unit DeleteRef;

interface

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

type
  TDeleteForm = class(TForm)
    Refs: TComboBox;
    DeleteButton: TButton;
    procedure FormCloseQuery(Sender: TObject; var CanClose: Boolean);
    procedure RefsDropDown(Sender: TObject);
    procedure RefsClick(Sender: TObject);
    procedure DeleteButtonClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  DeleteForm: TDeleteForm;
  DeleteIndex: Integer;

implementation

Uses
   Base, ChangeMenu, Add, Menu, Change;

{$R *.dfm}

procedure TDeleteForm.DeleteButtonClick(Sender: TObject);
var
   i: Integer;
   Temp: TRef;
begin
   seek(MyFile, DeleteIndex - 1);
   for i := DeleteIndex - 1 to FileSize(MyFile) - 2 do
   begin
      seek(MyFile, i + 1);
      read(MyFile, Temp);
      seek(MyFile, i);
      Write(MyFile, Temp);
   end;
   seek(MyFile, FileSize(MyFile) - 1);
   truncate(MyFile);
   Reset(MyFile);
   i := 0;
   While not eof(MyFile) do
   begin
      Read(MyFile, Ref[i]);
      Inc(i);
   end;
   n := i;
   Refs.Clear;
   DeleteForm.Hide;
   BaseForm.Show;
end;


procedure TDeleteForm.RefsClick(Sender: TObject);
begin
   DeleteButton.Enabled := True;
   DeleteIndex := Refs.Items.IndexOf(Refs.Text) + 1;
end;

procedure TDeleteForm.RefsDropDown(Sender: TObject);
var
   i: Integer;
begin
   Refs.Clear;
   for i := 0 to n - 1 do
      Refs.Items.Add(Ref[i].Topic);
end;

procedure TDeleteForm.FormCloseQuery(Sender: TObject; var CanClose: Boolean);
begin
   DeleteButton.Enabled := False;
   Refs.Clear;
   BaseForm.Show;
   MenuForm.Hide;
   ChangeMenuForm.Hide;
   AddForm.Hide;
   DeleteForm.Hide;
   ChangeForm.Hide;
end;

end.