// Copyright (c) 2012 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 "ui/native_theme/native_theme_aura.h"

#include <limits>
#include <utility>

#include "base/logging.h"
#include "build/build_config.h"
#include "ui/base/layout.h"
#include "ui/base/material_design/material_design_controller.h"
#include "ui/gfx/animation/tween.h"
#include "ui/gfx/canvas.h"
#include "ui/gfx/color_palette.h"
#include "ui/gfx/geometry/rect.h"
#include "ui/gfx/geometry/size.h"
#include "ui/gfx/image/image_skia.h"
#include "ui/gfx/path.h"
#include "ui/gfx/skia_util.h"
#include "ui/native_theme/common_theme.h"
#include "ui/native_theme/native_theme_switches.h"

namespace ui {

namespace {

SkAlpha ThumbAlphaForState(NativeTheme::State state) {
  bool overlay = IsOverlayScrollbarEnabled();
  switch (state) {
    case NativeTheme::kDisabled:
      return 0x00;
    case NativeTheme::kHovered:
      return overlay ? 0xB2 : 0x4D;
    case NativeTheme::kNormal:
      return overlay ? 0x8C : 0x33;
    case NativeTheme::kPressed:
      return overlay ? 0xB2 : 0x80;
    case NativeTheme::kNumStates:
      break;
  }

  NOTREACHED();
  return 0xFF;
}

SkAlpha ThumbStrokeAlphaForState(NativeTheme::State state) {
  DCHECK(IsOverlayScrollbarEnabled());
  switch (state) {
    case NativeTheme::kDisabled:
      return 0x00;
    case NativeTheme::kHovered:
    case NativeTheme::kPressed:
      return 0x33;
    case NativeTheme::kNormal:
      return 0x26;
    case NativeTheme::kNumStates:
      break;
  }

  NOTREACHED();
  return 0xFF;
}

const SkColor kTrackColor = SkColorSetRGB(0xF1, 0xF1, 0xF1);

}  // namespace

#if !defined(OS_WIN)
// static
NativeTheme* NativeTheme::GetInstanceForWeb() {
  return NativeThemeAura::instance();
}

// static
NativeThemeAura* NativeThemeAura::instance() {
  CR_DEFINE_STATIC_LOCAL(NativeThemeAura, s_native_theme, ());
  return &s_native_theme;
}
#endif

NativeThemeAura::NativeThemeAura() {
  // We don't draw scrollbar buttons.
#if defined(OS_CHROMEOS)
  set_scrollbar_button_length(0);
#endif

  // Images and alphas declarations assume the following order.
  static_assert(kDisabled == 0, "states unexpectedly changed");
  static_assert(kHovered == 1, "states unexpectedly changed");
  static_assert(kNormal == 2, "states unexpectedly changed");
  static_assert(kPressed == 3, "states unexpectedly changed");
}

NativeThemeAura::~NativeThemeAura() {
}

// This implementation returns hardcoded colors.
SkColor NativeThemeAura::GetSystemColor(ColorId color_id) const {
  return GetAuraColor(color_id, this);
}

void NativeThemeAura::PaintMenuPopupBackground(
    SkCanvas* canvas,
    const gfx::Size& size,
    const MenuBackgroundExtraParams& menu_background) const {
  SkColor color = GetSystemColor(NativeTheme::kColorId_MenuBackgroundColor);
  if (menu_background.corner_radius > 0) {
    SkPaint paint;
    paint.setStyle(SkPaint::kFill_Style);
    paint.setFlags(SkPaint::kAntiAlias_Flag);
    paint.setColor(color);

    gfx::Path path;
    SkRect rect = SkRect::MakeWH(SkIntToScalar(size.width()),
                                 SkIntToScalar(size.height()));
    SkScalar radius = SkIntToScalar(menu_background.corner_radius);
    SkScalar radii[8] = {radius, radius, radius, radius,
                         radius, radius, radius, radius};
    path.addRoundRect(rect, radii);

    canvas->drawPath(path, paint);
  } else {
    canvas->drawColor(color, SkXfermode::kSrc_Mode);
  }
}

void NativeThemeAura::PaintMenuItemBackground(
    SkCanvas* canvas,
    State state,
    const gfx::Rect& rect,
    const MenuItemExtraParams& menu_item) const {
  CommonThemePaintMenuItemBackground(canvas, state, rect, menu_item);
}

