NewAuthHandler creates a new instance of Handler with the given Service.

NewAuthService creates a new instance of authServiceImpl with the provided services and configuration.

NewOAuthProviders initializes and registers the OAuth providers using the Goth library.

OAuthCallbackMiddleware is a Gin middleware function that handles the callback from the OAuth provider.

OAuthMiddleware is a Gin middleware function that handles the initial OAuth request.

Router sets up the routes for authentication-related API endpoints It groups the routes under "api/v1/auth" and assigns handler functions to the routes.

Handler handles authentication-related requests.

Service defines the methods that our authentication service will implement.