/**
* Fetch random exercise of lesson
*
* Exercise that user knows less have more chance to be returned.
* Exercise that user knows more have less chance to be returned.
*
* @param int $lessonId
* @param int $userId
* @param int|null $previousExerciseId
* @return Exercise
* @throws Exception
* @throws NotEnoughExercisesException
*/
public function fetchRandomExerciseOfLesson(int $lessonId, int $userId, int $previousExerciseId = null) : Exercise
{
/** @var Exercise[]|Collection $exercises */
$exercises = Exercise::select('exercises.*')->with('results')->join('lessons', 'lessons.id', '=', 'exercises.lesson_id')->where('lessons.id', '=', $lessonId)->where('exercises.id', '!=', $previousExerciseId)->get();
if ($exercises->count() == 1) {
return $exercises->first();
}
if ($exercises->isEmpty()) {
throw new NotEnoughExercisesException();
}
$tmp = [];
foreach ($exercises as $exercise) {
if ($exercise->results->isEmpty()) {
/*
* If results relation is not loaded, that means user has no answers for this exercises yet,
* so we know that percent of good answers is 0
*/
$percentOfGoodAnswers = 0;
} else {
/*
* Using already loaded relation (so no extra db call is required) check percent of good answers
* of a user
*/
$percentOfGoodAnswers = $exercise->results->filter(function ($item) use($userId) {
return $item->user_id == $userId;
})->first()->percent_of_good_answers;
}
/*
* Fill $tmp array with $exercises multiplied by number of points.
*
* This way exercises with higher number of points (so lower user knowledge),
* will have bigger chance to be returned.
*/
for ($i = $this->calculateNumberOfPoints($percentOfGoodAnswers); $i > 0; $i--) {
$tmp[] = $exercise;
}
}
// do randomization
shuffle($tmp);
return $tmp[array_rand($tmp)];
}
/**
* @param UpdateExerciseRequest $request
* @param Exercise $exercise
* @return JsonResponse
*/
public function updateExercise(UpdateExerciseRequest $request, Exercise $exercise)
{
$exercise->update($request->all());
return $this->response($exercise);
}
public function test_handleBadAnswer()
{
$this->exerciseRepository->expects($this->once())->method('handleBadAnswer')->with($this->exercise->id, $this->user->id);
$this->exercise->handleBadAnswer($this->user->id);
}
/**
* @param Exercise $exercise
* @param UpdateExerciseRequest $request
* @return RedirectResponse
*/
public function update(Exercise $exercise, UpdateExerciseRequest $request) : RedirectResponse
{
$exercise->update($request->all());
return redirect('/lessons/' . $exercise->lesson_id);
}
/**
* @param Exercise $exercise
*/
public function handleBadAnswer(Exercise $exercise)
{
$this->authorizeForUser($this->user(), 'learn', $exercise->lesson);
$exercise->handleBadAnswer($this->user()->id);
}