Users.vb

Public Class Users
    Private id As Integer
    Private ids As New ArrayList
    Private usernames As New ArrayList
    Private passwords As New ArrayList

    Public Function addUser(ByVal username As String, ByVal password As String)
        If usernames.Contains(username) Then
            MsgBox("A username with the name " + username + " Already exists!", MsgBoxStyle.Critical, "Error!")
            Return False
        End If

        If password.Length < 6 Then
            MsgBox("Passowrd must be 6 characters or  longer!", MsgBoxStyle.Critical, "Error!")
            Return False
        End If

        If username.Length < 4 Then
            MsgBox("Username must be 4 characters or  longer!", MsgBoxStyle.Critical, "Error!")
            Return False
        End If

        If password = username Then
            MsgBox("Passowrd can't be equal to the username!", MsgBoxStyle.Critical, "Error!")
            Return False
        End If

        If username.Contains(" ") Then
            MsgBox("Username can't contain whitespaces!", MsgBoxStyle.Critical, "Error!")
            Return False
        End If

        If password.Contains(" ") Then
            MsgBox("Passowrd can't contain whitespaces!", MsgBoxStyle.Critical, "Error!")
            Return False
        End If

        ids.Add(id)
        usernames.Add(username)
        passwords.Add(password)
        id += 1
        MsgBox("The user " + username + " was registered successfully", MsgBoxStyle.OkOnly, "Success!")
        Return True
    End Function

    Public Function getUserFromUsername(ByVal username As String)
        If Not usernames.Contains(username) Then
            Return "User dosen't exist please register!"
        End If
        Dim user As New ArrayList
        user.Add(usernames(usernames.IndexOf(username)))
        user.Add(passwords(usernames.IndexOf(username)))
        user.Add(ids(usernames.IndexOf(username)))

        Return user

    End Function

    Public Function getUserFromID(ByVal id As Integer)
        If Not ids.Contains(id) Then
            Return "User dosen't exist please register!"
        End If
        Dim user As New ArrayList
        user.Add(usernames(id))
        user.Add(passwords(id))
        user.Add(ids(id))

        Return user
    End Function

    Public Function Login(ByVal username As String, ByVal password As String) As Boolean
        Dim user = getUserFromUsername(username)
        If user Is "User dosen't exist please register!" Then
            MsgBox(user, MsgBoxStyle.Critical, "Error!")
            Return False
        Else
            If user(0) = username And user(1) = password Then
                MsgBox("Login successfull", MsgBoxStyle.OkOnly, "Success!")
                Return True
            Else
                MsgBox("Password is incorrect", MsgBoxStyle.Critical, "Error!")
                Return False
            End If
        End If

    End Function

End Class