Imports System.IO 'imports the system io library
Imports System.Text.RegularExpressions
Imports System.Windows.Forms.VisualStyles.VisualStyleElement.StartPanel

Public Class Login
    Private Sub Login_Load(sender As Object, e As EventArgs) Handles MyBase.Load

        'when the form loads, the getfilelocation subroutine runs
        getfilelocation() 'finds the location of the staff file, and creates it if it doesn't exist
        txt_Username.Clear() 'clears the username textbox
        txt_Password.Clear() 'clears the password textbox

    End Sub

    Private Sub btn_Login_Click(sender As Object, e As EventArgs) Handles btn_Login.Click

        Dim validation As New Validation 'allows the use of the validation class

        Dim passwordMatch As Boolean = False 'creates a varaible that will be used to check if the password is incorrect
        Dim usernameMatch As Boolean = False 'creates a varaible that will be used to check if the username is incorrect

        Dim username As String 'creates a username variable
        Dim password As String 'creates a password variable

        Dim currentUser As String 'creates a variable to store the current user information
        Dim loginFields() As String 'creates a variable to store the information input into the login fields

        Dim match As Boolean = False 'creates match variable to check if username and password match later on
        username = UCase(txt_Username.Text) 'sets the username variable to an uppercase version of the username in textbox
        password = txt_Password.Text 'sets the password variable to the data in password textbox

        'check if username and password textboxes are empty (presence check):
        If Validation.presenceCheck(username) = False Or Validation.presenceCheck(password) = False Then

            MsgBox("Please input data into both textboxes") 'shows message to ask user to input data into texboxes
            txt_Username.Clear() 'clears username textbox
            txt_Password.Clear() 'clears password textbox

        End If

        Dim sr As New StreamReader(staffFile) 'opens streamread, to allow the staff file to be read
        While sr.Peek >= 0 'while the file isn't at the end line

            currentUser = sr.ReadLine 'reads the the first line of the file, then each loop reads the next line
            loginFields = currentUser.Split(",") 'the line is split into different sections by splitting at every comma


            'if the username matches the first field in the staff text file with all caps, and the password matches the second field in the staff text file, then:
            If username = UCase(Decryption(loginFields(1))) AndAlso password = Decryption(loginFields(2)) Then

                'match has been found:
                Security = Decryption(loginFields(5)) 'sets the access level to the lowest to allow the next form to be accessed

                usernameMatch = True
                passwordMatch = True
                match = True 'checks if the input data matches any data in the textfile
                Exit While 'ends the loop as a match has been found


            End If

            If username = UCase(Decryption(loginFields(1))) Then

                usernameMatch = True 'username is correct

            End If

            If password = UCase(Decryption(loginFields(2))) Then

                passwordMatch = True 'password is correct

            End If

        End While

        If passwordMatch = False Then

            MsgBox("Incorrect password, please try again")
            txt_Password.Clear()

        End If

        If usernameMatch = False Then

            MsgBox("Incorrect username, please try again")
            txt_Username.Clear()

        End If

        sr.Close() 'closes streamreader to avoid data loss

        If match = True Then 'if a match has been found:

            Me.Visible = False
            LibraryMenu.Visible = True

        End If

    End Sub

    Private Sub pbx_ExitButton_Click(sender As Object, e As EventArgs) Handles pbx_ExitButton.Click

        If MsgBox("Are you sure you want to quit the program?", vbYesNo) = vbYes Then

            'when the exit button is clicked, exit the program if yes is selected
            Application.Exit() 'closes the program

        End If

    End Sub

    Private Sub btn_Forgotten_Click(sender As Object, e As EventArgs) Handles btn_Forgotten.Click

        Me.Visible = False 'hides the login form
        ForgottenPassword.Visible = True 'shows the forgotten password form

    End Sub

    Private Sub btn_Help_Click(sender As Object, e As EventArgs) Handles btn_Help.Click

        Help.txt_help.Text = "This is the login form. Input your username into the username textbox, and input your password into the password textbox," _
            & " Then click the login button. If you aren't redirected to the menu form, then either your username or password is incorrect. If you have" _
            & " forgotten your password, then you can click on the 'forgotten password' button to be redirected to that form. If you click the cross button" _
            & " in the top right of the form, you will exit the program."

        Help.Show()

    End Sub
End Class