// Copyright 2012 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/ui/toolbar/back_forward_menu_model.h"

#include <stddef.h>

#include <algorithm>

#include "base/containers/contains.h"
#include "base/functional/bind.h"
#include "base/functional/callback_helpers.h"
#include "base/metrics/histogram_functions.h"
#include "base/metrics/user_metrics.h"
#include "base/strings/string_number_conversions.h"
#include "build/build_config.h"
#include "chrome/app/vector_icons/vector_icons.h"
#include "chrome/browser/favicon/favicon_service_factory.h"
#include "chrome/browser/favicon/favicon_utils.h"
#include "chrome/browser/profiles/profile.h"
#include "chrome/browser/ui/browser.h"
#include "chrome/browser/ui/browser_commands.h"
#include "chrome/browser/ui/browser_navigator_params.h"
#include "chrome/browser/ui/browser_window.h"
#include "chrome/browser/ui/singleton_tabs.h"
#include "chrome/browser/ui/tabs/tab_strip_model.h"
#include "chrome/common/chrome_features.h"
#include "chrome/common/url_constants.h"
#include "components/favicon_base/favicon_types.h"
#include "components/feature_engagement/public/feature_constants.h"
#include "components/grit/components_scaled_resources.h"
#include "components/strings/grit/components_strings.h"
#include "content/public/browser/favicon_status.h"
#include "content/public/browser/navigation_controller.h"
#include "content/public/browser/navigation_entry.h"
#include "content/public/browser/web_contents.h"
#include "net/base/registry_controlled_domains/registry_controlled_domain.h"
#include "ui/base/accelerators/menu_label_accelerator_util.h"
#include "ui/base/l10n/l10n_util.h"
#include "ui/base/models/image_model.h"
#include "ui/base/resource/resource_bundle.h"
#include "ui/base/ui_base_features.h"
#include "ui/base/window_open_disposition.h"
#include "ui/base/window_open_disposition_utils.h"
#include "ui/color/color_id.h"
#include "ui/color/color_provider.h"
#include "ui/gfx/text_elider.h"
#include "ui/menus/simple_menu_model.h"

using base::UserMetricsAction;
using content::NavigationController;
using content::NavigationEntry;
using content::WebContents;

const size_t BackForwardMenuModel::kMaxHistoryItems = 12;
const size_t BackForwardMenuModel::kMaxChapterStops = 5;
static const int kMaxBackForwardMenuWidth = 700;

BackForwardMenuModel::BackForwardMenuModel(Browser* browser,
                                           ModelType model_type)
    : browser_(browser), model_type_(model_type) {}

BackForwardMenuModel::~BackForwardMenuModel() = default;

base::WeakPtr<ui::MenuModel> BackForwardMenuModel::AsWeakPtr() {
  return weak_ptr_factory_.GetWeakPtr();
}

size_t BackForwardMenuModel::GetItemCount() const {
  size_t items = GetHistoryItemCount();
  if (items == 0) {
    return items;
  }

  size_t chapter_stops = 0;

  // Next, we count ChapterStops, if any.
  if (items == kMaxHistoryItems) {
    chapter_stops = GetChapterStopCount(items);
  }

  if (chapter_stops) {
    items += chapter_stops + 1;  // Chapter stops also need a separator.
  }

  // If the current mode is incognito, "Show Full History" should not be
  // visible.
  if (!ShouldShowFullHistoryBeVisible()) {
    return items;
  }

  // If the menu is not empty, add two positions in the end
  // for a separator and a "Show Full History" item.
  items += 2;
  return items;
}

ui::MenuModel::ItemType BackForwardMenuModel::GetTypeAt(size_t index) const {
  return IsSeparator(index) ? TYPE_SEPARATOR : TYPE_COMMAND;
}

ui::MenuSeparatorType BackForwardMenuModel::GetSeparatorTypeAt(
    size_t index) const {
  return ui::NORMAL_SEPARATOR;
}

int BackForwardMenuModel::GetCommandIdAt(size_t index) const {
  return static_cast<int>(index);
}

std::u16string BackForwardMenuModel::GetLabelAt(size_t index) const {
  // Return label "Show Full History" for the last item of the menu.
  if (ShouldShowFullHistoryBeVisible() && index == GetItemCount() - 1) {
    return l10n_util::GetStringUTF16(IDS_HISTORY_SHOWFULLHISTORY_LINK);
  }

