// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CHROME_BROWSER_THEMES_THEME_HELPER_H_
#define CHROME_BROWSER_THEMES_THEME_HELPER_H_

#include <optional>

#include "base/memory/scoped_refptr.h"
#include "base/sequence_checker.h"
#include "third_party/skia/include/core/SkColor.h"
#include "ui/base/resource/resource_scale_factor.h"
#include "ui/base/theme_provider.h"

class CustomThemeSupplier;

namespace theme_service_internal {
class ThemeServiceTest;
}

namespace gfx {
class ImageSkia;
class Image;
}  // namespace gfx

namespace color_utils {
struct HSL;
}

// Helper functions for ThemeService as part of implementing the
// ui::ThemeProvider interface with respect to a given CustomThemeSupplier and
// incognito state.
class ThemeHelper {
 public:
  // The default theme if we haven't installed a theme yet or if we've clicked
  // the "Use Classic" button.
  static const char kDefaultThemeID[];

  // Whether |theme_supplier| is installed through extensions.
  // |UsingExtensionTheme| and |UsingDefaultTheme| are not mutually exclusive as
  // default theme can be installed through extensions.
  static bool IsExtensionTheme(const CustomThemeSupplier* theme_supplier);

  // Whether we are using an autogenerated theme.
  static bool IsAutogeneratedTheme(const CustomThemeSupplier* theme_supplier);

  // Whether |theme_supplier| is a default theme.
  static bool IsDefaultTheme(const CustomThemeSupplier* theme_supplier);

  // Whether |theme_supplier| is what users would think of as a "custom theme"
  // (that is, an extension or autogenerated theme).
  static bool IsCustomTheme(const CustomThemeSupplier* theme_supplier);

  static bool HasCustomImage(int id, const CustomThemeSupplier* theme_supplier);

  ThemeHelper();
  virtual ~ThemeHelper();

  ThemeHelper(const ThemeHelper&) = delete;
  ThemeHelper& operator=(const ThemeHelper&) = delete;

  // Gets the effective value of a themeable display property, either from the
  // `theme_supplier` if available or the default.
  int GetDisplayProperty(int id,
                         const CustomThemeSupplier* theme_supplier) const;

  scoped_refptr<base::RefCountedMemory> GetRawData(
      int id,
      const CustomThemeSupplier* theme_supplier,
      ui::ResourceScaleFactor scale_factor) const;

  // Get the specified tint - |id| is one of the TINT_* enum values.
  color_utils::HSL GetTint(int id,
                           bool incognito,
                           const CustomThemeSupplier* theme_supplier) const;

  // These methods provide the implementation for ui::ThemeProvider (exposed
  // via BrowserThemeProvider).
  gfx::ImageSkia* GetImageSkiaNamed(
      int id,
      bool incognito,
      const CustomThemeSupplier* theme_supplier) const;

  // Implementation for ui::ThemeProvider.
  virtual bool ShouldUseNativeFrame(
      const CustomThemeSupplier* theme_supplier) const;

  void DCheckCalledOnValidSequence() const {
    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
  }

  // Gets the default value of a themeable display property.
  virtual int GetDefaultDisplayProperty(int id) const;

 private:
  friend class theme_service_internal::ThemeServiceTest;

  // Whether dark default colors/tints should be used, if available.
  static bool UseDarkModeColors(const CustomThemeSupplier* theme_supplier);

  // Returns a cross platform image for an id.
  gfx::Image GetImageNamed(int id,
                           bool incognito,
                           const CustomThemeSupplier* theme_supplier) const;

  SEQUENCE_CHECKER(sequence_checker_);
};

#endif  // CHROME_BROWSER_THEMES_THEME_HELPER_H_