implement all TODOs

src/main/java/Main.java

@@ -14,7 +14,15 @@ public class Main {
             throw new IOException("products.csv not found");
         }
         Scanner scanner = new Scanner(input);
-
+        while(scanner.hasNextLine())
+        {
+            String line = scanner.nextLine();
+            String[] information = line.split(",");
+            int productId = Integer.parseInt(information[0].trim());
+            String productName = information[1].trim();
+            double price = Double.parseDouble(information[2].trim());
+            productCatalog.add(new Product(productId, productName, price));
+        }
         // TODO:
         // - Read each line from products.csv
         // - For each line, parse productId, name, and price

src/main/java/ReportGenerator.java

@@ -1,3 +1,7 @@
+import java.io.IOException;
+import java.lang.reflect.Field;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import java.util.List;
 
 public class ReportGenerator {
@@ -55,6 +59,63 @@ public class ReportGenerator {
         //      - increment totalInvalidLines
         //      - skip the line and continue processing the next line
         // 12. Close all file resources
+        Path path = Path.of(ordersFilePath);
+        try
+        {
+            List<String> lines = Files.readAllLines(path);
+            for(String line: lines)
+            {
+                String[] information = line.split(",");
+                int productId;
+                int quantity;
+                double discountPercent;
+                try
+                {
+                    productId = Integer.parseInt((information[0].trim()));
+                    quantity = Integer.parseInt(information[1].trim());
+                    discountPercent = Double.parseDouble(information[2].trim());
+                }
+                catch (NumberFormatException e)
+                {
+                    totalInvalidLines++;
+                    continue;
+                }
+                if((productId <= 0) || (quantity <= 0))
+                {
+                    totalInvalidLines++;
+                    continue;
+                }
+                else if((discountPercent <= 0) || (discountPercent > 99))
+                {
+                    totalInvalidLines++;
+                    continue;
+                }
+                boolean haveValidId = false;
+                for (Product product: productList)
+                {
+                    if(productId == product.getProductID())
+                    {
+                        haveValidId = true;
+                        double subtotal = quantity * product.getPrice();
+                        double discountValue = subtotal * discountPercent / 100;
+                        double finalCost = subtotal - discountValue;
+                        totalQuantity += quantity;
+                        totalFinalCost += finalCost;
+                        totalDiscountValue += discountValue;
+                        break;
+                    }
+                }
+                if(!haveValidId)
+                {
+                    totalInvalidLines++;
+                }
+            }
+        }
+        catch (IOException e)
+        {
+            throw new RuntimeException(e);
+        }
+
     }
 
     public void saveReport()
@@ -79,5 +140,24 @@ public class ReportGenerator {
         Invalid Rows: 3
         ================================
         */
+        String report = String.format(
+                "========= SALES REPORT =========\n" +
+                        "Total Quantity Sold: %d\n" +
+                        "Total Final Cost: $%.2f\n" +
+                        "Total Discount Value: $%.2f\n" +
+                        "Invalid Rows: %d\n" +
+                        "================================",
+                totalQuantity,
+                totalFinalCost,
+                totalDiscountValue,
+                totalInvalidLines
+        );
+
+        Path path = Path.of("report.txt");
+        try {
+            Files.write(path, List.of(report));
+        } catch (IOException e) {
+            System.out.println("Making report file failed!");
+        }
     }
 }