  // Return an empty string for a separator.
  if (IsSeparator(index)) {
    return std::u16string();
  }

  // Return the entry title, escaping any '&' characters and eliding it if it's
  // super long.
  NavigationEntry* entry = GetNavigationEntry(index);
  std::u16string menu_text(entry->GetTitleForDisplay());
  menu_text = ui::EscapeMenuLabelAmpersands(menu_text);
  menu_text = gfx::ElideText(menu_text, gfx::FontList(),
                             kMaxBackForwardMenuWidth, gfx::ELIDE_TAIL);

  return menu_text;
}

bool BackForwardMenuModel::IsItemDynamicAt(size_t index) const {
  // This object is only used for a single showing of a menu.
  return false;
}

bool BackForwardMenuModel::GetAcceleratorAt(
    size_t index,
    ui::Accelerator* accelerator) const {
  return false;
}

bool BackForwardMenuModel::IsItemCheckedAt(size_t index) const {
  return false;
}

int BackForwardMenuModel::GetGroupIdAt(size_t index) const {
  return false;
}

ui::ImageModel BackForwardMenuModel::GetIconAt(size_t index) const {
  if (!ItemHasIcon(index)) {
    return ui::ImageModel();
  }

  // Return icon of "Show Full History" for the last item of the menu.
  if (ShouldShowFullHistoryBeVisible() && index == GetItemCount() - 1) {
    return ui::ImageModel::FromVectorIcon(
        kHistoryIcon, ui::kColorMenuIcon,
        ui::SimpleMenuModel::kDefaultIconSize);
  }
  NavigationEntry* entry = GetNavigationEntry(index);
  content::FaviconStatus fav_icon = entry->GetFavicon();
  if (!fav_icon.valid && menu_model_delegate()) {
    // FetchFavicon is not const because it caches the result, but GetIconAt
    // is const because it is not be apparent to outside observers that an
    // internal change is taking place. Compared to spreading const in
    // unintuitive places (e.g. making menu_model_delegate() const but
    // returning a non-const while sprinkling virtual on member variables),
    // this const_cast is the lesser evil.
    const_cast<BackForwardMenuModel*>(this)->FetchFavicon(entry);
  }

  // Only apply theming to certain chrome:// favicons.
  if (favicon::ShouldThemifyFaviconForEntry(entry)) {
    const ui::ColorProvider* const cp = &GetWebContents()->GetColorProvider();
    gfx::ImageSkia themed_favicon = favicon::ThemeFavicon(
        fav_icon.image.AsImageSkia(), cp->GetColor(ui::kColorMenuIcon),
        cp->GetColor(ui::kColorMenuItemBackgroundHighlighted),
        cp->GetColor(ui::kColorMenuBackground));
    return ui::ImageModel::FromImageSkia(themed_favicon);
  }

  return ui::ImageModel::FromImage(fav_icon.image);
}

ui::ButtonMenuItemModel* BackForwardMenuModel::GetButtonMenuItemAt(
    size_t index) const {
  return nullptr;
}

bool BackForwardMenuModel::IsEnabledAt(size_t index) const {
  return index < GetItemCount() && !IsSeparator(index);
}

ui::MenuModel* BackForwardMenuModel::GetSubmenuModelAt(size_t index) const {
  return nullptr;
}

void BackForwardMenuModel::ActivatedAt(size_t index) {
  ActivatedAt(index, 0);
}

void BackForwardMenuModel::ActivatedAt(size_t index, int event_flags) {
  DCHECK(!IsSeparator(index));

