unit Unit_Login;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Vcl.ExtCtrls;

type
  TfrmLogin = class(TForm)
    lbledtUsername: TLabeledEdit;
    lbledtPassword: TLabeledEdit;
    btnEnter: TButton;
    Exit: TButton;
    procedure btnEnterClick(Sender: TObject);
    procedure ExitClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  frmLogin: TfrmLogin;

implementation
uses
 Unit_AddLogin,UnitStudent_menu,Unit_TeacherMenu;  //Allows access to the form add login and studnet menu
{$R *.dfm}
type
TUsername = record //creating a record for the file to store usernames
Username : string[20];
end;

type
TPassword = record    //creating a record for the file to store passwords.
Password:string[20];
end;

var
UsernameFile : File of TUsername;
PasswordFile : File of Tpassword;    // This will be the file whch stores the usernames
New_username : array  [1..1000] of Tusername;    //An array used to store multiple usernames
New_Password : array [1..1000] of TPassword;       //An array used to store multiple Passwords

procedure TfrmLogin.btnEnterClick(Sender: TObject);
var
count,counter,I,Temp_num : integer;
begin
  {Code to check if teacher is trying to login in to the system}
  if (lbledtusername.Text = 'David.Searle') and (lbledtPassword.Text = 'Tudor') then  //This is the hardcoded login detials for Mr Searl's account
      begin
      frmTeacherMenu.Show;      //Shows the form where the teacher can create new users
      end;

  {Code to check if a student is logging in to the system}
   AssignFile(Usernamefile,'loginsave.dat');    //assigns exsiting file to New_usernamefile
   reset(UsernameFile);                       //opens the file

   AssignFile(PasswordFile ,'Password.dat');   //assigns exsiting file to New_Passwordfile
   reset(PasswordFile );             //opens the file

   count := 0;    //intialises count

   while not Eof(Usernamefile) and not Eof (passwordfile) do {This will repeat the code below untill
    the end of file is reached}
    begin
      count := count + 1;
      Read(Usernamefile,New_username[count]);   //reads the usernames from Usernamefile
      Read(Passwordfile,New_Password[count]);  //reads the password from Passwordfile
      if (lbledtusername.Text = New_username[count].Username) and
      (lbledtPassword.Text = New_Password[count].Password) then
       begin
        frmStudentmenu.Show;   //if the username is correct it shows the student menu
       end;
    end;
    Closefile(Usernamefile);  //closes file which contains username
    Closefile(Passwordfile);  //Closes file which contains passwords


   {Code to output incorrect login}
    I := 0;
   for counter  := 1 to count do
    begin
      I := I + 1;
      if (lbledtusername.Text = New_username[I].Username) and
       (lbledtPassword.Text = New_Password[I].Password)  then
       begin
        Temp_num:= I;
       end;
      end;
   //This checks that the user enters either teacher or student login
  if  ((lbledtusername.Text <> New_username[temp_num].Username) or
       (lbledtPassword.Text <> New_Password[temp_num].Password)) and ((lbledtusername.Text <>
       'David.Searle')or (lbledtPassword.Text <> 'Tudor'))   then
        Showmessage('Incorrect Login');

end;



procedure TfrmLogin.ExitClick(Sender: TObject);
begin
  close;
end;

end.