// Copyright (c) 2010 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 "chrome/browser/views/extensions/extension_shelf.h"

#include <algorithm>

#include "app/resource_bundle.h"
#include "base/logging.h"
#include "base/message_loop.h"
#include "base/stl_util-inl.h"
#include "base/string_util.h"
#include "chrome/browser/browser.h"
#include "chrome/browser/browser_theme_provider.h"
#include "chrome/browser/extensions/extension_host.h"
#include "chrome/browser/extensions/extension_process_manager.h"
#include "chrome/browser/extensions/extensions_service.h"
#include "chrome/browser/profile.h"
#include "chrome/browser/tab_contents/tab_contents.h"
#include "chrome/browser/views/extensions/extension_view.h"
#include "chrome/browser/view_ids.h"
#include "chrome/common/chrome_switches.h"
#include "chrome/common/extensions/extension.h"
#include "chrome/common/notification_service.h"
#include "chrome/common/pref_names.h"
#include "views/controls/label.h"
#include "views/screen.h"
#include "views/widget/root_view.h"

namespace {

// This is the slight padding that is there around the edge of the browser. This
// has been determined empirically.
// TODO(sidchat): Compute this value from the root view of the extension shelf.
static const int kExtensionShelfPaddingOnLeft = 4;

// Margins around the content.
static const int kTopMarginWhenExtensionsOnTop = 1;
static const int kTopMarginWhenExtensionsOnBottom = 2;
static const int kBottomMargin = 2;
static const int kLeftMargin = 0;
static const int kRightMargin = 0;

// Padding on left and right side of an extension toolstrip.
static const int kToolstripPadding = 2;

// Width of the toolstrip divider.
static const int kToolstripDividerWidth = 2;

// Preferred height of the ExtensionShelf.
static const int kShelfHeight = 29;

// Preferred height of the Extension shelf when only shown on the new tab page.
const int kNewtabShelfHeight = 58;

// How inset the extension shelf is when displayed on the new tab page. This is
// in addition to the margins above.
static const int kNewtabHorizontalPadding = 8;
static const int kNewtabVerticalPadding = 12;

// We need an extra margin to the left of all the toolstrips in detached mode,
// so that the first toolstrip doesn't look so squished against the rounded
// corners of the extension shelf.
static const int kNewtabExtraHorMargin = 2;
static const int kNewtabExtraVerMargin = 2;

// Padding for the title inside the handle.
static const int kHandlePadding = 4;

// Inset for the extension view when displayed either dragging or expanded.
static const int kWindowInset = 1;

// Delays for showing and hiding the shelf handle.
static const int kShowDelayMs = 500;
static const int kHideDelayMs = 300;

}  // namespace


// A view that holds the place for a toolstrip in the shelf while the toolstrip
// is being dragged or moved.
// TODO(erikkay) this should draw a dimmed out version of the toolstrip.
class ExtensionShelf::PlaceholderView : public views::View {
 public:
  PlaceholderView() {}

  void SetWidth(int width) {
    SetBounds(x(), y(), width, height());
    PreferredSizeChanged();
  }

  // ExtensionShelf resizes its views to their preferred size at layout,
  // so just always prefer the current size.
  gfx::Size GetPreferredSize() { return size(); }

 private:
  DISALLOW_COPY_AND_ASSIGN(PlaceholderView);
};

// A wrapper class for the ExtensionHost displayed as a toolstrip.
// The class itself also acts as the View for the handle of the toolstrip
// it represents.
class ExtensionShelf::Toolstrip : public views::View,
                                  public BrowserBubble::Delegate,
                                  public AnimationDelegate {
 public:
  Toolstrip(ExtensionShelf* shelf, ExtensionHost* host,
            const Extension::ToolstripInfo& info);
  virtual ~Toolstrip();

  // Convenience to calculate just the size of the handle.
  gfx::Size GetHandlePreferredSize();

  // View methods:
  virtual void Paint(gfx::Canvas* canvas);
  virtual gfx::Size GetPreferredSize();
  virtual void Layout();
  virtual void OnMouseEntered(const views::MouseEvent& event);
  virtual void OnMouseExited(const views::MouseEvent& event);
  virtual bool OnMousePressed(const views::MouseEvent& event);
  virtual bool OnMouseDragged(const views::MouseEvent& event);
  virtual void OnMouseReleased(const views::MouseEvent& event, bool canceled);
  virtual bool IsFocusable() const { return true; }
  virtual void ChildPreferredSizeChanged(View* child);

  // Adjust the size and position of the window/handle.
  void LayoutWindow();

  // Is the toolstrip window visible (not necessarily the handle).
  bool window_visible() { return (window_.get() && window_->visible()); }

  // Is the handle for this toolstrip currently visible.
  bool handle_visible() { return (window_visible() && handle_visible_); }

  // Is the toolstrip opened in expanded mode.
  bool expanded() { return expanded_; }

