CoursesController.php

<?php

class CoursesController
{
    private $coursesView;
    private $courseCategoriesRepository;
    private $courseProgramsRepository;
    private $coursesToViewData;

    public function __construct(
        $coursesView,
        $courseCategoriesRepository,
        $courseProgramsRepository,
        $coursesToViewData
    ) {
        $this->courseCategoriesRepository = $courseCategoriesRepository;
        $this->courseProgramsRepository = $courseProgramsRepository;
        $this->coursesView = $coursesView;
        $this->coursesToViewData = $coursesToViewData;
    }

    public function listCourses($categoryName)
    {
        $courseProgramsData = $this->getCourseProgramsData($categoryName);

        return $this->coursesView->render($courseProgramsData, $categoryName);
    }

    private function getCourseProgramsData($categoryName)
    {
        $categoryId = $this->courseCategoriesRepository->getIdForCategoryWithName($categoryName);

        $coursePrograms = $this->courseProgramsRepository->getAllWithCourseCategoryId($categoryId);

        return $this->coursesToViewData->translate($coursePrograms, $categoryName);
    }
}