Pre simplification changes

market-contract/Forc.lock

@@ -2,10 +2,18 @@
 name = "core"
 source = "path+from-root-566CA1D5F8BEAFBF"
 
+[[package]]
+name = "fixed_point"
+source = "git+https://github.com/FuelLabs/sway-libs?tag=v0.18.0#8d196e9379463d4596ac582a20a84ed52ff58c69"
+dependencies = ["std"]
+
 [[package]]
 name = "market-contract"
 source = "member"
-dependencies = ["std"]
+dependencies = [
+    "fixed_point",
+    "std",
+]
 
 [[package]]
 name = "std"

market-contract/Forc.toml

@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "market-contract"
 
 [dependencies]
+fixed_point = { git = "https://github.com/FuelLabs/sway-libs", tag = "v0.18.0" }

market-contract/src/main.sw

@@ -340,6 +340,7 @@ impl Market for Contract {
                 alice_account_delta,
                 bob_order_amount_decrease,
                 bob_account_delta,
+                bob_unlock_amount,
             ) = trade.unwrap();
 
             // Update the order quantities with the amounts that can be traded
@@ -364,7 +365,7 @@ impl Market for Contract {
             alice_account.locked.debit(alice_account_delta, asset_1);
             alice_account.liquid.credit(bob_account_delta, asset_2);
 
-            bob_account.locked.debit(bob_account_delta, asset_2);
+            bob_account.locked.debit(bob_account_delta, asset_2); //todo
             bob_account.liquid.credit(alice_account_delta, asset_1);
 
             // Save bob's account because his order is finished
@@ -376,6 +377,15 @@ impl Market for Contract {
                 require(storage.orders.remove(bob_id), OrderError::FailedToRemove);
                 remove_user_order(bob.owner, bob_id);
 
+                // Edge case to rescue funds when bob's price was greater and they reduced alice
+                // amount to 0
+                // Ex. Alice sell 1 BTC @ 70k, Bob buy 1 BTC @ 71k. Rescue 1k worth of locked funds
+                if bob_unlock_amount != 0 {
+                    bob_account.locked.debit(bob_unlock_amount, asset_2); //todo
+                    bob_account.liquid.credit(bob_unlock_amount, asset_2);
+                    storage.account.insert(bob.owner, bob_account);
+                }
+
                 // TODO: Emit event
                 // log(TradeEvent {
                 //     order_id: bob_id,

market-contract/src/math.sw

@@ -4,6 +4,7 @@ use ::data_structures::{asset_type::AssetType, order::Order, order_type::OrderTy
 use ::errors::TradeError;
 
 use std::u128::U128;
+use fixed_point::ufp128::UFP128;
 
 impl u64 {
     pub fn mul_div(self, mul_to: u64, div_to: u64) -> u64 {
@@ -26,9 +27,9 @@ impl u64 {
 }
 
 fn calc_amount(buy_amount: u64, buy_price: u64, sell_price: u64) -> u64 {
-    let price_ratio = U128::from((0, buy_price)) / U128::from((0, sell_price));
-    let amount = price_ratio * U128::from((0, buy_amount));
-    amount.as_u64().unwrap()
+    let price_ratio = UFP128::from((0, buy_price)) / UFP128::from((0, sell_price));
+    let amount = price_ratio * UFP128::from((0, buy_amount));
+    U128::from(amount.into()).as_u64().unwrap()
 }
 
 pub fn attempt_trade(
@@ -37,7 +38,7 @@ pub fn attempt_trade(
     base_asset_decimals: u32,
     quote_asset_decimals: u32,
     price_decimals: u32,
-) -> Result<(u64, u64, u64, u64), TradeError> {
+) -> Result<(u64, u64, u64, u64, u64), TradeError> {
     // In this function:   
     //  Decrease the order size for alice and bob until they are 0 == their orders are fulfilled
     //  Track the amount that each account has to transfer for their trade
@@ -50,9 +51,10 @@ pub fn attempt_trade(
         mut seller_account_delta,
         mut buyer_order_amount_decrease,
         mut buyer_account_delta,
+        mut bob_unlock_amount,
     ) = match alice.order_type {
-        OrderType::Sell => (alice, bob, 0, 0, 0, 0),
-        OrderType::Buy => (bob, alice, 0, 0, 0, 0),
+        OrderType::Sell => (alice, bob, 0, 0, 0, 0, 0),
+        OrderType::Buy => (bob, alice, 0, 0, 0, 0, 0),
     };
 
     if buyer.price < seller.price {
@@ -73,11 +75,12 @@ pub fn attempt_trade(
                     price_decimals,
                     quote_asset_decimals,
                 );
+                bob_unlock_amount = buyer.price - seller.price;
             } else if buyer_buy_amount < seller.amount {
                 seller_order_amount_decrease = buyer_buy_amount;
-                buyer_order_amount_decrease = buyer_buy_amount;
+                buyer_order_amount_decrease = buyer.amount;
                 buyer_account_delta = base_to_quote_amount(
-                    buyer_order_amount_decrease,
+                    seller_order_amount_decrease,
                     base_asset_decimals,
                     buyer.price,
                     price_decimals,
@@ -110,6 +113,7 @@ pub fn attempt_trade(
                     price_decimals,
                     quote_asset_decimals,
                 );
+                bob_unlock_amount = buyer.price - seller.price;
             } else if buyer_buy_amount < seller.amount {
                 seller_order_amount_decrease = buyer_buy_amount;
                 buyer_order_amount_decrease = buyer_buy_amount;
@@ -143,12 +147,14 @@ pub fn attempt_trade(
             seller_account_delta,
             buyer_order_amount_decrease,
             buyer_account_delta,
+            bob_unlock_amount,
         )),
         OrderType::Buy => Result::Ok((
             buyer_order_amount_decrease,
             buyer_account_delta,
             seller_order_amount_decrease,
             seller_account_delta,
+            bob_unlock_amount,
         )),
     }
 }