  // Is the toolstrip being dragged.
  bool dragging() { return dragging_; }

  // Accessors for the host and its view.
  ExtensionHost* host() const { return host_; }
  ExtensionView* view() const { return host_->view(); }

  // The view that's currently displayed in the shelf.  This could be
  // either the ExtensionView or |placeholder_view_| depending on the
  // current state.
  View* GetShelfView() const {
    if (placeholder_view_)
      return placeholder_view_;
    return view();
  }

  // Detaching the toolstrip from the shelf means that the ExtensionView is
  // displayed inside of the BrowserBubble rather than the shelf. This may
  // still visually appear to be part of the shelf (expanded) or completely
  // separate (dragging).
  // If |browser| is true, it also will detach/attach to the browser window.
  void DetachFromShelf(bool browser);
  void AttachToShelf(bool browser);

  // Show / Hide the shelf handle.
  void ShowShelfHandle();
  void DoShowShelfHandle();
  void HideShelfHandle(int delay_ms);
  void DoHideShelfHandle();
  void StopHandleTimer();
  void HideWindow();
  void ShowWindow();

  // Expand / Collapse
  void Expand(int height, const GURL& url);
  void Collapse(const GURL& url);

  // BrowserBubble::Delegate
  virtual void BubbleBrowserWindowMoved(BrowserBubble* bubble);
  virtual void BubbleBrowserWindowClosing(BrowserBubble* bubble);

  // AnimationDelegate
  virtual void AnimationProgressed(const Animation* animation);
  virtual void AnimationEnded(const Animation* animation);

 private:
  // The actual renderer that this toolstrip contains.
  ExtensionHost* host_;

  // Manifest definition of this toolstrip.
  Extension::ToolstripInfo info_;

  // A window that can be logically attached to the browser window.  This is
  // used for two purposes: a handle that sits above the toolstrip when it's
  // collapsed and not dragging, and as a container for the toolstrip when it's
  // dragging or expanded.
  scoped_ptr<BrowserBubble> window_;

  // Used for drawing the name of the extension in the handle.
  scoped_ptr<views::Label> title_;

  // Pointer back to the containing shelf.
  ExtensionShelf* shelf_;

  // When dragging, a placeholder view is put into the shelf to hold space
  // for the ExtensionView.  This view is parent owned when it's in the view
  // hierarchy, so there's no ownership issues here.
  PlaceholderView* placeholder_view_;

  // Current state of the toolstrip, currently can't both be expanded and
  // dragging.
  // TODO(erikkay) Support dragging while expanded.
  bool dragging_;
  bool expanded_;
  bool handle_visible_;

  // The target expanded height of the toolstrip (used for animation).
  int expanded_height_;

  // If dragging, where did the drag start from.
  gfx::Point initial_drag_location_;

  // We have to remember the initial drag point in screen coordinates, because
  // later, when the toolstrip is being dragged around, there is no good way of
  // computing the screen coordinates given the initial drag view coordinates.
  gfx::Point initial_drag_screen_point_;

  // Timers for tracking mouse hovering.
  ScopedRunnableMethodFactory<ExtensionShelf::Toolstrip> timer_factory_;

  // Animate opening and closing the mole.
  scoped_ptr<SlideAnimation> mole_animation_;

  DISALLOW_COPY_AND_ASSIGN(Toolstrip);
};

ExtensionShelf::Toolstrip::Toolstrip(ExtensionShelf* shelf,
                                     ExtensionHost* host,
                                     const Extension::ToolstripInfo& info)
    : host_(host),
      info_(info),
      shelf_(shelf),
      placeholder_view_(NULL),
      dragging_(false),
      expanded_(false),
      handle_visible_(false),
      expanded_height_(0),
      ALLOW_THIS_IN_INITIALIZER_LIST(timer_factory_(this)) {
  DCHECK(host->view());
  // We're owned by shelf_, not the bubble that we get inserted in and out of.
  set_parent_owned(false);

  mole_animation_.reset(new SlideAnimation(this));

  std::wstring name = UTF8ToWide(host_->extension()->name());
  // |title_| isn't actually put in the view hierarchy.  We just use it
  // to draw in place.  The reason for this is so that we can properly handle
  // the various mouse events necessary for hovering and dragging.
  ResourceBundle& rb = ResourceBundle::GetSharedInstance();
  title_.reset(new views::Label(name, rb.GetFont(ResourceBundle::BaseFont)));
  title_->SetBounds(kHandlePadding, kHandlePadding, 100, 100);
  title_->SizeToPreferredSize();

  SizeToPreferredSize();
}

ExtensionShelf::Toolstrip::~Toolstrip() {
  if (window_.get() && window_->attached())
    window_->DetachFromBrowser();
}

void ExtensionShelf::Toolstrip::Paint(gfx::Canvas* canvas) {
  // Paint the background.
  SkColor theme_toolbar_color =
      shelf_->GetThemeProvider()->GetColor(BrowserThemeProvider::COLOR_TOOLBAR);
  canvas->FillRectInt(theme_toolbar_color, 0, 0, width(), height());

