Collection View Cell Duplicates every time I press this button (Swift) - ios

Question

Every time I tap on the like button (heart icon) the cell gets updated just fine but it gets duplicate too. I researched and tried to figure it out on my own but I couldn't see why it's being duplicated.
I investigated and I found that probably this might be a problem with the cellForRowAtIndexPath function but that function looks good to me.
Here's the relevant code:
HomeController.swift:
class HomeController: UICollectionViewController, UICollectionViewDelegateFlowLayout, HomePostCellDelegate {
let cellId = "cellId"
override func viewDidLoad() {
super.viewDidLoad()
collectionView?.register(HomePostCell.self, forCellWithReuseIdentifier: cellId)
let refreshControll = UIRefreshControl()
refreshControll.addTarget(self, action: #selector(handleRefresh), for: .valueChanged)
if #available(iOS 10.0, *) {
collectionView?.refreshControl = refreshControll
} else {
// Fallback on earlier versions
}
setupNavigationItems()
fetchAllPost()
}
#objc func handleUpdateFeed() {
handleRefresh()
}
#objc func handleRefresh() {
posts.removeAll()
fetchAllPost()
}
fileprivate func fetchAllPost() {
fetchPosts()
fetchFollowingUserIds()
}
fileprivate func fetchFollowingUserIds() {
guard let uid = FIRAuth.auth()?.currentUser?.uid else { return }
FIRDatabase.database().reference().child("following").child(uid).observeSingleEvent(of: .value, with: { (snapshot) in
guard let userIdsDictionary = snapshot.value as? [String: Any] else { return }
userIdsDictionary.forEach({ (key, value) in
FIRDatabase.fetchUserWithUid(uid: key, completion: { (user) in
self.fetchPostsWithUser(user: user)
})
})
}) { (err) in
print("failed to fetch following users ids:", err)
}
}
var posts = [Post]()
fileprivate func fetchPosts() {
guard let currentUserID = FIRAuth.auth()?.currentUser?.uid else { return }
FIRDatabase.fetchUserWithUid(uid: currentUserID) { (user) in
self.fetchPostsWithUser(user: user)
}
}
fileprivate func fetchPostsWithUser(user: User) {
let ref = FIRDatabase.database().reference().child("posts/\(user.uid)/")
ref.observeSingleEvent(of: .value, with: { (snapshot) in
if #available(iOS 10.0, *) {
self.collectionView?.refreshControl?.endRefreshing()
} else {
// Fallback on earlier versions
}
guard let dictionaries = snapshot.value as? [String: Any] else { return }
dictionaries.forEach({ (key,value) in
guard let dictionary = value as? [String: Any] else { return }
var post = Post(user: user, dictionary: dictionary)
post.id = key
guard let uid = FIRAuth.auth()?.currentUser?.uid else { return }
FIRDatabase.database().reference().child("likes").child(key).child(uid).observe(.value, with: { (snapshot) in
if let value = snapshot.value as? Int, value == 1 {
post.hasLiked = true
} else {
post.hasLiked = false
}
self.posts.append(post)
self.posts.sort(by: { (p1, p2) -> Bool in
return p1.creationDate.compare(p2.creationDate) == .orderedDescending
})
self.collectionView?.reloadData()
print("fetch post with user reload data")
}, withCancel: { (err) in
print("Failed to fetch info for post")
})
})
}) { (error) in
print("Failed to fetch posts", error)
}
}
override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return posts.count
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let height: CGFloat = 310 // username + userProfileImageView
return CGSize(width: view.frame.width - 27.5, height: height)
}
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath) as! HomePostCell
cell.post = posts[indexPath.item]
cell.delegate = self
cell.photoImageView.image = nil
// Makes cell corners round
cell.layer.masksToBounds = true
cell.layer.cornerRadius = 17
return cell
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
return 20
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
return 5
}
func didLike(for cell: HomePostCell) {
guard let indexPath = collectionView?.indexPath(for: cell) else { return }
var post = self.posts[indexPath.item]
guard let postId = post.id else { return }
guard let uid = FIRAuth.auth()?.currentUser?.uid else { return }
let values = [uid : post.hasLiked == true ? 0 : 1]
FIRDatabase.database().reference().child("likes").child(postId).updateChildValues(values) { (err, _) in
if let err = err {
print("Failed to like post", err)
return
}
print("Successfully liked post!")
post.hasLiked = !post.hasLiked
self.posts[indexPath.item] = post
self.collectionView?.reloadItems(at: [indexPath])
}
}
}
Let me know if you have any questions, Thank you!