unit MainFormUnit;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, ExtCtrls,
  StdCtrls, DateUtils;

type

  { TMainForm }

  TMainForm = class(TForm)
    RestartButton: TButton;
    CountdownLabel: TLabel;
    TimeoutTimer: TTimer;
    procedure FormCreate(Sender: TObject);
    procedure Restart(Sender: TObject);
    procedure UpdateCountdownLabel(Sender: TObject);

  private
    procedure SetTimeoutDate();

  private
    TimeoutDate: TDateTime;
  end;


const
  COUNTDOWN_SECONDS = 5;

var
  MainForm: TMainForm;

implementation

{$R *.lfm}

{ TMainForm }

procedure TMainForm.Restart(Sender: TObject);
begin
  SetTimeoutDate();
end;

procedure TMainForm.UpdateCountdownLabel(Sender: TObject);
begin
  if TimeoutDate >= Now then
  begin
    CountdownLabel.Caption := 'Pozostalo ' + IntToStr(SecondsBetween(TimeoutDate, Now)) + 's';
  end;
end;

procedure TMainForm.FormCreate(Sender: TObject);
begin
  SetTimeoutDate();
  UpdateCountdownLabel(nil);
end;

procedure TMainForm.SetTimeoutDate;
begin
  self.TimeoutDate := IncSecond(Now, COUNTDOWN_SECONDS);
  UpdateCountdownLabel(nil);
end;

end.