I can help you create an application to generate practice tests with the capabilities you've described. Let's break this down into components and create a basic structure for your application using Next.js and React. We'll use the App Router for this project.

Let's start by creating the main components of the application:

This code structure provides a basic implementation of the practice test generator application you described. Here's a breakdown of the components and their functionalities:

1. The main page.tsx file renders the TestGenerator component.

2. The TestGenerator component:

   • Handles the form for user input (field of study, level of expertise, and number of questions) 1.
   • Manages the state for the generated questions.
   • Provides functions for generating questions, regenerating individual questions, and exporting to PDF or CSV.

3. The QuestionList component:

   • Displays the generated questions.
   • Allows users to regenerate individual questions.

Here are some key points about the implementation:

1. We're using React state to manage the application's data flow 1.
2. The question generation is currently simulated with a timeout. In a real application, this would be an API call to a backend service that generates the questions based on the user's input.
3. The export functionality (PDF and CSV) is not implemented yet. You would need to add libraries like jspdf for PDF generation and a custom function for CSV export.
4. The application uses shadcn/ui components for a clean and consistent UI 1.

To complete the application, you would need to:

1. Implement the actual question generation logic, either on the client-side or preferably on the server-side using Next.js API routes or server actions 1.
2. Add the PDF and CSV export functionality.
3. Implement a way for users to select which questions they want to keep.
4. Add error handling and validation to the form and question generation process.
5. Improve the UI/UX with loading states, error messages, and more detailed question display.

Would you like me to expand on any specific part of this implementation or add any additional features?

I apologize for missing that validation. Let's update the TestGenerator component to ensure that the expertise level is also required for question generation. We'll modify the form submission logic to check if all fields, including the expertise level, are filled before generating questions.

These changes accomplish the following:

1. The handleGenerate function now checks if all fields (including the expertise level) are filled before proceeding with question generation. If any field is empty, it shows an alert to the user.
2. The Select component for the expertise level now includes the required attribute, which is consistent with the other input fields.
3. The "Generate Questions" button is now disabled not only when questions are being generated but also when any of the required fields (field of study, expertise level, or number of questions) are empty. This provides visual feedback to the user that all fields need to be filled before they can generate questions.

These updates ensure that the expertise level is treated as a required field, just like the other inputs. The user won't be able to generate questions unless all fields, including the expertise level, are filled out.

Is there anything else you'd like me to modify or add to the application?