feat: Add methods to builder to set chain and strategy independently

--- don't change below this line ---
ENG-4246 Took 15 minutes

examples/quickstart/main.rs

@@ -21,7 +21,9 @@ fn main() {
         .expect("Failed to create user address");
 
     // Initialize the encoder
-    let encoder = EVMEncoderBuilder::tycho_router(TychoCoreChain::Ethereum, swapper_pk, None)
+    let encoder = EVMEncoderBuilder::new()
+        .chain(TychoCoreChain::Ethereum)
+        .tycho_router(swapper_pk, None)
         .expect("Failed to create encoder builder")
         .build()
         .expect("Failed to build encoder");

src/bin/tycho-encode.rs

@@ -103,14 +103,16 @@ fn encode_swaps(
     let solution: Solution = serde_json::from_str(input)?;
     let chain = Chain::Ethereum;
 
-    let encoder = if use_tycho_router {
+    let mut builder = EVMEncoderBuilder::new().chain(chain);
+    builder = if use_tycho_router {
         let private_key = swapper_pk.ok_or(EncodingError::FatalError(
             "Swapper private key is required for tycho_router".to_string(),
         ))?;
-        EVMEncoderBuilder::tycho_router(chain, private_key, config_path)?.build()?
+        builder.tycho_router(private_key, config_path)?
     } else {
-        EVMEncoderBuilder::direct_execution(chain, config_path)?.build()?
+        builder.direct_execution(config_path)?
     };
+    let encoder = builder.build()?;
 
     let transactions = encoder.encode_router_calldata(vec![solution])?;
 

src/encoding/evm/encoder_builder.rs

@@ -11,34 +11,66 @@ use crate::encoding::{
 };
 
 pub struct EVMEncoderBuilder {
-    strategy: Box<dyn StrategyEncoder>,
-    chain: Chain,
+    strategy: Option<Box<dyn StrategyEncoder>>,
+    chain: Option<Chain>,
+}
+
+impl Default for EVMEncoderBuilder {
+    fn default() -> Self {
+        Self::new()
+    }
 }
 
 impl EVMEncoderBuilder {
-    pub fn new(chain: Chain, strategy: Box<dyn StrategyEncoder>) -> Self {
-        EVMEncoderBuilder { chain, strategy }
+    pub fn new() -> Self {
+        EVMEncoderBuilder { chain: None, strategy: None }
+    }
+    pub fn chain(mut self, chain: Chain) -> Self {
+        self.chain = Some(chain);
+        self
+    }
+    pub fn strategy_encoder(mut self, strategy: Box<dyn StrategyEncoder>) -> Self {
+        self.strategy = Some(strategy);
+        self
     }
     pub fn tycho_router(
-        chain: Chain,
+        self,
         swapper_pk: String,
         executors_file_path: Option<String>,
     ) -> Result<Self, EncodingError> {
-        let swap_encoder_registry = SwapEncoderRegistry::new(executors_file_path, chain)?;
-        let strategy =
-            Box::new(SplitSwapStrategyEncoder::new(swapper_pk, chain, swap_encoder_registry)?);
-        Ok(EVMEncoderBuilder { chain, strategy })
+        if let Some(chain) = self.chain {
+            let swap_encoder_registry = SwapEncoderRegistry::new(executors_file_path, chain)?;
+            let strategy =
+                Box::new(SplitSwapStrategyEncoder::new(swapper_pk, chain, swap_encoder_registry)?);
+            Ok(EVMEncoderBuilder { chain: Some(chain), strategy: Some(strategy) })
+        } else {
+            Err(EncodingError::FatalError(
+                "Please set the chain before setting the strategy".to_string(),
+            ))
+        }
     }
     pub fn direct_execution(
-        chain: Chain,
+        self,
         executors_file_path: Option<String>,
     ) -> Result<Self, EncodingError> {
-        let swap_encoder_registry = SwapEncoderRegistry::new(executors_file_path, chain)?;
-        let strategy = Box::new(ExecutorStrategyEncoder::new(swap_encoder_registry));
-        Ok(EVMEncoderBuilder { chain, strategy })
+        if let Some(chain) = self.chain {
+            let swap_encoder_registry = SwapEncoderRegistry::new(executors_file_path, chain)?;
+            let strategy = Box::new(ExecutorStrategyEncoder::new(swap_encoder_registry));
+            Ok(EVMEncoderBuilder { chain: Some(chain), strategy: Some(strategy) })
+        } else {
+            Err(EncodingError::FatalError(
+                "Please set the chain before setting the strategy".to_string(),
+            ))
+        }
     }
 
     pub fn build(self) -> Result<EVMTychoEncoder, EncodingError> {
-        EVMTychoEncoder::new(self.chain, self.strategy)
+        if let (Some(chain), Some(strategy)) = (self.chain, self.strategy) {
+            EVMTychoEncoder::new(chain, strategy)
+        } else {
+            Err(EncodingError::FatalError(
+                "Please set the chain and strategy before building the encoder".to_string(),
+            ))
+        }
     }
 }