// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "views/controls/native/native_view_host.h"

#include "base/logging.h"
#include "ui/gfx/canvas.h"
#include "views/controls/native/native_view_host_views.h"
#include "views/controls/native/native_view_host_wrapper.h"
#include "views/widget/widget.h"

namespace views {

// static
const char NativeViewHost::kViewClassName[] = "views/NativeViewHost";

#if defined(OS_LINUX)
// GTK renders the focus.
// static
const bool NativeViewHost::kRenderNativeControlFocus = false;
#else
// static
const bool NativeViewHost::kRenderNativeControlFocus = true;
#endif

////////////////////////////////////////////////////////////////////////////////
// NativeViewHost, public:

NativeViewHost::NativeViewHost()
    : native_view_(NULL),
      views_view_(NULL),
      fast_resize_(false),
      focus_view_(NULL) {
}

NativeViewHost::~NativeViewHost() {
}

void NativeViewHost::Attach(gfx::NativeView native_view) {
  DCHECK(native_view);
  DCHECK(!native_view_);
  DCHECK(!views_view_);
  native_view_ = native_view;
  // If set_focus_view() has not been invoked, this view is the one that should
  // be seen as focused when the native view receives focus.
  if (!focus_view_)
    focus_view_ = this;
  native_wrapper_->NativeViewAttached();
}

void NativeViewHost::AttachToView(View* view) {
  if (view == views_view_)
    return;
  DCHECK(view);
  DCHECK(!native_view_);
  DCHECK(!views_view_);
  native_wrapper_.reset(new NativeViewHostViews(this));
  views_view_ = view;
  // If set_focus_view() has not been invoked, this view is the one that should
  // be seen as focused when the native view receives focus.
  if (!focus_view_)
    focus_view_ = this;
  native_wrapper_->NativeViewAttached();
}

void NativeViewHost::Detach() {
  Detach(false);
}

void NativeViewHost::SetPreferredSize(const gfx::Size& size) {
  preferred_size_ = size;
  PreferredSizeChanged();
}

void NativeViewHost::NativeViewDestroyed() {
  // Detach so we can clear our state and notify the native_wrapper_ to release
  // ref on the native view.
  Detach(true);
}

////////////////////////////////////////////////////////////////////////////////
// NativeViewHost, View overrides:

gfx::Size NativeViewHost::GetPreferredSize() {
  return preferred_size_;
}

void NativeViewHost::Layout() {
  if ((!native_view_ && !views_view_) || !native_wrapper_.get())
    return;

  gfx::Rect vis_bounds = GetVisibleBounds();
  bool visible = !vis_bounds.IsEmpty();

  if (visible && !fast_resize_) {
    if (vis_bounds.size() != size()) {
      // Only a portion of the Widget is really visible.
      int x = vis_bounds.x();
      int y = vis_bounds.y();
      native_wrapper_->InstallClip(x, y, vis_bounds.width(),
                                   vis_bounds.height());
    } else if (native_wrapper_->HasInstalledClip()) {
      // The whole widget is visible but we installed a clip on the widget,
      // uninstall it.
      native_wrapper_->UninstallClip();
    }
  }

  if (visible) {
    // Since widgets know nothing about the View hierarchy (they are direct
    // children of the Widget that hosts our View hierarchy) they need to be
    // positioned in the coordinate system of the Widget, not the current
    // view.  Also, they should be positioned respecting the border insets
    // of the native view.
    gfx::Rect local_bounds = ConvertRectToWidget(GetContentsBounds());
    native_wrapper_->ShowWidget(local_bounds.x(), local_bounds.y(),
                                local_bounds.width(),
                                local_bounds.height());
  } else {
    native_wrapper_->HideWidget();
  }
}

void NativeViewHost::OnPaint(gfx::Canvas* canvas) {
  // Paint background if there is one. NativeViewHost needs to paint
  // a background when it is hosted in a TabbedPane. For Gtk implementation,
  // NativeTabbedPaneGtk uses a NativeWidgetGtk as page container and because
  // NativeWidgetGtk hook "expose" with its root view's paint, we need to
  // fill the content. Otherwise, the tab page's background is not properly
  // cleared. For Windows case, it appears okay to not paint background because
  // we don't have a container window in-between. However if you want to use
  // customized background, then this becomes necessary.
  OnPaintBackground(canvas);

  // The area behind our window is black, so during a fast resize (where our
  // content doesn't draw over the full size of our native view, and the native
  // view background color doesn't show up), we need to cover that blackness
  // with something so that fast resizes don't result in black flash.
  //
  // It would be nice if this used some approximation of the page's
  // current background color.
  if (native_wrapper_->HasInstalledClip())
    canvas->FillRect(SK_ColorWHITE, GetLocalBounds());
}

void NativeViewHost::VisibilityChanged(View* starting_from, bool is_visible) {
  Layout();
}

bool NativeViewHost::NeedsNotificationWhenVisibleBoundsChange() const {
  // The native widget is placed relative to the root. As such, we need to
  // know when the position of any ancestor changes, or our visibility relative
  // to other views changed as it'll effect our position relative to the root.
  return true;
}

void NativeViewHost::OnVisibleBoundsChanged() {
  Layout();
}

void NativeViewHost::ViewHierarchyChanged(bool is_add, View* parent,
                                          View* child) {
  if (is_add && GetWidget()) {
    if (!native_wrapper_.get())
      native_wrapper_.reset(NativeViewHostWrapper::CreateWrapper(this));
    native_wrapper_->AddedToWidget();
  } else if (!is_add) {
    native_wrapper_->RemovedFromWidget();
  }
}

std::string NativeViewHost::GetClassName() const {
  return kViewClassName;
}

void NativeViewHost::OnFocus() {
  native_wrapper_->SetFocus();
  GetWidget()->NotifyAccessibilityEvent(
      this, ui::AccessibilityTypes::EVENT_FOCUS, true);
}

gfx::NativeViewAccessible NativeViewHost::GetNativeViewAccessible() {
  if (native_wrapper_.get()) {
    gfx::NativeViewAccessible accessible_view =
        native_wrapper_->GetNativeViewAccessible();
    if (accessible_view)
      return accessible_view;
  }

  return View::GetNativeViewAccessible();
}

////////////////////////////////////////////////////////////////////////////////
// NativeViewHost, private:

void NativeViewHost::Detach(bool destroyed) {
  if (native_view_ || views_view_) {
    native_wrapper_->NativeViewDetaching(destroyed);
    native_view_ = NULL;
    views_view_ = NULL;
  }
}

}  // namespace views