From dc0dbc62bef4453da115465d391aa7402f21431b Mon Sep 17 00:00:00 2001
From: AntiochP <30642645+antiochp@users.noreply.github.com>
Date: Tue, 10 Oct 2017 13:30:34 -0400
Subject: [PATCH] Set approximate wallet fee to avoid LowFeeTransaction (#163)

Set approximate wallet fee when building a transaction so we avoid getting a LowFeeTransaction error from the pool

* rustfmt
---
 pool/src/pool.rs       |  7 ++++++-
 wallet/src/receiver.rs | 11 +++++++----
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/pool/src/pool.rs b/pool/src/pool.rs
index 4cad0a803..8500e4bd4 100644
--- a/pool/src/pool.rs
+++ b/pool/src/pool.rs
@@ -567,6 +567,11 @@ where
 			// TODO evict old/large transactions instead
 			return Err(PoolError::OverCapacity);
 		}
+
+		// for a basic transaction (1 input, 2 outputs) -
+		// (-1 * 1) + (4 * 2) + 1 = 8
+		// 8 * 10 = 80
+		//
 		if self.config.accept_fee_base > 0 {
 			let mut tx_weight = -1 * (tx.inputs.len() as i32) + (4 * tx.outputs.len() as i32) + 1;
 			if tx_weight < 1 {
@@ -1055,7 +1060,7 @@ mod tests {
 
 	fn test_setup(dummy_chain: &Arc<DummyChainImpl>) -> TransactionPool<DummyChainImpl> {
 		TransactionPool {
-			config: PoolConfig{
+			config: PoolConfig {
 				accept_fee_base: 0,
 				max_pool_size: 10_000,
 			},
diff --git a/wallet/src/receiver.rs b/wallet/src/receiver.rs
index 1c7894291..4519b8b3c 100644
--- a/wallet/src/receiver.rs
+++ b/wallet/src/receiver.rs
@@ -234,10 +234,13 @@ fn receive_transaction(
 		let derivation = wallet_data.next_child(fingerprint.clone());
 		let pubkey = keychain.derive_pubkey(derivation)?;
 
-		// TODO - replace with real fee calculation
-		// TODO - note we are not enforcing this in consensus anywhere yet
-		// Note: consensus rules require this to be an even value so it can be split
-		let fee_amount = 10;
+		// from pool.rs
+		// (-1 * num_inputs) + (4 * num_outputs) + 1
+		// then multiply by accept_fee_base==10
+		// so 80 is basically the minimum fee for a basic transaction
+		// so lets use 100 for now (revisit this)
+
+		let fee_amount = 100;
 		let out_amount = amount - fee_amount;
 
 		let (tx_final, _) = build::transaction(vec![