  // Paints the handle for the toolstrip (only called on mouse-hover).
  SkColor border_color = ResourceBundle::toolbar_separator_color;
  canvas->FillRectInt(border_color, 0, 0, width(), 1);
  canvas->FillRectInt(border_color, 0, 0, 1, height() - 1);
  canvas->FillRectInt(border_color, width() - 1, 0, 1, height() - 1);
  int ext_width = view()->width() + kToolstripPadding +
      kToolstripDividerWidth;
  if (ext_width < width()) {
    canvas->FillRectInt(border_color, ext_width, height() - 1,
                        width() - ext_width, 1);
  }

  if (handle_visible_) {
    // Draw the title using a Label as a stamp.
    // See constructor for comment about this.
    title_->ProcessPaint(canvas);

    if (dragging_) {
      // When we're dragging, draw the bottom border.
      canvas->FillRectInt(border_color, 0, height() - 1, width(), 1);
    }
  }
}

gfx::Size ExtensionShelf::Toolstrip::GetHandlePreferredSize() {
  gfx::Size sz;
  if (handle_visible_) {
    sz = title_->GetPreferredSize();
    sz.set_width(std::max(view()->width(), sz.width()));
    sz.Enlarge(2 + kHandlePadding * 2, kHandlePadding * 2);
  }
  return sz;
}

gfx::Size ExtensionShelf::Toolstrip::GetPreferredSize() {
  gfx::Size sz;
  if (handle_visible_)
    sz = GetHandlePreferredSize();
  if (view()->GetParent() == this) {
    gfx::Size extension_size = view()->GetPreferredSize();
    sz.Enlarge(0, extension_size.height());
    sz.set_width(extension_size.width());
  }

  // The view is inset slightly when displayed in the window.
  sz.Enlarge(kWindowInset * 2, kWindowInset * 2);
  return sz;
}

void ExtensionShelf::Toolstrip::Layout() {
  if (view()->GetParent() == this) {
    int view_y = kWindowInset;
    if (handle_visible_)
      view_y += GetHandlePreferredSize().height();
    view()->SetBounds(kWindowInset, view_y, view()->width(), view()->height());
  }
}

void ExtensionShelf::Toolstrip::OnMouseEntered(const views::MouseEvent& event) {
  if (dragging_)
    return;
  ShowShelfHandle();
}

void ExtensionShelf::Toolstrip::OnMouseExited(const views::MouseEvent& event) {
  if (dragging_)
    return;
  HideShelfHandle(kHideDelayMs);
}

bool ExtensionShelf::Toolstrip::OnMousePressed(const views::MouseEvent& event) {
  initial_drag_location_ = event.location();
  initial_drag_screen_point_ = views::Screen::GetCursorScreenPoint();
  return true;
}

bool ExtensionShelf::Toolstrip::OnMouseDragged(const views::MouseEvent& event) {
  if (expanded_) {
    // Do nothing for now.
  } else if (!dragging_) {
    int y_delta = abs(initial_drag_location_.y() - event.location().y());
    int x_delta = abs(initial_drag_location_.x() - event.location().x());
    if (y_delta > GetVerticalDragThreshold() ||
        x_delta > GetHorizontalDragThreshold()) {
      dragging_ = true;
      StopHandleTimer();
      DetachFromShelf(true);
    }
  } else {
    // When freely dragging a window, you can really only trust the
    // actual screen point.  Local coordinate conversions don't work.
    gfx::Point screen = views::Screen::GetCursorScreenPoint();

    // However, the handle is actually a child of the browser window
    // so we need to convert it back to local coordinates.
    gfx::Point origin(0, 0);
    views::View::ConvertPointToScreen(shelf_->GetRootView(), &origin);
    int screen_x = screen.x() - initial_drag_location_.x() - origin.x();

    // Restrict the horizontal and vertical motions of the toolstrip so that it
    // cannot be dragged out of the extension shelf. If the extension shelf is
    // on the top along with the bookmark bar, the toolstrip cannot be dragged
    // into the space allocated for bookmarks. The toolstrip cannot be dragged
    // out of the browser window.
    if (screen_x < kExtensionShelfPaddingOnLeft) {
      screen_x = kExtensionShelfPaddingOnLeft;
    } else if (screen_x > shelf_->width() - width() +
               kExtensionShelfPaddingOnLeft) {
      screen_x = shelf_->width() - width() + kExtensionShelfPaddingOnLeft;
    }
    screen.set_x(screen_x);
    screen.set_y(initial_drag_screen_point_.y() - origin.y() -
        initial_drag_location_.y());

