implement ReportGenerator

src/main/java/ReportGenerator.java

@@ -1,4 +1,9 @@
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileWriter;
+import java.io.IOException;
 import java.util.List;
+import java.util.Scanner;
 
 public class ReportGenerator {
 
@@ -17,67 +22,83 @@ 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
+        File file = new File(ordersFilePath);
+        if(!file.exists())
+        {
+            System.err.println("File is not found!");
+            return;
+        }
+        try(Scanner scanner = new Scanner(file))
+        {
+            while (scanner.hasNextLine())
+            {
+                String line = scanner.nextLine();
+                if(line.isBlank()) continue;
+                try
+                {
+                    String[] parts = line.split(",");
+                    int productId = Integer.parseInt(parts[0].trim());
+                    int quantity = Integer.parseInt(parts[1].trim());
+                    int discountPercent = Integer.parseInt(parts[2].trim());
+
+                    if( quantity<=0 || discountPercent < 0 || discountPercent >99)
+                    {
+                        throw new Exception("invalid value!");
+                    }
+
+                    Product product = null;
+                    for (Product p : productList)
+                    {
+                        if(p.getProductID() == productId)
+                        {
+                            product = p;
+                            break;
+                        }
+                    }
+                    if(product == null)
+                    {
+                        throw new Exception("Product not found");
+                    }
+
+                    double subtotal = quantity * product.getPrice();
+                    double discountValue = subtotal * discountPercent / 100;
+                    double finalCost = subtotal - discountValue;
+
+                    totalQuantity += quantity;
+                    totalFinalCost += finalCost;
+                    totalDiscountValue += discountValue;
+
+
+                }
+                catch (Exception e)
+                {
+                    totalInvalidLines++;
+                }
+            }
+        }
+        catch (FileNotFoundException e)
+        {
+            System.out.println(e.getMessage());
+        }
     }
 
-    public void saveReport()
-    {
-        // TODO:
-        // 1. Build a formatted report string
-        // 2. Include:
-        //      - total quantity
-        //      - total final cost
-        //      - total discount value
-        //      - total invalid lines
-        // 3. Create/open output report file (name it report.txt)
-        // 4. Write report string into file
-        // 5. Handle file writing exceptions
-        // 6. Close writer resources
+    public void saveReport() throws IOException {
+        String report = "========= SALES REPORT =========\n" +
+                "Total Quantity: " + totalQuantity + "\n" +
+                "Total Final Cost: " + totalFinalCost + "\n" +
+                "Total Discount Value: " + totalDiscountValue + "\n" +
+                "Invalid Lines: " + totalInvalidLines + "\n" +
+                "================================";
 
-        /* Example Structure
-        ========= SALES REPORT =========
-        Total Quantity Sold: 42
-        Total Final Cost: $1520.75
-        Total Discount Value: $230.50
-        Invalid Rows: 3
-        ================================
-        */
+        try
+        {
+            FileWriter writer = new FileWriter("report.txt");
+            writer.write(report);
+            writer.close();
+        }
+        catch (IOException e)
+        {
+            System.err.println("ERROR!");
+        }
     }
 }