// Copyright 2013 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 "ash/shelf/shelf_button.h"

#include <algorithm>

#include "ash/ash_constants.h"
#include "ash/ash_switches.h"
#include "ash/shelf/shelf_button_host.h"
#include "ash/shelf/shelf_layout_manager.h"
#include "grit/ash_resources.h"
#include "skia/ext/image_operations.h"
#include "ui/accessibility/ax_view_state.h"
#include "ui/base/resource/resource_bundle.h"
#include "ui/compositor/layer.h"
#include "ui/compositor/scoped_layer_animation_settings.h"
#include "ui/events/event_constants.h"
#include "ui/gfx/animation/animation_delegate.h"
#include "ui/gfx/animation/throb_animation.h"
#include "ui/gfx/canvas.h"
#include "ui/gfx/image/image.h"
#include "ui/gfx/image/image_skia_operations.h"
#include "ui/gfx/skbitmap_operations.h"
#include "ui/views/controls/image_view.h"

namespace {

// Size of the bar. This is along the opposite axis of the shelf. For example,
// if the shelf is aligned horizontally then this is the height of the bar.
const int kBarSize = 3;
const int kIconSize = 32;
const int kIconPad = 5;
const int kIconPadVertical = 6;
const int kAttentionThrobDurationMS = 800;

// Simple AnimationDelegate that owns a single ThrobAnimation instance to
// keep all Draw Attention animations in sync.
class ShelfButtonAnimation : public gfx::AnimationDelegate {
 public:
  class Observer {
   public:
    virtual void AnimationProgressed() = 0;

   protected:
    virtual ~Observer() {}
  };

  static ShelfButtonAnimation* GetInstance() {
    static ShelfButtonAnimation* s_instance = new ShelfButtonAnimation();
    return s_instance;
  }

  void AddObserver(Observer* observer) {
    observers_.AddObserver(observer);
  }

  void RemoveObserver(Observer* observer) {
    observers_.RemoveObserver(observer);
    if (!observers_.might_have_observers())
      animation_.Stop();
  }

  int GetAlpha() {
    return GetThrobAnimation().CurrentValueBetween(0, 255);
  }

  double GetAnimation() {
    return GetThrobAnimation().GetCurrentValue();
  }

 private:
  ShelfButtonAnimation()
      : animation_(this) {
    animation_.SetThrobDuration(kAttentionThrobDurationMS);
    animation_.SetTweenType(gfx::Tween::SMOOTH_IN_OUT);
  }

  virtual ~ShelfButtonAnimation() {
  }

  gfx::ThrobAnimation& GetThrobAnimation() {
    if (!animation_.is_animating()) {
      animation_.Reset();
      animation_.StartThrobbing(-1 /*throb indefinitely*/);
    }
    return animation_;
  }

  // gfx::AnimationDelegate
  virtual void AnimationProgressed(const gfx::Animation* animation) OVERRIDE {
    if (animation != &animation_)
      return;
    if (!animation_.is_animating())
      return;
    FOR_EACH_OBSERVER(Observer, observers_, AnimationProgressed());
  }

  gfx::ThrobAnimation animation_;
  ObserverList<Observer> observers_;

  DISALLOW_COPY_AND_ASSIGN(ShelfButtonAnimation);
};

}  // namespace

namespace ash {

////////////////////////////////////////////////////////////////////////////////
// ShelfButton::BarView

class ShelfButton::BarView : public views::ImageView,
                             public ShelfButtonAnimation::Observer {
 public:
  BarView(ShelfButton* host)
      : host_(host),
        show_attention_(false) {
  }

  virtual ~BarView() {
    if (show_attention_)
      ShelfButtonAnimation::GetInstance()->RemoveObserver(this);
  }

  // views::View:
  virtual bool CanProcessEventsWithinSubtree() const OVERRIDE {
    // Send events to the parent view for handling.
    return false;
  }

  virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE {
    if (show_attention_) {
      int alpha = ShelfButtonAnimation::GetInstance()->GetAlpha();
      canvas->SaveLayerAlpha(alpha);
      views::ImageView::OnPaint(canvas);
      canvas->Restore();
    } else {
      views::ImageView::OnPaint(canvas);
    }
  }