    // TODO(erikkay) as this gets dragged around, update the placeholder view
    // on the shelf to show where it will get dropped to.
    window_->MoveTo(screen.x(), screen.y());
  }
  return true;
}

void ExtensionShelf::Toolstrip::OnMouseReleased(const views::MouseEvent& event,
                                                bool canceled) {
  StopHandleTimer();
  if (dragging_) {
    // Drop the toolstrip roughly where it is now.
    views::View::OnMouseReleased(event, canceled);
    dragging_ = false;
    // |this| and |shelf_| are in different view hierarchies, so we need to
    // convert to screen coordinates and back again to map locations.
    gfx::Point loc = event.location();
    View::ConvertPointToScreen(this, &loc);
    View::ConvertPointToView(NULL, shelf_, &loc);
    shelf_->DropExtension(this, loc, canceled);
    AttachToShelf(true);
  } else if (!canceled) {
    // Toggle mole to either expanded or collapsed.
    // TODO(erikkay) If there's no valid URL in the manifest, should we
    // post an event to the toolstrip in this case?
    if (expanded_) {
      if (info_.toolstrip.is_valid())
        shelf_->CollapseToolstrip(host_, info_.toolstrip);
    } else {
     if (info_.mole.is_valid())
       shelf_->ExpandToolstrip(host_, info_.mole, info_.mole_height);
    }
  }
}

void ExtensionShelf::Toolstrip::LayoutWindow() {
  if (!window_visible() && !handle_visible_ && !expanded_)
    return;

  if (!window_.get()) {
    window_.reset(new BrowserBubble(this, shelf_->GetWidget(),
                                    gfx::Point(0, 0),
                                    false));  //  Do not add a drop-shadow.
    window_->set_delegate(this);
  }

  gfx::Size window_size = GetPreferredSize();
  if (mole_animation_->is_animating()) {
    // We only want to animate the body of the mole window.  When we're
    // expanding, this is everything except for the handle.  When we're
    // collapsing, this is everything except for the handle and the toolstrip.
    // We subtract this amount from the target height, figure out the step in
    // the animation from the rest, and then add it back in.
    int window_offset = shelf_->height();
    if (!mole_animation_->IsShowing())
      window_offset += GetPreferredSize().height();
    else
      window_offset += GetHandlePreferredSize().height();
    int h = expanded_height_ - window_offset;
    window_size.set_height(window_offset +
        static_cast<int>(h * mole_animation_->GetCurrentValue()));
  } else if (!expanded_ && !dragging_) {
    window_size.set_height(GetHandlePreferredSize().height());
  }

  // Now figure out where to place the window on the screen.  Since it's a top-
  // level widget, we need to do some coordinate conversion to get this right.
  gfx::Point origin(-kToolstripPadding, 0);
  if (expanded_ || mole_animation_->is_animating()) {
    origin.set_y(GetShelfView()->height() - window_size.height());
    views::View::ConvertPointToView(GetShelfView(), shelf_->GetRootView(),
                                    &origin);
  } else {
    origin.set_y(-(window_size.height() + kToolstripPadding - 1));
    views::View::ConvertPointToWidget(view(), &origin);
  }
  SetBounds(0, 0, window_size.width(), window_size.height());
  window_->SetBounds(origin.x(), origin.y(),
                     window_size.width(), window_size.height());
}

void ExtensionShelf::Toolstrip::ChildPreferredSizeChanged(View* child) {
  if (child == view()) {
    child->SizeToPreferredSize();
    Layout();
    if (window_visible())
      LayoutWindow();
    if (expanded_) {
      placeholder_view_->SetWidth(child->width());
      shelf_->Layout();
    }
  }
}

void ExtensionShelf::Toolstrip::BubbleBrowserWindowMoved(
    BrowserBubble* bubble) {
  if (!expanded_)
    HideWindow();
}

void ExtensionShelf::Toolstrip::BubbleBrowserWindowClosing(
    BrowserBubble* bubble) {
  HideWindow();
}

void ExtensionShelf::Toolstrip::AnimationProgressed(
    const Animation* animation) {
  LayoutWindow();
}

void ExtensionShelf::Toolstrip::AnimationEnded(const Animation* animation) {
  if (window_visible())
    LayoutWindow();
  if (!expanded_) {
    AttachToShelf(false);
    HideShelfHandle(kHideDelayMs);
  }
}

void ExtensionShelf::Toolstrip::DetachFromShelf(bool browserDetach) {
  DCHECK(window_.get());
  DCHECK(!placeholder_view_);
  if (browserDetach && window_->attached())
    window_->DetachFromBrowser();

  // Construct a placeholder view to replace the view.
  placeholder_view_ = new PlaceholderView();
  placeholder_view_->SetBounds(view()->bounds());
  shelf_->AddChildView(placeholder_view_);