void NativeThemeAura::PaintArrowButton(SkCanvas* canvas,
                                       const gfx::Rect& rect,
                                       Part direction,
                                       State state) const {
  SkColor bg_color = kTrackColor;
  // Aura-win uses slightly different arrow colors.
  SkColor arrow_color = gfx::kPlaceholderColor;
  switch (state) {
    case kDisabled:
      arrow_color = GetArrowColor(state);
      break;
    case kHovered:
      bg_color = SkColorSetRGB(0xD2, 0xD2, 0xD2);
    // Fall through.
    case kNormal:
      arrow_color = SkColorSetRGB(0x50, 0x50, 0x50);
      break;
    case kPressed:
      bg_color = SkColorSetRGB(0x78, 0x78, 0x78);
      arrow_color = SK_ColorWHITE;
      break;
    case kNumStates:
      break;
  }
  DCHECK_NE(arrow_color, gfx::kPlaceholderColor);

  SkPaint paint;
  paint.setColor(bg_color);
  canvas->drawIRect(gfx::RectToSkIRect(rect), paint);

  PaintArrow(canvas, rect, direction, arrow_color);
}

void NativeThemeAura::PaintScrollbarTrack(
    SkCanvas* canvas,
    Part part,
    State state,
    const ScrollbarTrackExtraParams& extra_params,
    const gfx::Rect& rect) const {
  // Overlay Scrollbar should never paint a scrollbar track.
  DCHECK(!IsOverlayScrollbarEnabled());
  SkPaint paint;
  paint.setColor(kTrackColor);
  canvas->drawIRect(gfx::RectToSkIRect(rect), paint);
}

void NativeThemeAura::PaintScrollbarThumb(SkCanvas* canvas,
                                          Part part,
                                          State state,
                                          const gfx::Rect& rect) const {
  // Do not paint if state is disabled.
  if (state == kDisabled)
    return;

  PaintScrollbarThumbStateTransition(canvas, part, state, state, 1.0, rect);
}

void NativeThemeAura::PaintScrollbarThumbStateTransition(
    SkCanvas* canvas,
    Part part,
    State start_state,
    State end_state,
    double progress,
    const gfx::Rect& rect) const {
  gfx::Rect thumb_rect(rect);
  if (IsOverlayScrollbarEnabled()) {
    // In overlay mode, draw a stroke (border).
    const int kStrokeWidth = 1;
    SkAlpha stroke_alpha = gfx::Tween::IntValueBetween(
        progress, ThumbStrokeAlphaForState(start_state),
        ThumbStrokeAlphaForState(end_state));
    SkPaint paint;
    paint.setColor(SkColorSetA(SK_ColorWHITE, stroke_alpha));
    paint.setStyle(SkPaint::kStroke_Style);
    paint.setStrokeWidth(kStrokeWidth);
    canvas->drawIRect(gfx::RectToSkIRect(thumb_rect), paint);

    thumb_rect.Inset(kStrokeWidth, kStrokeWidth, kStrokeWidth, kStrokeWidth);
  } else {
    // If there are no scrollbuttons then provide some padding so that the thumb
    // doesn't touch the top of the track.
    const int kThumbPadding = 2;
    const int extra_padding =
        (scrollbar_button_length() == 0) ? kThumbPadding : 0;
    if (part == NativeTheme::kScrollbarVerticalThumb)
      thumb_rect.Inset(kThumbPadding, extra_padding);
    else
      thumb_rect.Inset(extra_padding, kThumbPadding);
  }

  SkPaint paint;
  SkAlpha alpha = gfx::Tween::IntValueBetween(
      progress, ThumbAlphaForState(start_state), ThumbAlphaForState(end_state));
  paint.setColor(SkColorSetA(SK_ColorBLACK, alpha));
  canvas->drawIRect(gfx::RectToSkIRect(thumb_rect), paint);
}

void NativeThemeAura::PaintScrollbarCorner(SkCanvas* canvas,
                                           State state,
                                           const gfx::Rect& rect) const {
  // Overlay Scrollbar should never paint a scrollbar corner.
  DCHECK(!IsOverlayScrollbarEnabled());
  SkPaint paint;
  paint.setColor(SkColorSetRGB(0xDC, 0xDC, 0xDC));
  canvas->drawIRect(RectToSkIRect(rect), paint);
}

}  // namespace ui