✈️ Trip Planner: Your Personal Travel Architect

Trip Planner is a sophisticated Flutter application designed to streamline the chaos of travel management. It allows users to effortlessly create detailed itineraries, manage travel budgets with real-time currency conversion, and organize trips with precision—all while functioning completely offline.

✨ Key Features

• Smart Trip Creation: Intuitive flow for setting destinations, travel dates, and trip names.
• Budgeting & Currency Conversion: Built-in currency converter that estimates your budget in foreign currencies using live rates (or cached data).
• Local Persistence: Powered by ObjectBox, an ultra-fast NoSQL database, ensuring your data is always available, even in remote locations without internet.
• Reactive State Management: Complex form validation and asynchronous operations managed seamlessly with BLoC/Cubit.
• Immutable Data Models: Robust data integrity using Freezed for immutable entities and state objects.

🏗 Architecture & Tech Stack

This project is built on Clean Architecture principles, enforcing a strict separation of concerns between the Domain, Data, and Presentation layers.

• Architecture: Clean Architecture + Feature-First Structure
• State Management: flutter_bloc (Cubits)
• Dependency Injection: get_it
• Database: objectbox (High-performance local database)
• Networking: dio (For currency conversion APIs)
• Navigation: auto_route
• Utilities: intl (Date/Currency formatting), freezed, flutter_animate

💻 Code Highlight: Clean State Management

The following snippet from TripPlanningCubit demonstrates how business logic is decoupled from the UI. It handles the complexity of input validation, asynchronous currency conversion, and UI state updates (Loading/Success/Error) in a readable, testable manner.

// lib/features/trip/presentation/blocs/trip_planning_cubit.dart

Future<void> convertBudget({
  required String fromCurrency,
  required String toCurrency,
  required String toCurrencySymbol,
}) async {
  // 1. Input Validation
  final amount = double.tryParse(state.budget);
  if (amount == null || amount <= 0) return;

  // 2. Emit Loading State
  emit(state.copyWith(conversionState: const ApiState.loading()));

  try {
    // 3. Execute Business Logic (Use Case)
    final result = await _convertCurrencyUseCase(
      fromCurrency: fromCurrency,
      toCurrency: toCurrency,
      amount: amount,
    );

    // 4. Format Data for Presentation
    final formatter = NumberFormat.currency(
      symbol: toCurrencySymbol,
      decimalDigits: 2,
    );
    
    // 5. Emit Success State
    emit(state.copyWith(
      conversionState: ApiState.success(data: result),
      convertedAmountDisplay: "≈ ${formatter.format(result)}",
    ));
  } catch (e) {
    // 6. Handle Errors gracefully
    emit(state.copyWith(
      conversionState: ApiState.error(message: e.toString()),
      convertedAmountDisplay: "Conversion failed",
    ));
  }
}

📂 Project Structure

The codebase is organized by Feature, ensuring scalability as the app grows.

lib/
├── core/                   # Shared logic (DI, Network, Generic UseCases)
├── features/
│   ├── destination/        # Logic for selecting destinations
│   ├── trip/               # Main Trip logic
│   │   ├── data/           # Repositories & Data Sources (ObjectBox)
│   │   ├── domain/         # Entities (Trip, Budget) & Use Cases
│   │   └── presentation/   # Cubits (TripPlanningCubit) & UI
│   └── weather/            # Weather forecasting feature
├── main.dart               # Entry point
└── objectbox-model.json    # Database schema definition

🚀 Installation & Setup

1. Clone the repository:

   git clone https://github.com/fadyphil/trip-planner.git
   cd trip-planner/trip_planner

2. Install dependencies:

   flutter pub get

3. Run Code Generation (Critical for Freezed & ObjectBox):

   dart run build_runner build --delete-conflicting-outputs

4. Run the App:

   flutter run