unit UnitLogin;

interface

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

type
  TfrmLogin = class(TForm)
    btnLogin: TButton; // btn prefix = button
    lbledtUsername: TLabeledEdit;
    // lbledt = label that data can be inputted into while program is running
    lbledtPassword: TLabeledEdit;
    btnAdd_New_User: TButton;
    lblLoginSuccessful: TLabel; // lbl prefix = label containing data
    btnContinue: TButton;
    lblMessage: TLabel;
    btnLogout: TButton;
    Shortcut: TButton;
    procedure btnLoginClick(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure btnAdd_New_UserClick(Sender: TObject);
    procedure btnContinueClick(Sender: TObject);
    procedure btnLogoutClick(Sender: TObject);
    procedure ShortcutClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
    Username, Password: string;
    Userfile: textfile;
    TextString: string;
  end;

var
  frmLogin: TfrmLogin;

implementation

{$R *.dfm}

procedure TfrmLogin.FormCreate(Sender: TObject);
begin
  lblMessage.show;
  lbledtUsername.show;
  lbledtPassword.show;
  btnAdd_New_User.show;
  btnLogin.show;

  lblLoginSuccessful.hide;
  btnContinue.hide;
  btnLogout.hide;
end;

procedure TfrmLogin.ShortcutClick(Sender: TObject);
begin
  GeneralTopics.Show;
end;

procedure TfrmLogin.btnAdd_New_UserClick(Sender: TObject);
begin
  FormNewUser.show; // show new user form
end;

procedure TfrmLogin.btnContinueClick(Sender: TObject);
begin
  FormMainMenu.show; // show quiz menu
end;

procedure TfrmLogin.btnLoginClick(Sender: TObject);
Var
  closing, found, Endendof, incpass: boolean;
begin
  closing := false;
  found := false;
  Endendof := false;
  incpass := false;
  Username := lbledtUsername.Text;
  Password := lbledtPassword.Text;

  AssignFile(Userfile, 'Usernames.txt'); // open and read Usernames file
  Reset(Userfile);
  while (closing = false) do
  begin
    readln(Userfile, TextString); // read file line by line
    if (TextString = Username) then
    // compare username stored in file to value entered in the username box
    begin

      readln(Userfile, TextString);
      if (TextString = Password) then
      // compare password under that username stored in file to value entered in the password box
      begin
        lbledtUsername.hide; // Hide Username Box
        lbledtPassword.hide; // Hide Password Box
        lblMessage.hide;
        btnLogout.show;
        btnAdd_New_User.hide; // Hide the Button to add new user
        btnLogin.hide; // Hide Button the check login details
        btnContinue.show;
        lblLoginSuccessful.show;
        closing := true;
        found := true;
      end
      else
      begin
        closing := true;
        Showmessage('Please enter your Log In details correctly');
        // Displaying error message
        incpass := true;
      end;

    end;

  end;

  if (found = false) then
  begin
    closing := true;

    if (incpass = false) then
    begin
      Showmessage('Incorrect Username');
    end;
    found := true;
  end;

  closefile(Userfile);
end;

procedure TfrmLogin.btnLogoutClick(Sender: TObject);
// returns to orignal login layout
begin
  lbledtUsername.show;
  lbledtPassword.show;
  btnAdd_New_User.show;
  btnLogin.show;
  lblLoginSuccessful.hide;
  btnContinue.hide;
  btnLogout.hide;
  lblMessage.show;
  lbledtUsername.Text := '';
  lbledtPassword.Text := '';
end;

end.