// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ui/aura/client/default_capture_client.h"

#include "base/no_destructor.h"
#include "base/observer_list.h"
#include "ui/aura/client/capture_client_observer.h"
#include "ui/aura/env.h"
#include "ui/aura/window.h"
#include "ui/aura/window_event_dispatcher.h"
#include "ui/aura/window_tree_host.h"

namespace aura {
namespace client {
namespace {

// Track the active capture window across root windows.
base::WeakPtr<Window>& GetGlobalCaptureWindowRef() {
  static base::NoDestructor<base::WeakPtr<Window>> global_capture_window;
  return *global_capture_window;
}

}  // namespace

DefaultCaptureClient::DefaultCaptureClient(Window* root_window)
    : root_window_(root_window), capture_window_(nullptr) {
  DCHECK(root_window_);
  SetCaptureClient(root_window_, this);
}

DefaultCaptureClient::~DefaultCaptureClient() {
  if (GetGlobalCaptureWindowRef().get() == capture_window_.get()) {
    GetGlobalCaptureWindowRef() = nullptr;
  }
  SetCaptureClient(root_window_, nullptr);
}

void DefaultCaptureClient::SetCapture(Window* window) {
  if (capture_window_.get() == window) {
    return;
  }
  auto new_capture_window_weak =
      window ? window->GetWeakPtrAsWindow() : nullptr;
  if (window)
    Env::GetInstance()->gesture_recognizer()->CancelActiveTouchesExcept(window);

  auto old_capture_window = capture_window_;

  capture_window_ = new_capture_window_weak;
  GetGlobalCaptureWindowRef() = new_capture_window_weak;

  CaptureDelegate* capture_delegate = nullptr;
  if (capture_window_) {
    DCHECK(!root_window_ || root_window_ == capture_window_->GetRootWindow());
    capture_delegate = capture_window_->GetHost()->dispatcher();
    capture_delegate->SetNativeCapture();
  } else {
    DCHECK(!root_window_ ||
           root_window_ == old_capture_window->GetRootWindow());
    capture_delegate = old_capture_window->GetHost()->dispatcher();
    capture_delegate->ReleaseNativeCapture();
  }

  capture_delegate->UpdateCapture(old_capture_window.get(),
                                  capture_window_.get());

  observers_.Notify(&CaptureClientObserver::OnCaptureChanged,
                    old_capture_window.get(), capture_window_.get());
}

void DefaultCaptureClient::ReleaseCapture(Window* window) {
  if (capture_window_.get() != window) {
    return;
  }
  SetCapture(nullptr);
}

Window* DefaultCaptureClient::GetCaptureWindow() {
  return capture_window_.get();
}

Window* DefaultCaptureClient::GetGlobalCaptureWindow() {
  return GetGlobalCaptureWindowRef().get();
}

void DefaultCaptureClient::AddObserver(CaptureClientObserver* observer) {
  observers_.AddObserver(observer);
}

void DefaultCaptureClient::RemoveObserver(CaptureClientObserver* observer) {
  observers_.RemoveObserver(observer);
}

}  // namespace client
}  // namespace aura