django multiple table query - django

Question

I have a form for filling out lessons that I want to limit who the students can select as their teacher to only confirmed connections. I have three models:
class User(AbstractBaseUser, PermissionsMixin):
email = models.EmailField(max_length=254, unique=True)
name = models.CharField(max_length=254, null=True, blank=True)
class Lesson(models.Model):
user = models.ForeignKey(User, related_name='fencer', on_delete=models.SET_NULL, null=True, blank=True)
teacher = models.ForeignKey(Fencer, related_name='instructor', on_delete=models.SET_NULL, null=True, blank=True)
lesson_date = models.DateField(default="1900-01-01")
title = models.CharField(max_length=100, null = True, blank=True)
description = models.TextField(null=True, blank=True)
class Connection(models.Model):
student = models.ForeignKey(User, related_name='student', on_delete=models.CASCADE, blank=True)
teacher = models.ForeignKey(User, related_name='teacher', on_delete=models.CASCADE, blank=True)
student_accepts = models.BooleanField(default=False)
teacher_accepts = models.BooleanField(default=False)
#property
def connected(self):
if self.student_accepts == True and self.teacher_accepts == True:
return True
else:
return False
My form so far is:
class LessonForm(ModelForm):
class Meta:
model = models.Lesson
#fields = ()
fields = '__all__'
def __init__(self, user, *args, **kwargs):
super().__init__(*args, **kwargs)
self.fields['teacher'].queryset = Users.objects.filter() # the best I have so far
How do I filter the User model based on the link made in the Connection model? Maybe I'm overcomplicating this or is there a better way?
Thank you in advance

Answer 1

Found the answer in this other question on here about spanning models.
I had a hard time getting django to see the fields for some reason so I will keep this ugly version.
def __init__(self, user, *args, **kwargs): # will need to pass the user to the form when used
super(LessonForm, self).__init__(*args, **kwargs)
# reduce options to just the coaches that the student is connected with
connected_teachers = Connection.objects.filter(Q(student=user) and (Q(student_accepts=True) and Q(teacher_accepts=True)))
teachers = User.objects.filter(teacher__in=connected_teachers)
self.fields['teacher'].queryset = teachers