Welcome back! In the previous lesson, we explored the importance of a robust system prompt and how it guides the behavior of our personal tutor. Now, we will delve into the next step of our journey: building the Session Manager. This lesson will focus on the model layer of the MVC (Model-View-Controller) architecture, which is crucial for organizing and managing data in a structured way. The SessionManager class will be the core component of our model layer, responsible for managing tutoring session data effectively. By the end of this lesson, you will understand how to create, manage, and retrieve session data using the SessionManager class.

The SessionManager class is designed to handle the storage and management of tutoring session data. It serves as the backbone of our tutor's data management system. We'll start by setting up the class and then gradually add methods to handle session creation, message addition, and conversation retrieval.

Let's begin by defining the SessionManager class and its constructor. The constructor initializes an empty object, this.sessions, which will store all session data.

In this setup, this.sessions is a nested object where the first key is the studentId, and the second key is the sessionId. This structure allows us to efficiently manage multiple tutoring sessions for different students.

Next, we'll add the createSession method. This method is responsible for creating a new session entry for a student. It takes three parameters: studentId, sessionId, and systemPrompt.

The createSession method checks if the studentId exists in this.sessions. If not, it creates a new entry. Then, it initializes the session with the provided systemPrompt and an empty array for messages.

To access a specific tutoring session, we need the getSession method. This method retrieves a session based on the studentId and sessionId.

The getSession method uses property checks to safely access the nested object, returning the session data if it exists.

Now, let's add the addMessage method. This method allows us to append messages to a session. It requires the studentId, sessionId, role, and content of the message.

The addMessage method first retrieves the session using getSession. If the session exists, it appends the message to the session's message array.

Finally, we'll implement the getConversation method. This method returns the entire conversation, including the system prompt and all messages.

The getConversation method retrieves the session and constructs an array starting with the system prompt, followed by the session messages. If the session does not exist, it returns an empty array.

By following these steps, we've built a fully functional SessionManager class that can create and manage tutoring sessions, add messages, and retrieve conversation histories.

Now that we've built our SessionManager class with all its key functionality, let's see how it works in a complete example. This will demonstrate the typical workflow of creating a session, adding messages, and retrieving conversation history.

In this example, we initialize the SessionManager, create a new session with the system prompt, add student and assistant messages to the conversation, and then retrieve and display the full conversation history. This workflow showcases how the different methods of the SessionManager work together to manage tutoring session data effectively.

In this lesson, we explored the SessionManager class and its role in managing tutoring session data within the model layer of our application. We learned how to create and manage sessions, add messages, and retrieve conversation histories. The SessionManager is a crucial component for organizing session data, ensuring that our personal tutor can handle multiple tutoring sessions efficiently.

As you move on to the practice exercises, take the opportunity to experiment with modifying and extending the SessionManager 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!