  // ShelfButtonAnimation::Observer
  virtual void AnimationProgressed() OVERRIDE {
    UpdateBounds();
    SchedulePaint();
  }

  void SetBarBoundsRect(const gfx::Rect& bounds) {
    base_bounds_ = bounds;
    UpdateBounds();
  }

  void ShowAttention(bool show) {
    if (show_attention_ != show) {
      show_attention_ = show;
      if (show_attention_)
        ShelfButtonAnimation::GetInstance()->AddObserver(this);
      else
        ShelfButtonAnimation::GetInstance()->RemoveObserver(this);
    }
    UpdateBounds();
  }

 private:
  void UpdateBounds() {
    gfx::Rect bounds = base_bounds_;
    if (show_attention_) {
      // Scale from .35 to 1.0 of the total width (which is wider than the
      // visible width of the image, so the animation "rests" briefly at full
      // visible width.
      double animation = ShelfButtonAnimation::GetInstance()->GetAnimation();
      double scale = (.35 + .65 * animation);
      if (host_->shelf_layout_manager()->GetAlignment() ==
          SHELF_ALIGNMENT_BOTTOM) {
        bounds.set_width(base_bounds_.width() * scale);
        int x_offset = (base_bounds_.width() - bounds.width()) / 2;
        bounds.set_x(base_bounds_.x() + x_offset);
      } else {
        bounds.set_height(base_bounds_.height() * scale);
        int y_offset = (base_bounds_.height() - bounds.height()) / 2;
        bounds.set_y(base_bounds_.y() + y_offset);
      }
    }
    SetBoundsRect(bounds);
  }

  ShelfButton* host_;
  bool show_attention_;
  gfx::Rect base_bounds_;

  DISALLOW_COPY_AND_ASSIGN(BarView);
};

////////////////////////////////////////////////////////////////////////////////
// ShelfButton::IconView

ShelfButton::IconView::IconView() : icon_size_(kIconSize) {
}

ShelfButton::IconView::~IconView() {
}

bool ShelfButton::IconView::CanProcessEventsWithinSubtree() const {
  // Return false so that events are sent to ShelfView for handling.
  return false;
}

////////////////////////////////////////////////////////////////////////////////
// ShelfButton

ShelfButton* ShelfButton::Create(views::ButtonListener* listener,
                                 ShelfButtonHost* host,
                                 ShelfLayoutManager* shelf_layout_manager) {
  ShelfButton* button = new ShelfButton(listener, host, shelf_layout_manager);
  button->Init();
  return button;
}

ShelfButton::ShelfButton(views::ButtonListener* listener,
                         ShelfButtonHost* host,
                         ShelfLayoutManager* shelf_layout_manager)
    : CustomButton(listener),
      host_(host),
      icon_view_(NULL),
      bar_(new BarView(this)),
      state_(STATE_NORMAL),
      shelf_layout_manager_(shelf_layout_manager),
      destroyed_flag_(NULL) {
  SetAccessibilityFocusable(true);

  const gfx::ShadowValue kShadows[] = {
    gfx::ShadowValue(gfx::Point(0, 2), 0, SkColorSetARGB(0x1A, 0, 0, 0)),
    gfx::ShadowValue(gfx::Point(0, 3), 1, SkColorSetARGB(0x1A, 0, 0, 0)),
    gfx::ShadowValue(gfx::Point(0, 0), 1, SkColorSetARGB(0x54, 0, 0, 0)),
  };
  icon_shadows_.assign(kShadows, kShadows + arraysize(kShadows));

  AddChildView(bar_);
}

ShelfButton::~ShelfButton() {
  if (destroyed_flag_)
    *destroyed_flag_ = true;
}

void ShelfButton::SetShadowedImage(const gfx::ImageSkia& image) {
  icon_view_->SetImage(gfx::ImageSkiaOperations::CreateImageWithDropShadow(
      image, icon_shadows_));
}

void ShelfButton::SetImage(const gfx::ImageSkia& image) {
  if (image.isNull()) {
    // TODO: need an empty image.
    icon_view_->SetImage(image);
    return;
  }

  if (icon_view_->icon_size() == 0) {
    SetShadowedImage(image);
    return;
  }

  // Resize the image maintaining our aspect ratio.
  int pref = icon_view_->icon_size();
  float aspect_ratio =
      static_cast<float>(image.width()) / static_cast<float>(image.height());
  int height = pref;
  int width = static_cast<int>(aspect_ratio * height);
  if (width > pref) {
    width = pref;
    height = static_cast<int>(width / aspect_ratio);
  }

  if (width == image.width() && height == image.height()) {
    SetShadowedImage(image);
    return;
  }

  SetShadowedImage(gfx::ImageSkiaOperations::CreateResizedImage(image,
      skia::ImageOperations::RESIZE_BEST, gfx::Size(width, height)));
}

const gfx::ImageSkia& ShelfButton::GetImage() const {
  return icon_view_->GetImage();
}

void ShelfButton::AddState(State state) {
  if (!(state_ & state)) {
    state_ |= state;
    Layout();
    if (state & STATE_ATTENTION)
      bar_->ShowAttention(true);
  }
}

void ShelfButton::ClearState(State state) {
  if (state_ & state) {
    state_ &= ~state;
    Layout();
    if (state & STATE_ATTENTION)
      bar_->ShowAttention(false);
  }
}

gfx::Rect ShelfButton::GetIconBounds() const {
  return icon_view_->bounds();
}

void ShelfButton::ShowContextMenu(const gfx::Point& p,
                                  ui::MenuSourceType source_type) {
  if (!context_menu_controller())
    return;

  bool destroyed = false;
  destroyed_flag_ = &destroyed;

