Add header for the Content Suggestions

ios/chrome/browser/ui/content_suggestions/content_suggestions_collection_updater.mm

 // 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.
 
 #import "ios/chrome/browser/ui/content_suggestions/content_suggestions_collection_updater.h"
 
 #include "base/logging.h"
 #include "base/mac/foundation_util.h"
 #include "base/time/time.h"
+#import "ios/chrome/browser/ui/collection_view/cells/collection_view_text_item.h"
 #import "ios/chrome/browser/ui/collection_view/collection_view_controller.h"
 #import "ios/chrome/browser/ui/collection_view/collection_view_model.h"
 #import "ios/chrome/browser/ui/content_suggestions/content_suggestion.h"
 #import "ios/chrome/browser/ui/content_suggestions/content_suggestion_identifier.h"
 #import "ios/chrome/browser/ui/content_suggestions/content_suggestions_article_item.h"
 #import "ios/chrome/browser/ui/content_suggestions/content_suggestions_data_sink.h"
 #import "ios/chrome/browser/ui/content_suggestions/content_suggestions_data_source.h"
 #import "ios/chrome/browser/ui/content_suggestions/content_suggestions_expandable_item.h"
 #import "ios/chrome/browser/ui/content_suggestions/content_suggestions_favicon_item.h"
 #import "ios/chrome/browser/ui/content_suggestions/content_suggestions_footer_item.h"
@@ skipping 12 matching lines @@
 namespace {
 
 // Enum defining the ItemType of this ContentSuggestionsCollectionUpdater.
 typedef NS_ENUM(NSInteger, ItemType) {
   ItemTypeText = kItemTypeEnumZero,
   ItemTypeArticle,
   ItemTypeExpand,
   ItemTypeStack,
   ItemTypeFavicon,
   ItemTypeFooter,
+  ItemTypeHeader,
 };
 
 typedef NS_ENUM(NSInteger, SectionIdentifier) {
   SectionIdentifierBookmarks = kSectionIdentifierEnumZero,
   SectionIdentifierArticles,
   SectionIdentifierDefault,
 };
 
 ItemType ItemTypeForContentSuggestionType(ContentSuggestionType type) {
   switch (type) {
@@ skipping 107 matching lines @@
     return;
 
   NSIndexPath* indexPath = [self.collectionViewController.collectionViewModel
              indexPathForItem:correspondingItem
       inSectionWithIdentifier:sectionIdentifier];
   [self.collectionViewController dismissEntryAtIndexPath:indexPath];
 }
 
 - (void)reloadAllData {
   [self resetModels];
-  [self.collectionViewController
-      addSuggestions:[self.dataSource allSuggestions]];
+
+  // The data is reset, add the new data directly in the model then reload the
+  // collection.
+  NSArray<ContentSuggestion*>* suggestions = [self.dataSource allSuggestions];
+  [self addSectionsForSuggestionsToModel:suggestions];
+  [self addSuggestionsToModel:suggestions];
+  [self.collectionViewController.collectionView reloadData];
 }
 
 - (void)clearSection:(ContentSuggestionsSectionInformation*)sectionInfo {
   SectionIdentifier sectionIdentifier = SectionIdentifierForInfo(sectionInfo);
   NSInteger section = [self.collectionViewController.collectionViewModel
       sectionIdentifierForSection:sectionIdentifier];
 
   [self.collectionViewController dismissSection:section];
 }
 
@@ skipping 59 matching lines @@
   for (ContentSuggestion* suggestion in suggestions) {
     ContentSuggestionsSectionInformation* sectionInfo =
         suggestion.suggestionIdentifier.sectionInfo;
     NSInteger sectionIdentifier = SectionIdentifierForInfo(sectionInfo);
 
     if (![model hasSectionForSectionIdentifier:sectionIdentifier]) {
       [model addSectionWithIdentifier:sectionIdentifier];
       self.sectionInfoBySectionIdentifier[@(sectionIdentifier)] = sectionInfo;
       [indexSet addIndex:[model sectionForSectionIdentifier:sectionIdentifier]];
 
+      [self addHeader:suggestion.suggestionIdentifier.sectionInfo];
       [self addFooterIfNeeded:suggestion.suggestionIdentifier.sectionInfo];
     }
   }
   return indexSet;
 }
 
 #pragma mark - ContentSuggestionsArticleItemDelegate
 
 - (void)loadImageForArticleItem:(ContentSuggestionsArticleItem*)articleItem {
   NSInteger sectionIdentifier =
@@ skipping 40 matching lines @@
                block:^{
                  [weakSelf runAdditionalActionForSection:sectionInfo];
                }];
 
     [self.collectionViewController.collectionViewModel
                        setFooter:footer
         forSectionWithIdentifier:sectionIdentifier];
   }
 }
 
+// Adds the header corresponding to |sectionInfo| to the section.
+- (void)addHeader:(ContentSuggestionsSectionInformation*)sectionInfo {
+  NSInteger sectionIdentifier = SectionIdentifierForInfo(sectionInfo);
+
+  if (![self.collectionViewController.collectionViewModel
+          headerForSectionWithIdentifier:sectionIdentifier]) {
+    CollectionViewTextItem* header =
+        [[CollectionViewTextItem alloc] initWithType:ItemTypeHeader];
+    header.text = sectionInfo.title;
+    [self.collectionViewController.collectionViewModel
+                       setHeader:header
+        forSectionWithIdentifier:sectionIdentifier];
+  }
+}
+
 // Resets the models, removing the current CollectionViewItem and the
 // SectionInfo.
 - (void)resetModels {
   [self.collectionViewController loadModel];
   self.sectionInfoBySectionIdentifier = [[NSMutableDictionary alloc] init];
 }
 
 // Runs the additional action for the section identified by |sectionInfo|.
 - (void)runAdditionalActionForSection:
     (ContentSuggestionsSectionInformation*)sectionInfo {
@@ skipping 19 matching lines @@
                          }];
 }
 
 // Adds the |suggestions| to the collection view. All the suggestions must have
 // the same sectionInfo.
 - (void)moreSuggestionsFetched:(NSArray<ContentSuggestion*>*)suggestions {
   [self.collectionViewController addSuggestions:suggestions];
 }
 
 @end