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 {

    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;
        totalFinalCost = 0 ;
        totalQuantity = 0;
        totalDiscountValue = 0;
        totalInvalidLines = 0 ;
    }

    public void processFile() throws FileNotFoundException {
        File file = new File(ordersFilePath);
        Scanner in = new Scanner(file);

        while (in.hasNextLine()){
            String line = in.nextLine();
            String[] lineArray = line.split(",");
            int productId;
            int quantity;
            int discountPercent;

            try {
                 productId = Integer.parseInt(lineArray[0]);
            }catch (NumberFormatException e){
                totalInvalidLines += 1;
                continue;
            }
            if (productId <= 0 )  {
                totalInvalidLines +=1;
                continue;
            }
            try {
                quantity = Integer.parseInt(lineArray[1]);

            }catch (NumberFormatException e){
                totalInvalidLines += 1;
                continue;
            }
            if (quantity <= 0  )  {
                totalInvalidLines +=1;
                continue;
            }
            try {
                discountPercent = Integer.parseInt(lineArray[2]);

            }catch (NumberFormatException e){
                totalInvalidLines +=1 ;
                continue;
            }
            if (discountPercent < 0 || discountPercent> 99 )  {
                totalInvalidLines +=1;
                continue;
            }
            boolean productIdExist = false;
            Product pro = null ;
            for (Product product : productList) {
                if (product.getProductID() == productId) {
                    pro = product;
                    productIdExist = true;
                    break;
                }
            }
            if (!productIdExist){
                totalInvalidLines += 1 ;
                continue;
            }

            double subtotal = quantity * pro.getPrice();
            double discountValue = subtotal * ((double) discountPercent / 100);
            double finalCost = subtotal - discountValue;


            totalQuantity += quantity;
            totalFinalCost += finalCost;
            totalDiscountValue += discountValue;
            }
            in.close();
        }


    public void saveReport() throws IOException {
        String report = "";
        report += ("========= SALES REPORT ========="+"\n");
        report += ("Total Quantity Sold: "+totalQuantity+"\n");
        report += ("Total Final Cost: $"+totalFinalCost+"\n");
        report += ("Total Discount Value: $"+totalDiscountValue+"\n");
        report += ("Invalid Rows: "+totalInvalidLines+"\n");
        report += ("================================"+"\n");
        File file = new File("report.txt");
        FileWriter fileWriter = new FileWriter(file);
        fileWriter.write(report);
        fileWriter.close();
    }
}