Welcome to the next step in building a personal tutor service with DeepSeek models. In the previous lesson, we explored the TutorService struct, which acts as a bridge between managing tutoring session data and generating AI responses. Now, we will focus on the TutorController, a crucial component that manages tutoring sessions and handles student queries by interacting with both the model and service layers. The controller is responsible for orchestrating the flow of data between the student interface and the backend services, ensuring that student interactions are processed efficiently and effectively.

The TutorController struct is the heart of our controller layer. It is responsible for managing tutoring sessions and processing student queries. Let's begin by examining the structure of the TutorController in Go.

In this snippet, we:

• Import the necessary packages, including our services package and the uuid package for generating unique identifiers.
• Define the TutorController struct, which holds a reference to the TutorService and a testSession map to simulate session management for testing purposes.
• Provide a constructor function, NewTutorController, to initialize the controller with its dependencies.

The testSession map is used to simulate session management for testing. In a real-world application, session management would be handled by a web framework or middleware, but for now, this map allows us to focus on the core logic of the controller.

Before creating a tutoring session, we need to ensure that a student session exists. The EnsureStudentSession method checks if a student ID is present in the testSession map. If not, it generates a new student ID using Go's uuid package.

This method checks the testSession map for a student_id. If it doesn't exist, a new UUID is generated and stored in the map. The method then returns the student ID, either the newly created one or the existing one.

One of the primary responsibilities of the TutorController is to create new tutoring sessions. The CreateSession method handles session creation requests and returns a standardized response.

In this method:

1. Retrieve the student_id: We check the testSession map for a student_id.
2. Handle Session Expiry: If the session has expired (i.e., no student_id is found), we return an error response using the ErrorResponse helper function with a 401 status code.
3. Create a Tutoring Session: If the session is valid, we call the CreateSession method of the TutorService with the student ID to create a new tutoring session. We then return a success response containing a unique session ID and a success message using the SuccessResponse helper function.

The SendQuery method is responsible for processing student queries and returning the tutor's response or an error message.

In this method:

1. We check if the student session is valid by retrieving the student_id from the testSession map. If not found, we return an error response with a 401 status code.
2. We validate that both sessionID and studentQuery are provided. If either is missing, we return an error response with a 400 status code.
3. If all validations pass, we attempt to process the query using the ProcessQuery method of the TutorService. This method takes the student_id, sessionID, and studentQuery as parameters.
4. If the query is processed successfully, we return the tutor's response in a success response format.
5. If an error occurs (such as the session not being found or an internal error), we return an error response with the appropriate status code.

The TutorController uses helper functions for formatting responses: SuccessResponse and ErrorResponse. These functions ensure consistent response formats throughout the controller.

These functions create standardized response formats:

• SuccessResponse returns a Response struct with a Status field set to "success" and a Data field containing the provided data.
• ErrorResponse returns a Response struct with a Status field set to "error" and an Error field with message and code details.

To see the TutorController in action, let's integrate it into the main application. This example demonstrates how to create a tutoring session and handle a student query, showcasing the controller's functionality.

In this example, we first initialize the TutorService and TutorController. We ensure a student session is available for testing. We then create a new tutoring session and handle the response. If successful, we simulate a student query about the differences between mitosis and meiosis and use the SendQuery method to process it. The response is checked for errors, and either the error message or the tutor's response is printed. This example demonstrates the flow from ensuring a student session to creating a tutoring session and handling a student query, highlighting the controller's role in managing interactions.

In this lesson, we explored the TutorController struct and its role in managing tutoring sessions and handling student queries in Go. We learned how to implement the controller, create tutoring sessions, and process student questions using the TutorService. The controller is a vital component of our personal tutor application, ensuring that student interactions are managed efficiently and effectively.

As you move on to the practice exercises, take the opportunity to experiment with the TutorController's functionality. This hands-on practice will reinforce the concepts covered in this lesson and prepare you for the next steps in our course. Keep up the great work, and I look forward to seeing your progress!