Flight Booking App

A Flutter-based flight booking application with search, filtering, and boarding pass features. Built with Clean Architecture principles and Riverpod state management.

Features

• Flight Search: Search flights by departure/arrival airports, date, and passengers
• Advanced Filtering: Filter by airline, price range, stops, and aircraft type
• Sorting Options: Sort by price, duration, or departure time
• Infinite Scroll: Paginated flight results with smooth infinite scrolling
• Flight Details: Comprehensive flight information with boarding pass view
• Boarding Pass Export: Save boarding pass to gallery or share
• Offline Support: Cached data available when offline with network status banner
• Pull-to-Refresh: Refresh data with pull gesture

App Preview

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Steps to Run the Project

Prerequisites

• Flutter SDK 3.38.2
• Dart SDK 3.8.0
• Android Studio / VS Code with Flutter extensions
• iOS Simulator (Mac) or Android Emulator

Installation

1. Clone the repository

   git clone <repository-url>
   cd flight_booking_app

2. Install dependencies

   flutter pub get

3. Generate code (Freezed models, Riverpod providers, routes)

   dart run build_runner build --delete-conflicting-outputs

4. Run the app

   # For development
   flutter run
   
   # For specific environment
   flutter run --dart-define=ENV=dev      # Development
   flutter run --dart-define=ENV=staging  # Staging
   flutter run --dart-define=ENV=prod     # Production

Running Tests

flutter test

Static Analysis

flutter analyze

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Dependencies Used

State Management

Package	Version	Purpose
flutter_riverpod	^2.5.1	State management with dependency injection
riverpod_annotation	^2.3.5	Code generation for Riverpod providers

Networking

Package	Version	Purpose
dio	^5.4.1	HTTP client for API requests
dio_cache_interceptor	^3.5.0	Response caching for offline support
dio_cache_interceptor_hive_store	^3.2.2	Persistent cache storage
connectivity_plus	^5.0.2	Network connectivity monitoring

Navigation

Package	Version	Purpose
go_router	^13.2.1	Declarative routing with type-safe routes

UI Components

Package	Version	Purpose
cached_network_image	^3.3.1	Image caching for airline logos
flutter_svg	^2.0.9	SVG rendering for barcodes
shimmer	^3.0.0	Loading skeleton animations
intl	^0.20.2	Date formatting

Data Models

Package	Version	Purpose
freezed_annotation	^2.4.1	Immutable data classes
json_annotation	^4.8.1	JSON serialization
equatable	^2.0.7	Value equality

Storage

Package	Version	Purpose
shared_preferences	^2.2.3	Key-value storage for preferences
hive	^2.2.3	NoSQL database for caching
hive_flutter	^1.1.0	Flutter integration for Hive

Export & Share

Package	Version	Purpose
screenshot	^3.0.0	Widget screenshot capture
path_provider	^2.1.2	File system paths
share_plus	^9.0.0	Share content with other apps
permission_handler	^11.3.1	Runtime permissions
gal	^2.3.0	Save images to gallery

Utilities

Package	Version	Purpose
dartz	^0.10.1	Functional programming (Either type for error handling)

Dev Dependencies

Package	Version	Purpose
build_runner	^2.4.8	Code generation runner
json_serializable	^6.7.1	JSON serialization code generation
freezed	^2.4.7	Immutable class code generation
riverpod_generator	^2.4.0	Riverpod provider code generation
go_router_builder	^2.4.1	Type-safe route code generation

