fn: added close_position to broker.rs

src/broker.rs

@@ -18,6 +18,7 @@ impl Broker {
 
     pub fn buy(&mut self, price: f64, lot_size: f64, timestamp: i64) {      // needs to modify the broker with new position. (.push works with the Vec::)
         self.positions.push(Position {
+            id: 0,
             entry_price: price,
             lot_size,
             is_long: true,
@@ -27,6 +28,7 @@ impl Broker {
 
     pub fn sell(&mut self, price: f64, lot_size: f64, timestamp: i64) {     // needs to modify the broker with new position. (.push works with the Vec::)
         self.positions.push(Position {
+            id : 0,
             entry_price: price,
             lot_size,
             is_long: false,
@@ -34,6 +36,29 @@ impl Broker {
         });
     }
 
+    pub fn close_position (&mut self, id: u64, price:f64, timestamp:i64) {
+        if let Some(index) = self.positions.iter().position(|p| p.id == id) {
+            let position = self.positions.remove(index);
+
+            let pnl = if position.is_long {
+                (price - position.entry_price) * position.lot_size
+            } else {
+                (position.entry_price - price) * position.lot_size
+            };
+
+            self.cash += pnl;
+            self.trade_history.push(Trade {
+                entry_price: position.entry_price,
+                lot_size: position.lot_size,
+                is_long: position.is_long,
+                pnl,
+                entry_timestamp: position.entry_timestamp,
+                exit_timestamp: timestamp,
+                exit_price: price
+            });            
+        }
+    }
+
     pub fn close_all (&mut self, price:f64, timestamp: i64) {       // Instead of .push it uses drain to calculate the close all positions
         for position in self.positions.drain(..) {
             let pnl = if position.is_long {

src/types.rs

@@ -10,6 +10,7 @@ pub struct Bar {            // Initialises the interface for the bar
 
 #[derive(Debug, Clone)]
 pub struct Position {       // this is for the trading position
+    pub id: u64,
     pub entry_price: f64,
     pub lot_size: f64,
     pub is_long: bool,