import java.util.List;

import java.io.*;
import java.util.Scanner;
import java.io.IOException;
import java.io.FileWriter;
import java.io.InputStream;
import java.util.List;

public class ReportGenerator {

    private final String ordersFilePath;
    private final List<Product> productList;

    private double totalFinalCost;
    private int totalQuantity;
    private double totalDiscountValue;
    private int totalInvalidLines;

    public ReportGenerator(String ordersFilePath, List<Product> productList) {
        this.ordersFilePath = ordersFilePath;
        this.productList = productList;
    }

    public void processFile() {
        // TODO:
        InputStream input = ReportGenerator.class
                .getClassLoader()
                .getResourceAsStream(ordersFilePath);
        if (input == null) {
            System.out.println("Order file not found");
            return;
        }
        Scanner scanner = new Scanner(input);
        while (scanner.hasNextLine()) {
            String line = scanner.nextLine();

            try {
                String[] parts = line.split(",");
                int productId = Integer.parseInt(parts[0]);
                int quantity = Integer.parseInt(parts[1]);
                int discountPercent = Integer.parseInt(parts[2]);
                if (productId <= 0 ||
                        quantity <= 0 ||
                        discountPercent < 0 ||
                        discountPercent > 99) {

                    totalInvalidLines++;
                    continue;
                }
                Product foundProduct = null;
                int i = 0;
                while (i < productList.size()) {
                    Product product = productList.get(i);
                    if (product.getProductID() == productId) {
                        foundProduct = product;
                        break;
                    }
                    i++;
                }

                if (foundProduct == null) {
                    totalInvalidLines++;
                    continue;
                }
                double subtotal = quantity * foundProduct.getPrice();
                double discountValue = subtotal * discountPercent / 100.0;
                double finalCost = subtotal - discountValue;
                totalQuantity += quantity;
                totalFinalCost += finalCost;
                totalDiscountValue += discountValue;
            } catch (NumberFormatException e) {
                totalInvalidLines++;

            }
        }

        scanner.close();
    }
    public void saveReport()
    {
        // TODO:
        String report =
                "======= SALES REPORT ========\n" +
                        "Total Quantity Sold: " + totalQuantity + "\n" +
                        "Total Final Cost: $" + totalFinalCost + "\n" +
                        "Total Discount Value: $" + totalDiscountValue + "\n" +
                        "Invalid Rows: " + totalInvalidLines + "\n" +
                        "================";
        try {
            FileWriter writer = new FileWriter("report.txt");
            writer.write(report);
            writer.close();
        } catch (IOException e) {
            System.out.println("Error writing report file");
        }
    }
}