// CEIS209 Course Project
// Module 3
// Methods and Arrays
// Topics: Methods, Arrays

// Define constants
const string userName = "Jonathan Waugh"; // Replace with your name
const string userCourseNumber = "CEIS209";
const string userSession = "May 2025"; // Replace with the session month and year


// Declare Lists for storing loan information
List<string> loanProvider = new List<string>();
List<string> loanPurpose = new List<string>();
List<string> loanAccountNumber = new List<string>();
List<DateTime> loanDates = new List<DateTime>();
List<decimal> loanAmount = new List<decimal>();
List<decimal> loanInterestRate = new List<decimal>();
List<decimal> loanMonthlyInterestRate = new List<decimal>();
List<decimal> loanTerm = new List<decimal>();
List<decimal> loanNumberOfPayments = new List<decimal>();
List<decimal> loanPayment = new List<decimal>();

// Call Main Menu function, passing lists by reference
MainMenu(ref loanProvider, ref loanPurpose, ref loanAccountNumber, ref loanDates, ref loanAmount, ref loanInterestRate, ref loanMonthlyInterestRate, ref loanTerm, ref loanNumberOfPayments, ref loanPayment);

// Main Menu Function - receives lists by reference
static void MainMenu(ref List<string> loanProvider, ref List<string> loanPurpose, ref List<string> loanAccountNumber,
    ref List<DateTime> loanDates, ref List<decimal> loanAmount, ref List<decimal> loanInterestRate,
    ref List<decimal> loanMonthlyInterestRate, ref List<decimal> loanTerm, ref List<decimal> loanNumberOfPayments,
    ref List<decimal> loanPayment)
{
    while (true)
    {
        Console.Clear();
        Console.ForegroundColor = ConsoleColor.Blue;
        Console.WriteLine(userName + " . " + userCourseNumber + " . " + userSession);
        Console.WriteLine(DateTime.Now);
        Console.ResetColor();
        Console.WriteLine("Loan Management System");
        Console.WriteLine("1. Add Loan");
        Console.WriteLine("2. Delete Loan");
        Console.WriteLine("3. Display Loan Details");
        Console.WriteLine("4. Report");
        Console.WriteLine("5. Save to File");
        Console.WriteLine("6. Load from File");
        Console.WriteLine("7. Exit");
        Console.Write("Select an option: ");

        string input = Console.ReadLine();
        
        switch (input) 
        {
            case "1":
                LoanAdd(ref loanProvider, ref loanPurpose, ref loanAccountNumber, ref loanDates, ref loanAmount, ref loanInterestRate, ref loanMonthlyInterestRate, ref loanTerm, ref loanNumberOfPayments, ref loanPayment);
                break;
            case "2":
                LoanDelete(ref loanProvider, ref loanPurpose, ref loanAccountNumber, ref loanDates, ref loanAmount, ref loanInterestRate, ref loanMonthlyInterestRate, ref loanTerm, ref loanNumberOfPayments, ref loanPayment);
                break;
            case "3":
                LoanDetails(ref loanProvider, ref loanPurpose, ref loanAccountNumber, ref loanDates, ref loanAmount, ref loanInterestRate, ref loanMonthlyInterestRate, ref loanTerm, ref loanNumberOfPayments, ref loanPayment);
                break;
            case "4":
                LoanReport(ref loanProvider, ref loanPurpose, ref loanAccountNumber, ref loanDates, ref loanAmount, ref loanInterestRate, ref loanMonthlyInterestRate, ref loanTerm, ref loanNumberOfPayments, ref loanPayment);
                break;
            case "5":
                LoanSave(ref loanProvider, ref loanPurpose, ref loanAccountNumber, ref loanDates, ref loanAmount, ref loanInterestRate, ref loanMonthlyInterestRate, ref loanTerm, ref loanNumberOfPayments, ref loanPayment);
                break;
            case "6":
                LoanLoad(ref loanProvider, ref loanPurpose, ref loanAccountNumber, ref loanDates, ref loanAmount, ref loanInterestRate, ref loanMonthlyInterestRate, ref loanTerm, ref loanNumberOfPayments, ref loanPayment);
                break;
            case "7":
                Console.WriteLine("Exiting program...");
                return;
                
            default:
                Console.WriteLine("Invalid option. Try again.");
                Console.WriteLine("Press Enter to Continue...");
                Console.ReadLine();
                break;
        }
    }
}

