Imports System.Threading
Module Module1
    Dim pass As String
    Dim newPass As String
    Dim numbers As Integer
    Dim charFromPass As String
    Dim charFromPass2 As String
    Dim charFromPass3 As String
    Dim length As Integer
    Dim MinLength As Integer = 8
    Dim Valid As Integer
    Dim CapCount As Integer
    Dim LowCount As Integer
    Dim Users As Integer
    Dim UI As Char
    Dim Counter As Integer

    Sub Main()

        Console.WriteLine("     - Username and Password Storage Program -     ")
        Console.WriteLine()
        Console.WriteLine(" # How many users would you like to store?")

        Do
            Console.Write(" # Users: ")
            Try
                Users = Console.ReadLine()
            Catch ex As Exception
                Console.WriteLine("Invalid Input. Please input a positive integer.")
            End Try
        Loop Until Users > 0

        Call UserName()
    End Sub

    Dim FName(Users) As String
    Dim SName(Users) As String
    Dim PassW(Users) As String

    Sub UserName()

        For index = 0 To Users - 1
            Console.Clear()
            Console.WriteLine(" # Username Input")
            Console.WriteLine()

            Console.WriteLine("Please enter the first name for user " & index & ".")
            Console.Write("Input: ")
            Dim Fname(index) As String
            FName(index) = Console.ReadLine()

            Console.WriteLine("Please enter the surname for user " & index & ".")
            Console.Write("Input: ")
            Dim Sname(index) As String
            SName(index) = Console.ReadLine()

        Next

        Call PasswordCheck()
    End Sub

    Sub PasswordCheck()

        Console.Clear()

        For index = 0 To Users - 1

            Console.WriteLine("Password Program")
            Console.WriteLine()

            Do
                Console.Write("Please Enter a New Password:> ")

                Dim PassW(index) As String
                PassW(index) = Console.ReadLine

                Console.WriteLine()
                Console.Write("Please Re-Enter Password:> ")

                newPass = Console.ReadLine

                If newPass = PassW(index) Then

                    Console.Clear()

                    Console.WriteLine("Thankyou - your password will now be sent for checking - please wait....")
                    Console.WriteLine()

                    For index2 = 1 To 12
                        Console.Write(".")
                        Thread.Sleep(200)

                    Next

                    Console.Write(" OK")
                    Thread.Sleep(200)
                    Console.WriteLine()
                    Console.WriteLine()

                Else

                    Console.WriteLine("Passwords do not match - Please Re-Enter")

                End If

                ' The benefit of using a named constant is that a user is able to modify the variable in one change much easier than searching the code for individual values.

                If PassW(index).Length >= MinLength Then
                    Valid = 1
                Else
                    Console.WriteLine("Password must be at least 8 characters long")
                End If
            Loop Until Valid = 1


            length = newPass.Length

            For position = 1 To length
                charFromPass = Mid(newPass, position, 1)
                If InStr("0123456789", charFromPass) > 1 Then
                    numbers = numbers + 1
                End If
            Next

            For position = 1 To length
                charFromPass2 = Mid(newPass, position, 1)
                If InStr("QWERTYUIOPASDFGHJKLZXCVBNM", charFromPass2) > 1 Then
                    CapCount = CapCount + 1
                End If
            Next

            For position = 1 To length
                charFromPass3 = Mid(newPass, position, 1)
                If InStr("qwertyuiopasdfghjklzxcvbnm", charFromPass3) > 1 Then
                    LowCount = LowCount + 1
                End If
            Next

            If numbers = 1 Then
                Console.WriteLine("Contains a number")
            Else
                Console.WriteLine("Containts at least two numbers")
            End If

            If LowCount > 0 And CapCount > 0 And numbers >= 2 Then
                Console.WriteLine("STRONG PASSWORD")
            ElseIf LowCount > 0 And CapCount > 0 And numbers = 0 Then
                Console.WriteLine("MEDIUM PASSWORD")
            ElseIf LowCount > 0 And numbers > 0 And CapCount = 0 Then
                Console.WriteLine("MEDIUM PASSWORD")
            ElseIf numbers > 0 And CapCount > 0 And LowCount = 0 Then
                Console.WriteLine("MEDIUM PASSWORD")
            ElseIf numbers = 0 And LowCount = 0 And CapCount = 0 Then
                Console.WriteLine("WEAK PASSWORD")

            End If

        Next

        Console.WriteLine("Would you like to display all users and relevant information? (Y/N)")
        Console.WriteLine("(N will exit the program.)")
        Console.Write("Input: ")

        Do

            Try
                UI = Console.ReadLine()
            Catch ex As Exception
                Console.WriteLine("That is not a valid input. Please try again.")

            End Try

            If UI = "Y" Or UI = "y" Then
                Counter = 1
            ElseIf UI = "N" Or "n" Then
                Counter = 0
            End If

        Loop Until Counter = 1

        Select Case UI
            Case "Y"
                Call Display()
            Case "y"
                Call Display()
            Case "N"
                Console.WriteLine("Exiting...")
                Thread.Sleep(200)
            Case "n"
                Console.WriteLine("Exiting...")
                Thread.Sleep(200)
        End Select
    End Sub

    Sub Display()

        Console.Clear()
        Console.WriteLine("Stored User Data:")
        Console.WriteLine("¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯")
        Console.WriteLine()

        For index = 0 To Users - 1
            Console.WriteLine(FName(index) & " " & SName(index) & " " & PassW(index))
        Next

        Console.ReadLine()
    End Sub
End Module