feat: UniswapV2 Swap Encoder

src/encoding/evm/swap_encoder/encoders.rs

@@ -1,7 +1,9 @@
 use std::str::FromStr;
 
+use alloy::hex::decode;
 use alloy_primitives::Address;
 use alloy_sol_types::SolValue;
+use tycho_core::Bytes;
 
 use crate::encoding::{
     errors::EncodingError,
@@ -16,17 +18,51 @@ pub struct UniswapV2SwapEncoder {
     executor_address: String,
 }
 
-impl UniswapV2SwapEncoder {}
+impl UniswapV2SwapEncoder {
+    fn get_zero_to_one(sell_token_address: Address, buy_token_address: Address) -> bool {
+        sell_token_address < buy_token_address
+    }
+}
+
 impl SwapEncoder for UniswapV2SwapEncoder {
     fn new(executor_address: String) -> Self {
         Self { executor_address }
     }
+
     fn encode_swap(
         &self,
-        _swap: Swap,
+        swap: Swap,
-        _encoding_context: EncodingContext,
+        encoding_context: EncodingContext,
     ) -> Result<Vec<u8>, EncodingError> {
-        todo!()
+        let token_in_address = bytes_to_address(&swap.token_in)?;
+        let token_out_address = bytes_to_address(&swap.token_out)?;
+
+        let zero_for_one = Self::get_zero_to_one(token_in_address, token_out_address);
+        let protocol_id = Bytes::from(
+            decode(
+                swap.component
+                    .id
+                    .trim_start_matches("0x"),
+            )
+            .map_err(|_| {
+                EncodingError::FatalError(format!(
+                    "Failed to parse component id: {}",
+                    swap.component.id
+                ))
+            })?,
+        );
+
+        // Sell token address is always needed to perform manual transfer from router into the pool,
+        // since no optimizations are performed that send from one pool to the next
+        let args = (
+            token_in_address,
+            bytes_to_address(&protocol_id)?,
+            bytes_to_address(&encoding_context.receiver)?,
+            zero_for_one,
+            encoding_context.exact_out,
+        );
+
+        Ok(args.abi_encode_packed())
     }
 
     fn executor_address(&self) -> &str {
@@ -77,8 +113,47 @@ impl SwapEncoder for BalancerV2SwapEncoder {
 
 #[cfg(test)]
 mod tests {
+    use alloy::hex::encode;
+    use tycho_core::{dto::ProtocolComponent, Bytes};
+
+    use super::*;
+
     #[tokio::test]
-    async fn test_encode_swap() {
+    async fn test_encode_uniswap_v2() {
-        // Dummy test to make CI pass. Please implement me.
+        let usv2_pool = ProtocolComponent {
+            id: String::from("0x88e6A0c2dDD26FEEb64F039a2c41296FcB3f5640"),
+            ..Default::default()
+        };
+        let swap = Swap {
+            component: usv2_pool,
+            token_in: Bytes::from("0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2"),
+            token_out: Bytes::from("0x6b175474e89094c44da98b954eedeac495271d0f"),
+            split: 0f64,
+        };
+        let encoding_context = EncodingContext {
+            receiver: Bytes::from("0x0000000000000000000000000000000000000001"),
+            exact_out: false,
+            address_for_approvals: Bytes::zero(20),
+        };
+        let encoder = super::UniswapV2SwapEncoder::new(String::from("0x"));
+        let encoded_swap = encoder
+            .encode_swap(swap, encoding_context)
+            .unwrap();
+        let hex_swap = encode(&encoded_swap);
+        assert_eq!(
+            hex_swap,
+            String::from(concat!(
+                // in token
+                "c02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
+                // component id
+                "88e6a0c2ddd26feeb64f039a2c41296fcb3f5640",
+                // receiver
+                "0000000000000000000000000000000000000001",
+                // zero for one
+                "00",
+                // exact out
+                "00",
+            ))
+        );
     }
 }

src/encoding/models.rs

@@ -76,5 +76,6 @@ pub struct Transaction {
 pub struct EncodingContext {
     pub receiver: Bytes,
     pub exact_out: bool,
+    // TODO I don't like this - what does this mean?
     pub address_for_approvals: Bytes,
 }