  AddChildView(view());
  SizeToPreferredSize();
  window_->ResizeToView();
  Layout();
}

void ExtensionShelf::Toolstrip::AttachToShelf(bool browserAttach) {
  DCHECK(window_.get());
  DCHECK(placeholder_view_);
  if (browserAttach && !window_->attached())
    window_->AttachToBrowser();

  // Move the view back into the shelf and remove the old placeholder.
  shelf_->AddChildView(view());

  // The size of the view may have changed, so just set the position.
  view()->SetX(placeholder_view_->x());
  view()->SetY(placeholder_view_->y());

  // Remove the old placeholder.
  shelf_->RemoveChildView(placeholder_view_);
  delete placeholder_view_;
  placeholder_view_ = NULL;

  SizeToPreferredSize();
  Layout();
  shelf_->Layout();
}

void ExtensionShelf::Toolstrip::DoShowShelfHandle() {
  if (!handle_visible()) {
    handle_visible_ = true;

    // Make sure the text color for the title matches the theme colors.
    title_->SetColor(
        shelf_->GetThemeProvider()->GetColor(
            BrowserThemeProvider::COLOR_BOOKMARK_TEXT));

    ShowWindow();
  }
}

void ExtensionShelf::Toolstrip::HideWindow() {
  if (!window_visible())
    return;
  handle_visible_ = false;
  window_->Hide();
  if (expanded_) {
    if (info_.toolstrip.is_valid())
      shelf_->CollapseToolstrip(host_, info_.toolstrip);
    else
      shelf_->CollapseToolstrip(host_, GURL());
  }
  if (window_->attached())
    window_->DetachFromBrowser();
  window_.reset(NULL);
  shelf_->Layout();
}

void ExtensionShelf::Toolstrip::ShowWindow() {
  DCHECK(handle_visible_ || expanded_);

  LayoutWindow();
  if (!window_visible())
    window_->Show(false);  // |false| means show, but don't activate.
}

void ExtensionShelf::Toolstrip::DoHideShelfHandle() {
  if (!handle_visible())
    return;
  handle_visible_ = false;
  if (expanded_) {
    LayoutWindow();
    Layout();
  } else {
    HideWindow();
  }
}

void ExtensionShelf::Toolstrip::StopHandleTimer() {
  if (!timer_factory_.empty())
    timer_factory_.RevokeAll();
}

void ExtensionShelf::Toolstrip::Expand(int height, const GURL& url) {
  DCHECK(!expanded_);

  expanded_ = true;
  ShowWindow();

  bool navigate = (!url.is_empty() && url != host_->GetURL());
  if (navigate)
    host_->NavigateToURL(url);

  StopHandleTimer();
  DetachFromShelf(false);

  mole_animation_->Show();

  gfx::Size extension_size = view()->GetPreferredSize();
  extension_size.set_height(height);
  view()->SetPreferredSize(extension_size);
  expanded_height_ = GetPreferredSize().height();

  // This is to prevent flickering as the page loads and lays out.
  // Once the navigation is finished, ExtensionView will wind up setting
  // visibility to true.
  if (navigate)
    view()->SetVisible(false);
}

void ExtensionShelf::Toolstrip::Collapse(const GURL& url) {
  DCHECK(expanded_);
  expanded_ = false;

  if (window_visible())
    mole_animation_->Hide();

  gfx::Size extension_size = view()->GetPreferredSize();
  extension_size.set_height(
      kShelfHeight - (shelf_->top_margin() + kBottomMargin));
  view()->SetPreferredSize(extension_size);

  if (!url.is_empty() && url != host_->GetURL()) {
    host_->NavigateToURL(url);

    // This is to prevent flickering as the page loads and lays out.
    // Once the navigation is finished, ExtensionView will wind up setting
    // visibility to true.
    view()->SetVisible(false);
  }

  if (!window_visible())
    AnimationEnded(NULL);
}

void ExtensionShelf::Toolstrip::ShowShelfHandle() {
  StopHandleTimer();
  if (handle_visible())
    return;
  MessageLoop::current()->PostDelayedTask(FROM_HERE,
      timer_factory_.NewRunnableMethod(
          &ExtensionShelf::Toolstrip::DoShowShelfHandle),
      kShowDelayMs);
}

void ExtensionShelf::Toolstrip::HideShelfHandle(int delay_ms) {
  StopHandleTimer();
  if (!handle_visible() || dragging_ || mole_animation_->is_animating())
    return;
  if (delay_ms) {
    MessageLoop::current()->PostDelayedTask(FROM_HERE,
        timer_factory_.NewRunnableMethod(
            &ExtensionShelf::Toolstrip::DoHideShelfHandle),
        delay_ms);
  } else {
    DoHideShelfHandle();
  }
}

