Invoice Generation API

This project is an API that allows users to manage a list of items for sale, create purchase orders, update those orders, and generate invoices in PDF format. The application facilitates the following actions:

• View available items with their details (name, price, description).
• Create and update a purchase order with the list of items and quantities.
• Generate and download invoices for purchases in PDF format.

Features

• Item Management: Allows the user to view available items with their details.
• Purchase Management: Enables creating and updating purchase orders with selected items.
• Invoice Generation: Generates and returns a PDF invoice for a given purchase.

Prerequisites

Make sure you have the following installed:

• Python 3.8+
• Django 3.2+
• Django Rest Framework
• ReportLab (for generating PDFs)
• SQLite (or any other database)

Installation

1. Clone the repository:

   git clone https://github.com/your-username/invoice-generator-api.git
   cd invoice-generator-api

2. Create a virtual environment:

   python -m venv env

3. Activate the virtual environment:

   • For macOS/Linux:

     source env/bin/activate

   • For Windows:

     .\env\Scripts\activate

4. Install the required dependencies:

   pip install -r requirements.txt

5. Apply database migrations:

   python manage.py migrate

6. Create a superuser (optional, for accessing the Django admin panel):

   python manage.py createsuperuser

API Endpoints

Item Management

• GET /api/items/
  Fetch all available items in the system. The response will include fields like name, price, description, and stock.

Purchase Management

• POST /api/purchases/
  Create a new purchase by sending a list of items with corresponding quantities.

• PUT /api/purchases/{id}/
  Update an existing purchase by modifying the list of items.

Invoice Generation

• GET /api/invoices/{purchase_id}/
  Generate a PDF invoice for a given purchase. The invoice will include all details such as the purchased items, quantities, total price, and purchase information.

Example API Requests

Create Purchase

To create a new purchase, send a POST request to /api/purchases/ with the following payload:

  "items": [
    {
      "id": 1,
      "quantity": 2
    },
    {
      "id": 3,
      "quantity": 1
    }
  ]
}

Update Purchase

To update an existing purchase, send a PUT request to /api/purchases/{id}/ with the following payload:

  "items": [
    {
      "id": 1,
      "quantity": 5
    },
    {
      "id": 2,
      "quantity": 3
    }
  ]
}

Generate Invoice

To generate a PDF invoice for a purchase, send a GET request to /api/invoices/{purchase_id}/. The API will return a PDF file containing the invoice.