  // Execute the command for the last item: "Show Full History".
  if (ShouldShowFullHistoryBeVisible() && index == GetItemCount() - 1) {
    base::RecordComputedAction(
        BuildActionName("ShowFullHistory", std::nullopt));
    ShowSingletonTabOverwritingNTP(browser_, GURL(chrome::kChromeUIHistoryURL));
    return;
  }

  // Log whether it was a history or chapter click.
  size_t items = GetHistoryItemCount();
  if (index < items) {
    base::RecordComputedAction(BuildActionName("HistoryClick", index));
  } else {
    const auto chapter_index =
        (index == items) ? std::nullopt : std::make_optional(index - items - 1);
    base::RecordComputedAction(BuildActionName("ChapterClick", chapter_index));
  }

  CHECK(menu_model_open_timestamp_.has_value());
  base::TimeDelta time =
      base::TimeTicks::Now() - menu_model_open_timestamp_.value();
  base::UmaHistogramLongTimes(
      "Navigation.BackForward.TimeFromOpenBackNavigationMenuToActivateItem",
      time);

  std::optional<size_t> controller_index = MenuIndexToNavEntryIndex(index);
  DCHECK(controller_index.has_value());

  WindowOpenDisposition disposition =
      ui::DispositionFromEventFlags(event_flags);
  chrome::NavigateToIndexWithDisposition(browser_, controller_index.value(),
                                         disposition);
}

void BackForwardMenuModel::MenuWillShow() {
  base::RecordComputedAction(BuildActionName("Popup", std::nullopt));
  requested_favicons_.clear();
  cancelable_task_tracker_.TryCancelAll();
  menu_model_open_timestamp_ = base::TimeTicks::Now();
  // Observe the web contents for navigation changes which could
  // happen while the menu is open.
  content::WebContentsObserver::Observe(GetWebContents());

  // Close the IPH popup if the user opens the menu.
  browser_->window()->NotifyFeaturePromoFeatureUsed(
      feature_engagement::kIPHBackNavigationMenuFeature,
      FeaturePromoFeatureUsedAction::kClosePromoIfPresent);
}

void BackForwardMenuModel::MenuWillClose() {
  content::WebContentsObserver::Observe(nullptr);
  CHECK(menu_model_open_timestamp_.has_value());
  base::TimeDelta time =
      base::TimeTicks::Now() - menu_model_open_timestamp_.value();
  base::UmaHistogramLongTimes(
      "Navigation.BackForward.TimeFromOpenBackNavigationMenuToCloseMenu", time);
}

void BackForwardMenuModel::NavigationEntryCommitted(
    const content::LoadCommittedDetails& load_details) {
  if (menu_model_delegate()) {
    menu_model_delegate()->OnMenuStructureChanged();
  }
}

void BackForwardMenuModel::NavigationEntriesDeleted() {
  if (menu_model_delegate()) {
    menu_model_delegate()->OnMenuStructureChanged();
  }
}

bool BackForwardMenuModel::IsSeparator(size_t index) const {
  size_t history_items = GetHistoryItemCount();
  // If the index is past the number of history items + separator,
  // we then consider if it is a chapter-stop entry.
  if (index > history_items) {
    // We either are in ChapterStop area, or at the end of the list (the "Show
    // Full History" link).
    size_t chapter_stops = GetChapterStopCount(history_items);
    if (chapter_stops == 0) {
      return false;  // We must have reached the "Show Full History" link.
    }
    // Otherwise, look to see if we have reached the separator for the
    // chapter-stops. If not, this is a chapter stop.
    return index == history_items + 1 + chapter_stops;
  }

