from django import forms
from django.contrib.auth.models import User
from .models import Student, Subject, Classroom

class StudentRegistrationForm(forms.ModelForm):
    first_name = forms.CharField(max_length=30, required=True, label="Full Name (First)")
    last_name = forms.CharField(max_length=30, required=True, label="Full Name (Last)")
    username = forms.CharField(max_length=150, required=True)
    email = forms.EmailField(required=True)
    password = forms.CharField(widget=forms.PasswordInput, required=True)
    
    classroom = forms.ModelChoiceField(queryset=Classroom.objects.all(), required=True, empty_label="Select Classroom")
    subjects = forms.ModelMultipleChoiceField(
        queryset=Subject.objects.all(), 
        required=False, 
        widget=forms.CheckboxSelectMultiple,
        label="Select Subjects"
    )

    class Meta:
        model = Student
        fields = ['mobile_number', 'moderate', 'city', 'avatar']
        widgets = {
            'avatar': forms.FileInput(attrs={'accept': 'image/*', 'capture': 'camera'}), # generic hint, but we'll use custom JS
        }

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        # optimize subjects loading
        self.fields['subjects'].queryset = Subject.objects.none()

        if 'classroom' in self.data:
            try:
                classroom_id = int(self.data.get('classroom'))
                self.fields['subjects'].queryset = Subject.objects.filter(classroom_id=classroom_id)
            except (ValueError, TypeError):
                pass
        elif self.instance.pk and self.instance.classroom:
            self.fields['subjects'].queryset = Subject.objects.filter(classroom=self.instance.classroom)

    def save(self, commit=True):
        # We need to save the User first, then the Student
        user = User.objects.create_user(
            username=self.cleaned_data['username'],
            email=self.cleaned_data['email'],
            password=self.cleaned_data['password'],
            first_name=self.cleaned_data['first_name'],
            last_name=self.cleaned_data['last_name']
        )
        student = super().save(commit=False)
        student.user = user
        student.classroom = self.cleaned_data['classroom']
        
        if commit:
            student.save()
            student.subscribed_subjects.set(self.cleaned_data['subjects'])
        return student