// Import dce-reactkit
import { genRouteHandler } from '../../../../dce-reactkit';

// Import types
import CanvasUser from '../../../types/CanvasUser';
import Router from '../../../types/Router';

// Import shared types
import CanvasAPI from '../../../shared/types/CanvasAPI';
import User from '../../../shared/types/User';

// Static helpers
const canvasUserToUser = (canvasUser: CanvasUser): User => {
  const {
    id: userId,
    first_name: userFirstName,
    last_name: userLastName,
  } = canvasUser;

  return {
    userId,
    userFirstName,
    userLastName,
  };
};

/**
 * Endpoint for retrieving the current Canvas course roster (list of students).
 * @author Benedikt Arnarsson
 * @param router the router that we are adding the endpoint to.
 * @param getCanvasAPI function to retrieve API for interacting with Canvas.
 */
const addGetRosterRoute = (
  router: Router,
  getCanvasAPI: () => CanvasAPI,
) => {
  router.get(
    '/students',
    genRouteHandler({
      handler: async () => {
        const canvas = getCanvasAPI();

        const canvasUserList = await canvas.course.listStudents();
        const userList = canvasUserList.map(canvasUserToUser);

        return userList;
      },
    }),
  );
};

export default addGetRosterRoute;