Suggestions UI - expandable item

ios/chrome/browser/ui/suggestions/suggestions_view_controller.mm

Index: ios/chrome/browser/ui/suggestions/suggestions_view_controller.mm
diff --git a/ios/chrome/browser/ui/suggestions/suggestions_view_controller.mm b/ios/chrome/browser/ui/suggestions/suggestions_view_controller.mm
index a27da97a063afef0786224ca5511cfd72ae5fbe0..0940e8db9b2fe0f8a11dfa179326090f669d3c53 100644
--- a/ios/chrome/browser/ui/suggestions/suggestions_view_controller.mm
+++ b/ios/chrome/browser/ui/suggestions/suggestions_view_controller.mm
@@ -4,6 +4,7 @@
 
 #import "ios/chrome/browser/ui/suggestions/suggestions_view_controller.h"
 
+#include "base/mac/foundation_util.h"
 #import "ios/chrome/browser/ui/collection_view/cells/MDCCollectionViewCell+Chrome.h"
 #import "ios/chrome/browser/ui/collection_view/cells/collection_view_item.h"
 #import "ios/chrome/browser/ui/collection_view/collection_view_model.h"
@@ -19,6 +20,10 @@
 
 @property(nonatomic, strong) SuggestionsCollectionUpdater* collectionUpdater;
 
+// Applies |interaction| to the item corresponding to |cell| if it is a
+// SuggestionsExpandableCell.
+- (void)expand:(BOOL)expand cell:(UICollectionViewCell*)cell;
+
 @end
 
 @implementation SuggestionsViewController
@@ -54,6 +59,16 @@
                          forItem:item];
 }
 
+#pragma mark - SuggestionsExpandableCellDelegate
+
+- (void)retractCell:(UICollectionViewCell*)cell {
+  [self expand:NO cell:cell];
+}
+
+- (void)expandCell:(UICollectionViewCell*)cell {
+  [self expand:YES cell:cell];
+}
+
 #pragma mark - SuggestionsItemActions
 
 - (void)addNewItem:(id)sender {
@@ -70,4 +85,29 @@
                             toSection:inputSection];
 }
 
+#pragma mark - Private
+
+- (void)expand:(BOOL)expand cell:(UICollectionViewCell*)cell {
+  NSIndexPath* indexPath = [self.collectionView indexPathForCell:cell];
+  CollectionViewItem* item =
+      [self.collectionViewModel itemAtIndexPath:indexPath];
+  if ([item isKindOfClass:[SuggestionsExpandableItem class]]) {
+    SuggestionsExpandableItem* expandableItem =
+        base::mac::ObjCCast<SuggestionsExpandableItem>(item);
+
+    NSInteger sectionIdentifier = [self.collectionViewModel
+        sectionIdentifierForSection:indexPath.section];
+
+    expandableItem.expanded = expand;
+    [self reconfigureCellsForItems:@[ expandableItem ]
+           inSectionWithIdentifier:sectionIdentifier];
+
+    [UIView
+        animateWithDuration:1
+                 animations:^{
+                   [self.collectionView.collectionViewLayout invalidateLayout];
+                 }];
+  }
+}
+
 @end