  // Look to see if we have reached the separator for the history items.
  return index == history_items;
}

void BackForwardMenuModel::FetchFavicon(NavigationEntry* entry) {
  // If the favicon has already been requested for this menu, don't do
  // anything.
  if (base::Contains(requested_favicons_, entry->GetUniqueID())) {
    return;
  }

  requested_favicons_.insert(entry->GetUniqueID());
  favicon::FaviconService* favicon_service =
      FaviconServiceFactory::GetForProfile(browser_->profile(),
                                           ServiceAccessType::EXPLICIT_ACCESS);
  if (!favicon_service) {
    return;
  }

  favicon_service->GetFaviconImageForPageURL(
      entry->GetURL(),
      base::BindOnce(&BackForwardMenuModel::OnFavIconDataAvailable,
                     base::Unretained(this), entry->GetUniqueID()),
      &cancelable_task_tracker_);
}

void BackForwardMenuModel::OnFavIconDataAvailable(
    int navigation_entry_unique_id,
    const favicon_base::FaviconImageResult& image_result) {
  if (image_result.image.IsEmpty()) {
    return;
  }

  // Find the current model_index for the unique id.
  NavigationEntry* entry = nullptr;
  size_t model_index = 0;
  for (size_t i = 0; i + 1 < GetItemCount(); ++i) {
    if (IsSeparator(i)) {
      continue;
    }
    if (GetNavigationEntry(i)->GetUniqueID() == navigation_entry_unique_id) {
      model_index = i;
      entry = GetNavigationEntry(i);
      break;
    }
  }

  if (!entry) {
    // The NavigationEntry wasn't found, this can happen if the user
    // navigates to another page and a NavigatationEntry falls out of the
    // range of kMaxHistoryItems.
    return;
  }

  // Now that we have a valid NavigationEntry, decode the favicon and assign
  // it to the NavigationEntry.
  entry->GetFavicon().valid = true;
  entry->GetFavicon().url = image_result.icon_url;
  entry->GetFavicon().image = image_result.image;
  if (menu_model_delegate()) {
    menu_model_delegate()->OnIconChanged(GetCommandIdAt(model_index));
  }
}

size_t BackForwardMenuModel::GetHistoryItemCount() const {
  WebContents* contents = GetWebContents();
  if (!contents) {
    return 0;
  }

  size_t items = contents->GetController().GetCurrentEntryIndex();
  if (model_type_ == ModelType::kForward) {
    // Only count items from n+1 to end (if n is current entry)
    items = contents->GetController().GetEntryCount() - items - 1;
  }

  return std::min(items, kMaxHistoryItems);
}

size_t BackForwardMenuModel::GetChapterStopCount(size_t history_items) const {
  if (history_items != kMaxHistoryItems) {
    return 0;
  }

  WebContents* contents = GetWebContents();
  size_t current_entry = contents->GetController().GetCurrentEntryIndex();

  const bool forward = model_type_ == ModelType::kForward;
  size_t chapter_id = current_entry;
  if (!forward && chapter_id < history_items) {
    return 0;
  }
  chapter_id =
      forward ? (chapter_id + history_items) : (chapter_id - history_items);

  size_t chapter_stops = 0;
  do {
    const std::optional<size_t> index =
        GetIndexOfNextChapterStop(chapter_id, forward);
    if (!index.has_value()) {
      break;
    }
    chapter_id = index.value();
    ++chapter_stops;
  } while (chapter_stops < kMaxChapterStops);

  return chapter_stops;
}

std::optional<size_t> BackForwardMenuModel::GetIndexOfNextChapterStop(
    size_t start_from,
    bool forward) const {
  // We want to advance over the current chapter stop, so we add one.
  // We don't need to do this when direction is backwards.
  if (forward) {
    start_from++;
  }

  NavigationController& controller = GetWebContents()->GetController();
  const size_t max_count = controller.GetEntryCount();
  if (start_from >= max_count) {
    return std::nullopt;  // Out of bounds.
  }

  NavigationEntry* start_entry = controller.GetEntryAtIndex(start_from);
  const GURL& url = start_entry->GetURL();

  auto same_domain_func = [&controller, &url](size_t i) {
    return net::registry_controlled_domains::SameDomainOrHost(
        url, controller.GetEntryAtIndex(i)->GetURL(),
        net::registry_controlled_domains::EXCLUDE_PRIVATE_REGISTRIES);
  };

  if (forward) {
    // When going forwards we return the entry before the entry that has a
    // different domain.
    for (size_t i = start_from + 1; i < max_count; ++i) {
      if (!same_domain_func(i)) {
        return i - 1;
      }
    }
    // Last entry is always considered a chapter stop.
    return max_count - 1;
  }