// LoanAdd Function
static void LoanAdd(ref List<string> loanProvider, ref List<string> loanPurpose, ref List<string> loanAccountNumber,
    ref List<DateTime> loanDate, ref List<decimal> loanAmount, ref List<decimal> loanInterestRate, ref List<decimal> loanMonthlyInterestRate, 
    ref List<decimal> loanTerm, ref List<decimal> loanNumberOfPayments, ref List<decimal> loanPayment)
{
    // Declare variables for new loan
    string new_loanProvider;
    string new_loanPurpose;
    string new_loanAccountNumber;
    DateTime new_loanDate;
    decimal new_loanAmount;
    decimal new_loanInterestRate;
    decimal new_loanMonthlyInterestRate;
    decimal new_loanTerm;
    decimal new_loanNumberOfPayments;
    decimal new_loanPayment;


    // Get Loan Information
    Console.Clear();
    Console.WriteLine("Loan Information ---");
    Console.Write("Please enter the provider of the loan (Enter for ABC Bank):");
    new_loanProvider = Console.ReadLine();
    new_loanProvider = new_loanProvider == "" ? "ABC Bank" : new_loanProvider;
    Console.Write("Please enter the purpose of the loan (Example \"Pickup Truck 1\"):");
    new_loanPurpose = Console.ReadLine();
    Console.Write("Please enter the account number of the loan (Example \"123456\"):");
    new_loanAccountNumber = Console.ReadLine();
    string currentDate = DateTime.Now.ToString("M/d/yyyy");
    Console.Write("Please enter the initiation date of the loan (Enter for " + currentDate + "):");
    string loanDateInput = Console.ReadLine();
    new_loanDate = loanDateInput == "" ? DateTime.Now : Convert.ToDateTime(loanDateInput);
    while (true)
    {
        Console.Write("Please enter the loan amount (Example \"75000\"): ");
        new_loanAmount = Convert.ToDecimal(Console.ReadLine());
        if (new_loanAmount > 0 && new_loanAmount <= 250000)
        {
            break;
        }
        else
        {
            Console.WriteLine("Invalid input. Please enter a value greater than zero and less than or equal to 250,000.");
        }   
        
    }
    
    while (true)
    {
        Console.Write("Please enter the interest rate (Example: 5.25 for 5.25%):");
        new_loanInterestRate = Convert.ToDecimal(Console.ReadLine());
        if (new_loanInterestRate > 0 && new_loanInterestRate <= 25)
        {
            break;
        }
        else
        {
            Console.WriteLine("Invalid input. Please enter a value greater than zero and less than or equal to 25.");
        }
    }
    
    while (true)
    {
        Console.Write("Please enter the loan term in years:");
        new_loanTerm = Convert.ToDecimal(Console.ReadLine());
        if (new_loanTerm > 0 && new_loanTerm <= 30)
        {
            break;
        }
        else
        {
            Console.WriteLine("Invalid input. Please enter a value greater than zero and less than or equal to 30.");
        }
    }
    
    // Calculate Monthly Payment
    new_loanMonthlyInterestRate = new_loanInterestRate / 1200;
    new_loanNumberOfPayments = new_loanTerm * 12;
    new_loanPayment = new_loanAmount * (new_loanMonthlyInterestRate * (decimal)Math.Pow((double)(1 + new_loanMonthlyInterestRate), (double)new_loanNumberOfPayments)) / ((decimal)Math.Pow((double)(1 + new_loanMonthlyInterestRate), (double)new_loanNumberOfPayments) - 1);

     // Add loan to lists
    loanProvider.Add(new_loanProvider);
    loanPurpose.Add(new_loanPurpose);
    loanAccountNumber.Add(new_loanAccountNumber);
    loanDate.Add(new_loanDate);
    loanAmount.Add(new_loanAmount);
    loanInterestRate.Add(new_loanInterestRate);
    loanMonthlyInterestRate.Add(new_loanMonthlyInterestRate);
    loanTerm.Add(new_loanTerm);
    loanNumberOfPayments.Add(new_loanNumberOfPayments);
    loanPayment.Add(new_loanPayment);


