TO-DO List Application

A clean architecture implementation of a command-line TODO list application in Python. This project demonstrates separation of concerns, dependency injection, and multiple storage options.

Features

• ✅ Create, read, update, and delete tasks
• ✅ Mark tasks as completed
• ✅ Multiple storage options (in-memory or file-based)
• ✅ Clean Architecture principles
• ✅ Interactive and simple CLI modes
• ✅ Unit tests included

Project Structure

TO-DO List/
├── core/
│   ├── entities/          # Domain entities
│   │   ├── task.py        # Task entity
│   │   └── repository.py  # Repository interface
│   ├── usecases/          # Business logic
│   │   └── task_usecase.py
│   ├── interfaces/        # Interface adapters
│   │   └── cli/
│   │       └── cli_handler.py
│   └── infrastructure/    # External implementations
│       └── persistence/
│           ├── in_memory_repository.py
│           └── file_repository.py
├── entrypoints/           # Application entry points
│   ├── cli_main.py        # Interactive CLI
│   └── simple_cli.py      # Command-line arguments
├── tests/                 # Unit tests
│   └── test_task_usecase.py
└── run.py                 # Demo script

Architecture

This application follows Clean Architecture principles:

• Entities: Core business objects (Task)
• Use Cases: Application business rules (TaskUseCase)
• Interface Adapters: CLI handlers and presenters
• Infrastructure: External implementations (repositories)

Installation

1. Clone the repository
2. Ensure you have Python 3.7+ installed
3. No external dependencies required (uses only standard library)

Usage

Interactive CLI Mode

Run the interactive shell:

# In-memory storage (default)
python entrypoints/cli_main.py

# File-based storage
python entrypoints/cli_main.py --file

Available commands in interactive mode:

• create <title> <description> - Create a new task
• list - List all tasks
• update <id> [--title=<title>] [--description=<desc>] [--completed=<true|false>] - Update a task
• complete <id> - Mark task as completed
• delete <id> - Delete a task
• help - Show help
• exit - Exit the application

Simple CLI Mode

Execute single commands:

# Create a task
python entrypoints/simple_cli.py create "Buy groceries" "Milk, bread, eggs"

# List all tasks
python entrypoints/simple_cli.py list

# Update a task
python entrypoints/simple_cli.py update 1 --title="Buy groceries updated"

# Complete a task
python entrypoints/simple_cli.py complete 1

# Delete a task
python entrypoints/simple_cli.py delete 1

Demo Script

Run the demo to see the application in action:

python run.py

Running Tests

Execute the test suite:

python -m unittest tests/test_task_usecase.py

Or run all tests:

python -m unittest discover tests

Storage Options

In-Memory Storage

• Tasks are stored in memory and lost when the application closes
• Fast and suitable for testing
• Default option for cli_main.py

File-Based Storage

• Tasks are persisted to tasks.json
• Data survives application restarts
• Used by simple_cli.py and optional in cli_main.py

Examples

Interactive Session

$ python entrypoints/cli_main.py
Using in-memory storage
Welcome to To-Do Application!

> create "Learn Python" "Study clean architecture"
Task created successfully (ID: 1)

> list
Tasks:
  1 [○] Learn Python            | Study clean architecture
     Created: 2025-10-19 14:30
     Updated: 2025-10-19 14:30

> complete 1
Task 'Learn Python' marked as completed

> exit
Goodbye!

Command-Line Usage

$ python entrypoints/simple_cli.py create "Meeting" "Team standup at 10am"
Task created with ID: 1

$ python entrypoints/simple_cli.py list
1. [○] Meeting - Team standup at 10am

$ python entrypoints/simple_cli.py complete 1
Task 1 completed

$ python entrypoints/simple_cli.py list
1. [✓] Meeting - Team standup at 10am

Design Patterns

• Repository Pattern: Abstract data access
• Dependency Injection: Loose coupling between components
• Use Case Pattern: Encapsulate business logic
• Abstract Base Classes: Define interfaces

Future Enhancements

• Database support (SQLite, PostgreSQL)
• Task priorities and due dates
• Task categories/tags
• Search and filter functionality
• REST API interface
• Web interface

License

This project is open source and available for educational purposes.

Contributing

Feel free to fork this project and submit pull requests for improvements.