[wallet] Add a TxBuilder struct to simplify create_tx()'s interface

src/wallet/tx_builder.rs

@@ -0,0 +1,71 @@
+use std::collections::BTreeMap;
+
+use bitcoin::{Address, OutPoint};
+
+#[derive(Debug, Default)]
+pub struct TxBuilder {
+    pub(crate) addressees: Vec<(Address, u64)>,
+    pub(crate) send_all: bool,
+    pub(crate) fee_perkb: Option<f32>,
+    pub(crate) policy_path: Option<BTreeMap<String, Vec<usize>>>,
+    pub(crate) utxos: Option<Vec<OutPoint>>,
+    pub(crate) unspendable: Option<Vec<OutPoint>>,
+}
+
+impl TxBuilder {
+    pub fn new() -> TxBuilder {
+        TxBuilder::default()
+    }
+
+    pub fn from_addressees(addressees: Vec<(Address, u64)>) -> TxBuilder {
+        let mut tx_builder = TxBuilder::default();
+        tx_builder.addressees = addressees;
+
+        tx_builder
+    }
+
+    pub fn add_addressee(&mut self, address: Address, amount: u64) -> &mut TxBuilder {
+        self.addressees.push((address, amount));
+        self
+    }
+
+    pub fn send_all(&mut self) -> &mut TxBuilder {
+        self.send_all = true;
+        self
+    }
+
+    pub fn fee_rate(&mut self, satoshi_per_vbyte: f32) -> &mut TxBuilder {
+        self.fee_perkb = Some(satoshi_per_vbyte * 1e3);
+        self
+    }
+
+    pub fn fee_rate_perkb(&mut self, satoshi_per_kb: f32) -> &mut TxBuilder {
+        self.fee_perkb = Some(satoshi_per_kb);
+        self
+    }
+
+    pub fn policy_path(&mut self, policy_path: BTreeMap<String, Vec<usize>>) -> &mut TxBuilder {
+        self.policy_path = Some(policy_path);
+        self
+    }
+
+    pub fn utxos(&mut self, utxos: Vec<OutPoint>) -> &mut TxBuilder {
+        self.utxos = Some(utxos);
+        self
+    }
+
+    pub fn add_utxo(&mut self, utxo: OutPoint) -> &mut TxBuilder {
+        self.utxos.get_or_insert(vec![]).push(utxo);
+        self
+    }
+
+    pub fn unspendable(&mut self, unspendable: Vec<OutPoint>) -> &mut TxBuilder {
+        self.unspendable = Some(unspendable);
+        self
+    }
+
+    pub fn add_unspendable(&mut self, unspendable: OutPoint) -> &mut TxBuilder {
+        self.unspendable.get_or_insert(vec![]).push(unspendable);
+        self
+    }
+}