////////////////////////////////////////////////////////////////////////////////

ExtensionShelf::ExtensionShelf(Browser* browser)
  :   background_needs_repaint_(true),
      browser_(browser),
      model_(browser->extension_shelf_model()),
      fullscreen_(false) {
  SetID(VIEW_ID_DEV_EXTENSION_SHELF);

  top_margin_ = kTopMarginWhenExtensionsOnBottom;

  model_->AddObserver(this);
  LoadFromModel();
  EnableCanvasFlippingForRTLUI(true);
  registrar_.Add(this,
                 NotificationType::EXTENSION_SHELF_VISIBILITY_PREF_CHANGED,
                 NotificationService::AllSources());

  size_animation_.reset(new SlideAnimation(this));
  if (IsAlwaysShown())
    size_animation_->Reset(1);
  else
    size_animation_->Reset(0);
}

ExtensionShelf::~ExtensionShelf() {
  if (model_) {
    int count = model_->count();
    for (int i = 0; i < count; ++i) {
      delete ToolstripAtIndex(i);
      model_->SetToolstripDataAt(i, NULL);
    }
    model_->RemoveObserver(this);
  }
}

void ExtensionShelf::PaintChildren(gfx::Canvas* canvas) {
  InitBackground(canvas);

  int max_x = width();
  if (IsDetached())
    max_x -= 2 * kNewtabHorizontalPadding;

  // Draw vertical dividers between Toolstrip items in the Extension shelf.
  int count = GetChildViewCount();
  for (int i = 0; i < count; ++i) {
    int right = GetChildViewAt(i)->bounds().right() + kToolstripPadding;
    if (right >= max_x)
      break;
    int vertical_padding = IsDetached() ? (height() - kShelfHeight) / 2 : 1;

    DetachableToolbarView::PaintVerticalDivider(
        canvas, right, height(), vertical_padding,
        DetachableToolbarView::kEdgeDividerColor,
        DetachableToolbarView::kMiddleDividerColor,
        GetThemeProvider()->GetColor(BrowserThemeProvider::COLOR_TOOLBAR));
  }
}

// static
void ExtensionShelf::ToggleWhenExtensionShelfVisible(Profile* profile) {
  PrefService* prefs = profile->GetPrefs();
  const bool always_show = !prefs->GetBoolean(prefs::kShowExtensionShelf);

  // The user changed when the Extension Shelf is shown, update the
  // preferences.
  prefs->SetBoolean(prefs::kShowExtensionShelf, always_show);
  prefs->ScheduleSavePersistentPrefs();

  // And notify the notification service.
  Source<Profile> source(profile);
  NotificationService::current()->Notify(
      NotificationType::EXTENSION_SHELF_VISIBILITY_PREF_CHANGED,
      source,
      NotificationService::NoDetails());
}

gfx::Size ExtensionShelf::GetPreferredSize() {
  return LayoutItems(true);
}

void ExtensionShelf::ChildPreferredSizeChanged(View* child) {
  PreferredSizeChanged();
}

void ExtensionShelf::Layout() {
  LayoutItems(false);
}

void ExtensionShelf::OnMouseEntered(const views::MouseEvent& event) {
}

void ExtensionShelf::OnMouseExited(const views::MouseEvent& event) {
}

bool ExtensionShelf::GetAccessibleRole(AccessibilityTypes::Role* role) {
  DCHECK(role);

  *role = AccessibilityTypes::ROLE_TOOLBAR;
  return true;
}

void ExtensionShelf::ThemeChanged() {
  // Refresh the CSS to update toolstrip text colors from theme.
  int count = model_->count();
  for (int i = 0; i < count; ++i)
    ToolstripAtIndex(i)->view()->host()->InsertThemedToolstripCSS();

  Layout();
}

void ExtensionShelf::ToolstripInsertedAt(ExtensionHost* host,
                                         int index) {
  model_->SetToolstripDataAt(index,
      new Toolstrip(this, host, model_->ToolstripAt(index).info));

  bool had_views = GetChildViewCount() > 0;
  ExtensionView* view = host->view();
  AddChildView(view);
  view->SetContainer(this);
  if (!had_views)
    PreferredSizeChanged();
  Layout();
}

void ExtensionShelf::ToolstripRemovingAt(ExtensionHost* host, int index) {
  // Delete the Toolstrip view and remove it from the model.
  Toolstrip* toolstrip = ToolstripAtIndex(index);
  View* view = toolstrip->GetShelfView();
  RemoveChildView(view);
  delete toolstrip;
  model_->SetToolstripDataAt(index, NULL);

