// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "chrome/browser/shortcuts/shortcut_icon_generator.h"

#include <string>

#include "base/i18n/break_iterator.h"
#include "base/i18n/case_conversion.h"
#include "build/build_config.h"
#include "cc/paint/paint_flags.h"
#include "chrome/grit/platform_locale_settings.h"
#include "components/url_formatter/url_formatter.h"
#include "net/base/registry_controlled_domains/registry_controlled_domain.h"
#include "third_party/skia/include/core/SkColor.h"
#include "ui/base/l10n/l10n_util.h"
#include "ui/gfx/canvas.h"
#include "ui/gfx/color_utils.h"
#include "ui/gfx/font.h"
#include "ui/gfx/font_list.h"
#include "ui/gfx/geometry/rect.h"
#include "ui/gfx/image/canvas_image_source.h"

namespace shortcuts {

namespace {

// Generates a square container icon of `output_size` by drawing the given
// `icon_letter` into a rounded background of `color`.
class GeneratedIconImageSource : public gfx::CanvasImageSource {
 public:
  GeneratedIconImageSource(std::u16string_view icon_letter,
                           SquareSizePx output_size)
      : gfx::CanvasImageSource(gfx::Size(output_size, output_size)),
        icon_letter_(icon_letter),
        output_size_(output_size) {}
  GeneratedIconImageSource(const GeneratedIconImageSource&) = delete;
  GeneratedIconImageSource& operator=(const GeneratedIconImageSource&) = delete;
  ~GeneratedIconImageSource() override = default;

 private:
  // gfx::CanvasImageSource overrides:
  void Draw(gfx::Canvas* canvas) override {
    SquareSizePx icon_size = output_size_ * 3 / 4;
    int icon_inset = output_size_ / 8;
    const size_t border_radius = output_size_ / 16;
    const size_t font_size = output_size_ * 7 / 16;

    std::string font_name =
        l10n_util::GetStringUTF8(IDS_SANS_SERIF_FONT_FAMILY);
#if BUILDFLAG(IS_CHROMEOS)
    // With adaptive icons, we generate full size square icons as they will be
    // masked by the OS.
    icon_size = output_size_;
    icon_inset = 0;
    const std::string kChromeOSFontFamily = "Noto Sans";
    font_name = kChromeOSFontFamily;
#endif

    // Use a dark gray so it will stand out on the black shelf.
    constexpr SkColor color = SK_ColorDKGRAY;

    // Draw a rounded rect of the given `color`.
    cc::PaintFlags background_flags;
    background_flags.setAntiAlias(true);
    background_flags.setColor(color);

    gfx::Rect icon_rect(icon_inset, icon_inset, icon_size, icon_size);
    canvas->DrawRoundRect(icon_rect, border_radius, background_flags);

    // The text rect's size needs to be odd to center the text correctly.
    gfx::Rect text_rect(icon_inset, icon_inset, icon_size + 1, icon_size + 1);
    canvas->DrawStringRectWithFlags(
        icon_letter_, gfx::FontList(gfx::Font(font_name, font_size)),
        color_utils::GetColorWithMaxContrast(color), text_rect,
        gfx::Canvas::TEXT_ALIGN_CENTER);
  }

  std::u16string icon_letter_;
  int output_size_;
};

// Gets the first grapheme of a string.
std::u16string_view FirstGrapheme(std::u16string_view str) {
  base::i18n::BreakIterator iter(str,
                                 base::i18n::BreakIterator::BREAK_CHARACTER);
  if (!iter.Init()) {
    return std::u16string_view();
  }

  if (!iter.Advance()) {
    return std::u16string_view();
  }

  return iter.GetString();
}

}  // namespace

SkBitmap GenerateBitmap(SquareSizePx output_size,
                        std::u16string_view icon_letter) {
  gfx::ImageSkia icon_image(
      std::make_unique<GeneratedIconImageSource>(icon_letter, output_size),
      gfx::Size(output_size, output_size));
  SkBitmap dst;
  if (dst.tryAllocPixels(icon_image.bitmap()->info())) {
    icon_image.bitmap()->readPixels(dst.info(), dst.getPixels(), dst.rowBytes(),
                                    0, 0);
  }
  return dst;
}

std::u16string GenerateIconLetterFromUrl(const GURL& app_url) {
  std::string app_url_part = " ";
  const std::string domain_and_registry =
      net::registry_controlled_domains::GetDomainAndRegistry(
          app_url,
          net::registry_controlled_domains::INCLUDE_PRIVATE_REGISTRIES);

  if (!domain_and_registry.empty()) {
    app_url_part = domain_and_registry;
  } else if (app_url.has_host()) {
    app_url_part = app_url.GetHost();
  }

  // Translate punycode into unicode before retrieving the first letter.
  const std::u16string string_for_display =
      url_formatter::IDNToUnicode(app_url_part);

  return base::i18n::ToUpper(FirstGrapheme(string_for_display));
}

std::u16string GenerateIconLetterFromName(std::u16string_view app_name) {
  CHECK(!app_name.empty());
  return base::i18n::ToUpper(FirstGrapheme(app_name));
}

}  // namespace shortcuts