/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this file,
 * You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "VibrancyManager.h"
#include "nsChildView.h"
#import <objc/message.h>

using namespace mozilla;

void
VibrancyManager::UpdateVibrantRegion(VibrancyType aType,
                                     const LayoutDeviceIntRegion& aRegion)
{
  if (aRegion.IsEmpty()) {
    mVibrantRegions.Remove(uint32_t(aType));
    return;
  }
  auto& vr = *mVibrantRegions.LookupOrAdd(uint32_t(aType));
  vr.UpdateRegion(aRegion, mCoordinateConverter, mContainerView, ^() {
    return this->CreateEffectView(aType);
  });
}

@interface NSView(CurrentFillColor)
- (NSColor*)_currentFillColor;
@end

static NSColor*
AdjustedColor(NSColor* aFillColor, VibrancyType aType)
{
  if (aType == VibrancyType::MENU && [aFillColor alphaComponent] == 1.0) {
    // The opaque fill color that's used for the menu background when "Reduce
    // vibrancy" is checked in the system accessibility prefs is too dark.
    // This is probably because we're not using the right material for menus,
    // see VibrancyManager::CreateEffectView.
    return [NSColor colorWithDeviceWhite:0.96 alpha:1.0];
  }
  return aFillColor;
}

NSColor*
VibrancyManager::VibrancyFillColorForType(VibrancyType aType)
{
  NSView* view = mVibrantRegions.LookupOrAdd(uint32_t(aType))->GetAnyView();

  if (view && [view respondsToSelector:@selector(_currentFillColor)]) {
    // -[NSVisualEffectView _currentFillColor] is the color that the view
    // draws in its drawRect implementation.
    return AdjustedColor([view _currentFillColor], aType);
  }
  return [NSColor whiteColor];
}

@interface NSView(FontSmoothingBackgroundColor)
- (NSColor*)fontSmoothingBackgroundColor;
@end

NSColor*
VibrancyManager::VibrancyFontSmoothingBackgroundColorForType(VibrancyType aType)
{
  NSView* view = mVibrantRegions.LookupOrAdd(uint32_t(aType))->GetAnyView();

  if (view && [view respondsToSelector:@selector(fontSmoothingBackgroundColor)]) {
    return [view fontSmoothingBackgroundColor];
  }
  return [NSColor clearColor];
}

static NSView*
HitTestNil(id self, SEL _cmd, NSPoint aPoint)
{
  // This view must be transparent to mouse events.
  return nil;
}

static BOOL
AllowsVibrancyYes(id self, SEL _cmd)
{
  // Means that the foreground is blended using a vibrant blend mode.
  return YES;
}

static Class
CreateEffectViewClass(BOOL aForegroundVibrancy, BOOL aIsContainer)
{
  // Create a class that inherits from NSVisualEffectView and overrides the
  // methods -[NSView hitTest:] and  -[NSVisualEffectView allowsVibrancy].
  Class NSVisualEffectViewClass = NSClassFromString(@"NSVisualEffectView");
  const char* className = aForegroundVibrancy
    ? "EffectViewWithForegroundVibrancy" : "EffectViewWithoutForegroundVibrancy";
  Class EffectViewClass = objc_allocateClassPair(NSVisualEffectViewClass, className, 0);
  if (!aIsContainer) {
    class_addMethod(EffectViewClass, @selector(hitTest:), (IMP)HitTestNil,
                    "@@:{CGPoint=dd}");
  }
  if (aForegroundVibrancy) {
    // Override the -[NSView allowsVibrancy] method to return YES.
    class_addMethod(EffectViewClass, @selector(allowsVibrancy), (IMP)AllowsVibrancyYes, "I@:");
  }
  return EffectViewClass;
}

static id
AppearanceForVibrancyType(VibrancyType aType)
{
  Class NSAppearanceClass = NSClassFromString(@"NSAppearance");
  switch (aType) {
    case VibrancyType::LIGHT:
    case VibrancyType::TOOLTIP:
    case VibrancyType::MENU:
    case VibrancyType::HIGHLIGHTED_MENUITEM:
    case VibrancyType::SHEET:
    case VibrancyType::SOURCE_LIST:
    case VibrancyType::SOURCE_LIST_SELECTION:
    case VibrancyType::ACTIVE_SOURCE_LIST_SELECTION:
      return [NSAppearanceClass performSelector:@selector(appearanceNamed:)
                                     withObject:@"NSAppearanceNameVibrantLight"];
    case VibrancyType::DARK:
      return [NSAppearanceClass performSelector:@selector(appearanceNamed:)
                                     withObject:@"NSAppearanceNameVibrantDark"];
  }
}