  // Technically, the toolstrip is still in the model at this point, but
  // the Layout code handles this case.
  Layout();
}

void ExtensionShelf::ToolstripDraggingFrom(ExtensionHost* host, int index) {
}

void ExtensionShelf::ToolstripMoved(ExtensionHost* host, int from_index,
                                    int to_index) {
  Layout();
}

void ExtensionShelf::ToolstripChanged(ExtensionShelfModel::iterator toolstrip) {
  Toolstrip* t = static_cast<Toolstrip*>(toolstrip->data);
  if (toolstrip->height > 0) {
    if (!t->expanded()) {
      t->Expand(toolstrip->height, toolstrip->url);
    }
  } else if (t->expanded()) {
    t->Collapse(toolstrip->url);
  }
}

void ExtensionShelf::ExtensionShelfEmpty() {
  PreferredSizeChanged();
}

void ExtensionShelf::ShelfModelReloaded() {
  // None of the child views are parent owned, so nothing is being leaked here.
  RemoveAllChildViews(false);
  LoadFromModel();
}

void ExtensionShelf::ShelfModelDeleting() {
  int count = model_->count();
  for (int i = 0; i < count; ++i) {
    delete ToolstripAtIndex(i);
    model_->SetToolstripDataAt(i, NULL);
  }
  model_->RemoveObserver(this);
  model_ = NULL;
}

void ExtensionShelf::AnimationProgressed(const Animation* animation) {
  if (browser_)
    browser_->ExtensionShelfSizeChanged();
}

void ExtensionShelf::AnimationEnded(const Animation* animation) {
  if (browser_)
    browser_->ExtensionShelfSizeChanged();

  Layout();
}

void ExtensionShelf::Observe(NotificationType type,
                             const NotificationSource& source,
                             const NotificationDetails& details) {
  switch (type.value) {
    case NotificationType::EXTENSION_SHELF_VISIBILITY_PREF_CHANGED: {
      if (fullscreen_)
        break;
      if (IsAlwaysShown())
        size_animation_->Show();
      else
        size_animation_->Hide();
      break;
    }
    default:
      NOTREACHED();
      break;
  }
}

void ExtensionShelf::OnExtensionMouseEvent(ExtensionView* view) {
  Toolstrip *toolstrip = ToolstripForView(view);
  if (toolstrip)
    toolstrip->ShowShelfHandle();
}

void ExtensionShelf::OnExtensionMouseLeave(ExtensionView* view) {
  Toolstrip *toolstrip = ToolstripForView(view);
  if (toolstrip)
    toolstrip->HideShelfHandle(kHideDelayMs);
}

void ExtensionShelf::DropExtension(Toolstrip* toolstrip, const gfx::Point& pt,
                                   bool cancel) {
  Toolstrip* dest_toolstrip = ToolstripAtX(pt.x());
  if (!dest_toolstrip) {
    if (pt.x() > 0)
      dest_toolstrip = ToolstripAtIndex(model_->count() - 1);
    else
      dest_toolstrip = ToolstripAtIndex(0);
  }
  if (toolstrip == dest_toolstrip)
    return;
  int from = model_->IndexOfHost(toolstrip->host());
  int to = model_->IndexOfHost(dest_toolstrip->host());
  DCHECK(from != to);
  model_->MoveToolstripAt(from, to);
}

void ExtensionShelf::ExpandToolstrip(ExtensionHost* host, const GURL& url,
                                     int height) {
  ExtensionShelfModel::iterator toolstrip = model_->ToolstripForHost(host);
  model_->ExpandToolstrip(toolstrip, url, height);
}

void ExtensionShelf::CollapseToolstrip(ExtensionHost* host, const GURL& url) {
  ExtensionShelfModel::iterator toolstrip = model_->ToolstripForHost(host);
  model_->CollapseToolstrip(toolstrip, url);
}

void ExtensionShelf::InitBackground(gfx::Canvas* canvas) {
  if (!background_needs_repaint_)
    return;

  // Capture a background bitmap to give to the toolstrips.
  SkRect background_rect = {
      SkIntToScalar(0),
      SkIntToScalar(0),
      SkIntToScalar(width()),
      SkIntToScalar(height())
  };

  // Tell all extension views about the new background.
  int count = model_->count();
  for (int i = 0; i < count; ++i) {
    ExtensionView* view = ToolstripAtIndex(i)->view();

    const SkBitmap& background = canvas->getDevice()->accessBitmap(false);

    SkRect mapped_subset = background_rect;
    gfx::Rect view_bounds = view->bounds();
    mapped_subset.offset(SkIntToScalar(view_bounds.x()),
                         SkIntToScalar(view_bounds.y()));
    bool result = canvas->getTotalMatrix().mapRect(&mapped_subset);
    DCHECK(result);

    SkIRect isubset;
    mapped_subset.round(&isubset);
    SkBitmap subset_bitmap;
    // This will create another bitmap that just references pixels in the
    // actual bitmap.
    result = background.extractSubset(&subset_bitmap, isubset);
    if (!result)
      return;

