feat: introduce Bitcoin PoC [WIP]

Cargo.toml

@@ -1,6 +1,6 @@
 [workspace]
 resolver = "2"
-members = ["crates/tx3-cardano", "crates/tx3-lang", "crates/tx3-test"]
+members = [ "crates/tx3-bitcoin","crates/tx3-cardano", "crates/tx3-lang", "crates/tx3-test"]
 
 [workspace.package]
 publish = true

crates/tx3-bitcoin/Cargo.toml

@@ -0,0 +1,22 @@
+[package]
+name = "tx3-bitcoin"
+description = "Bitcoin compiler for tx3-lang protocols"
+publish.workspace = true
+authors.workspace = true
+edition.workspace = true
+license.workspace = true
+repository.workspace = true
+version.workspace = true
+keywords.workspace = true
+documentation.workspace = true
+homepage.workspace = true
+readme.workspace = true
+
+[dependencies]
+bitcoin = "0.32.6"
+hex = "0.4.3"
+serde = "1.0.219"
+thiserror = "2.0.12"
+tokio = "1.45.1"
+trait-variant = "0.1.2"
+tx3-lang = { version = "0.5.0", path = "../tx3-lang" }

crates/tx3-bitcoin/src/compile.rs

@@ -0,0 +1,69 @@
+use bitcoin::{
+    absolute::LockTime, hashes::Hash, transaction::Version, OutPoint, ScriptBuf, Sequence,
+    Transaction, TxIn, TxOut,
+};
+
+use tx3_lang::ir;
+
+use crate::Error;
+
+pub fn expr_into_amount(expr: &ir::Expression) -> Result<bitcoin::Amount, Error> {
+    match expr {
+        ir::Expression::Number(x) => Ok(bitcoin::Amount::from_sat(*x as u64)),
+        ir::Expression::Assets(x) if x.len() == 1 => expr_into_amount(&x[0].amount),
+        _ => Err(Error::CoerceError(
+            format!("{:?}", expr),
+            "Number".to_string(),
+        )),
+    }
+}
+
+fn compile_single_output(output: &ir::Output) -> Result<TxOut, Error> {
+    let value = output
+        .amount
+        .as_ref()
+        .map_or(Err(Error::MissingAmount), expr_into_amount)?;
+
+    let script_pubkey = output
+        .address
+        .as_ref()
+        .map_or(Err(Error::MissingAddress), expr_into_script_pubkey)?;
+
+    Ok(TxOut {
+        value,
+        script_pubkey,
+    })
+}
+
+fn compile_outputs(tx: &ir::Tx) -> Result<Vec<TxOut>, Error> {
+    tx.outputs.iter().map(compile_single_output).collect()
+}
+
+fn compile_inputs(tx: &ir::Tx) -> Result<Vec<TxIn>, Error> {
+    tx.inputs
+        .iter()
+        .flat_map(|input| input.refs.iter())
+        .map(|ref_| {
+            let txid = Hash::hash(ref_.txid.as_slice());
+            let vout = ref_.index as u32;
+
+            TxIn {
+                previous_output: OutPoint::new(txid, vout),
+                script_sig: ScriptBuf::new(),
+                sequence: Sequence::ZERO,
+                witness: Default::default(),
+            }
+        })
+        .collect()
+}
+
+pub fn compile_tx(tx: &ir::Tx, pparams: &PParams) -> Result<Transaction, Error> {
+    let tx = Transaction {
+        version: Version::TWO,
+        lock_time: LockTime::ZERO,
+        input: compile_inputs(tx)?,
+        output: compile_outputs(tx)?,
+    };
+
+    Ok(tx)
+}

crates/tx3-bitcoin/src/lib.rs

@@ -0,0 +1,11 @@
+mod compile;
+mod resolve;
+
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+    #[error("error coercing {0} into {1}")]
+    CoerceError(String, String),
+
+    #[error("missing amount")]
+    MissingAmount,
+}