  CustomButton::ShowContextMenu(p, source_type);

  if (!destroyed) {
    destroyed_flag_ = NULL;
    // The menu will not propagate mouse events while its shown. To address,
    // the hover state gets cleared once the menu was shown (and this was not
    // destroyed).
    ClearState(STATE_HOVERED);
  }
}

bool ShelfButton::OnMousePressed(const ui::MouseEvent& event) {
  CustomButton::OnMousePressed(event);
  host_->PointerPressedOnButton(this, ShelfButtonHost::MOUSE, event);
  return true;
}

void ShelfButton::OnMouseReleased(const ui::MouseEvent& event) {
  CustomButton::OnMouseReleased(event);
  host_->PointerReleasedOnButton(this, ShelfButtonHost::MOUSE, false);
}

void ShelfButton::OnMouseCaptureLost() {
  ClearState(STATE_HOVERED);
  host_->PointerReleasedOnButton(this, ShelfButtonHost::MOUSE, true);
  CustomButton::OnMouseCaptureLost();
}

bool ShelfButton::OnMouseDragged(const ui::MouseEvent& event) {
  CustomButton::OnMouseDragged(event);
  host_->PointerDraggedOnButton(this, ShelfButtonHost::MOUSE, event);
  return true;
}

void ShelfButton::OnMouseMoved(const ui::MouseEvent& event) {
  CustomButton::OnMouseMoved(event);
  host_->MouseMovedOverButton(this);
}

void ShelfButton::OnMouseEntered(const ui::MouseEvent& event) {
  AddState(STATE_HOVERED);
  CustomButton::OnMouseEntered(event);
  host_->MouseEnteredButton(this);
}

void ShelfButton::OnMouseExited(const ui::MouseEvent& event) {
  ClearState(STATE_HOVERED);
  CustomButton::OnMouseExited(event);
  host_->MouseExitedButton(this);
}

void ShelfButton::GetAccessibleState(ui::AXViewState* state) {
  state->role = ui::AX_ROLE_BUTTON;
  state->name = host_->GetAccessibleName(this);
}

void ShelfButton::Layout() {
  const gfx::Rect button_bounds(GetContentsBounds());
  int icon_pad =
      shelf_layout_manager_->GetAlignment() != SHELF_ALIGNMENT_BOTTOM ?
      kIconPadVertical : kIconPad;
  int x_offset = shelf_layout_manager_->PrimaryAxisValue(0, icon_pad);
  int y_offset = shelf_layout_manager_->PrimaryAxisValue(icon_pad, 0);

  int icon_width = std::min(kIconSize,
      button_bounds.width() - x_offset);
  int icon_height = std::min(kIconSize,
      button_bounds.height() - y_offset);

  // If on the left or top 'invert' the inset so the constant gap is on
  // the interior (towards the center of display) edge of the shelf.
  if (SHELF_ALIGNMENT_LEFT == shelf_layout_manager_->GetAlignment())
    x_offset = button_bounds.width() - (kIconSize + icon_pad);

  if (SHELF_ALIGNMENT_TOP == shelf_layout_manager_->GetAlignment())
    y_offset = button_bounds.height() - (kIconSize + icon_pad);

  // Center icon with respect to the secondary axis, and ensure
  // that the icon doesn't occlude the bar highlight.
  if (shelf_layout_manager_->IsHorizontalAlignment()) {
    x_offset = std::max(0, button_bounds.width() - icon_width) / 2;
    if (y_offset + icon_height + kBarSize > button_bounds.height())
      icon_height = button_bounds.height() - (y_offset + kBarSize);
  } else {
    y_offset = std::max(0, button_bounds.height() - icon_height) / 2;
    if (x_offset + icon_width + kBarSize > button_bounds.width())
      icon_width = button_bounds.width() - (x_offset + kBarSize);
  }

  icon_view_->SetBoundsRect(gfx::Rect(
      button_bounds.x() + x_offset,
      button_bounds.y() + y_offset,
      icon_width,
      icon_height));

  // Icon size has been incorrect when running
  // PanelLayoutManagerTest.PanelAlignmentSecondDisplay on valgrind bot, see
  // http://crbug.com/234854.
  DCHECK_LE(icon_width, kIconSize);
  DCHECK_LE(icon_height, kIconSize);

  bar_->SetBarBoundsRect(button_bounds);

