// Copyright 2021 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef ASH_WM_DESKS_TEMPLATES_SAVED_DESK_ICON_VIEW_H_
#define ASH_WM_DESKS_TEMPLATES_SAVED_DESK_ICON_VIEW_H_

#include <cstdint>
#include <string>

#include "base/memory/raw_ptr.h"
#include "base/memory/weak_ptr.h"
#include "base/task/cancelable_task_tracker.h"
#include "ui/base/metadata/metadata_header_macros.h"
#include "ui/views/view.h"

namespace gfx {
class ImageSkia;
}  // namespace gfx

namespace views {
class Label;
}  // namespace views

namespace ash {
class RoundedImageView;

// Identifies an icon to be shown.
struct SavedDeskIconIdentifier {
  // This is either a:
  //   1. A regular URL that we'll attempt to load a favicon for.
  //   2. A special identifier (like "incognito_window").
  //   3. An app ID - this is used for ARC apps etc.
  std::string url_or_id;

  // This type is used as a map key.
  auto operator<=>(const SavedDeskIconIdentifier&) const = default;
};

// The base class of SavedDeskRegularIconView and SavedDeskOverflowIconView.
// A class for loading and displaying the icon of apps/urls used in a
// SavedDeskItemView. Depending on the `count_` and `icon_identifier_`,
// the SavedDeskRegularIconView may have only an icon, or an icon with a count
// label; while the SavedDeskOverflowIconView has only a count label.
class SavedDeskIconView : public views::View {
  METADATA_HEADER(SavedDeskIconView, views::View)

 public:
  // Create an icon view for an app. Sets `count` to `count_`. `sorting_key` is
  // the key that is used for sorting by the icon container.
  SavedDeskIconView(int count, size_t sorting_key);

  SavedDeskIconView(const SavedDeskIconView&) = delete;
  SavedDeskIconView& operator=(const SavedDeskIconView&) = delete;
  ~SavedDeskIconView() override;

  // views::View:
  gfx::Size CalculatePreferredSize(
      const views::SizeBounds& available_size) const override;

  // Sets `count_` to `count` and updates the `count_label_`. Please note,
  // currently it does not support update on regular icon.
  virtual void UpdateCount(int count);

  // Sorting key that is used by the container for sorting all icons. Icon with
  // higher keys will be displayed at the end in the icon container.
  // Values are designed as follows:
  //   - Non-default icon: index from its original order, starting from 0
  //   - Default icon:  `kDefaultIconSortingKey`
  //   - Overflow icon: `kOverflowIconSortingKey`
  virtual size_t GetSortingKey() const = 0;

  virtual int GetCount() const = 0;

  // The count number will be shown on a label view. For the regular icon view,
  // with or without default icon image, this should be `count_` - 1; while for
  // the overflow icon view, this should be `count_`.
  virtual int GetCountToShow() const = 0;

  // Returns true if the icon view is a overflow icon view; otherwise, returns
  // false;
  virtual bool IsOverflowIcon() const = 0;

 protected:
  // Creates the child view for the count label.
  void CreateCountLabelChildView(bool show_plus, int inset_size);

  // The number of instances of this icon's respective app/url stored in this's
  // respective SavedDesk.
  int count_ = 0;

  // Sorting key that is used for sorting icons in the container.
  size_t sorting_key_;

  // Owned by the views hierarchy.
  raw_ptr<views::Label> count_label_ = nullptr;

 private:
  friend class SavedDeskIconViewTestApi;

  base::WeakPtrFactory<SavedDeskIconView> weak_ptr_factory_{this};
};

class SavedDeskRegularIconView : public SavedDeskIconView {
  METADATA_HEADER(SavedDeskRegularIconView, SavedDeskIconView)

 public:
  // `on_icon_loaded` is the callback for updating the icon container.
  SavedDeskRegularIconView(
      const ui::ColorProvider* incognito_window_color_provider,
      const SavedDeskIconIdentifier& icon_identifier,
      const std::string& app_title,
      int count,
      size_t sorting_key,
      base::OnceCallback<void(views::View*)> on_icon_loaded);

  SavedDeskRegularIconView(const SavedDeskRegularIconView&) = delete;
  SavedDeskRegularIconView& operator=(const SavedDeskRegularIconView&) = delete;
  ~SavedDeskRegularIconView() override;

  bool is_showing_default_icon() const { return is_showing_default_icon_; }
  const SavedDeskIconIdentifier& icon_identifier() const {
    return icon_identifier_;
  }

  // views::View:
  void Layout(PassKey) override;

  // SavedDeskIconView:
  void OnThemeChanged() override;
  size_t GetSortingKey() const override;
  int GetCount() const override;
  int GetCountToShow() const override;
  bool IsOverflowIcon() const override;

 private:
  // Creates the child views for this icon view. Will start the asynchronous
  // task of loading icons if necessary.
  void CreateChildViews(
      const ui::ColorProvider* incognito_window_color_provider,
      const std::string& app_title);

  // Callbacks for when the app icon/favicon has been fetched. If the result is
  // non-null/empty then we'll set this's image to the result. Otherwise, we'll
  // use a placeholder icon.
  void OnIconLoaded(const gfx::ImageSkia& icon);

  // Loads the default favicon to `icon_view_`. Should be called when we fail to
  // load an icon.
  void LoadDefaultIcon();

  // True if this icon view is showing the default (fallback) icon.
  bool is_showing_default_icon_ = false;

  // Identifies the icon to show.
  SavedDeskIconIdentifier icon_identifier_;

  raw_ptr<RoundedImageView> icon_view_ = nullptr;

  // Callback from the icon container that updates the icon order and overflow
  // icon.
  base::OnceCallback<void(views::View*)> on_icon_loaded_;

  // Used for favicon loading tasks.
  base::CancelableTaskTracker cancelable_task_tracker_;

  base::WeakPtrFactory<SavedDeskRegularIconView> weak_ptr_factory_{this};
};

class SavedDeskOverflowIconView : public SavedDeskIconView {
  METADATA_HEADER(SavedDeskOverflowIconView, SavedDeskIconView)

 public:
  // Create an icon view that only has a count and an optional plus.
  SavedDeskOverflowIconView(int count, bool show_plus);

  SavedDeskOverflowIconView(const SavedDeskOverflowIconView&) = delete;
  SavedDeskOverflowIconView& operator=(const SavedDeskOverflowIconView&) =
      delete;
  ~SavedDeskOverflowIconView() override;

  // views::View:
  void Layout(PassKey) override;

  // SavedDeskIconView:
  void UpdateCount(int count) override;
  size_t GetSortingKey() const override;
  int GetCount() const override;
  int GetCountToShow() const override;
  bool IsOverflowIcon() const override;
};

}  // namespace ash

#endif  // ASH_WM_DESKS_TEMPLATES_SAVED_DESK_ICON_VIEW_H_