Instagram Stories-like Feature Implementation

Architectural Overview

This project implements an Instagram Stories-like feature using the MVVM (Model-View-ViewModel) architecture pattern with SwiftUI. The app consists of two main screens:

1. Stories List Screen: Displays a horizontal scrollable list of story avatars with indicators for seen/unseen status
2. Story View Screen: Fullscreen view for viewing individual stories with like functionality and navigation gestures

Key Components:

• Models: Define the data structures (User, Story, StoryState)
• ViewModels: Handle business logic and state management
• Views: Display the UI and handle user interactions
• Services: Provide data and functionality (Network, Image Loading, State Persistence)

Design Decisions

1. MVVM Architecture

• Clean separation of concerns
• Testable components
• SwiftUI-friendly approach

2. Pagination Implementation

• Infinite scrolling using a page-based approach
• When the end of available data is reached, the app cycles through existing data
• Loading indicators for better UX

3. State Persistence

• User story states (seen/unseen, liked/unliked) are persisted using UserDefaults
• Each story has its own state, allowing for granular tracking

4. Image Loading

• Custom AsyncImage implementation for efficient image loading
• Placeholders during loading for better UX

5. Gesture-Based Navigation

• Tap left/right areas to navigate between stories
• Swipe gestures for more intuitive navigation
• Double-tap to like feature

Assumptions and Limitations

Assumptions:

• Story content is primarily image-based (could be extended to support videos)
• The app doesn't require user authentication
• Stories are generated on-device rather than fetched from a server
• Story viewing has a fixed duration (5 seconds per story)

Limitations:

• No backend integration for posting stories
• Limited media types (images only)
• Local state persistence (not synced across devices)
• Basic animation and transitions
• No camera integration for creating stories

External Libraries

This implementation uses only native iOS frameworks to keep the app lightweight and avoid unnecessary dependencies.

Future Improvements

• Add support for video stories
• Implement story creation functionality
• Add more interactive elements (polls, questions, etc.)
• Improve animations and transitions
• Implement a more sophisticated data persistence strategy