeemScript and submit transactions on Core. If a RedeemScript is provided,
+ * relayer will use it directly. Otherwise, relayer will construct the redeem script based
+ * on the timelock and the information in the transaction inputs.
+ *
+ * @returns Buffer OP_RETURN buffer
+ */
+export function createCoreDaoOpReturnBuffer({
+  version,
+  chainId,
+  delegator,
+  validator,
+  fee,
+  redeemScript,
+  timelock,
+}: {
+  version: number;
+  chainId: string;
+  delegator: string;
+  validator: string;
+  fee: string;
+  redeemScript?: string;
+  timelock?: number;
+}): Buffer {
+  const versionBuffer = Buffer.alloc(1, version);
+
+  const chainIdBuffer = Buffer.from(chainId, 'hex');
+  if (!(chainIdBuffer.equals(CORE_DAO_TESTNET_CHAIN_ID) || chainIdBuffer.equals(CORE_DAO_MAINNET_CHAIN_ID))) {
+    throw new Error('Invalid chain ID');
+  }
+  const delegatorBuffer = Buffer.from(delegator, 'hex');
+  if (delegatorBuffer.length !== 20) {
+    throw new Error('Invalid delegator address');
+  }
+
+  const validatorBuffer = Buffer.from(validator, 'hex');
+  if (validatorBuffer.length !== 20) {
+    throw new Error('Invalid validator address');
+  }
+
+  const feeBuffer = Buffer.from(fee, 'hex');
+  if (feeBuffer.length !== 1) {
+    throw new Error('Invalid fee');
+  }
+
+  const redeemScriptBuffer = Buffer.from(redeemScript ?? '', 'hex');
+  const timelockBuffer = timelock ? Buffer.alloc(4, timelock) : Buffer.from([]);
+
+  const totalLength =
+    CORE_DAO_SATOSHI_PLUS_IDENTIFIER.length +
+    versionBuffer.length +
+    chainIdBuffer.length +
+    delegatorBuffer.length +
+    validatorBuffer.length +
+    feeBuffer.length +
+    redeemScriptBuffer.length +
+    timelockBuffer.length;
+
+  if (totalLength > 76) {
+    throw new Error('OP_RETURN data exceeds maximum length');
+  }
+
+  return Buffer.concat([
+    Buffer.from([0x6a]),
+    Buffer.alloc(1, totalLength),
+    CORE_DAO_SATOSHI_PLUS_IDENTIFIER,
+    versionBuffer,
+    chainIdBuffer,
+    delegatorBuffer,
+    validatorBuffer,
+    feeBuffer,
+    redeemScriptBuffer,
+    timelockBuffer,
+  ]);
+}