CLI Task Manager Program

A robust, Object-Oriented command-line application built in Python for managing users and tasks.

This program was developed with a strong focus on Defensive Programming, Data Integrity, and Clean Code Architecture, strictly adhering to modern Python standards and Ruff linter compliance.

Key Technical Highlights for Reviewers

• Defensive Programming & Validation: Comprehensive input sanitisation and validation. Handles edge cases such as delimiter collisions (preventing CSV corruption from rogue commas), enforces alphanumeric-only usernames, and validates strict date formats using try-except-else control flows.
• Object-Oriented Design (OOP): Deeply modular architecture separating concerns into distinct classes (User, Admin, Task) and data managers (UserManager, TaskManager) to encapsulate logic and state.
• Modular Refactoring: Transitioned from a monolithic script to a professional multi-module architecture, improving maintainability and testability.
• Linter & Standard Compliance: The codebase passes strict Ruff linting, specifically engineered to maintain low McCabe Cyclomatic Complexity (C901), avoid Boolean Traps (FBT), and implement clean early-return/break logic (RET).
• Safe File I/O: Utilises Python's modern pathlib for cross-platform compatibility and explicitly enforces utf-8 encoding to prevent character crashes across different operating systems.
• Secure CLI Experience: Integrates the getpass module to obfuscate passwords in the terminal and uses dynamic string formatting (f-strings with alignment padding and textwrap) to generate pixel-perfect, responsive statistics tables.

Architecture Overview

The program is split into specialised modules to ensure a Separation of Concerns:

• main.py: The entry point. Uses a lightweight execution loop and dictionary-based dispatching for menu actions to keep the code flat and readable.
• models.py: Contains core data structures (User, Admin, Task). Utilises inheritance to manage different user permission levels.
• managers.py: Orchestrates data persistence. Handles the lifecycle of loading, instantiating, and saving objects to the data source.
• actions.py: The business logic layer. Contains the high-level functions for registering users, managing tasks, and generating reports.
• utils.py: A dedicated toolbox for reusable helper functions, specifically focused on recursive validation and CLI formatting.
• constants.py: Centralised configuration for file paths, date formats, and UI styling.

Future Roadmap & Improvements

While the current version is a robust CLI tool, the following architectural enhancements are planned to improve scalability and performance:

1. Database Integration (SQLite)

• Current State: Data is stored in comma-separated .txt files.
• The Goal: Transition to a Relational Database Management System (RDBMS) using SQLite.
• Why:
  • Data Integrity: Enforce strict relationships between Users and Tasks using Foreign Keys.
  • Concurrency: Better handling of simultaneous read/write operations.
  • Performance: Replace O(n) file parsing with indexed SQL queries for faster data retrieval as the task count grows.

2. Password Hashing

• Current State: Passwords are stored in plain text.
• The Goal: Implement the hashlib or bcrypt library to store salted SHA-256 hashes.
• Why: To ensure industry-standard security practices and protect user credentials in the event of a data breach.

3. Unit Testing

• The Goal: Implement a comprehensive test suite using pytest.
• Why: To ensure that new features or refactors (like the SQLite transition) do not introduce regressions into the core business logic.

How to Run the Program

Prerequisites: Python 3.x installed on your machine.

1. Clone this repository:

   git clone https://github.com/WaleedMatheson/task_manager.git

2. Navigate to the project directory:

   cd task_manager

3. Run the program:

   python src/main.py

Note: The program requires a data/user.txt file with at least one admin user to function. It will automatically generate data/tasks.txt upon first run if missing.

Tech Stack

• Language: Python 3
• Libraries: pathlib, datetime, getpass, textwrap, sys
• Code Quality: Ruff (Linter)