feat: Implement ProtocolSim for VMPoolstate get_spot_prices

Add spot_prices as an attribute and rename get_spot_prices (from VMPoolstate) to set_spot_prices. This way set_spot_prices needs to be called at some point by the user every time that the spot prices change. The get_spot_prices from ProtocolSim will only read from this cached spot prices

--- don't change below this line ---
ENG-3760 Took 43 minutes

src/protocol/vm/protosim_contract.rs

@@ -53,7 +53,7 @@ pub struct ProtoSimResponse {
 /// # Errors
 /// Returns errors of type `ProtosimError` when encoding, decoding, or simulation operations fail.
 /// These errors provide detailed feedback on potential issues.
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub struct ProtosimContract<D: DatabaseRef + std::clone::Clone> {
     abi: Abi,
     address: Address,

src/protocol/vm/state.rs

@@ -1,6 +1,7 @@
 // TODO: remove skip for clippy dead_code check
 #![allow(dead_code)]
 
+use std::any::Any;
 use tracing::warn;
 
 use crate::{
@@ -40,12 +41,19 @@ use revm::{
     DatabaseRef,
 };
 use std::collections::{HashMap, HashSet};
+use tycho_core::dto::ProtocolStateDelta;
 
 // Necessary for the init_account method to be in scope
 #[allow(unused_imports)]
 use crate::evm::engine_db_interface::EngineDatabaseInterface;
+use crate::protocol::{
+    errors::{TradeSimulationError, TransitionError},
+    events::{EVMLogMeta, LogIndex},
+    models::GetAmountOutResult,
+    state::{ProtocolEvent, ProtocolSim},
+};
 
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub struct VMPoolState<D: DatabaseRef + EngineDatabaseInterface + Clone> {
     /// The pool's identifier
     pub id: String,
@@ -59,6 +67,8 @@ pub struct VMPoolState<D: DatabaseRef + EngineDatabaseInterface + Clone> {
     /// If given, balances will be overwritten here instead of on the pool contract during
     /// simulations
     pub balance_owner: Option<H160>,
+    /// Spot prices of the pool by token pair
+    pub spot_prices: HashMap<(ERC20Token, ERC20Token), f64>,
     /// The supported capabilities of this pool
     pub capabilities: HashSet<Capability>,
     /// Storage overwrites that will be applied to all simulations. They will be cleared
@@ -102,6 +112,7 @@ impl VMPoolState<PreCachedDB> {
             block,
             balances,
             balance_owner,
+            spot_prices: HashMap::new(),
             capabilities,
             block_lasting_overwrites,
             involved_contracts,
@@ -330,12 +341,8 @@ impl VMPoolState<PreCachedDB> {
         Ok(())
     }
 
-    async fn get_spot_prices(
-        &mut self,
-        tokens: Vec<ERC20Token>,
-    ) -> Result<HashMap<(ERC20Token, ERC20Token), f64>, ProtosimError> {
+    pub async fn set_spot_prices(&mut self, tokens: Vec<ERC20Token>) -> Result<(), ProtosimError> {
         self.ensure_capability(Capability::PriceFunction)?;
-        let mut spot_prices: HashMap<(ERC20Token, ERC20Token), f64> = HashMap::new();
         for [sell_token, buy_token] in tokens
             .iter()
             .permutations(2)
@@ -378,9 +385,10 @@ impl VMPoolState<PreCachedDB> {
                     10f64.powi(buy_token.decimals as i32)
             };
 
-            spot_prices.insert(((*sell_token).clone(), (*buy_token).clone()), price);
+            self.spot_prices
+                .insert(((*sell_token).clone(), (*buy_token).clone()), price);
         }
-        Ok(spot_prices)
+        Ok(())
     }
 
     /// Retrieves the sell amount limit for a given pair of tokens, where the first token is treated
@@ -535,6 +543,62 @@ impl VMPoolState<PreCachedDB> {
     }
 }
 
+impl ProtocolSim for VMPoolState<PreCachedDB> {
+    fn fee(&self) -> f64 {
+        todo!()
+    }
+
+    fn spot_price(&self, base: &ERC20Token, quote: &ERC20Token) -> f64 {
+        *self
+            .spot_prices
+            .get(&(base.clone(), quote.clone()))
+            .expect("Spot price not found")
+    }
+
+    fn get_amount_out(
+        &self,
+        _amount_in: U256,
+        _token_in: &ERC20Token,
+        _token_out: &ERC20Token,
+    ) -> Result<GetAmountOutResult, TradeSimulationError> {
+        todo!()
+    }
+
+    fn delta_transition(
+        &mut self,
+        _delta: ProtocolStateDelta,
+    ) -> Result<(), TransitionError<String>> {
+        todo!()
+    }
+
+    fn event_transition(
+        &mut self,
+        _protocol_event: Box<dyn ProtocolEvent>,
+        _log: &EVMLogMeta,
+    ) -> Result<(), TransitionError<LogIndex>> {
+        todo!()
+    }
+
+    fn clone_box(&self) -> Box<dyn ProtocolSim> {
+        Box::new(self.clone())
+    }
+
+    fn as_any(&self) -> &dyn Any {
+        self
+    }
+
+    fn eq(&self, other: &dyn ProtocolSim) -> bool {
+        if let Some(other_state) = other
+            .as_any()
+            .downcast_ref::<VMPoolState<PreCachedDB>>()
+        {
+            self.id == other_state.id
+        } else {
+            false
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -721,18 +785,20 @@ mod tests {
     }
 
     #[tokio::test]
-    async fn test_get_spot_prices() {
+    async fn test_set_spot_prices() {
         let mut pool_state = setup_pool_state().await;
 
-        let spot_prices = pool_state
-            .get_spot_prices(pool_state.tokens.clone())
+        pool_state
+            .set_spot_prices(pool_state.tokens.clone())
             .await
             .unwrap();
 
-        let dai_bal_spot_price = spot_prices
+        let dai_bal_spot_price = pool_state
+            .spot_prices
             .get(&(pool_state.tokens[0].clone(), pool_state.tokens[1].clone()))
             .unwrap();
-        let bal_dai_spot_price = spot_prices
+        let bal_dai_spot_price = pool_state
+            .spot_prices
             .get(&(pool_state.tokens[1].clone(), pool_state.tokens[0].clone()))
             .unwrap();
         assert_eq!(dai_bal_spot_price, &0.137_778_914_319_047_9);