Program.cs

using InterestCalculator.Services;

namespace InterestCalculator;

class Program
{
    static void Main(string[] args)
    {
        Console.WriteLine("╔══════════════════════════════════════════════════════════════╗");
        Console.WriteLine("║           Interest Calculator - Borrowing Analysis           ║");
        Console.WriteLine("╚══════════════════════════════════════════════════════════════╝");
        Console.WriteLine();

        // Determine file paths
        var basePath = AppDomain.CurrentDomain.BaseDirectory;
        var borrowingsFile = Path.Combine(basePath, "borrowing.csv");
        var parametersFile = Path.Combine(basePath, "parameters.csv");
        var outputDirectory = Path.Combine(basePath, "output");

        // Allow command line overrides
        if (args.Length >= 1)
            borrowingsFile = args[0];
        if (args.Length >= 2)
            parametersFile = args[1];
        if (args.Length >= 3)
            outputDirectory = args[2];

        Console.WriteLine($"Borrowings file: {borrowingsFile}");
        Console.WriteLine($"Parameters file: {parametersFile}");
        Console.WriteLine($"Output directory: {outputDirectory}");
        Console.WriteLine();

        // Validate input files exist
        if (!File.Exists(borrowingsFile))
        {
            Console.WriteLine($"Error: Borrowings file not found: {borrowingsFile}");
            Console.WriteLine();
            Console.WriteLine("Please create a borrowing.csv file with the following format:");
            Console.WriteLine("amount,start_date,end_date,interest_rate,commission");
            Console.WriteLine("10000.00,2024-01-01,2024-12-31,0.05,0.01");
            Environment.Exit(1);
        }

        if (!File.Exists(parametersFile))
        {
            Console.WriteLine($"Error: Parameters file not found: {parametersFile}");
            Console.WriteLine();
            Console.WriteLine("Please create a parameters.csv file with the following format:");
            Console.WriteLine("interest_rate,commission,start_date,end_date");
            Console.WriteLine("0.05,0.01,2024-01-01,2024-06-30");
            Environment.Exit(1);
        }

        // Initialize services
        var csvReader = new CsvReaderService();
        var calculator = new InterestCalculatorService();
        var reportGenerator = new MarkdownGeneratorService();

        try
        {
            // Read input files
            Console.WriteLine("Reading borrowing data...");
            var borrowings = csvReader.ReadBorrowings(borrowingsFile);
            Console.WriteLine($"  Found {borrowings.Count} borrowing(s)");

            Console.WriteLine("Reading parameters data...");
            var parameters = csvReader.ReadParameters(parametersFile);
            Console.WriteLine($"  Found {parameters.Count} parameter period(s)");
            Console.WriteLine();

            if (borrowings.Count == 0)
            {
                Console.WriteLine("No borrowings to process. Exiting.");
                Environment.Exit(0);
            }

            // Process each borrowing
            Console.WriteLine("Processing borrowings...");
            Console.WriteLine(new string('─', 60));

            for (int i = 0; i < borrowings.Count; i++)
            {
                var borrowing = borrowings[i];
                var borrowingNumber = i + 1;

                Console.WriteLine($"\nBorrowing {borrowingNumber}:");
                Console.WriteLine($"  Amount: {borrowing.Amount:N2}");
                Console.WriteLine($"  Period: {borrowing.StartDate:yyyy-MM-dd} to {borrowing.EndDate:yyyy-MM-dd}");

                // Calculate
                var calculation = calculator.Calculate(borrowing, parameters, borrowingNumber);

                Console.WriteLine($"  Periods: {calculation.Periods.Count}");
                Console.WriteLine($"  Total Interest: {calculation.TotalInterest:N2}");
                Console.WriteLine($"  Total Commission: {calculation.TotalCommission:N2}");
                Console.WriteLine($"  Total Cost: {calculation.TotalCost:N2}");
                Console.WriteLine($"  Final Amount: {calculation.FinalAmount:N2}");

                // Generate report
                var reportPath = reportGenerator.SaveReport(calculation, outputDirectory);
                Console.WriteLine($"  Report saved: {reportPath}");
            }

            Console.WriteLine();
            Console.WriteLine(new string('─', 60));
            Console.WriteLine($"✓ Successfully processed {borrowings.Count} borrowing(s)");
            Console.WriteLine($"✓ Reports saved to: {outputDirectory}");
        }
        catch (Exception ex)
        {
            Console.WriteLine($"Error: {ex.Message}");
            Environment.Exit(1);
        }
    }
}