def main(request):
    try:
        company = models.Company.objects.get(user__user__id=request.user.id)
    except ObjectDoesNotExist as e:
        return render_to_response('errors.html', {'error': e})
    balance = utils.get_balance(company)

    if request.method == 'GET':
        form = forms.PeriodForm(request.GET)
        if form.is_valid():
            start_period = datetime.strptime(form['start_period'].value(), '%d.%m.%Y')
            end_period = datetime.strptime(form['end_period'].value(), '%d.%m.%Y')
            transactions = utils.filter_transactions(company, start_period, end_period)
            context = {
                    'summary_data': utils.get_summary_data(transactions),
                    'card_transactions': utils.get_card_transactions(transactions),
                    'form': form,
                    'company': company,
                    'balance': balance,
                    }

            return render_to_response('card_transactions.html', context)
    context = {
        'form': forms.PeriodForm,
        'company': company,
        'balance': balance
        }
    return render_to_response('card_transactions.html', context)