    Console.WriteLine("Loan added successfully.");
    Console.WriteLine("Press Enter to continue ...");
    Console.ReadLine();

}

// Delete Loan Function
static void LoanDelete(ref List<string> loanProvider, ref List<string> loanPurpose, ref List<string> loanAccountNumber,
    ref List<DateTime> loanDates, ref List<decimal> loanAmount, ref List<decimal> loanInterestRate, ref List<decimal> loanMonthlyInterestRate,
    ref List<decimal> loanTerm, ref List<decimal> loanNumberOfOffers, ref List<decimal> loanPayment)
{
    Console.Clear();
    Console.WriteLine("Function Under Construction...");
    Console.WriteLine("Press Enter to continue ...");
    Console.ReadLine();
}

// Display Loan Details Function
static void LoanDetails(ref List<string> loanProvider, ref List<string> loanPurpose, ref List<string> loanAccountNumber,
    ref List<DateTime> loanDates, ref List<decimal> loanAmount, ref List<decimal> loanInterestRate, ref List<decimal> loanMonthlyInterestRate,
    ref List<int> loanTerm, ref List<decimal> loanNumberOfPayments, ref List<decimal> loanPayment)
{
    //Display Loan Details for each loan using a loop
    Console.Clear();
    Console.WriteLine("Loan Details ---");
    // Print column headings
    Console.WriteLine("{0,10} {1,15} {2,15} {3,20} {4,15} {5,15} {6,20} {7,20} {8,20}",
        "Loan", "Provider", "Purpose", "Account Number", "Date", "Amount", "Interest Rate", "Term", "Monthly Payment");

    // Print a separator line
    Console.WriteLine(new string('-', 170));

    // Print loan details in columns
    for (int i = 0; i < loanProvider.Count; i++)
    {
        Console.WriteLine("{0,10} {1,15} {2,15} {3,20} {4,15} {5,15} {6,20} {7,20} {8,20}",
            "Loan " + (i + 1),
            loanProvider[i],
            loanPurpose[i],
            loanAccountNumber[i],
            loanDates[i].ToString("MM/dd/yyyy"),
            loanAmount[i].ToString("C"),
            loanInterestRate[i].ToString(),
            loanTerm[i] + " years",
            loanPayment[i].ToString("C"));
    }
    Console.WriteLine();
    Console.WriteLine("Press Enter to continue ...");
    Console.ReadLine();
}

// Display Loan Report Function
static void LoanReport(ref List<string> loanProvider, ref List<string> loanPurpose, ref List<string> loanAccountNumber,
    ref List<DateTime> loanDates, ref List<decimal> loanAmount, ref List<decimal> loanInterestRate, ref List<decimal> loanMonthlyInterestRate,
    ref List<decimal> loanTerm, ref List<decimal> loanNumberOfOffers, ref List<decimal> loanPayment)
{
    Console.Clear();
    Console.WriteLine("Function Under Construction...");
    Console.WriteLine("Press Enter to continue ...");
    Console.ReadLine();
}

// Save Loan Information to File Function
static void LoanSave(ref List<string> loanProvider, ref List<string> loanPurpose, ref List<string> loanAccountNumber,
    ref List<DateTime> loanDates, ref List<decimal> loanAmount, ref List<decimal> loanInterestRate, ref List<decimal> loanMonthlyInterestRate,
    ref List<decimal> loanTerm, ref List<decimal> loanNumberOfOffers, ref List<decimal> loanPayment)
{
    Console.Clear();
    Console.WriteLine("Function Under Construction...");
    Console.WriteLine("Press Enter to continue ...");
    Console.ReadLine();
}

// Load Loan Information from File Function
static void LoanLoad(ref List<string> loanProvider, ref List<string> loanPurpose, ref List<string> loanAccountNumber,
    ref List<DateTime> loanDates, ref List<decimal> loanAmount, ref List<decimal> loanInterestRate, ref List<decimal> loanMonthlyInterestRate,
    ref List<decimal> loanTerm, ref List<decimal> loanNumberOfOffers, ref List<decimal> loanPayment)
{
    Console.Clear();
    Console.WriteLine("Function Under Construction...");
    Console.WriteLine("Press Enter to continue ...");
    Console.ReadLine();
}

// End of Program