ReturnBooks.cs

// DON-CODE
using Terminal.Gui;
using System;
using System.Text.RegularExpressions;

public class ReturnBooksWindow {
	private bool IsNumeric(string input) {
		return int.TryParse(input, out _);
	}
	private bool IsValidDateFormat(string date) {
		DateTime parsedDate;
		return DateTime.TryParseExact(date, "yyyy-MM-dd", null, System.Globalization.DateTimeStyles.None, out parsedDate);
	}
    public Window CreateReturnBooksWindow(Window leftWindow, String databasePath) {
		string currentDate = DateTime.Now.ToString("yyyy-MM-dd");
        var createReturnBooksWindow = new Window() {
            X = Pos.Right(leftWindow), // Position it to the right of the leftWindow
            Y = 1, // Leave one row for the top-level menu
            Width = Dim.Fill(), // Fill the remaining space
            Height = Dim.Fill()
        };
        var mainTitleLabel = new Label("  ___     _                   ___   \n | _ \\___| |_ _  _ _ _ _ _   | _ )  \n |   / -_|  _| || | '_| ' \\  | _ \\_ \n |_|_\\___|\\__|\\_,_|_| |_||_| |___(_)") {
            X = 6,
            Y = 1,
            Width = Dim.Fill(),
            Height = 1,
            LayoutStyle = LayoutStyle.Computed, // Use computed layout
        };
        var transactionIDLabel = new Label("Transaction ID") {
            X = 2,
            Y = Pos.Bottom(mainTitleLabel) + 2,
            Width = 17
        };
        var transactionIDInput = new TextField ("") {
            X = Pos.Right(transactionIDLabel) + 1,
            Y = Pos.Top(transactionIDLabel),
            Width = 30,
            Height = 1
        };
        var returnDateLabel = new Label("Return Date") {
            X = Pos.Left(transactionIDLabel),
            Y = Pos.Bottom(transactionIDLabel) + 1,
            Width = 17
        };
        var returnDateInput = new TextField ("") {
            X = Pos.Right(returnDateLabel) + 1,
            Y = Pos.Top(returnDateLabel),
            Width = 30,
            Height = 1
        };
        var explainLabel = new Label("*[Date format: YYYY-MM-DD]") {
            X = Pos.Left(returnDateLabel) + 10,
            Y = Pos.Bottom(returnDateLabel) + 1,            
        };
        var clearButton = new Button("Clear") {
            X = Pos.Left(transactionIDLabel) + 29,
            Y = Pos.Bottom(returnDateLabel) + 3,            
        };
        clearButton.Clicked += () => {
            // Clear the text fields when the Clear button is clicked
            transactionIDInput.Text = "";
            returnDateInput.Text = "";
        };
        var okButton = new Button("  Ok ") {
            X = Pos.Right(clearButton) + 1,
            Y = Pos.Bottom(returnDateLabel) + 3,
        };
okButton.Clicked += () => {
    string transactionID = transactionIDInput.Text.ToString();
    string returnDate = returnDateInput.Text.ToString();

    // Check if any of the required fields are empty
    if (string.IsNullOrWhiteSpace(transactionID) || string.IsNullOrWhiteSpace(returnDate)) {
        MessageBox.ErrorQuery("Error", "All required fields must be filled in.", "OK");
        return; // Exit the event handler
    }

    // Check if Transaction ID contains only numbers
    if (!IsNumeric(transactionID)) {
        MessageBox.ErrorQuery("Error", "Transaction ID must contain only numbers.", "OK");
        return; // Exit the event handler
    }

    // Check if Return Date is in the format "YYYY-MM-DD"
    if (!IsValidDateFormat(returnDate)) {
        MessageBox.ErrorQuery("Error", "Return Date must be in the format 'YYYY-MM-DD'.", "OK");
        return; // Exit the event handler
    }

    // Convert strings to integers and parse dates
    int parsedTransactionID;
    if (!int.TryParse(transactionID, out parsedTransactionID)) {
        MessageBox.ErrorQuery("Error", "Failed to parse Transaction ID.", "OK");
        return; // Exit the event handler
    }

    DateTime parsedReturnDate;
    if (!DateTime.TryParse(returnDate, out parsedReturnDate)) {
        MessageBox.ErrorQuery("Error", "Failed to parse Return Date.", "OK");
        return; // Exit the event handler
    }

    // Call the ReturnBook function
    var (success, message) = new LibraryFunctions(databasePath).ReturnBook(parsedTransactionID, parsedReturnDate);

    if (success) {
        MessageBox.Query("Return Book Result", "Book returned successfully.", "OK");
    } else {
        MessageBox.ErrorQuery("Error", message, "OK");
    }
};

        
        transactionIDLabel.FocusFirst();
		createReturnBooksWindow.Add(
			mainTitleLabel,
			transactionIDLabel, transactionIDInput,
            returnDateLabel, returnDateInput,
			explainLabel,
			clearButton, okButton
		);        
        return createReturnBooksWindow;
    }
}