Imports System
Imports System.Globalization

Module SpaceTripCalculator
    Sub Main()
        Dim distance As Double
        Dim speedFraction As Double

        Console.WriteLine("Space Trip Time Dilation Calculator")
        Console.WriteLine("-----------------------------------")

        ' Input distance to the destination (in light years)
        While True
            Console.Write("Enter the distance to your destination (in light years): ")
            Dim inputDistance As String = Console.ReadLine()
            ' Replace comma with dot for decimal conversion
            inputDistance = inputDistance.Replace(",", ".")
            If Double.TryParse(inputDistance, NumberStyles.Float, CultureInfo.InvariantCulture, distance) Then
                Exit While
            Else
                Console.WriteLine("Invalid input. Please enter a numeric value.")
            End If
        End While

        ' Input speed as a fraction of the speed of light (e.g., 0.9 for 90% of the speed of light)
        While True
            Console.Write("Enter your speed as a fraction of the speed of light (0 - 1): ")
            Dim inputSpeed As String = Console.ReadLine()
            ' Replace comma with dot for decimal conversion
            inputSpeed = inputSpeed.Replace(",", ".")
            If Double.TryParse(inputSpeed, NumberStyles.Float, CultureInfo.InvariantCulture, speedFraction) AndAlso speedFraction >= 0 AndAlso speedFraction < 1 Then
                Exit While
            Else
                Console.WriteLine("Invalid input. Please enter a numeric value between 0 and 1 (exclusive).")
            End If
        End While

        ' Calculate the time taken (time from observer's perspective)
        Dim speedOfLight As Double = 1.0 ' Speed of light in light years per year (for simplicity)
        Dim travelTimeObserver As Double = distance / speedFraction

        ' Calculate time dilation
        Dim timeDilationFactor As Double = 1.0 / Math.Sqrt(1 - speedFraction * speedFraction)
        Dim travelTimeTraveler As Double = travelTimeObserver / timeDilationFactor

        ' Output results
        Console.WriteLine($"Travel time for observer: {travelTimeObserver:F2} years")
        Console.WriteLine($"Travel time experienced by traveler: {travelTimeTraveler:F2} years")

        ' Wait for user to close the console
        Console.WriteLine("Press any key to exit...")
        Console.ReadKey()
    End Sub
End Module