Add more info to staking creation event (#238)

Fixes: #237

- Adding `PkScript` makes is possible to listen to confirmation event
using lnd libraries (and therefore btc lightclients)
- Addinng `StakingOutputIndex` makes it possible to identify staking
output as utxo i.e tuple (hash, idx)

CHANGELOG.md

@@ -46,6 +46,11 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 * [#235](https://github.com/babylonlabs-io/babylon/pull/235) Change default values
 for iavl cache when using `testnet` command
 
+### API Breaking
+
+* [238](https://github.com/babylonlabs-io/babylon/pull/238) Add additional data
+to delegation creation event
+
 ## v0.14.1
 
 ### API Breaking

proto/babylon/btcstaking/v1/events.proto

@@ -147,26 +147,30 @@ message EventBTCDelegationCreated {
   // staking_tx_hash is the hash of the staking tx.
   // It uniquely identifies a BTC delegation
   string staking_tx_hash = 1 [(amino.dont_omitempty) = true];
+  // staking_output_pk_script is the hex encoded PK script of the staking output
+  string staking_output_pk_script = 2 [(amino.dont_omitempty) = true];
+  // staking_output_index is the index of the staking output in the staking tx
+  string staking_output_index = 3 [(amino.dont_omitempty) = true];
   // version of the params used to validate the delegation
-  string params_version = 2 [(amino.dont_omitempty) = true];
+  string params_version = 4 [(amino.dont_omitempty) = true];
   // finality_provider_btc_pks_hex is the list of hex str of Bitcoin secp256k1 PK of
   // the finality providers that this BTC delegation delegates to
   // the PK follows encoding in BIP-340 spec
-  repeated string finality_provider_btc_pks_hex = 3 [(amino.dont_omitempty) = true];
+  repeated string finality_provider_btc_pks_hex = 5 [(amino.dont_omitempty) = true];
   // staker_btc_pk_hex is the hex str of Bitcoin secp256k1 PK of the staker that
   // creates this BTC delegation the PK follows encoding in BIP-340 spec
-  string staker_btc_pk_hex = 4 [(amino.dont_omitempty) = true];
+  string staker_btc_pk_hex = 6 [(amino.dont_omitempty) = true];
   // staking_time is the timelock of the staking tx specified in the BTC script
-  string staking_time = 5 [(amino.dont_omitempty) = true];
+  string staking_time = 7 [(amino.dont_omitempty) = true];
   // staking_amount is the total amount of BTC stake in this delegation
   // quantified in satoshi
-  string staking_amount = 6 [(amino.dont_omitempty) = true];
+  string staking_amount = 8 [(amino.dont_omitempty) = true];
   // unbonding_time is the time is timelock on unbonding tx chosen by the staker
-  string unbonding_time = 7 [(amino.dont_omitempty) = true];
+  string unbonding_time = 9 [(amino.dont_omitempty) = true];
   // unbonding_tx is hex encoded bytes of the unsigned unbonding tx
-  string unbonding_tx = 8 [(amino.dont_omitempty) = true];
+  string unbonding_tx = 10 [(amino.dont_omitempty) = true];
   // new_state of the BTC delegation
-  string new_state = 9 [(amino.dont_omitempty) = true];
+  string new_state = 11 [(amino.dont_omitempty) = true];
 }
 
 // EventCovenantSignatureReceived is the event emitted when a covenant committee

x/btcstaking/types/btc_delegation.go

@@ -162,6 +162,16 @@ func (d *BTCDelegation) MustGetStakingTxHash() chainhash.Hash {
 	return txHash
 }
 
+func (d *BTCDelegation) MustGetStakingTx() *wire.MsgTx {
+	stakingTx, err := bbn.NewBTCTxFromBytes(d.StakingTx)
+
+	if err != nil {
+		panic(err)
+	}
+
+	return stakingTx
+}
+
 func (d *BTCDelegation) ValidateBasic() error {
 	if _, err := sdk.AccAddressFromBech32(d.StakerAddr); err != nil {
 		return fmt.Errorf("invalid staker address: %s - %w", d.StakerAddr, err)

x/btcstaking/types/events.go

@@ -93,6 +93,8 @@ func NewBtcDelCreationEvent(
 ) *EventBTCDelegationCreated {
 	return &EventBTCDelegationCreated{
 		StakingTxHash:             stakingTxHash,
+		StakingOutputPkScript:     hex.EncodeToString(btcDel.MustGetStakingTx().TxOut[btcDel.StakingOutputIdx].PkScript),
+		StakingOutputIndex:        strconv.FormatUint(uint64(btcDel.StakingOutputIdx), 10),
 		ParamsVersion:             strconv.FormatUint(uint64(btcDel.ParamsVersion), 10),
 		FinalityProviderBtcPksHex: btcDel.FinalityProviderKeys(),
 		StakerBtcPkHex:            btcDel.BtcPk.MarshalHex(),