import { Request, Response, NextFunction } from 'express';

declare global {
  // eslint-disable-next-line @typescript-eslint/no-namespace
  namespace Express {
    interface Locals {
      // When the query params contains...
      //
      //   select=name,department.name
      //
      // ... it becomes available as follow in handlers:
      //
      //   ['name', 'department.name']
      selects: string[];
    }
  }
}

function extractSelects(req: Request, res: Response, next: NextFunction) {
  const rawSelect = req.query.select;

  if (typeof rawSelect === 'string') {
    res.locals.selects = rawSelect.split(',').map(select => decodeURIComponent(select));
  } else {
    res.locals.selects = [];
  }

  next();
}

export default extractSelects;