from django import forms
from .models import TaxDocument
class UploadForm(forms.ModelForm):
 class Meta:
  model=TaxDocument
  fields=['kind','file']
 def clean_file(self):
  f=self.cleaned_data['file']
  if f.size>20*1024*1024: raise forms.ValidationError('Maximum PDF size is 20 MB.')
  if not f.name.lower().endswith('.pdf'): raise forms.ValidationError('Only PDFs are accepted in Phase 1.')
  head=f.read(5); f.seek(0)
  if head!=b'%PDF-': raise forms.ValidationError('This is not a valid PDF header.')
  return f