From 150c0b5de8137ff8e5920daac5da56cfddfad794 Mon Sep 17 00:00:00 2001
From: priyanshiiit <priyanshiiit@gmail.com>
Date: Fri, 17 Jun 2022 21:07:17 +0530
Subject: [PATCH] lnwallet: adds RequiredReserve method

---
 lntest/mock/walletcontroller.go |  5 +++++
 lnwallet/btcwallet/btcwallet.go | 16 ++++++++++++++++
 lnwallet/interface.go           |  6 ++++++
 3 files changed, 27 insertions(+)

diff --git a/lntest/mock/walletcontroller.go b/lntest/mock/walletcontroller.go
index 0256a3164..3cd237076 100644
--- a/lntest/mock/walletcontroller.go
+++ b/lntest/mock/walletcontroller.go
@@ -105,6 +105,11 @@ func (w *WalletController) ListAccounts(string,
 	return nil, nil
 }
 
+// RequiredReserve currently returns a dummy value.
+func (w *WalletController) RequiredReserve(uint32) btcutil.Amount {
+	return 0
+}
+
 // ImportAccount currently returns a dummy value.
 func (w *WalletController) ImportAccount(string, *hdkeychain.ExtendedKey,
 	uint32, *waddrmgr.AddressType, bool) (*waddrmgr.AccountProperties,
diff --git a/lnwallet/btcwallet/btcwallet.go b/lnwallet/btcwallet/btcwallet.go
index 40e4a9867..c92823cb8 100644
--- a/lnwallet/btcwallet/btcwallet.go
+++ b/lnwallet/btcwallet/btcwallet.go
@@ -711,6 +711,22 @@ func (b *BtcWallet) ListAccounts(name string,
 	return res, nil
 }
 
+// RequiredReserve returns the minimum amount of satoshis that should be
+// kept in the wallet in order to fee bump anchor channels if necessary.
+// The value scales with the number of public anchor channels but is
+// capped at a maximum.
+func (b *BtcWallet) RequiredReserve(
+	numAnchorChans uint32) btcutil.Amount {
+
+	anchorChanReservedValue := lnwallet.AnchorChanReservedValue
+	reserved := btcutil.Amount(numAnchorChans) * anchorChanReservedValue
+	if reserved > lnwallet.MaxAnchorChanReservedValue {
+		reserved = lnwallet.MaxAnchorChanReservedValue
+	}
+
+	return reserved
+}
+
 // ImportAccount imports an account backed by an account extended public key.
 // The master key fingerprint denotes the fingerprint of the root key
 // corresponding to the account public key (also known as the key with
diff --git a/lnwallet/interface.go b/lnwallet/interface.go
index 71602789e..146fb8e58 100644
--- a/lnwallet/interface.go
+++ b/lnwallet/interface.go
@@ -244,6 +244,12 @@ type WalletController interface {
 	ListAccounts(string, *waddrmgr.KeyScope) ([]*waddrmgr.AccountProperties,
 		error)
 
+	// RequiredReserve returns the minimum amount of satoshis that should be
+	// kept in the wallet in order to fee bump anchor channels if necessary.
+	// The value scales with the number of public anchor channels but is
+	// capped at a maximum.
+	RequiredReserve(uint32) btcutil.Amount
+
 	// ImportAccount imports an account backed by an account extended public
 	// key. The master key fingerprint denotes the fingerprint of the root
 	// key corresponding to the account public key (also known as the key