Imports System.Security.Cryptography
Imports System.Data.SqlClient
Imports System.Data

Public Class commonFunctions
    Public Sub createLoginCookie()
        If HttpContext.Current.Session("loginToken") Is Nothing Then
            Call updateLoginToken()
        Else
            Dim loginCookie As New HttpCookie("evecp")
            loginCookie.Values("userName") = HttpContext.Current.Session("userName")
            loginCookie.Values("loginToken") = HttpContext.Current.Session("loginToken")
            loginCookie.Expires = Date.Now.AddMonths(1)
            HttpContext.Current.Response.Cookies.Add(loginCookie)
        End If
    End Sub

    Public Sub updateLoginToken()
        HttpContext.Current.Session("loginToken") = Guid.NewGuid.ToString
        Using dbConnection As New SqlConnection("Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\evecp.mdf;Integrated Security=True;User Instance=True")
            Using dbCommand As New SqlCommand("UPDATE tblUsers SET loginToken = @loginToken WHERE userName = @userName;")
                dbCommand.Connection = dbConnection
                dbCommand.Parameters.AddWithValue("@loginToken", HttpContext.Current.Session("loginToken"))
                dbCommand.Parameters.AddWithValue("@userName", HttpContext.Current.Session("userName"))
                dbConnection.Open()
                dbCommand.ExecuteNonQuery()
                dbConnection.Close()
            End Using
        End Using
        Call createLoginCookie()
    End Sub

    Public Function retrieveLoginToken(userName As String)
        Using dbConnection As New SqlConnection("Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\evecp.mdf;Integrated Security=True;User Instance=True")
            Using dbAdapter As New SqlDataAdapter("SELECT TOP 1 loginToken FROM tblUsers WHERE userName = @userName;", dbConnection)
                dbAdapter.SelectCommand.Parameters.AddWithValue("@userName", userName)
                Using dtLoginToken As New DataTable
                    dbAdapter.Fill(dtLoginToken)
                    Return dtLoginToken.Rows(0)(0).ToString
                End Using
            End Using
        End Using
    End Function

    Public Function hashPassword(plainTextPassword As String, passwordSalt As String)
        Dim passwordHasher As New SHA1Managed()
        Dim hashedPassword As String = BitConverter.ToString(passwordHasher.ComputeHash(Encoding.UTF8.GetBytes(plainTextPassword & passwordSalt)))
        Return hashedPassword
    End Function

    Public Sub purgeLogin()
        Dim loginCookie As New HttpCookie("evecp")
        loginCookie.Expires = Date.Now.AddDays(-1)
        HttpContext.Current.Response.Cookies.Add(loginCookie)
        HttpContext.Current.Session.Abandon()
    End Sub
End Class