unit DAssistHookMain;

interface

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

type
  TInstallWindowActiveHook = function: Integer; stdcall;//function(sShareMapFilename: PChar): Integer; stdcall;
  TUninstallWindowActiveHook = function: Integer; stdcall;

  TDlgAssistHookMain = class(TForm)
    tCheckMutex: TTimer;
    procedure tCheckMutexTimer(Sender: TObject);
  private
    { Private declarations }
    hHookDLL_: THandle;
  public
    { Public declarations }
    Constructor Create(aOwner: TComponent); override;
    Destructor Destroy; override;
  end;

var
  DlgAssistHookMain: TDlgAssistHookMain;

implementation

uses
  Define, Tocsg.Win32;

{$R *.dfm}

Constructor TDlgAssistHookMain.Create(aOwner: TComponent);

  procedure LoadHookDLL;
  var
    hUser32: THandle;
    sPath: String;
    fnInstallWindowActiveHook: TInstallWindowActiveHook;
  begin
    sPath := ExtractFilePath(Application.ExeName) + gParam.HookDllName;
    if FileExists(sPath) then
    begin
      hHookDLL_ := LoadLibrary(PChar(sPath));
      if hHookDLL_ > 0 then
      begin
        fnInstallWindowActiveHook := nil;
        @fnInstallWindowActiveHook := GetProcAddress(hHookDLL_, 'InstallWindowActiveHook');
        if @fnInstallWindowActiveHook <> nil then
        {$IFDEF DEBUG}
          ASSERT(fnInstallWindowActiveHook = 0);
        {$ELSE}
          fnInstallWindowActiveHook;
        {$ENDIF}
      end;
    end;
  end;

begin
  Inherited Create(aOwner);

  if MutexExists(gParam.WatchMutex) then
    LoadHookDLL;
  tCheckMutex.Enabled := true;
end;

Destructor TDlgAssistHookMain.Destroy;
var
  fnUnInstallWindowActiveHook: TUninstallWindowActiveHook;
begin
  if hHookDLL_ > 0 then
  begin
    @fnUnInstallWindowActiveHook := nil;
    @fnUnInstallWindowActiveHook := GetProcAddress(hHookDLL_, 'UnInstallWindowActiveHook');
    if @fnUnInstallWindowActiveHook <> nil then
      fnUnInstallWindowActiveHook;

    FreeLibrary(hHookDLL_);
    hHookDLL_ := 0;
  end;

  Inherited;
end;

procedure TDlgAssistHookMain.tCheckMutexTimer(Sender: TObject);
begin
  if not MutexExists(gParam.WatchMutex) then
    Close;
//    TerminateProcess(GetCurrentProcess, 0);
end;

end.