Imports System.Security.Cryptography
Imports System.Text
Imports System.IO
Imports System.Data.SqlClient

Public Class MyFunction
    Public Shared Property lines As String() = IO.File.ReadAllLines("cfg.txt")
    Public Shared Function MD5StringHash(ByVal strString As String) As String
        Dim MD5 As New MD5CryptoServiceProvider
        Dim Data As Byte()
        Dim Result As Byte()
        Dim Res As String = ""
        Dim Tmp As String = ""

        Data = Encoding.ASCII.GetBytes(strString)
        Result = MD5.ComputeHash(Data)
        For i As Integer = 0 To Result.Length - 1
            Tmp = Hex(Result(i))
            If Len(Tmp) = 1 Then Tmp = "0" & Tmp
            Res += Tmp
        Next
        Return Res
    End Function

    'The function used to encrypt the text
    Public Shared Function Encrypt(ByVal strText As String) As String
        Dim strEncrKey As String = "v59!=cCD"
        Dim byKey() As Byte = {}
        Dim IV() As Byte = {&H12, &H34, &H56, &H78, &H90, &HAB, &HCD, &HEF}

        Try
            byKey = System.Text.Encoding.UTF8.GetBytes(Left(strEncrKey, 8))

            Dim des As New DESCryptoServiceProvider()
            Dim inputByteArray() As Byte = Encoding.UTF8.GetBytes(strText)
            Dim ms As New MemoryStream()
            Dim cs As New CryptoStream(ms, des.CreateEncryptor(byKey, IV), CryptoStreamMode.Write)
            cs.Write(inputByteArray, 0, inputByteArray.Length)
            cs.FlushFinalBlock()
            Return Convert.ToBase64String(ms.ToArray())

        Catch ex As Exception
            Return ex.Message
        End Try
    End Function

    'The function used to decrypt the text
    Public Shared Function Decrypt(ByVal strText As String) As String
        Dim sDecrKey As String = "txd.v?tx"
        Dim byKey() As Byte = {}
        Dim IV() As Byte = {&H12, &H34, &H56, &H78, &H90, &HAB, &HCD, &HEF}
        Dim inputByteArray(strText.Length) As Byte

        Try
            byKey = System.Text.Encoding.UTF8.GetBytes(Left(sDecrKey, 8))
            Dim des As New DESCryptoServiceProvider()
            inputByteArray = Convert.FromBase64String(strText)
            Dim ms As New MemoryStream()
            Dim cs As New CryptoStream(ms, des.CreateDecryptor(byKey, IV), CryptoStreamMode.Write)

            cs.Write(inputByteArray, 0, inputByteArray.Length)
            cs.FlushFinalBlock()
            Dim encoding As System.Text.Encoding = System.Text.Encoding.UTF8

            Return encoding.GetString(ms.ToArray())

        Catch ex As Exception
            Return ex.Message
        End Try
    End Function

    Public Shared Function ConnectToSQL(ByVal sUsername As String, ByVal sUserPass As String) As String
        Dim con As New SqlConnection
        Dim returnString As String = Nothing
        Try
            If Not sUsername <> "" Or Not sUserPass <> "" Then
                Return "Account0"
                Throw New Exception(DateTime.Now.ToString & vbTab & "Arguments not filled -> TokenFunction")
            End If
            con.ConnectionString = "Server=" & lines(8).Split("=")(1) & ";Database=" & lines(9).Split("=")(1) & ";Integrated Security=SSPI;"
            Dim cmd As New SqlCommand("SELECT COUNT(*) FROM tAccounts WHERE sUsername = @sUsername;", con)
            cmd.Parameters.AddWithValue("@sUsername", sUsername)
            con.Open()
            If cmd.ExecuteScalar = 0 Then
                returnString = "Account0"
            Else
                Dim sUserPassSalt As String = Nothing
                Dim nAuthID As String = Nothing
                Dim cmd2 As New SqlCommand("SELECT sUserPassSalt, nAuthID FROM tAccounts WHERE sUsername = @sUsername;", con)
                cmd2.Parameters.AddWithValue("@sUsername", sUsername)
                Dim reader As SqlDataReader = cmd2.ExecuteReader
                While reader.Read
                    sUserPassSalt = reader.GetString(0)
                    nAuthID = reader.GetInt32(1)
                End While
                reader.Close()

                Dim cmd3 As New SqlCommand("SELECT COUNT(*) FROM tAuth WHERE nAuthID = @nAuthID AND nLoginable = 1;", con)
                cmd3.Parameters.AddWithValue("@nAuthID", nAuthID)
                If cmd3.ExecuteScalar = 1 Then
                    'sUserPass = MD5StringHash(MD5StringHash(sUserPass).ToLower & MD5StringHash(sUserPassSalt).ToLower).ToLower
                    Dim cmd4 As New SqlCommand("SELECT COUNT(*) FROM tAccounts WHERE sUsername = @sUsername AND sUserPass = @sUserPass;", con)
                    cmd4.Parameters.AddWithValue("@sUsername", sUsername)
                    cmd4.Parameters.AddWithValue("@sUserPass", sUserPass)
                    If cmd4.ExecuteScalar = 1 Then
                        Dim Token As String = MyFunction.GenerateRandomString(30)
                        Dim cmd5 As New SqlCommand("SELECT COUNT(*) FROM tTokens WHERE nEMID = (SELECT nEMID FROM tAccounts WHERE sUsername = @sUsername);", con)
                        cmd5.Parameters.AddWithValue("@sUsername", sUsername)
                        If cmd5.ExecuteScalar >= 1 Then
                            Dim cmd6 As New SqlCommand("DELETE FROM tTokens WHERE nEMID = (SELECT nEMID FROM tAccounts WHERE sUsername = @sUsername);", con)
                            cmd6.Parameters.AddWithValue("@sUsername", sUsername)
                            cmd6.ExecuteNonQuery()
                            Dim cmd7 As New SqlCommand("INSERT INTO tTokens (nEMID, sToken) VALUES ((SELECT nEMID FROM tAccounts WHERE sUsername = @sUsername), @sToken);", con)
                            cmd7.Parameters.AddWithValue("@sUsername", sUsername)
                            cmd7.Parameters.AddWithValue("@sToken", Token)
                            cmd7.ExecuteNonQuery()
                        Else
                            Dim cmd7 As New SqlCommand("INSERT INTO tTokens (nEMID, sToken) VALUES ((SELECT nEMID FROM tAccounts WHERE sUsername = @sUsername), @sToken);", con)
                            cmd7.Parameters.AddWithValue("@sUsername", sUsername)
                            cmd7.Parameters.AddWithValue("@sToken", Token)
                            cmd7.ExecuteNonQuery()
                        End If
                        returnString = "AccountPass1" & vbTab & MyFunction.EncryptToken(Token)
                    Else
                        returnString = "AccountPass0"
                    End If
                Else
                    Dim cmd4 As New SqlCommand("SELECT sMessage FROM tAuth WHERE nAuthID = @nAuthID;", con)
                    cmd4.Parameters.AddWithValue("@nAuthID", nAuthID)
                    Dim reader2 As SqlDataReader = cmd4.ExecuteReader
                    While reader2.Read
                        returnString = "Maintenance1" & vbTab & reader2.GetString(0)
                    End While
                    reader2.Close()
                End If
            End If
        Catch ex As Exception
            My.Computer.FileSystem.WriteAllText("SQLException.txt", DateTime.Now() & vbTab & ex.Message & vbNewLine, True)
        Finally
            con.Close()
        End Try
        Return returnString
    End Function

    Public Shared Function TestSQLConnection() As Boolean
        Dim con As New SqlConnection
        Dim r As Boolean = True
        Try
            con.ConnectionString = "Server=" & lines(8).Split("=")(1) & ";Database=" & lines(9).Split("=")(1) & ";Integrated Security=SSPI;"
            con.Open()
        Catch ex As Exception
            r = False
            Console.ForegroundColor = ConsoleColor.Red
            Console.WriteLine("SQL Connection not stable" & vbNewLine & ex.Message)
            My.Computer.FileSystem.WriteAllText("Debug.txt", DateTime.Now() & vbTab & "SQL Connection not stable" & ex.Message & vbNewLine, True)
        Finally
            con.Close()
        End Try
        Return r
    End Function

    Public Shared Function GenerateRandomString(ByRef iLength As Integer) As String
        Dim rdm As New Random()
        Dim allowChrs() As Char = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLOMNOPQRSTUVWXYZ0123456789".ToCharArray()
        Dim sResult As String = ""

        For i As Integer = 0 To iLength - 1
            sResult += allowChrs(rdm.Next(0, allowChrs.Length))
        Next

        Return sResult
    End Function

    Public Shared Function EncryptToken(S As String)
        Dim rijnKey As Byte() = System.Text.Encoding.UTF8.GetBytes(Left("C-;){+W6wRPw/[4kmVU?@6Hg88E!++Hz", 32))
        Dim rijnIV As Byte() = {&H31, &H55, &H94, &H69, &H59, &H66, &H87, &H48, &H52, &H36, &H96, &H52, &H96, &H98, &H75, &H42}
        'Creates the default implementation, which is RijndaelManaged.
        Dim rijn As SymmetricAlgorithm = SymmetricAlgorithm.Create()
        Dim encrypted() As Byte
        Using msEncrypt As New MemoryStream()
            Dim csEncrypt As New CryptoStream(msEncrypt, rijn.CreateEncryptor(rijnKey, rijnIV), CryptoStreamMode.Write)
            Using swEncrypt As New StreamWriter(csEncrypt)
                'Write all data to the stream.
                swEncrypt.Write(S)
            End Using
            encrypted = msEncrypt.ToArray()
        End Using

        ' You cannot convert the byte to a string or you will get strange characters so base64 encode the string
        ' Replace any + that will lead to the error
        Return Convert.ToBase64String(encrypted).Replace("+", "BIN00101011BIN")
    End Function
End Class