Complete code

src/main/java/Main.java

@@ -15,15 +15,18 @@ public class Main {
         }
         Scanner scanner = new Scanner(input);
 
-        // TODO:
-        // - Read each line from products.csv
-        // - For each line, parse productId, name, and price
-        // - The format of the file is like this:
-        //      [productId],[name],[price]
-        // - Store Product objects in the productCatalog ArrayList
+        while(scanner.hasNextLine()){
+            String[] parts = scanner.nextLine().split(",");
 
-        // NOTE
-        // - The data in products.csv is guaranteed to be valid.
+            int productID = Integer.parseInt(parts[0]);
+            String productName = parts[1];
+            double productPrice = Double.parseDouble(parts[2]);
+
+            Product product = new Product(productID, productName, productPrice);
+            productCatalog.add(product);
+        }
+
+        scanner.close();
     }
 
     public static void main(String[] args)

src/main/java/ReportGenerator.java

@@ -1,4 +1,10 @@
+import java.io.FileWriter;
+import java.io.IOException;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.rmi.ServerError;
 import java.util.List;
+import java.util.Scanner;
 
 public class ReportGenerator {
 
@@ -17,48 +23,90 @@ public class ReportGenerator {
 
     public void processFile()
     {
-        // TODO:
-        // 1. Open the order details CSV file
-        // 2. Read the file line by line
-        // 3. Split each line using comma delimiter
-        //      (each line is guaranteed to contain exactly two commas)
-        // 4. Each line contains exactly 3 values in the format:
-        //      [productId],[quantity],[discountPercent]
-        // 5. Attempt to convert values:
-        //      - productId -> int
-        //      - quantity -> int
-        //      - discountPercent -> int
-        //    NOTE:
-        //      - quantity and discountPercent may contain invalid characters
-        //        (e.g., letters instead of numbers).
-        //      - If parsing any value fails (NumberFormatException),
-        //        the entire line must be considered invalid.
-        //      - Use try-catch blocks and exception handling to safely
-        //        handle parsing and validation errors without stopping
-        //        the processing of the remaining lines.
-        // 6. Validate parsed values:
-        //      - productId must be greater than 0
-        //      - quantity must be greater than 0
-        //      - discountPercent must be between 0 and 99 inclusive
-        // 7. Look for a Product in productList that matches productId
-        // 8. If no Product with that ID exists in the catalog,
-        //      the entire line is considered invalid
-        // 9. If all values are valid and the product exists, calculate:
-        //      subtotal = quantity * product price
-        //      discountValue = subtotal * discountPercent / 100
-        //      finalCost = subtotal - discountValue
-        // 10. Update report totals:
-        //      - totalQuantity += quantity
-        //      - totalFinalCost += finalCost
-        //      - totalDiscountValue += discountValue
-        // 11. If any parsing error, validation failure, or missing product occurs:
-        //      - increment totalInvalidLines
-        //      - skip the line and continue processing the next line
-        // 12. Close all file resources
+
+        Path path = Paths.get(ordersFilePath);
+        try {
+            Scanner scanner = new Scanner(path);
+
+            while(scanner.hasNextLine()){
+                String[] parts = scanner.nextLine().split(",");
+                int productID, quantity, discount;
+
+                // product ID should be a valid integer
+                try{
+                    productID = Integer.parseInt(parts[0]);
+                    if(productID <= 0){
+                        totalInvalidLines++;
+                        continue;
+                    }
+                } catch(NumberFormatException e){
+                    totalInvalidLines++;
+                    continue;
+                }
+
+                // quantity should be a valid integer and not less than 1
+                try{
+                    quantity = Integer.parseInt(parts[1]);
+                    if(quantity <= 0){
+                        totalInvalidLines++;
+                        continue;
+                    }
+                } catch(NumberFormatException e){
+                    totalInvalidLines++;
+                    continue;
+                }
+
+                // discount should be a valid integer and between 0 and 99
+                try{
+                    discount = Integer.parseInt(parts[2]);
+                    if(discount < 0 || discount > 99){
+                        totalInvalidLines++;
+                        continue;
+                    }
+                } catch(NumberFormatException e){
+                    totalInvalidLines++;
+                    continue;
+                }
+
+                try{
+                    Product product = productList.get(productID - 1);
+
+                    double subTotal = quantity * product.getPrice();
+                    double discountValue = subTotal * discount / 100;
+                    double finalCost = subTotal - discountValue;
+                    totalQuantity += quantity;
+                    totalFinalCost += finalCost;
+                    totalDiscountValue += discountValue;
+                } catch(IndexOutOfBoundsException e){ // product id should be in product list ids
+                    totalDiscountValue++;
+                    continue;
+                }
+
+            }
+
+            scanner.close();
+        }
+        catch (IOException e){
+            System.out.println("Cannot read order details file.");
+        }
+
     }
 
     public void saveReport()
     {
+        try{
+            FileWriter file = new FileWriter("report.txt");
+            String output = "========= SALES REPORT =========\n" +
+                    "Total Quantity Sold: " + totalQuantity + "\n" +
+                    "Total Final Cost: $" + totalFinalCost + "\n" +
+                    "Total Discount Value: " + totalDiscountValue + "\n" +
+                    "Invalid Rows: " + totalInvalidLines + "\n" +
+                    "================================";
+            file.write(output);
+            file.close();
+        } catch(IOException e){
+            System.out.println(e.getMessage());
+        }
         // TODO:
         // 1. Build a formatted report string
         // 2. Include: