From 92868cfaa565b18d72fc61d5bdac4f58451a6454 Mon Sep 17 00:00:00 2001
From: Olaoluwa Osuntokun <laolu32@gmail.com>
Date: Mon, 16 Jan 2023 19:57:03 -0800
Subject: [PATCH] input: add PayToTaprootScript helper func

In this commit, we add a helper function to take a taproot output key
and turn it into a v1 witness program.
---
 input/taproot.go | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/input/taproot.go b/input/taproot.go
index 78294f03a..935050f78 100644
--- a/input/taproot.go
+++ b/input/taproot.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 
 	"github.com/btcsuite/btcd/btcec/v2"
+	"github.com/btcsuite/btcd/btcec/v2/schnorr"
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcwallet/waddrmgr"
@@ -135,3 +136,15 @@ func TapscriptFullKeyOnly(taprootKey *btcec.PublicKey) *waddrmgr.Tapscript {
 		FullOutputKey: taprootKey,
 	}
 }
+
+// PayToTaprootScript creates a new script to pay to a version 1 (taproot)
+// witness program. The passed public key will be serialized as an x-only key
+// to create the witness program.
+func PayToTaprootScript(taprootKey *btcec.PublicKey) ([]byte, error) {
+	builder := txscript.NewScriptBuilder()
+
+	builder.AddOp(txscript.OP_1)
+	builder.AddData(schnorr.SerializePubKey(taprootKey))
+
+	return builder.Script()
+}