Trim the Usd and Price precision only before sending to the UI feed

Create newtypes for Price and Usd that are sent to the UI with 2 digits precision.

Store and send higher precision prices between maker and taker; currently 24
digits, it can be changed with one constant.

Round percents visible in the UI to single digit.

daemon/src/model.rs

@@ -25,7 +25,7 @@ pub enum Error {
     NegativePrice,
 }
 
-#[derive(Debug, Copy, Clone, PartialEq, PartialOrd)]
+#[derive(Debug, Copy, Clone, PartialEq, PartialOrd, Serialize, Deserialize)]
 pub struct Usd(Decimal);
 
 impl Usd {
@@ -40,6 +40,11 @@ impl Usd {
     pub fn try_into_f64(&self) -> Result<f64> {
         self.0.to_f64().context("Could not fit decimal into f64")
     }
+
+    #[must_use]
+    pub fn into_decimal(self) -> Decimal {
+        self.0
+    }
 }
 
 impl fmt::Display for Usd {
@@ -48,26 +53,6 @@ impl fmt::Display for Usd {
     }
 }
 
-impl Serialize for Usd {
-    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-    where
-        S: serde::Serializer,
-    {
-        <Decimal as Serialize>::serialize(&self.0.round_dp(2), serializer)
-    }
-}
-
-impl<'de> Deserialize<'de> for Usd {
-    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
-    where
-        D: serde::Deserializer<'de>,
-    {
-        let dec = <Decimal as Deserialize>::deserialize(deserializer)?.round_dp(2);
-
-        Ok(Usd(dec))
-    }
-}
-
 impl str::FromStr for Usd {
     type Err = anyhow::Error;
 
@@ -77,7 +62,7 @@ impl str::FromStr for Usd {
     }
 }
 
-#[derive(Debug, Copy, Clone, PartialEq, PartialOrd)]
+#[derive(Debug, Copy, Clone, PartialEq, PartialOrd, Serialize, Deserialize)]
 pub struct Price(Decimal);
 
 impl Price {
@@ -100,25 +85,10 @@ impl Price {
     pub fn try_into_f64(&self) -> Result<f64> {
         self.0.to_f64().context("Could not fit decimal into f64")
     }
-}
-
-impl Serialize for Price {
-    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-    where
-        S: serde::Serializer,
-    {
-        <Decimal as Serialize>::serialize(&self.0.round_dp(2), serializer)
-    }
-}
-
-impl<'de> Deserialize<'de> for Price {
-    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
-    where
-        D: serde::Deserializer<'de>,
-    {
-        let dec = <Decimal as Deserialize>::deserialize(deserializer)?.round_dp(2);
 
-        Ok(Price(dec))
+    #[must_use]
+    pub fn into_decimal(self) -> Decimal {
+        self.0
     }
 }
 
@@ -137,7 +107,7 @@ impl str::FromStr for Price {
     }
 }
 
-#[derive(Debug, Copy, Clone, PartialEq, PartialOrd)]
+#[derive(Debug, Copy, Clone, PartialEq, PartialOrd, Serialize, Deserialize)]
 pub struct InversePrice(Decimal);
 
 impl InversePrice {
@@ -162,26 +132,6 @@ impl InversePrice {
     }
 }
 
-impl Serialize for InversePrice {
-    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-    where
-        S: serde::Serializer,
-    {
-        <Decimal as Serialize>::serialize(&self.0.round_dp(2), serializer)
-    }
-}
-
-impl<'de> Deserialize<'de> for InversePrice {
-    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
-    where
-        D: serde::Deserializer<'de>,
-    {
-        let dec = <Decimal as Deserialize>::deserialize(deserializer)?.round_dp(2);
-
-        Ok(InversePrice(dec))
-    }
-}
-
 #[derive(Debug, Copy, Clone, Serialize, Deserialize, PartialEq, sqlx::Type)]
 pub struct Leverage(u8);
 
@@ -400,32 +350,19 @@ impl Div<Leverage> for Leverage {
     }
 }
 
-#[derive(Debug, Copy, Clone, PartialEq)]
+#[derive(Debug, Copy, Clone, PartialEq, Serialize, Deserialize)]
 pub struct Percent(Decimal);
 
-impl fmt::Display for Percent {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        self.0.round_dp(2).fmt(f)
+impl Percent {
+    #[must_use]
+    pub fn round_dp(self, digits: u32) -> Self {
+        Self(self.0.round_dp(digits))
     }
 }
 
-impl Serialize for Percent {
-    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-    where
-        S: serde::Serializer,
-    {
-        <Decimal as Serialize>::serialize(&self.0.round_dp(2), serializer)
-    }
-}
-
-impl<'de> Deserialize<'de> for Percent {
-    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
-    where
-        D: serde::Deserializer<'de>,
-    {
-        let dec = <Decimal as Deserialize>::deserialize(deserializer)?.round_dp(2);
-
-        Ok(Percent(dec))
+impl fmt::Display for Percent {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        self.0.round_dp(2).fmt(f)
     }
 }
 
@@ -587,25 +524,10 @@ impl Timestamp {
 #[cfg(test)]
 mod tests {
     use rust_decimal_macros::dec;
-    use serde_test::{assert_de_tokens, assert_ser_tokens, Token};
     use time::macros::datetime;
 
     use super::*;
 
