create custom nested tableview cells - swift

Question

I want to create a nested comment section. I am using Firebase as my database. In my app I have a comment section on each post. Logged in users have the ability to comment on a post and their comments can also be commented on, creating a nested effect.
So first I display the comments that were made to the original post. What I want to do is to go through each comment and check to see if there is a comment for that comment and if there is a comment, I want it to display directly under that comment. Just like Instagram or Facebook.
Here is a JSON example of what a nested comment would look like in Firebase
{
"author" : "patient0",
"comments" : {
"comment-487" : {
"author" : "Doctor1",
"comments" : {
"comment-489" : {
"content" : "Your internal capsule in your cerebrum was affected by the stroke",
"id" : "comment-489",
"reply_to" : "comment-487",
"reply_to_type" : "comment"
},
"comment-490" : {
"author" : "Doctor2",
"content" : "Your internal capsule is closely associated with your basal ganglia structures",
"id" : "comment-490",
"reply_to" : "comment-487",
"reply_to_type" : "comment"
}
},
"content" : "I recently had a stroke",
"id" : "comment-487",
"post_id" : "post-1069",
"reply_to" : "post-1069",
"reply_to_type" : "post"
},
"comment-491" : {
"author" : "MedStudent",
"comments" : {
"c_1531642274921" : {
"content" : "Wow! I wonder what cranial nerves were affected due to the hemorrhage",
"id" : "c_1531642274921",
"post_id" : "post-1069",
"pub_time" : 1531642274922,
"reply_to" : "comment-491",
"reply_to_type" : "comment"
}
},
"content" : "The hemorrhage was by the pons and cranial nerve 3 is by the pons, maybe the patient lost the ability to accommodate their eye sight and keep their eyes open.",
"id" : "comment-491",
"num_likes" : 0,
"post_id" : "post-1069",
"reply_to" : "post-1069",
"reply_to_type" : "post"
}
},
"content" : "I have a headache",
"id" : "post-1069",
"num_comments" : 5,
"title" : "I have a headache, should I go to the hospital",
}
As of now I am able to get the inital comments to print (the comments made directly to the post)
func loadComments(){
Database.database().reference().child("main").child("posts").child(postID!).child("comments").queryOrdered(byChild: "id").observeSingleEvent(of: .value, with: { (snapshot:DataSnapshot) in
if let postsDictionary = snapshot .value as? [String: AnyObject] {
for testingkey in postsDictionary.keys {
Database.database().reference().child("main").child("posts").child(self.postID!).child("comments").child(testingkey).child("comments").queryOrdered(byChild: "post_id").observeSingleEvent(of: .value, with: { (snapshot:DataSnapshot) in
if let postsDictionary = snapshot .value as? [String: AnyObject] {
for post in postsDictionary {
}
DispatchQueue.main.async(execute: {
self.TableView.reloadData()
})
}
})
}
for post in postsDictionary {
//main comments
self.Comments.add(post.value)
}
DispatchQueue.main.async(execute: {
self.TableView.reloadData()
})
}
})
}
I just don't know how to go through each post to check to see if there is a comment associated with it. Also if there is a comment associated with the original comment, I want it to print out in a custom cell.

Answer 1

I'd create a class or struct for comment, with an array of comments as a property.
class Comment {
let id: String
let author: String
var content: String
var comments: [Comment]
}
Then I'd create a TopLevelComment class as a subclass of Comment
class TopLevelComment: Comment {
// Whatever special properties you want your top level comments to have
}
You can now check if a comment is replying to a post or a comment by simply using
comment is TopLevelComment
Then you should restructure your database appropriately so you can cast it to the Comment class
For your tableView, I'd use a tableview for each top level comment, maybe even a section for each.

Answer 2

You can create an element for comment elements .
var commentElements = [CustomStruct]()
After creating Custom Element pull the variables from Firebase and save .
if let postsDictionary = snapshot .value as? [String: AnyObject] {
guard let comment = postsDictionary["comments"] as? NSArray else { return }
for com in comment {
guard let commentObject = com as? [String:Any] else { return }
let id = commentObject["id"]
let type = commentObject["reply_to_type"]
let replyTo = commentObject["reply_to"]
let content = commentObject["content"]
let element = CustomStruct(id:id , type:type , ....)
commentElements.append(element)
}
for post in postsDictionary {
}
DispatchQueue.main.async(execute: {
self.TableView.reloadData()
})
}
After pulling all elements , you may group based on comment Id . And you can show with Section in TableView.You sort the first element "reply_to_type" : "post"

Answer 3

As per your question, I believe that you are having difficulty in figuring out how to parse the JSON to a format (or view model) which can be used to display your posts and comments.
You can use the following model sample (with reworks or tweaks of your own, if needed) to parse and organize your posts and it's comments.
class Post {
var author: String?
var comments: [Post] = []
var content: String?
var id: String?
var numComments: Int?
var title: String?
init(dict: [String: AnyObject]?) {
author = dict?["author"] as? String
content = dict?["content"] as? String
id = dict?["id"] as? String
numComments = dict?["num_comments"] as? Int
title = dict?["title"] as? String
if let commentsDict = dict?["comments"] as? [String: AnyObject] {
// Sort the comments based on the id which seems to be appended to the comment key.
let commentIds = commentsDict.keys.sorted()
for id in commentIds {
let comment = commentsDict[id] as? [String : AnyObject]
comments.append(Post(dict: comment))
}
}
}
}
Usage:
//
// postDict is your dictionary object corresponding to one post.
//
// Assign your post's dictionary item to this variable.
//
var postDict: [String: AnyObject]?
// "Post" object which has recursive comments within up to any number of levels.
// Comments are also using the same model object.
// If you want to use another, you can create one with the corresponding elements.
let post = Post(dict: postDict)
P.S: The JSON structure looks to be not of a unique structure. You might want to rework on this structure to make sure that your content gets mapped neatly.