create_transaction deep refactoring

src/silentpayments.rs

@@ -27,52 +27,12 @@ impl TsUnsignedTransaction {
 }
 
 pub fn create_transaction(
-    mandatory_inputs: Vec<OutPoint>,
+    available_outpoints: Vec<(OutPoint, OwnedOutput)>,
-    mut available_outpoints: HashMap<OutPoint, OwnedOutput>,
-    freezed_utxos: &HashSet<OutPoint>,
     sp_client: &SpClient,
     mut recipients: Vec<Recipient>,
     payload: Option<Vec<u8>>,
-    fee_rate: Amount,
+    fee_rate: FeeRate,
 ) -> Result<SilentPaymentUnsignedTransaction> {
-    let sum_outputs = recipients
-        .iter()
-        .fold(Amount::from_sat(0), |acc, x| acc + x.amount);
-
-    let zero_value_recipient = recipients
-        .iter_mut()
-        .find(|r| r.amount == Amount::from_sat(0));
-
-    let mut inputs: HashMap<OutPoint, OwnedOutput> = HashMap::new();
-    let mut total_available = Amount::from_sat(0);
-    for outpoint in mandatory_inputs {
-        let (must_outpoint, must_output) = available_outpoints
-            .remove_entry(&outpoint)
-            .ok_or_else(|| Error::msg(format!("Mandatory outpoint unknown: {}", outpoint)))?;
-        total_available += must_output.amount;
-        inputs.insert(must_outpoint, must_output);
-    }
-
-    let fee_provision = Amount::from_sat(1000);
-
-    for (outpoint, output) in &available_outpoints {
-        if freezed_utxos.contains(outpoint) { continue }
-        if total_available > sum_outputs.checked_add(fee_provision).unwrap() {
-            break;
-        }
-        total_available += output.amount;
-        inputs.insert(*outpoint, output.clone());
-    }
-
-    if total_available <= sum_outputs.checked_add(fee_provision).unwrap() {
-        return Err(Error::msg("Not enough available funds"));
-    }
-
-    if let Some(recipient) = zero_value_recipient {
-        // update the amount for the recipient
-        recipient.amount = total_available;
-    }
-
     let mut commitment = [0u8; 32];
     if let Some(ref p) = payload {
         commitment.copy_from_slice(&p);
@@ -80,10 +40,15 @@ pub fn create_transaction(
         thread_rng().fill(&mut commitment);
     }
 
+    recipients.push(Recipient { 
+        address: sp_client::RecipientAddress::Data(commitment.to_vec()), 
+        amount: Amount::ZERO 
+    });
+
     let new_transaction = sp_client.create_new_transaction(
-        available_outpoints.into_iter().collect(), 
+        available_outpoints, 
         recipients, 
-        fee_rate.to_btc() as f32, 
+        fee_rate,
         sp_client.get_network()
     )?;