#!/usr/bin/env python
"""
This module provides a template for generating Django API endpoints based on
requirements documents. It includes necessary imports, comprehensive docstrings,
PEP 8 style adherence, example usage in the __main__ block, and error handling.
"""

import os
import json
import logging

from django.http import JsonResponse
from django.views import View
from django.conf import settings

# Configure logging
logging.basicConfig(level=logging.INFO,
                    format='%(asctime)s - %(levelname)s - %(message)s')

class GenericAPIView(View):
    """
    A generic API view class that handles common API functionalities
    such as request validation, data processing, and response formatting.
    """

    def __init__(self, *args, **kwargs):
        """
        Initializes the GenericAPIView.
        """
        super().__init__(*args, **kwargs)
        self.logger = logging.getLogger(__name__)

    def validate_request(self, request):
        """
        Validates the incoming request.  Override this method in subclasses
        to implement specific validation logic.

        Args:
            request: The Django request object.

        Returns:
            A tuple containing a boolean indicating validation success and
            an optional error message.  Returns (True, None) for success.
        """
        try:
            # Attempt to parse JSON body.  This is a basic validation example.
            json.loads(request.body)
            return True, None
        except json.JSONDecodeError as e:
            self.logger.error(f"Invalid JSON: {e}")
            return False, "Invalid JSON in request body."
        except Exception as e:
            self.logger.exception("Unexpected error during request validation.")
            return False, f"Unexpected validation error: {e}"


    def process_data(self, data):
        """
        Processes the validated data.  Override this method in subclasses
        to implement specific data processing logic.

        Args:
            data: The validated data (e.g., from request.body).

        Returns:
            The processed data.  Can be any data type.
        """
        # Default implementation: simply returns the data as-is.
        return data

    def format_response(self, data):
        """
        Formats the processed data into a JSON response.

        Args:
            data: The processed data.

        Returns:
            A JsonResponse object.
        """
        return JsonResponse({"data": data})

    def handle_exception(self, e):
        """
        Handles exceptions that occur during request processing.

        Args:
            e: The exception object.

        Returns:
            A JsonResponse object with an error message and appropriate status code.
        """
        self.logger.exception("Exception occurred during request processing.")
        return JsonResponse({"error": str(e)}, status=500)

    def post(self, request, *args, **kwargs):
        """
        Handles POST requests to the API endpoint.
        """
        try:
            is_valid, error_message = self.validate_request(request)
            if not is_valid:
                return JsonResponse({"error": error_message}, status=400)

            data = json.loads(request.body)  # Parse body *after* validation.
            processed_data = self.process_data(data)
            response = self.format_response(processed_data)
            return response

        except Exception as e:
            return self.handle_exception(e)


if __name__ == '__main__':
    # Example Usage (This would normally be in views.py and urls.py)
    # To run this example, you would need to set up a Django project
    # and configure the URL patterns to point to this view.
    #
    # 1. Create a Django project: django-admin startproject myproject
    # 2. Create a Django app: python manage.py startapp myapp
    # 3. Add 'myapp' to INSTALLED_APPS in settings.py
    # 4. Create urls.py in myapp and include the following:
    #
    # from django.urls import path
    # from .templates.django_api_template import GenericAPIView  # Adjust import path
    #
    # urlpatterns = [
    #     path('api/example/', GenericAPIView.as_view(), name='example_api'),
    # ]
    #
    # 5. Include myapp.urls in myproject.urls.py:
    #
    # from django.urls import include, path
    #
    # urlpatterns = [
    #     path('myapp/', include('myapp.urls')),
    # ]
    #
    # 6. Run the development server: python manage.py runserver

    # This example shows how to use the GenericAPIView in a Django project.
    # Due to the nature of this script running in isolation, we can't
    # demonstrate a live API call.
    print("Example Usage: This template needs to be integrated into a Django project.")
    print("See comments in __main__ for setup instructions.")