#if !defined(MAC_OS_X_VERSION_10_10) || MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_10
enum {
  NSVisualEffectStateFollowsWindowActiveState,
  NSVisualEffectStateActive,
  NSVisualEffectStateInactive
};

enum {
  NSVisualEffectMaterialTitlebar = 3
};
#endif

#if !defined(MAC_OS_X_VERSION_10_11) || MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_11
enum {
  NSVisualEffectMaterialMenu = 5,
  NSVisualEffectMaterialSidebar = 7
};
#endif

static NSUInteger
VisualEffectStateForVibrancyType(VibrancyType aType)
{
  switch (aType) {
    case VibrancyType::TOOLTIP:
    case VibrancyType::MENU:
    case VibrancyType::HIGHLIGHTED_MENUITEM:
    case VibrancyType::SHEET:
      // Tooltip and menu windows are never "key" and sheets always looks
      // active, so we need to tell the vibrancy effect to look active
      // regardless of window state.
      return NSVisualEffectStateActive;
    default:
      return NSVisualEffectStateFollowsWindowActiveState;
  }
}

static BOOL
HasVibrantForeground(VibrancyType aType)
{
  switch (aType) {
    case VibrancyType::MENU:
      return YES;
    default:
      return NO;
  }
}

#if !defined(MAC_OS_X_VERSION_10_12) || MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_12
enum {
  NSVisualEffectMaterialSelection = 4
};
#endif

@interface NSView(NSVisualEffectViewMethods)
- (void)setState:(NSUInteger)state;
- (void)setMaterial:(NSUInteger)material;
- (void)setEmphasized:(BOOL)emphasized;
@end

NSView*
VibrancyManager::CreateEffectView(VibrancyType aType, BOOL aIsContainer)
{
  static Class EffectViewWithoutForegroundVibrancy = CreateEffectViewClass(NO, NO);
  static Class EffectViewWithForegroundVibrancy = CreateEffectViewClass(YES, NO);
  static Class EffectViewContainer = CreateEffectViewClass(NO, YES);

  // Pick the right NSVisualEffectView subclass for the desired vibrancy mode.
  // For "container" views, never use foreground vibrancy, because returning
  // YES from allowsVibrancy forces on foreground vibrancy for all descendant
  // views which can have unintended effects.
  Class EffectViewClass = aIsContainer
                              ? EffectViewContainer
                              : (HasVibrantForeground(aType) ? EffectViewWithForegroundVibrancy
                                                             : EffectViewWithoutForegroundVibrancy);
  NSView* effectView = [[EffectViewClass alloc] initWithFrame:NSZeroRect];
  [effectView performSelector:@selector(setAppearance:)
                   withObject:AppearanceForVibrancyType(aType)];
  [effectView setState:VisualEffectStateForVibrancyType(aType)];

  BOOL canUseElCapitanMaterials = nsCocoaFeatures::OnElCapitanOrLater();
  if (aType == VibrancyType::MENU) {
    // Before 10.11 there is no material that perfectly matches the menu
    // look. Of all available material types, NSVisualEffectMaterialTitlebar
    // is the one that comes closest.
    [effectView setMaterial:canUseElCapitanMaterials ? NSVisualEffectMaterialMenu
                                                     : NSVisualEffectMaterialTitlebar];
  } else if (aType == VibrancyType::SOURCE_LIST && canUseElCapitanMaterials) {
    [effectView setMaterial:NSVisualEffectMaterialSidebar];
  } else if (aType == VibrancyType::HIGHLIGHTED_MENUITEM ||
             aType == VibrancyType::SOURCE_LIST_SELECTION ||
             aType == VibrancyType::ACTIVE_SOURCE_LIST_SELECTION) {
    [effectView setMaterial:NSVisualEffectMaterialSelection];
    if ([effectView respondsToSelector:@selector(setEmphasized:)] &&
        aType != VibrancyType::SOURCE_LIST_SELECTION) {
      [effectView setEmphasized:YES];
    }
  }

  return effectView;
}

static bool
ComputeSystemSupportsVibrancy()
{
#ifdef __x86_64__
  return NSClassFromString(@"NSAppearance") &&
      NSClassFromString(@"NSVisualEffectView");
#else
  // objc_allocateClassPair doesn't work in 32 bit mode, so turn off vibrancy.
  return false;
#endif
}

/* static */ bool
VibrancyManager::SystemSupportsVibrancy()
{
  static bool supportsVibrancy = ComputeSystemSupportsVibrancy();
  return supportsVibrancy;
}