Feat: Adding buy and sell buttons on stocks tab

src/main/java/millions/controller/GameController.java

@@ -1,18 +1,22 @@
 package millions.controller;
 
-
 import java.math.BigDecimal;
+import java.math.RoundingMode;
 import java.nio.file.Path;
+import java.util.ArrayList;
 import java.util.Comparator;
 import java.util.List;
+import java.math.RoundingMode;
 import java.util.stream.Collectors;
-
 import millions.controller.fileIO.CSV.CSVFileHandler;
 import millions.controller.fileIO.InvalidFormatException;
 import millions.controller.fileIO.UncheckedFileNotFoundException;
 import millions.model.Exchange;
 import millions.model.Player;
+import millions.model.Share;
 import millions.model.Stock;
+import millions.model.Transaction;
+import millions.model.calculators.PurchaseCalculator;
 
 /** Controls game initialization. */
 public class GameController {
@@ -35,9 +39,9 @@ public void startGame(
 
       player = new Player(name, startingMoney);
 
-    } catch(UncheckedFileNotFoundException e) {
+    } catch (UncheckedFileNotFoundException e) {
       throw new UncheckedFileNotFoundException(e.getMessage());
-    } catch(InvalidFormatException e) {
+    } catch (InvalidFormatException e) {
       throw new InvalidFormatException(e.getMessage());
     }
   }
@@ -80,4 +84,56 @@ public List<Stock> searchStocks(String searchTerm) {
   public Stock getStock(String symbol) {
     return exchange.getStock(symbol);
   }
+
+  public Transaction buyStock(String symbol, BigDecimal quantity) {
+    if (quantity == null || quantity.compareTo(BigDecimal.ZERO) <= 0) {
+      throw new IllegalArgumentException("Quantity must be positive");
+    }
+    return exchange.buy(symbol, player, quantity);
+  }
+
+  public Transaction sellShare(Share share) {
+    if (share == null) {
+      throw new IllegalArgumentException("Share cannot be null");
+    }
+    return exchange.sell(share, player);
+  }
+
+  public List<Share> getOwnedShares(String symbol) {
+    return new ArrayList<>(player.getPortfolio().getShares(symbol));
+  }
+
+  public void advanceWeek() {
+    exchange.advance();
+  }
+
+  public BigDecimal getOwnedQuantity(String symbol) {
+    return player.getPortfolio().getShares(symbol).stream()
+        .map(Share::getQuantity)
+        .reduce(BigDecimal.ZERO, BigDecimal::add);
+  }
+
+  public int getMaxBuyableQuantity(String symbol) {
+    Stock stock = getStock(symbol);
+    if (stock == null || player == null) {
+      return 0;
+    }
+
+    BigDecimal money = player.getMoney();
+    BigDecimal price = stock.getSalesPrice();
+    if (price.compareTo(BigDecimal.ZERO) <= 0) {
+      return 0;
+    }
+
+    int upperBound = money.divide(price, 0, RoundingMode.FLOOR).intValue();
+    // Loop so we take care of comission/tax stuff
+    for (int quantity = upperBound; quantity >= 1; quantity--) {
+      Share share = new Share(stock, quantity, price);
+      BigDecimal total = new PurchaseCalculator(share).calculateTotal();
+      if (total.compareTo(money) <= 0) {
+        return quantity;
+      }
+    }
+    return 0;
+  }
 }