-    #[test]
-    fn usd_serializes_with_only_cents() {
-        let usd = Usd::new(dec!(1000.12345));
-
-        assert_ser_tokens(&usd, &[Token::Str("1000.12")]);
-    }
-
-    #[test]
-    fn usd_deserializes_trims_precision() {
-        let usd = Usd::new(dec!(1000.12));
-
-        assert_de_tokens(&usd, &[Token::Str("1000.12345")]);
-    }
-
     #[test]
     fn to_olivia_url() {
         let url = BitMexPriceEventId::with_20_digits(datetime!(2021-09-23 10:00:00).assume_utc())

daemon/src/to_sse_event.rs

@@ -1,7 +1,7 @@
 use crate::model::cfd::{
     Dlc, OrderId, Payout, Role, SettlementKind, UpdateCfdProposal, UpdateCfdProposals,
 };
-use crate::model::{Leverage, Position, Price, Timestamp, TradingPair, Usd};
+use crate::model::{Leverage, Position, Timestamp, TradingPair};
 use crate::{bitmex_price_feed, model};
 use bdk::bitcoin::{Amount, Network, SignedAmount, Txid};
 use rocket::request::FromParam;
@@ -12,6 +12,64 @@ use std::convert::TryInto;
 use time::OffsetDateTime;
 use tokio::sync::watch;
 
+#[derive(Debug, Clone)]
+pub struct Usd {
+    inner: model::Usd,
+}
+
+impl Usd {
+    fn new(usd: model::Usd) -> Self {
+        Self {
+            inner: model::Usd::new(usd.into_decimal().round_dp(2)),
+        }
+    }
+}
+
+impl From<model::Usd> for Usd {
+    fn from(usd: model::Usd) -> Self {
+        Self::new(usd)
+    }
+}
+
+impl Serialize for Usd {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        <Decimal as Serialize>::serialize(&self.inner.into_decimal(), serializer)
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct Price {
+    inner: model::Price,
+}
+
+impl Price {
+    fn new(price: model::Price) -> Self {
+        Self {
+            inner: model::Price::new(price.into_decimal().round_dp(2)).expect(
+                "rounding a valid price to 2 decimal places should still result in a valid price",
+            ),
+        }
+    }
+}
+
+impl From<model::Price> for Price {
+    fn from(price: model::Price) -> Self {
+        Self::new(price)
+    }
+}
+
+impl Serialize for Price {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        <Decimal as Serialize>::serialize(&self.inner.into_decimal(), serializer)
+    }
+}
+
 #[derive(Debug, Clone, Serialize)]
 pub struct Cfd {
     pub order_id: OrderId,
@@ -183,7 +241,7 @@ pub trait ToSseEvent {
 /// by UI
 pub struct CfdsWithAuxData {
     pub cfds: Vec<model::cfd::Cfd>,
-    pub current_price: Price,
+    pub current_price: model::Price,
     pub pending_proposals: UpdateCfdProposals,
     pub network: Network,
 }
@@ -242,14 +300,14 @@ impl ToSseEvent for CfdsWithAuxData {
 
                 Cfd {
                     order_id: cfd.order.id,
-                    initial_price: cfd.order.price,
+                    initial_price: cfd.order.price.into(),
                     leverage: cfd.order.leverage,
                     trading_pair: cfd.order.trading_pair.clone(),
                     position: cfd.position(),
-                    liquidation_price: cfd.order.liquidation_price,
-                    quantity_usd: cfd.quantity_usd,
+                    liquidation_price: cfd.order.liquidation_price.into(),
+                    quantity_usd: cfd.quantity_usd.into(),
                     profit_btc,
-                    profit_in_percent: profit_in_percent.to_string(),
+                    profit_in_percent: profit_in_percent.round_dp(1).to_string(),
                     state: state.clone(),
                     actions: available_actions(state, cfd.role()),
                     state_transition_timestamp: cfd.state.get_transition_timestamp().seconds(),
@@ -274,11 +332,11 @@ impl ToSseEvent for Option<model::cfd::Order> {
             id: order.id,
             trading_pair: order.trading_pair,
             position: order.position,
-            price: order.price,
-            min_quantity: order.min_quantity,
-            max_quantity: order.max_quantity,
+            price: order.price.into(),
+            min_quantity: order.min_quantity.into(),
+            max_quantity: order.max_quantity.into(),
             leverage: order.leverage,
-            liquidation_price: order.liquidation_price,
+            liquidation_price: order.liquidation_price.into(),
             creation_timestamp: order.creation_timestamp,
             settlement_time_interval_in_secs: order
                 .settlement_time_interval_hours
@@ -417,8 +475,8 @@ pub struct Quote {
 impl ToSseEvent for bitmex_price_feed::Quote {
     fn to_sse_event(&self) -> Event {
         let quote = Quote {
-            bid: self.bid,
-            ask: self.ask,
+            bid: self.bid.into(),
+            ask: self.ask.into(),
             last_updated_at: self.timestamp,
         };
         Event::json(&quote).event("quote")
@@ -457,6 +515,9 @@ fn available_actions(state: CfdState, role: Role) -> Vec<CfdAction> {
 mod tests {
     use super::*;
 
+    use rust_decimal_macros::dec;
+    use serde_test::{assert_ser_tokens, Token};
+
     #[test]
     fn state_snapshot_test() {
         // Make sure to update the UI after changing this test!
@@ -484,4 +545,18 @@ mod tests {
         let json = serde_json::to_string(&CfdState::SetupFailed).unwrap();
         assert_eq!(json, "\"SetupFailed\"");
     }
+
+    #[test]
+    fn usd_serializes_with_only_cents() {
+        let usd = Usd::new(model::Usd::new(dec!(1000.12345)));
+
+        assert_ser_tokens(&usd, &[Token::Str("1000.12")]);
+    }
+
+    #[test]
+    fn price_serializes_with_only_cents() {
+        let price = Price::new(model::Price::new(dec!(1000.12345)).unwrap());
+
+        assert_ser_tokens(&price, &[Token::Str("1000.12")]);
+    }
 }