  UpdateState();
}

void ShelfButton::ChildPreferredSizeChanged(views::View* child) {
  Layout();
}

void ShelfButton::OnFocus() {
  AddState(STATE_FOCUSED);
  CustomButton::OnFocus();
}

void ShelfButton::OnBlur() {
  ClearState(STATE_FOCUSED);
  CustomButton::OnBlur();
}

void ShelfButton::OnPaint(gfx::Canvas* canvas) {
  CustomButton::OnPaint(canvas);
  if (HasFocus()) {
    gfx::Rect paint_bounds(GetLocalBounds());
    paint_bounds.Inset(1, 1, 1, 1);
    canvas->DrawSolidFocusRect(paint_bounds, kFocusBorderColor);
  }
}

void ShelfButton::OnGestureEvent(ui::GestureEvent* event) {
  switch (event->type()) {
    case ui::ET_GESTURE_TAP_DOWN:
      AddState(STATE_HOVERED);
      return CustomButton::OnGestureEvent(event);
    case ui::ET_GESTURE_END:
      ClearState(STATE_HOVERED);
      return CustomButton::OnGestureEvent(event);
    case ui::ET_GESTURE_SCROLL_BEGIN:
      host_->PointerPressedOnButton(this, ShelfButtonHost::TOUCH, *event);
      event->SetHandled();
      return;
    case ui::ET_GESTURE_SCROLL_UPDATE:
      host_->PointerDraggedOnButton(this, ShelfButtonHost::TOUCH, *event);
      event->SetHandled();
      return;
    case ui::ET_GESTURE_SCROLL_END:
    case ui::ET_SCROLL_FLING_START:
      host_->PointerReleasedOnButton(this, ShelfButtonHost::TOUCH, false);
      event->SetHandled();
      return;
    default:
      return CustomButton::OnGestureEvent(event);
  }
}

void ShelfButton::Init() {
  icon_view_ = CreateIconView();

  // TODO: refactor the layers so each button doesn't require 2.
  icon_view_->SetPaintToLayer(true);
  icon_view_->SetFillsBoundsOpaquely(false);
  icon_view_->SetHorizontalAlignment(views::ImageView::CENTER);
  icon_view_->SetVerticalAlignment(views::ImageView::LEADING);

  AddChildView(icon_view_);
}

ShelfButton::IconView* ShelfButton::CreateIconView() {
  return new IconView;
}

bool ShelfButton::IsShelfHorizontal() const {
  return shelf_layout_manager_->IsHorizontalAlignment();
}

void ShelfButton::UpdateState() {
  UpdateBar();

  icon_view_->SetHorizontalAlignment(
      shelf_layout_manager_->PrimaryAxisValue(views::ImageView::CENTER,
                                              views::ImageView::LEADING));
  icon_view_->SetVerticalAlignment(
      shelf_layout_manager_->PrimaryAxisValue(views::ImageView::LEADING,
                                              views::ImageView::CENTER));
  SchedulePaint();
}

void ShelfButton::UpdateBar() {
  if (state_ & STATE_HIDDEN) {
    bar_->SetVisible(false);
    return;
  }

  int bar_id = 0;
  if (state_ & STATE_ACTIVE)
    bar_id = IDR_ASH_SHELF_UNDERLINE_ACTIVE;
  else if (state_ & STATE_RUNNING)
    bar_id = IDR_ASH_SHELF_UNDERLINE_RUNNING;

  if (bar_id != 0) {
    ResourceBundle& rb = ResourceBundle::GetSharedInstance();
    const gfx::ImageSkia* image = rb.GetImageNamed(bar_id).ToImageSkia();
    if (shelf_layout_manager_->GetAlignment() == SHELF_ALIGNMENT_BOTTOM) {
      bar_->SetImage(*image);
    } else {
      bar_->SetImage(gfx::ImageSkiaOperations::CreateRotatedImage(*image,
          shelf_layout_manager_->SelectValueForShelfAlignment(
              SkBitmapOperations::ROTATION_90_CW,
              SkBitmapOperations::ROTATION_90_CW,
              SkBitmapOperations::ROTATION_270_CW,
              SkBitmapOperations::ROTATION_180_CW)));
    }
    bar_->SetHorizontalAlignment(
        shelf_layout_manager_->SelectValueForShelfAlignment(
            views::ImageView::CENTER,
            views::ImageView::LEADING,
            views::ImageView::TRAILING,
            views::ImageView::CENTER));
    bar_->SetVerticalAlignment(
        shelf_layout_manager_->SelectValueForShelfAlignment(
            views::ImageView::TRAILING,
            views::ImageView::CENTER,
            views::ImageView::CENTER,
            views::ImageView::LEADING));
    bar_->SchedulePaint();
  }

  bar_->SetVisible(bar_id != 0 && state_ != STATE_NORMAL);
}

}  // namespace ash