Verification of payments and ceiling of trainings in Laravel - php

Question

My goal is that when I encode a student for a payment. He (student) can follow 2 trainings per payment. (this is the ceiling - 1 payment = 2 trainings)
In my form Payment, I encode a student for example Menier.
The student is entitled to two trainings, (this is the ceiling)
In my form Training: I encode 2 trainings for the student Menier.
My first question: how can I block the number of trainings by two?
(so, if I encode another training, it must block!)
My second queston, if I encode 2 payments for the same student. The student is entitled to 4 trainings. How to create this type of algorithm?
Here is my code for now, I know it's not a lot...
Edit 05-10-2019 - Controller Training
public function store(Request $request)
{
$request->validate([
'date_seance' => 'required',
'hour_start' => 'required',
'hour_end' => 'required',
'fk_motorbike' => 'required',
'fk_former' => 'required',
'fk_student' => 'required',
'fk_typeseance' => 'required'
]);
$date_seance = $request->get('date_seance');
$hour_start = $request->get('hour_start');
$hour_end = $request->get('hour_end');
$fk_motorbike = $request->get('fk_motorbike');
$fk_student = $request->get('fk_student');
$fk_former = $request->get('fk_former');
$fk_typeseance = $request->get('fk_typeseance');
$payments = Payment::where('fk_student', $request->get('fk_student'))->first();
if(!isset($payments)){
return redirect()->route('trainings.index')
->with('error', 'No payment, no training! ');
}
$thisStudentsTrainings = Training::where('fk_student', $fk_student)->get();
if(count($thisStudentsTrainings) >= 2){
return redirect()->route('trainings.index')
->with('error', 'The ceiling is 2 trainings! ');
}
$thisStudentsPayments = Payment::where('fk_student', $request->get('fk_student'))->get();
if( (count($thisStudentsPayments) * 2) < count($thisStudentsTrainings) ) {
return redirect()->route('trainings.index')
->with('error', 'test!');
}
else{
Training::create($request->all());
return redirect()->route('trainings.index')
->with('success', 'Add');
}
}
Do you have an idea of how I could solve my problems, I am still a beginner in laravel.
For Watercayman
Thank you for your time.

Answer 1

This is not too bad to do. Since the payment is not directly associated with a specific training (ie you have a credit system), you can do this pretty easily with a couple of queries.
My first question: how can I block the number of trainings by two?
Start with the basics and find the number of trainings in the database for this student:
$thisStudentsTrainings = Training::where('fk_student', $fk_student)->get();
Or you can come in from the reverse for this simply query:
$student = Student::with('trainings')->get();
$thisStudentsTrainings = $student->trainings;
Then, to limit to two trainings (without payment consideration yet):
if(count($thisStudentsTrainings) >= 2){ too many trainings }
Now that you have a count of trainings, if you also want to make sure they have a payment in the system, lets get the payments:
$thisStudentsPayments = Payment::where('fk_student', $request->get('fk_student'))->get();
To check if they have paid for trainings, you now have both pieces of data that you need. You just have to figure out if they have paid for the right amount of trainings based on 2 payments = 1 training. So:
if( (count($thisStudentsPayments) * 2) < count($thisStudentsTrainings) ) {
// They have not made enough payments!
}
My second queston, if I encode 2 payments for the same student. The student is entitled to 4 trainings. How to create this type of algorithm?
The above will work for 2 or 4 or whatever you want.
Now, if you want to enforce a max of 2 trainings per each payment, we can check on this too. BUT, this is starting to get a little complex or circular in the logic. If you can avoid this, it will be a lot easier. But, let's check on the max of 2 per payment, which is just the adding an equals check, AFTER the one above:
if( (count($thisStudentsTrainings) >= count($thisStudentsPayments) * 2) {
// They are at their limit of trainings based on their payments!
// Note we include >= so that if they have purchased 2 trainings,
// this blocks them from a 3rd until they pay again.
}
This should solve your issue. However, you didn't ask, but I assume you don't want a student to allow a training if they have already used up a payment. IE if they've taken a training and they have 'spent their credit', they should not be allowed to take the training. If this is important to you, I suggest that in another part of your program, you write to the database when a payment has been consumed. So - if a student uses 2 trainings and has paid for them, maybe a boolean field on the Payment model spent (or something to indicate the payment is no longer valid). You could also remove the payment from the system if you don't need historical data. But, assuming you do, and you use $payment->spent, you can still do the above algorithm, just add the spent line to the query something like:
$student = Student::with(['trainings' => function($query){
$query->where('spent', 0)
}])->get();
Then all the rest should be the same. This isn't cut & paste, but I think now that you have separated out payments and trainings, this should be a pretty easy solve to understand based on the above. :)