/*
 *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#ifndef MODULES_DESKTOP_CAPTURE_WINDOW_FINDER_H_
#define MODULES_DESKTOP_CAPTURE_WINDOW_FINDER_H_

#include <memory>

#include "modules/desktop_capture/desktop_capture_types.h"
#include "modules/desktop_capture/desktop_geometry.h"

namespace webrtc {

#if defined(USE_X11)
class XAtomCache;
#endif

// An interface to return the id of the visible window under a certain point.
class WindowFinder {
 public:
  WindowFinder() = default;
  virtual ~WindowFinder() = default;

  // Returns the id of the visible window under |point|. This function returns
  // kNullWindowId if no window is under |point| and the platform does not have
  // "root window" concept, i.e. the visible area under |point| is the desktop.
  // |point| is always in system coordinate, i.e. the primary monitor always
  // starts from (0, 0).
  virtual WindowId GetWindowUnderPoint(DesktopVector point) = 0;

  struct Options {
#if defined(USE_X11)
    XAtomCache* cache = nullptr;
#endif
  };

  // Creates a platform-independent WindowFinder implementation. This function
  // returns nullptr if |options| does not contain enough information or
  // WindowFinder does not support current platform.
  static std::unique_ptr<WindowFinder> Create(const Options& options);
};

}  // namespace webrtc

#endif  // MODULES_DESKTOP_CAPTURE_WINDOW_FINDER_H_