  // When going backwards we return the first entry we find that has a
  // different domain.
  for (size_t i = start_from; i > 0; --i) {
    if (!same_domain_func(i - 1)) {
      return i - 1;
    }
  }
  // We have reached the beginning without finding a chapter stop.
  return std::nullopt;
}

std::optional<size_t> BackForwardMenuModel::FindChapterStop(size_t offset,
                                                            bool forward,
                                                            size_t skip) const {
  WebContents* contents = GetWebContents();
  size_t entry = contents->GetController().GetCurrentEntryIndex();
  if (!forward && entry < offset) {
    return std::nullopt;
  }
  entry = forward ? (entry + offset) : (entry - offset);
  for (size_t i = 0; i <= skip; ++i) {
    const std::optional<size_t> index =
        GetIndexOfNextChapterStop(entry, forward);
    if (!index.has_value()) {
      return std::nullopt;
    }
    entry = index.value();
  }

  return entry;
}

bool BackForwardMenuModel::ItemHasCommand(size_t index) const {
  return index < GetItemCount() && !IsSeparator(index);
}

bool BackForwardMenuModel::ItemHasIcon(size_t index) const {
  return index < GetItemCount() && !IsSeparator(index);
}

std::u16string BackForwardMenuModel::GetShowFullHistoryLabel() const {
  return l10n_util::GetStringUTF16(IDS_HISTORY_SHOWFULLHISTORY_LINK);
}

WebContents* BackForwardMenuModel::GetWebContents() const {
  // We use the test web contents if the unit test has specified it.
  return test_web_contents_
             ? test_web_contents_.get()
             : browser_->tab_strip_model()->GetActiveWebContents();
}

std::optional<size_t> BackForwardMenuModel::MenuIndexToNavEntryIndex(
    size_t index) const {
  WebContents* contents = GetWebContents();
  size_t history_items = GetHistoryItemCount();

  // Convert anything above the History items separator.
  if (index < history_items) {
    const size_t current_index =
        contents->GetController().GetCurrentEntryIndex();
    const bool forward = model_type_ == ModelType::kForward;
    if (!forward && current_index <= index) {
      return std::nullopt;
    }
    return forward ? (current_index + index + 1)
                   : (current_index - (index + 1));
  }
  if (index == history_items) {
    return std::nullopt;  // Don't translate the separator for history items.
  }

  if (index >= history_items + 1 + GetChapterStopCount(history_items)) {
    return std::nullopt;  // This is beyond the last chapter stop so we abort.
  }

  // This menu item is a chapter stop located between the two separators.
  return FindChapterStop(history_items, model_type_ == ModelType::kForward,
                         index - history_items - 1);
}

NavigationEntry* BackForwardMenuModel::GetNavigationEntry(size_t index) const {
  std::optional<size_t> controller_index = MenuIndexToNavEntryIndex(index);
  NavigationController& controller = GetWebContents()->GetController();

  DCHECK(controller_index.has_value());
  DCHECK_LT(controller_index.value(),
            static_cast<size_t>(controller.GetEntryCount()));

  return controller.GetEntryAtIndex(controller_index.value());
}

std::string BackForwardMenuModel::BuildActionName(
    const std::string& action,
    std::optional<size_t> index) const {
  DCHECK(!action.empty());
  std::string metric_string;
  if (model_type_ == ModelType::kForward) {
    metric_string += "ForwardMenu_";
  } else {
    metric_string += "BackMenu_";
  }
  metric_string += action;
  if (index.has_value()) {
    // +1 is for historical reasons (indices used to start at 1).
    metric_string += base::NumberToString(index.value() + 1);
  }
  return metric_string;
}

bool BackForwardMenuModel::ShouldShowFullHistoryBeVisible() const {
  return !browser_->profile()->IsOffTheRecord();
}