RandomUser App

This iOS application displays a list of random users fetched from randomuser.me API.
It implements key features such as infinite scrolling, user deletion, search functionality, user persistence across sessions, and a detailed user information screen.

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Features

• ✅ Fetch a list of random users from API
• ✅ Remove duplicated users based on UUID
• ✅ Display user:
  • Name and Surname
  • Email
  • Phone number
  • Profile picture
• ✅ Infinite scroll to load more users
• ✅ Delete a user (permanently removes even after new API fetch)
• ✅ Search users by name, surname, or email
• ✅ Detailed user screen including:
  • Gender
  • Full Name
  • Location (Street, City, State)
  • Registered Date
  • Email
  • Profile Picture
• ✅ Persistence of user list across application launches
• ✅ Programmatic UI (no Storyboards, no XIBs)
• ✅ Modular architecture (VIPER)
• ✅ Smooth animations using Diffable Data Source
• ✅ Modern list layouts using Compositional Layout
• ✅ Show alert to user on network/server errors
• ✅ Unit tests for critical parts (Network, List, Search, Delete, Persistence)

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Architecture and Design Patterns

The project is built with a modular and scalable architecture inspired by the VIPER (View, Interactor, Presenter, Entity, Router) design.

In addition, the UI layer heavily relies on Diffable Data Source and Compositional Layout.

• Diffable Data Source ensures efficient and smooth updates to lists, preventing duplicated entries and allowing easier snapshot management.
• Compositional Layout offers a flexible, declarative way to design complex collection view layouts that can easily scale as the project grows.

These modern techniques complement VIPER by keeping the UI layer highly decoupled, performant, and adaptable.

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Design Patterns and Techniques Used

Pattern/Technique	Usage
Builder Pattern	UserListBuilder and UserDetailBuilder create and configure modules.
Delegate Pattern	UserListCellProtocols, UserCollectionViewCellDelegate for cell actions back to presenter.
Diffable Data Source	Smooth animated updates, efficient list mutations, and duplicate handling via snapshots.
Compositional Layout	Declarative and flexible layout creation for complex lists and detail views.
Dependency Injection	NetworkService and UserPersistenceManager are injected into Interactors.
Swift Collections - OrderedSet	Used via Swift Package Manager for efficient duplicate removal while preserving order.
SPM Integration	Swift Collections added for OrderedSet usage.

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How to Run

1. Clone the repository

   git clone https://github.com/emircanuzel/RandomUser.git

2. Open in Xcode

   open RandomUser/RandomUser.xcodeproj

3. Run (Cmd + R)

• Minimum Deployment Target: iOS 15.0
• Xcode Version: 15.0+

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Testing

• Unit tests are written using XCTest.
• Tested modules:
  • NetworkService
  • UserListPresenter
  • UserListCollectionViewManager
  • UserPersistenceManager
• Run tests:
  • Select RandomUserTests scheme.
  • Press Cmd + U.

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Libraries and Frameworks

• UIKit (Programmatic UI)
• XCTest (for testing)
• Swift Collections (OrderedSet)

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Project Structure

RandomUser/
├── Core/
│   ├── Network/
│   └── UserPersistence/
├── Modules/
│   ├── UserList/
│   └── UserDetail/
├── Resources/
├── RandomUserTests/

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Notes

• Duplicate users are prevented by checking the unique uuid field from the API (login.uuid).
• The list management is powered by Diffable Data Source, enabling smooth animations, atomic snapshot updates, and avoiding duplicates naturally.
• Compositional Layout is used for modern, highly customizable and flexible list layouts across both UserList and UserDetail screens.
• Data persistence across application launches is handled using UserDefaults through a custom UserPersistenceManager.
• In case of network or server errors, the app gracefully shows an alert to the user to inform them about the issue.
• No Storyboards were used: the entire UI is built programmatically using UIKit.
• Infinite scrolling and loading indicators are designed to provide a seamless and reactive user experience.
• Great attention has been paid to code modularization, clarity, and extendability to real-world scaling.