I'm relatively new to Swift and Firebase, so I'm not very familiar with the intricacies of how both work together. I'm building a chat app that has messages and threads. A user can send a message, struct Message, and if another user wants to directly reply to that message, a thread is created. For each message, I'm storing an array of Firebase document references to the other messages in the thread, threadBefore: [Message].
struct Message: Codable, Identifiable {
var id: String
var content: String
var name: String
var upvotes: Int
var likedByUser: Bool
var dontShow: Bool
var sentAt: Date
var threadsArray: [Message]
}
The following is my code for fetching all the chat messages from Firebase: dontShow property: if dontShow == true means that the message is inside the thread and shouldn't be displayed like a regular message in the chat. However, the very last message in the thread is displayed and has dontShow = false.
func fetchMessages(docId: String, collectionType: String, isThreadMember: Bool) {
if (user != nil) {
db.collection("chatrooms").document(docId).collection(collectionType).order(by: "sentAt", descending: false).addSnapshotListener { (snapshot, error) in
guard let documents = snapshot?.documents else {
print("No messages")
return
}
// let threadsTemp: [Message]()
let classroomId = docId
if !isThreadMember {
if collectionType == "messages" {
self.messages = documents.map { doc -> Message in
let data = doc.data()
let docId1 = doc.documentID
let content = data["content"] as? String ?? ""
let displayName = data["displayName"] as? String ?? ""
let likedUsersArr = data["likedUsers"] as? Array ?? [""]
// if message is in thread (but not last message), then don't show as normal message, but in thread
let dontShow = data["dontShow"] as? Bool ?? false
let sentAt = data["sentAt"] as? Date ?? Date()
let threadBefore = data["threadBefore"] as? [DocumentReference] ?? [DocumentReference]()
// using reference array
if dontShow == false {
if (threadBefore.count > 0) {
// reset the temporary array that holds the threads to be added afterwards
self.threadsTemp = []
for docRef in threadBefore {
docRef.getDocument { (doc2, error) in
if let doc2 = doc2, doc2.exists {
let docId2 = doc2.documentID
self.fetchThreadMessages(classroomId: classroomId, parentMessageId: docId1, docId: docId2)
} else {
print("Document does not exist")
}
}
}
}
}
return Message(id: docId1,
content: content,
name: displayName,
upvotes: likedUsersArr.count,
likedByUser: likedUsersArr.contains(self.user!.uid) ? true : false,
dontShow: dontShow,
sentAt: sentAt,
threadsArray: self.threadsTemp)
}
}
Another function: fetchThreadMessages:
// fetch a specified message and then append to the temporary threads array, threadsTemp
func fetchThreadMessages(classroomId: String, parentMessageId: String, docId: String) -> Message {
if (user != nil) {
let docRef = db.collection("chatrooms").document(classroomId).collection("messages").document(docId)
docRef.getDocument { (doc, error) in
if let doc = doc, doc.exists {
if let data = doc.data(){
let docId = doc.documentID
print("docid")
print(docId)
let content = data["content"] as? String ?? ""
let displayName = data["displayName"] as? String ?? ""
let likedUsersArr = data["likedUsers"] as? Array ?? [""]
// if message is in thread (but not last message), then don't show as normal message, but in thread
let dontShow = data["dontShow"] as? Bool ?? false
let sentAt = data["sentAt"] as? Date ?? Date()
self.threadsTemp.append(Message(id: docId,
content: content,
name: displayName,
upvotes: likedUsersArr.count,
likedByUser: likedUsersArr.contains(self.user!.uid) ? true : false,
dontShow: true,
sentAt: sentAt,
threadsArray: []))
}
}
}
}
}
I haven't implemented how the sendMessage() function updates the threadBefore array, but I'm currently updating this field directly on Firebase just for testing.
func sendMessage(messageContent: String, docId: String, collectionType: String, isReply: Bool, threadId: String) {
if (user != nil) {
if isReply {
let docRef = db.collection("chatrooms").document(docId).collection(collectionType).document(threadId)
self.threadRef = db.document(docRef.path)
}
db.collection("chatrooms").document(docId).collection(collectionType).addDocument(data: [
"sentAt": Date(),
"displayName": user!.email ?? "",
"content": messageContent,
"likedUsers": [String](),
"sender": user!.uid,
"threadBefore": isReply ? [threadRef] : [DocumentReference](),
"dontShow": false])
}
}
A little bit more on how I'm fetching and retrieving the document references from threadsBefore: For each message in the collection, I loop its threadsArray, which consists of DocumentReferences to other messesages that are in that thread. For each of those document references, I run self.fetchThreadMessages. This retrieves that message and stores a Message() instance in threadsTemp. Then, back in self.fetchMessage, when I'm done filling up the self.threadsTemp with all of the documents retrieved from threadsBefore, I store it in threadsArray property in the Message struct.
Now, look at the return state in self.fetchMessages above, the very last assignment inside Message() is threadsArray: self.threadsTemp. But the problem here is that this is just a reference? And it would change based on the last assignment to self.threadsTemp?
I've tried multiple ways to implement this entire storing and retrieving thing. But all came with several complicated errors. I tried using dictionaries, or storing just the document id's for the thread messages and then look them up in self.Messages (since it has all of the messages stored in it).
What's the best way to implement this? Or fix my errors? I know my code is probably a mishmash of inefficient and confused coding practices. But I'm trying to learn.
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