[New CL] Add bookmark provider for content suggestions

components/ntp_snippets/bookmarks/bookmark_suggestions_provider.cc

Index: components/ntp_snippets/bookmarks/bookmark_suggestions_provider.cc
diff --git a/components/ntp_snippets/bookmarks/bookmark_suggestions_provider.cc b/components/ntp_snippets/bookmarks/bookmark_suggestions_provider.cc
new file mode 100644
index 0000000000000000000000000000000000000000..c5a88cec278e582af22d3fe63f8ace50d055221b
--- /dev/null
+++ b/components/ntp_snippets/bookmarks/bookmark_suggestions_provider.cc
@@ -0,0 +1,158 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "components/ntp_snippets/bookmarks/bookmark_suggestions_provider.h"
+
+#include <utility>
+#include <vector>
+
+#include "base/strings/utf_string_conversions.h"
+#include "components/bookmarks/browser/bookmark_model.h"
+#include "components/ntp_snippets/bookmarks/bookmark_last_visit_utils.h"
+#include "components/ntp_snippets/category_factory.h"
+#include "components/ntp_snippets/content_suggestion.h"
+
+using bookmarks::BookmarkModel;
+using bookmarks::BookmarkNode;
+
+namespace {
+
+const int kMaxBookmarks = 10;
+const int kMaxBookmarkAgeInDays = 42;
+
+base::Time GetThresholdTime() {
+  return base::Time::Now() - base::TimeDelta::FromDays(kMaxBookmarkAgeInDays);
+}
+
+}  // namespace
+
+namespace ntp_snippets {
+
+BookmarkSuggestionsProvider::BookmarkSuggestionsProvider(
+    ContentSuggestionsProvider::Observer* observer,
+    CategoryFactory* category_factory,
+    bookmarks::BookmarkModel* bookmark_model)
+    : ContentSuggestionsProvider(observer, category_factory),
+      category_status_(CategoryStatus::AVAILABLE_LOADING),
+      provided_category_(
+          category_factory->FromKnownCategory(KnownCategories::BOOKMARKS)),
+      bookmark_model_(bookmark_model),
+      fetch_requested_(false),
+      end_of_list_last_visit_date_(GetThresholdTime()) {
+  bookmark_model_->AddObserver(this);
+  FetchBookmarks();
+}
+
+BookmarkSuggestionsProvider::~BookmarkSuggestionsProvider() {
+  bookmark_model_->RemoveObserver(this);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Private methods
+
+std::vector<Category> BookmarkSuggestionsProvider::GetProvidedCategories() {
+  return std::vector<Category>({provided_category_});
+}
+
+CategoryStatus BookmarkSuggestionsProvider::GetCategoryStatus(
+    Category category) {
+  return category_status_;
+}
+
+void BookmarkSuggestionsProvider::DismissSuggestion(
+    const std::string& suggestion_id) {
+  // TODO(jkrcal): Implement blacklisting bookmarks until they are next visited.
+  // Then also implement ClearDismissedSuggestionsForDebugging.
+}
+
+void BookmarkSuggestionsProvider::FetchSuggestionImage(
+    const std::string& suggestion_id,
+    const ImageFetchedCallback& callback) {
+  callback.Run(suggestion_id, gfx::Image());
+}
+
+void BookmarkSuggestionsProvider::ClearCachedSuggestionsForDebugging() {
+  // Ignored.
+}
+
+void BookmarkSuggestionsProvider::ClearDismissedSuggestionsForDebugging() {
+  // TODO(jkrcal): Implement when discarded suggestions are supported.
+}
+
+void BookmarkSuggestionsProvider::BookmarkModelLoaded(
+    bookmarks::BookmarkModel* model,
+    bool ids_reassigned) {
+  DCHECK_EQ(bookmark_model_, model);
+  if (fetch_requested_) {
+    fetch_requested_ = false;
+    FetchBookmarksInternal();
+  }
+}
+
+void BookmarkSuggestionsProvider::OnWillChangeBookmarkMetaInfo(
+    BookmarkModel* model,
+    const BookmarkNode* node) {
+  // Store the last visit date of the node that is about to change.
+  node_to_change_last_visit_date_ = GetLastVisitDateForBookmark(node);
+}
+
+void BookmarkSuggestionsProvider::BookmarkMetaInfoChanged(
+    BookmarkModel* model,
+    const BookmarkNode* node) {
+  base::Time time = GetLastVisitDateForBookmark(node);
+  if (time == node_to_change_last_visit_date_ ||
+      time < end_of_list_last_visit_date_)
+    return;
+
+  // Last visit date of a node has changed (and is relevant for the list), we
+  // should update the suggestions.
+  FetchBookmarks();
+}
+
+void BookmarkSuggestionsProvider::FetchBookmarksInternal() {
+  DCHECK(bookmark_model_->loaded());
+
+  NotifyStatusChanged(CategoryStatus::AVAILABLE);
+
+  std::vector<const BookmarkNode*> bookmarks = GetRecentlyVisitedBookmarks(
+      bookmark_model_, kMaxBookmarks, GetThresholdTime());
+
+  std::vector<ContentSuggestion> suggestions;
+  for (const BookmarkNode* bookmark : bookmarks) {
+    ContentSuggestion suggestion(
+        MakeUniqueID(provided_category_, bookmark->url().spec()),
+        bookmark->url());
+
+    suggestion.set_title(bookmark->GetTitle());
+    suggestion.set_snippet_text(base::string16());
+    suggestion.set_publish_date(GetLastVisitDateForBookmark(bookmark));
+    suggestion.set_publisher_name(base::UTF8ToUTF16(bookmark->url().host()));
+    suggestions.emplace_back(std::move(suggestion));
+  }
+
+  if (suggestions.empty())
+    end_of_list_last_visit_date_ = GetThresholdTime();
+  else
+    end_of_list_last_visit_date_ = suggestions.back().publish_date();
+
+  observer()->OnNewSuggestions(this, provided_category_,
+                               std::move(suggestions));
+}
+
+void BookmarkSuggestionsProvider::FetchBookmarks() {
+  if (bookmark_model_->loaded())
+    FetchBookmarksInternal();
+  else
+    fetch_requested_ = true;
+}
+
+void BookmarkSuggestionsProvider::NotifyStatusChanged(
+    CategoryStatus new_status) {
+  if (category_status_ == new_status)
+    return;
+  category_status_ = new_status;
+  observer()->OnCategoryStatusChanged(this, provided_category_, new_status);
+}
+
+}  // namespace ntp_snippets