From 4da3f46e930a8d9b6c20d767c871f5637bb1ebff Mon Sep 17 00:00:00 2001
From: julio4 <jules.doumeche@gmail.com>
Date: Tue, 10 Oct 2023 18:02:13 +0900
Subject: [PATCH] feat: update to 2.3.0 + support custom fee

---
 .../ch02-applications/constant_product_amm/Scarb.toml  |  2 +-
 .../src/constant_product_amm.cairo                     | 10 ++++++----
 .../constant_product_amm/src/lib.cairo                 |  2 ++
 .../constant_product_amm/src/tests.cairo               |  6 +++---
 4 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/listings/ch02-applications/constant_product_amm/Scarb.toml b/listings/ch02-applications/constant_product_amm/Scarb.toml
index 840d36ec..94c4c902 100644
--- a/listings/ch02-applications/constant_product_amm/Scarb.toml
+++ b/listings/ch02-applications/constant_product_amm/Scarb.toml
@@ -3,7 +3,7 @@ name = "constant_product_amm"
 version = "0.1.0"
 
 [dependencies]
-starknet = ">=2.2.0"
+starknet = ">=2.3.0-rc0"
 openzeppelin = { git = "https://github.com/OpenZeppelin/cairo-contracts.git", tag = "v0.7.0" }
 
 [[target.starknet-contract]]
diff --git a/listings/ch02-applications/constant_product_amm/src/constant_product_amm.cairo b/listings/ch02-applications/constant_product_amm/src/constant_product_amm.cairo
index 0916b864..a90efbc8 100644
--- a/listings/ch02-applications/constant_product_amm/src/constant_product_amm.cairo
+++ b/listings/ch02-applications/constant_product_amm/src/constant_product_amm.cairo
@@ -21,11 +21,14 @@ mod ConstantProductAmm {
         reserve0: u256,
         reserve1: u256,
         total_supply: u256,
-        balance_of: LegacyMap::<ContractAddress, u256>
+        balance_of: LegacyMap::<ContractAddress, u256>,
+        fee: u256,
     }
 
     #[constructor]
-    fn constructor(ref self: ContractState, token0: ContractAddress, token1: ContractAddress) {
+    fn constructor(ref self: ContractState, token0: ContractAddress, token1: ContractAddress, fee: u256) {
+        assert(fee <= 1000, 'fee > 1000')
+        self.fee.write(fee);
         self.token0.write(IERC20Dispatcher { contract_address: token0 });
         self.token1.write(IERC20Dispatcher { contract_address: token1 });
     }
@@ -98,9 +101,8 @@ mod ConstantProductAmm {
             // y - xy / (x + dx) = dy
             // (yx + ydx - xy) / (x + dx) = dy
             // ydx / (x + dx) = dy
-            // 0.3% fee
 
-            let amount_in_with_fee = (amount_in * 997) / 1000;
+            let amount_in_with_fee = (amount_in * (1000 - fee)) / 1000;
             let amount_out = (reserve_out * amount_in_with_fee) / (reserve_in + amount_in_with_fee);
 
             token_out.transfer(caller, amount_out);
diff --git a/listings/ch02-applications/constant_product_amm/src/lib.cairo b/listings/ch02-applications/constant_product_amm/src/lib.cairo
index 78295f2f..d538d2c7 100644
--- a/listings/ch02-applications/constant_product_amm/src/lib.cairo
+++ b/listings/ch02-applications/constant_product_amm/src/lib.cairo
@@ -1,2 +1,4 @@
 mod constant_product_amm;
+
+#[cfg(test)]
 mod tests;
diff --git a/listings/ch02-applications/constant_product_amm/src/tests.cairo b/listings/ch02-applications/constant_product_amm/src/tests.cairo
index 7286e7f4..e0ae300e 100644
--- a/listings/ch02-applications/constant_product_amm/src/tests.cairo
+++ b/listings/ch02-applications/constant_product_amm/src/tests.cairo
@@ -1,4 +1,3 @@
-#[cfg(test)]
 mod tests {
     use core::traits::TryInto;
     use openzeppelin::token::erc20::{
@@ -17,8 +16,6 @@ mod tests {
     use starknet::testing::set_contract_address;
     use starknet::class_hash::Felt252TryIntoClassHash;
 
-    use debug::PrintTrait;
-
     const BANK: felt252 = 0x123;
     const INITIAL_SUPPLY: u256 = 10_000;
 
@@ -51,6 +48,9 @@ mod tests {
         calldata.append_serde(token0_address);
         calldata.append_serde(token1_address);
 
+        // 0.3% fee
+        calldata.append_serde(3)
+
         let contract_address = utils::deploy(ConstantProductAmm::TEST_CLASS_HASH, calldata);
         Deployment { contract: IConstantProductAmmDispatcher { contract_address }, token0, token1 }
     }