Add ContentSuggestionsMediator

ios/chrome/browser/content_suggestions/content_suggestions_mediator.mm

+// Copyright 2017 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/content_suggestions/content_suggestions_mediator.h"
+
+#include "base/memory/ptr_util.h"
+#include "components/ntp_snippets/category.h"
+#include "components/ntp_snippets/content_suggestion.h"
+#import "ios/chrome/browser/content_suggestions/content_suggestions_data_holder.h"
+#import "ios/chrome/browser/content_suggestions/content_suggestions_service_bridge_observer.h"
+#import "ios/chrome/browser/ui/content_suggestions/content_suggestions_data_sink.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+@interface ContentSuggestionsMediator ()<
+    ContentSuggestionsServiceBridgeObserver> {
+  // Bridge for this class to become an observer of a ContentSuggestionsService.
+  std::unique_ptr<ContentSuggestionsServiceBridge> _suggestionBridge;
+}
+
+@property(nonatomic, assign)
+    ntp_snippets::ContentSuggestionsService* contentService;
+
+// Converts the data in |category| to ContentSuggestionsDataHolder and adds them
+// to the |contentArray|.
+- (void)addContentInCategory:(ntp_snippets::Category&)category
+                     toArray:(NSMutableArray<ContentSuggestionsDataHolder*>*)
+                                 contentArray;
+
+// Converts the |contentsuggestion| to a ContentSuggestionsDataHolder.
+- (ContentSuggestionsDataHolder*)convertContentSuggestion:
+    (const ntp_snippets::ContentSuggestion&)contentsuggestion;
+
+@end
+
+@implementation ContentSuggestionsMediator
+
+@synthesize contentService = _contentService;
+@synthesize dataSink = _dataSink;
+
+- (instancetype)initWithContentService:
+    (ntp_snippets::ContentSuggestionsService*)contentService {
+  self = [super init];
+  if (self) {
+    _suggestionBridge =
+        base::MakeUnique<ContentSuggestionsServiceBridge>(self, contentService);
+    _contentService = contentService;
+  }
+  return self;
+}
+
+#pragma mark - ContentSuggestionsDataSource
+
+- (NSArray<ContentSuggestionsDataHolder*>*)getData {
+  std::vector<ntp_snippets::Category> categories =
+      self.contentService->GetCategories();
+  NSMutableArray<ContentSuggestionsDataHolder*>* dataHolders =
+      [NSMutableArray array];
+  for (auto& category : categories) {
+    [self addContentInCategory:category toArray:dataHolders];
+  }
+  return dataHolders;
+}
+
+- (NSArray<ContentSuggestionsDataHolder*>*)getMoreData {
+  return nil;
+}
+
+#pragma mark - ContentSuggestionsServiceBridgeObserver
+
+- (void)onNewSuggestions:(ntp_snippets::Category)category {
+  [self.dataSink dataAvailable];
+}
+
+- (void)onCategory:(ntp_snippets::Category)category
+     statusChanged:(ntp_snippets::CategoryStatus)status {
+  // Update dataSink.
+}
+
+- (void)onSuggestionInvalidated:
+    (const ntp_snippets::ContentSuggestion::ID&)suggestion_id {
+  // Update dataSink.
+}
+
+- (void)onFullRefreshRequired {
+  // Update dataSink.
+}
+
+- (void)contentSuggestionsServiceShutdown {
+  // Update dataSink.
+}
+
+#pragma mark - Private
+
+- (void)addContentInCategory:(ntp_snippets::Category&)category
+                     toArray:(NSMutableArray<ContentSuggestionsDataHolder*>*)
+                                 contentArray {
+  const std::vector<ntp_snippets::ContentSuggestion>& suggestions =
+      self.contentService->GetSuggestionsForCategory(category);
+  for (auto& contentSuggestion : suggestions) {
+    [contentArray addObject:[self convertContentSuggestion:contentSuggestion]];
+  }
+}
+
+- (ContentSuggestionsDataHolder*)convertContentSuggestion:
+    (const ntp_snippets::ContentSuggestion&)contentsuggestion {
+  return [[ContentSuggestionsDataHolder alloc] init];
+}
+
+@end