from datetime import timedelta

import pytest
from django import test
from django.urls import reverse
from django.utils import timezone

from oscar.apps.dashboard.vouchers import forms
from oscar.core.loading import get_model
from oscar.test.factories.offer import (
    BenefitFactory, ConditionalOfferFactory, ConditionFactory, RangeFactory)
from oscar.test.factories.voucher import VoucherSetFactory

ConditionalOffer = get_model('offer', 'ConditionalOffer')
Voucher = get_model('voucher', 'Voucher')


class TestVoucherForm(test.TestCase):

    def test_doesnt_crash_on_empty_date_fields(self):
        """
        There was a bug fixed in 02b3644 where the voucher form would raise an
        exception (instead of just failing validation) when being called with
        empty fields. This tests exists to prevent a regression.
        """
        offer = ConditionalOfferFactory(offer_type=ConditionalOffer.VOUCHER,
                                        benefit=BenefitFactory(range=None),
                                        condition=ConditionFactory(range=None, value=1))
        data = {
            'code': '',
            'name': '',
            'start_datetime': '',
            'end_datetime': '',
            'usage': 'Single use',
            'offers': [offer.pk],
        }
        form = forms.VoucherForm(data=data)
        try:
            form.is_valid()
        except Exception as e:
            import traceback
            self.fail(
                "Exception raised while validating voucher form: %s\n\n%s" % (
                    e.message, traceback.format_exc()))


@pytest.mark.django_db
class TestVoucherSetForm:

    def test_valid_form(self):
        a_range = RangeFactory(includes_all_products=True)
        offer = ConditionalOfferFactory(offer_type=ConditionalOffer.VOUCHER,
                                        benefit=BenefitFactory(range=a_range),
                                        condition=ConditionFactory(range=a_range, value=1))
        start = timezone.now()
        end = start + timedelta(days=1)
        data = {
            'name': 'test',
            'code_length': 12,
            'description': 'test',
            'start_datetime': start,
            'end_datetime': end,
            'count': 10,
            'usage': Voucher.MULTI_USE,
            'offers': [offer.pk],
        }
        form = forms.VoucherSetForm(data=data)
        assert form.is_valid()
        instance = form.save()
        assert instance.count == instance.vouchers.count()
        assert instance.start_datetime == start
        assert instance.end_datetime == end

    def test_valid_form_reduced_count(self):
        voucher_set = VoucherSetFactory(count=5)
        voucher = voucher_set.vouchers.first()
        data = {
            'name': voucher_set.name,
            'code_length': voucher_set.code_length,
            'description': voucher_set.description,
            'start_datetime': voucher_set.start_datetime,
            'end_datetime': voucher_set.end_datetime,
            'count': 4,
            'usage': voucher.usage,
            'offers': voucher.offers.all(),
        }
        form = forms.VoucherSetForm(data, instance=voucher_set)
        assert not form.is_valid()
        assert form.errors['count'][0] == (
            'This cannot be used to delete vouchers (currently 5) in this set. '
            'You can do that on the <a href="%s">detail</a> page.') % reverse('dashboard:voucher-set-detail',
                                                                              kwargs={'pk': voucher_set.pk})