import re

def refactor_create_view():
    with open('expenses/views.py', 'r', encoding='utf-8') as f:
        content = f.read()

    old_create_view = """@login_required
@transaction.atomic  # Integridad de datos
def expense_create(request):
    # Only allow creation if user is admin or allowed to
    if request.method == 'POST':
        form = ExpenseForm(request.POST, request.FILES)
        if form.is_valid():
            expense = form.save(commit=False)
            expense.user = request.user
            # Auto convert to USD if CLP
            setting, _ = SystemSetting.objects.get_or_create(id=1)
            if expense.currency == CurrencyEnum.CLP:
                expense.amount_usd = expense.amount_clp / setting.usd_exchange_rate
            else:
                expense.amount_usd = expense.amount_clp
                expense.amount_clp = expense.amount_usd * setting.usd_exchange_rate
            
            expense.save()
            
            receipts = request.FILES.getlist('receipt')
            if receipts:
                from .models import Document
                import os
                cat_name = expense.category.name if expense.category else 'Evidencia'
                proj_code = expense.project.code if expense.project else 'PROY'
                for idx, f in enumerate(receipts, start=1):
                    ext = os.path.splitext(f.name)[1].lower()
                    semantic_title = f"{proj_code} · {cat_name} · Doc {idx:02d}{ext}"
                    Document.objects.create(
                        expense=expense,
                        file=f,
                        title=semantic_title,
                        uploaded_by=request.user
                    )
                
            AuditLog.objects.create(
                user=request.user,
                action="Gasto Creado",
                entity_name="Expense",
                entity_id=expense.expense_code,
                description=f"Se creó el gasto por {expense.amount_clp} CLP"
            )
            messages.success(request, 'Gasto registrado exitosamente.')
            return redirect('expense_list')
    else:
        form = ExpenseForm()
    
    context = {
        'form': form,
        'regions_communes_json': json.dumps(REGIONS_COMMUNES)
    }
    return render(request, 'expenses/expense_form.html', context)"""

    new_create_view = """from django.utils.decorators import method_decorator

@method_decorator(transaction.atomic, name='dispatch')
class ExpenseCreateView(LoginRequiredMixin, CreateView):
    model = Expense
    form_class = ExpenseForm
    template_name = 'expenses/expense_form.html'
    success_url = reverse_lazy('expense_list')

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['regions_communes_json'] = json.dumps(REGIONS_COMMUNES)
        return context

    def form_valid(self, form):
        expense = form.save(commit=False)
        expense.user = self.request.user
        
        setting, _ = SystemSetting.objects.get_or_create(id=1)
        if expense.currency == CurrencyEnum.CLP:
            expense.amount_usd = expense.amount_clp / setting.usd_exchange_rate
        else:
            expense.amount_usd = expense.amount_clp
            expense.amount_clp = expense.amount_usd * setting.usd_exchange_rate
            
        expense.save()
        
        receipts = self.request.FILES.getlist('receipt')
        if receipts:
            from .models import Document
            import os
            cat_name = expense.category.name if expense.category else 'Evidencia'
            proj_code = expense.project.code if expense.project else 'PROY'
            for idx, f in enumerate(receipts, start=1):
                ext = os.path.splitext(f.name)[1].lower()
                semantic_title = f"{proj_code} · {cat_name} · Doc {idx:02d}{ext}"
                Document.objects.create(
                    expense=expense,
                    file=f,
                    title=semantic_title,
                    uploaded_by=self.request.user
                )
                
        AuditLog.objects.create(
            user=self.request.user,
            action="Gasto Creado",
            entity_name="Expense",
            entity_id=expense.expense_code,
            description=f"Se creó el gasto por {expense.amount_clp} CLP"
        )
        messages.success(self.request, 'Gasto registrado exitosamente.')
        return super().form_valid(form)"""

    content = content.replace(old_create_view, new_create_view)
    
    with open('expenses/views.py', 'w', encoding='utf-8') as f:
        f.write(content)

def refactor_urls_create():
    with open('expenses/urls.py', 'r', encoding='utf-8') as f:
        content = f.read()
    content = content.replace("path('gastos/nuevo/', views.expense_create, name='expense_create')", "path('gastos/nuevo/', views.ExpenseCreateView.as_view(), name='expense_create')")
    with open('expenses/urls.py', 'w', encoding='utf-8') as f:
        f.write(content)

if __name__ == '__main__':
    refactor_create_view()
    refactor_urls_create()
    print("Refactorización a POO completada para expense_create.")