Home Unit Calculation Application

This is a desktop application built with PyQt5 for calculating and managing home unit consumption and costs. It allows users to input meter readings, calculate differences, add additional costs, calculate room-specific consumption, save records locally (CSV) or to a Supabase database, generate PDF reports, and view historical data.

Features

• Main Calculation Tab:
  • Input current meter readings (Meter 1, Meter 2, Meter 3).
  • Automatically calculates the difference from previous readings.
  • Input additional amounts (e.g., service charges).
  • Displays calculated total units and per-unit cost.
• Room Calculation Tab:
  • Dynamically generated input fields for each room based on configuration (requires setup or data loading).
  • Input present and previous meter readings for each room.
  • Calculates individual room consumption and cost.
• History Tab:
  • View historical calculation records.
  • Filter history by month and year.
  • Load previous records into the main calculation fields.
  • Edit and delete historical records (requires Supabase integration).
• Data Persistence:
  • Save calculation records to a local CSV file (meter_calculation_history.csv).
  • Save calculation records to a Supabase database (requires configuration).
  • Load historical data from CSV or Supabase.
• PDF Report Generation:
  • Generate a detailed PDF report of the current calculation.
• Custom UI and Navigation:
  • Custom styled widgets using CSS-like stylesheets.
  • Custom navigation between input fields using arrow keys and Enter/Return.
  • Auto-scrolling in areas with many inputs.
  • Basic accessibility features.

Installation

1. Clone the repository:

   git clone <repository_url>
   cd HomeUnitCalculator

2. Install dependencies: Make sure you have Python installed. Then install the required packages using pip:

   pip install -r requirements.txt

3. Supabase Configuration (Optional): If you plan to use the Supabase integration for cloud saving and loading, create a .env file in the project root directory with your Supabase project URL and Anon key:

   SUPABASE_URL="YOUR_SUPABASE_URL"
   SUPABASE_KEY="YOUR_SUPABASE_ANON_KEY"

   Replace "YOUR_SUPABASE_URL" and "YOUR_SUPABASE_ANON_KEY" with your actual Supabase project details.

Usage

To run the application, execute the main Python script:

python HomeUnitCalculator.py

The application window will open, allowing you to input data, perform calculations, and manage records.

Project Structure

• HomeUnitCalculator.py: The main application script containing the PyQt5 GUI logic and calculation functions.
• styles.py: Contains functions that return CSS-like strings for styling the application's widgets.
• utils.py: Contains utility functions, such as resource_path for handling file paths in a way that works with PyInstaller.
• requirements.txt: Lists the Python dependencies required to run the application.
• meter_calculation_history.csv: (Created on first save) Stores calculation history in CSV format.
• icons/: Directory containing icons used in the application.
• README.md: This file.

Dependencies

The project relies on the following Python libraries, listed in requirements.txt:

• PyQt5: For creating the graphical user interface.
• reportlab: For generating PDF reports.
• supabase: The Supabase Python client library for database interaction.
• python-dotenv: For loading environment variables from a .env file.
• postgrest: A dependency for the Supabase client.

Styling

The application's look and feel are controlled by the styles defined in styles.py. This file provides various CSS-like stylesheets for different PyQt5 widgets, ensuring a consistent and visually appealing interface.

Utility Functions

The utils.py file contains helper functions. Currently, it includes the resource_path function, which is essential for correctly locating application resources (like icons) whether the application is run directly as a script or as a bundled executable created by tools like PyInstaller.

Supabase Integration

The application includes functionality to save and load calculation records from a Supabase database. This feature requires a Supabase project and the correct configuration in a .env file. The relevant logic is handled within the HomeUnitCalculator.py file, utilizing the supabase and postgrest libraries.

PDF Generation

Users can generate a PDF report of the current calculation using the "Save as PDF" button. The PDF generation logic is implemented using the reportlab library, formatting the calculation details into a printable document.

CSV Handling

Calculation history can be saved to and loaded from a local CSV file (meter_calculation_history.csv). This provides a simple way to persist data without requiring a database setup. The csv module is used for reading and writing this file.

Navigation and Accessibility

Custom navigation is implemented for input fields using the CustomLineEdit and CustomNavButton classes, allowing users to navigate using arrow keys and the Enter/Return key. The AutoScrollArea class provides automatic scrolling when the mouse is near the edges. Basic accessibility features are also included to improve usability.

Error Handling

Basic error handling is included using try...except blocks, particularly for file operations and database interactions. The traceback module is used to log detailed error information when exceptions occur.

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Feel free to contribute to the project or report any issues!