This endpoint returns all chat conversations associated with the currently authenticated user. A valid JWT token must be included in the Authorization header. The user's ID is extracted from the token claims and used to fetch the relevant chat data.

If the user ID is missing or not a valid GUID, a 401 Unauthorized response is returned. Appropriate error responses are returned in case of validation failures or internal errors.

This endpoint returns a paginated list of messages from a conversation.
If fromMessageId is provided, it returns messages after that ID;
if fromMessageId is null, it returns an empty list (with 200 OK).
A valid JWT token must be included in the Authorization header.
If conversationId is missing, empty, or invalid, an error response is returned.

This endpoint allows an authenticated user to send a friend invitation by providing the sender's and recipient's GUIDs. Returns appropriate HTTP responses based on validation, conflicts, or if the recipient is not found.

Returns all pending friend invitations for the specified user GUID. If the user does not exist or input is invalid, returns appropriate error responses.

Authenticated users can search for other users by username or display name. The search excludes users who are already friends or already invited. Requires a valid JWT token with user GUID.

Allows an authenticated user to decline a friend invitation by providing sender and recipient GUIDs. Returns appropriate errors if the invitation is invalid, already handled, or missing.

Allows an authenticated user to accept a friend invitation by sender and recipient GUIDs. On success, users are added to each other's friend lists. Returns errors for invalid input, not found invitations, or conflicts.

Fetches all users marked as friends of the specified user GUID. Returns errors for invalid input or unexpected issues.

This endpoint creates a new user using a username and password. If the username already exists, a conflict response is returned. On success, basic user data is returned.

This endpoint validates the provided login credentials. On success, it returns a JWT access token and a refresh token. If authentication fails, a detailed error is returned.

This endpoint checks the provided refresh token and issues a new access token if it's valid.

Authenticated users can change their username. The new username must be unique.

Authenticated users can upload a new avatar image. The uploaded file must meet specific requirements:

• Maximum file size: 5 MB.

• Maximum dimensions: 500x500 pixels.

• Supported formats: JPEG, PNG, etc.

Requires authorization. This endpoint returns a simplified user DTO corresponding to the given GUID.

Optionally excludes the currently authenticated user from the results.