    // We do a deep copy because extractSubset() returns a bitmap that
    // references pixels in the original one and we want to actually make a
    // smaller copy that will have a long lifetime.
    SkBitmap smaller_copy;
    if (!subset_bitmap.copyTo(&smaller_copy, SkBitmap::kARGB_8888_Config))
      return;
    DCHECK(smaller_copy.readyToDraw());

    view->SetBackground(smaller_copy);
  }

  background_needs_repaint_ = false;
}

ExtensionShelf::Toolstrip* ExtensionShelf::ToolstripAtX(int x) {
  int count = model_->count();
  if (count == 0)
    return NULL;

  if (x < 0)
    return NULL;

  for (int i = 0; i < count; ++i) {
    Toolstrip* toolstrip = ToolstripAtIndex(i);
    View* view = toolstrip->GetShelfView();
    int x_mirrored = view->GetRootView()->MirroredXCoordinateInsideView(x);
    if (x_mirrored > view->x() + view->width() + kToolstripPadding)
      continue;
    return toolstrip;
  }

  return NULL;
}

ExtensionShelf::Toolstrip* ExtensionShelf::ToolstripAtIndex(int index) {
  return static_cast<Toolstrip*>(model_->ToolstripAt(index).data);
}

ExtensionShelf::Toolstrip* ExtensionShelf::ToolstripForView(
    ExtensionView* view) {
  int count = model_->count();
  for (int i = 0; i < count; ++i) {
    Toolstrip* toolstrip = ToolstripAtIndex(i);
    if (view == toolstrip->view())
      return toolstrip;
  }
  return NULL;
}

void ExtensionShelf::LoadFromModel() {
  int count = model_->count();
  for (int i = 0; i < count; ++i)
    ToolstripInsertedAt(model_->ToolstripAt(i).host, i);
}

gfx::Size ExtensionShelf::LayoutItems(bool compute_bounds_only) {
  if (!GetParent() || !model_ || !model_->count())
    return gfx::Size(0, 0);

  gfx::Size prefsize;
  int x = kLeftMargin;
  int y = top_margin_;
  int content_height = kShelfHeight - top_margin_ - kBottomMargin;
  int max_x = width() - kRightMargin;

  if (OnNewTabPage()) {
    double current_state = 1 - size_animation_->GetCurrentValue();
    x += static_cast<int>(static_cast<double>
        (kNewtabHorizontalPadding + kNewtabExtraHorMargin) * current_state);
    y += static_cast<int>(static_cast<double>
        (kNewtabVerticalPadding + kNewtabExtraVerMargin) * current_state);
    max_x -= static_cast<int>(static_cast<double>
        (2 * kNewtabHorizontalPadding) * current_state);
  }

  int count = model_->count();
  for (int i = 0; i < count; ++i) {
    x += kToolstripPadding;  // Left padding.
    Toolstrip* toolstrip = ToolstripAtIndex(i);
    if (!toolstrip)  // Can be NULL while in the process of removing.
      continue;
    View* view = toolstrip->GetShelfView();
    gfx::Size pref = view->GetPreferredSize();

    // |next_x| is the x value for where the next toolstrip in the list will be.
    int next_x = x + pref.width() + kToolstripPadding;  // Right padding.
    if (!compute_bounds_only) {
      bool clipped = next_x >= max_x;
      if (clipped)
        pref.set_width(std::max(0, max_x - x));
      if (view == toolstrip->view())
        toolstrip->view()->SetIsClipped(clipped);
      view->SetBounds(x, y, pref.width(), content_height);
      view->Layout();
      if (toolstrip->window_visible())
        toolstrip->LayoutWindow();
    }
    x = next_x + kToolstripDividerWidth;
  }

  if (!compute_bounds_only) {
    background_needs_repaint_ = true;
    SchedulePaint();
  } else {
    if (OnNewTabPage()) {
      prefsize.set_height(kShelfHeight + static_cast<int>(static_cast<double>
                              (kNewtabShelfHeight - kShelfHeight) *
                              (1 - size_animation_->GetCurrentValue())));
    } else {
      prefsize.set_height(static_cast<int>(static_cast<double>(kShelfHeight) *
                              size_animation_->GetCurrentValue()));
    }

    x += kRightMargin;
    prefsize.set_width(x);
  }

  return prefsize;
}

bool ExtensionShelf::IsDetached() const {
  return OnNewTabPage() && (size_animation_->GetCurrentValue() != 1);
}

bool ExtensionShelf::IsAlwaysShown() const {
  Profile* profile = browser_->profile();
  return profile->GetPrefs()->GetBoolean(prefs::kShowExtensionShelf);
}

bool ExtensionShelf::OnNewTabPage() const {
  return (browser_ && browser_->GetSelectedTabContents() &&
      browser_->GetSelectedTabContents()->IsExtensionShelfAlwaysVisible());
}

void ExtensionShelf::OnFullscreenToggled(bool fullscreen) {
  if (fullscreen == fullscreen_)
    return;
  fullscreen_ = fullscreen;
  if (!IsAlwaysShown())
    return;
  size_animation_->Reset(fullscreen ? 0 : 1);
}