Messenger clone iOS 14+

This is the source code for the Messenger clone application. The app demonstrates how you can build the core functionality of Messenger in Swift, supporting iOS 14+ without any UI-libraries except SDWebImage. Since the app supports iOS 14, the application is built as a hybrid where 95% of the UI is UIKit and 5% is SwiftUI.

Tutorials and a full demo are on my YouTube channel, with articles to accommodate them on my website.

About the project

Features

• MVVM
• Coordinators
• Combine
• Modern Swift concurrency
• Supports iOS 14+
• Hybrid; 95% UIKit and 5% SwiftUI
• Firebase
  • Auth for authentication
  • Firestore as the remote database for the users (better queries)
  • RTDB as the remote database for the chat data (better for simple queries and frequent data)
• My custom library FireThel for simplifying redundant Firebase code
• GRDB for local caching of the users
• UICollectionViewCompositionalLayout
  • Lists created with list configuration instead of UITableViews
  • Cells with custom UIContentConfiguration
  • Diffable data source instead of UICollectionViewDataSource
• My own custom sheet (a native customizable sheet is only available in iOS 15+)

Screenshots

Comparison

Here are some screenshots from the authentication flow:

Messenger	Messenger clone

NOTE: The screenshots are from 2023, but Meta has updated their UI recently.

Chat structure

// chatId is combined of userId + recipientId. 
// Will always be unique for the same two users in a one to one chat
// If group chat is supported, a unique id for the chatId 
// will suffice (it is not supported at the moment).


chatMessages
    |
    |----- chat_room_\(chatId)
                |
                |------ lastMessageId
                                |
                                |---- ChatMessage model

lastMessage // the content of the message in MessagesViewController (.value listener on chatId)
    |
    |----- chat_room_\(chatId)
                |
                |------ LastMessage model

userChats // the amount of chats (.childAdded on userId)
    |
    |----- userId
                |       
                |----- chat_room_\(chatId)
                |               |
                |               |----- chatRoomId: chatId
                |               |----- isMemeber: true
                |
                |------- chat_room_\(chatId) 
                

What should be done

Here is a list of things I would do if I had more time. I may clone the repository in the future and implement them.

• Move all the UI into a separate repo, like Finn. Why? The code is too long, and it is hard to test the components. There is also room for composition.
• Create a cloud function for creating an account. Why? A single operation for authenticating users and creating documents can’t be implemented through Firebase Auth and Firestore.
• Clean up the flows where users and chats are loaded simultaneously. Why? All the errors aren't properly handled, and there is some inconsistency.
• Add the option for group chats and update the components accordingly.

Installation

1. Clone the repo
2. Create a new project in your Firebase console by clicking "Add project"
3. Create a Cloud Firestore database and RTDB database
4. Enable sign-in with email and password in Firebase Auth
5. Add the GoogleService-Info.plist to the project
6. Run the app