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Architecture & Approach

Project Structure

The project follows Feature-based Clean Architecture with clear separation of concerns:

lib/
├── core/                    # Global utilities and configuration
│   ├── constants/           # App colors, API constants, strings
│   ├── network/             # Dio client, interceptors, cache config
│   ├── theme/               # App theme and typography
│   ├── error/               # Failure classes for error handling
│   ├── l10n/                # Localization strings
│   └── utils/               # Utility functions (date formatting, etc.)
│
├── features/                # Feature modules
│   ├── home/                # Home screen feature
│   │   ├── data/            # Data sources and repository implementations
│   │   ├── domain/          # Models and repository interfaces
│   │   └── presentation/    # Screens, widgets, and providers
│   │
│   ├── flight_search/       # Flight search and results feature
│   │   ├── data/
│   │   ├── domain/
│   │   └── presentation/
│   │
│   └── flight_details/      # Flight details and boarding pass feature
│       ├── data/
│       ├── domain/
│       └── presentation/
│
├── shared/                  # Shared components
│   ├── services/            # Connectivity, storage services
│   └── widgets/             # Reusable widgets (shimmer, buttons, etc.)
│
├── routes/                  # GoRouter configuration
├── app.dart                 # App widget with MaterialApp
└── main.dart                # Entry point

Design Patterns Used

1. Repository Pattern: Abstracts data sources from business logic
2. Either Pattern: Functional error handling with dartz package
3. Provider Pattern: State management with Riverpod
4. Dependency Injection: Via Riverpod providers
5. Factory Pattern: Freezed-generated factory constructors

Key Technical Decisions

State Management - Riverpod

• Chosen for its compile-time safety and code generation
• AsyncValue handles loading/error/data states elegantly
• Auto-dispose providers prevent memory leaks

Networking - Dio with Interceptors

• Retry Interceptor: Automatic retry with exponential backoff (3 retries)
• Cache Interceptor: Response caching with Hive storage
• Deduplication Interceptor: Prevents duplicate concurrent requests
• Offline Queue Interceptor: Queues failed requests for later
• Logger Interceptor: Debug logging for requests/responses

Data Models - Freezed

• Immutable data classes with copyWith
• Automatic JSON serialization
• Value equality out of the box

Error Handling

• Either<Failure, T> pattern for explicit error handling
• Typed failure classes (NetworkFailure, ServerFailure, etc.)
• Localized error messages

Offline Support

• API responses cached with configurable duration
• Custom cache keys include POST body for unique caching
• Network status banner when offline
• Prefetch critical data on app launch

Thought Process

1. Started with Clean Architecture: Established clear boundaries between layers to ensure testability and maintainability.

2. API-First Approach: Analyzed the API documentation to design data models and repository interfaces before implementation.

3. Incremental Feature Development: Built features incrementally:

   • Phase 1: Core setup (networking, models, navigation)
   • Phase 2: Home screen with search card
   • Phase 3: Flight search with filters
   • Phase 4: Flight details and boarding pass
   • Phase 5: Polish (animations, offline support, caching)

4. Performance Considerations:

   • Implemented infinite scroll instead of loading all data
   • Added image caching for airline logos
   • Used shimmer loading for better perceived performance
   • Prefetch airports for faster dropdown loading

5. Offline-First Thinking: Designed caching strategy early to ensure good offline experience.

6. User Experience Focus:

   • Pull-to-refresh for manual data refresh
   • Active filter chips to show applied filters
   • Smooth animations and transitions
   • Clear error states with retry options

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API Integration

Base URL

https://flight.wigian.in/flight_api.php

Endpoints Implemented

Endpoint	Purpose
POST /search	Search flights with filters and sorting
POST /flight	Get flight details by ID
POST /airports/from	Get departure airports
POST /airports/to	Get arrival airports
POST /airlines	Get airlines list
POST /aircraft-types	Get aircraft types

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Time Taken

Phase	Description	Approximate Hours
Phase 1	Project setup, architecture, core modules	2-3 hours
Phase 2	Home screen, search card, airport selection	3-4 hours
Phase 3	Flight search, results, filtering, sorting	4-5 hours
Phase 4	Flight details, boarding pass, barcode	3-4 hours
Phase 5	Caching, offline support, polish	3-4 hours
Phase 6	Bug fixes, testing, documentation	2-3 hours
Total		~18-23 hours

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License

This project is for assessment purposes.