from django.test import TestCase
from django.contrib.auth import get_user_model
from datetime import datetime, date, timedelta

from .models import *

class BillingTestCase(TestCase):
    def setUp(self):
        self.user = get_user_model().objects.create(
                username='jdoe',
                email='john.doe@domain.tld')

    def test_truth(self):
        self.assertEqual(1+1, 2)

    def test_basic_monthly_billing(self):
        one_time_price = 10
        recurring_price = 20
        description = "Test Product 1"

        # Three months: full, full, partial.
        starting_date = datetime.fromisoformat('2020-03-01')
        ending_date   = datetime.fromisoformat('2020-05-08')

        # Create order to be billed.
        order = Order.objects.create(
                owner=self.user,
                starting_date=starting_date,
                ending_date=ending_date,
                recurring_period=RecurringPeriod.PER_MONTH)
        order.add_record(one_time_price, recurring_price, description)

        # Generate & check bill for first month: full recurring_price + setup.
        first_month_bills = order.bills # Initial bill generated at order creation.
        self.assertEqual(len(first_month_bills), 1)
        self.assertEqual(first_month_bills[0].total, one_time_price + recurring_price)

        # Generate & check bill for second month: full recurring_price.
        second_month_bills = Bill.generate_for(2020, 4, self.user)
        self.assertEqual(len(second_month_bills), 1)
        self.assertEqual(second_month_bills[0].total, recurring_price)

        # Generate & check bill for third and last month: partial recurring_price.
        third_month_bills = Bill.generate_for(2020, 5, self.user)
        self.assertEqual(len(third_month_bills), 1)
        # 31 days in May.
        self.assertEqual(float(third_month_bills[0].total),
                round((7/31) * recurring_price, AMOUNT_DECIMALS))

        # Check that running Bill.generate_for() twice does not create duplicates.
        self.assertEqual(len(Bill.generate_for(2020, 3, self.user)), 0)

    def test_basic_yearly_billing(self):
        one_time_price = 10
        recurring_price = 150
        description = "Test Product 1"

        starting_date = datetime.fromisoformat('2020-03-31T08:05:23')

        # Create order to be billed.
        order = Order.objects.create(
                owner=self.user,
                starting_date=starting_date,
                recurring_period=RecurringPeriod.PER_YEAR)
        order.add_record(one_time_price, recurring_price, description)

        # Generate & check bill for first year: recurring_price + setup.
        first_year_bills = order.bills # Initial bill generated at order creation.
        self.assertEqual(len(first_year_bills), 1)
        self.assertEqual(first_year_bills[0].starting_date.date(),
                date.fromisoformat('2020-03-31'))
        self.assertEqual(first_year_bills[0].ending_date.date(),
                date.fromisoformat('2021-03-30'))
        self.assertEqual(first_year_bills[0].total,
                recurring_price + one_time_price)

        # Generate & check bill for second year: recurring_price.
        second_year_bills = Bill.generate_for(2021, 3, self.user)
        self.assertEqual(len(second_year_bills), 1)
        self.assertEqual(second_year_bills[0].starting_date.date(),
                date.fromisoformat('2021-03-31'))
        self.assertEqual(second_year_bills[0].ending_date.date(),
                date.fromisoformat('2022-03-30'))
        self.assertEqual(second_year_bills[0].total, recurring_price)

        # Check that running Bill.generate_for() twice does not create duplicates.
        self.assertEqual(len(Bill.generate_for(2020, 3, self.user)), 0)
        self.assertEqual(len(Bill.generate_for(2020, 4, self.user)), 0)
        self.assertEqual(len(Bill.generate_for(2020, 2, self.user)), 0)
        self.assertEqual(len(Bill.generate_for(2021, 3, self.user)), 0)

    def test_basic_hourly_billing(self):
        one_time_price = 10
        recurring_price = 1.4
        description = "Test Product 1"

        starting_date = datetime.fromisoformat('2020-03-31T08:05:23')
        ending_date   = datetime.fromisoformat('2020-04-01T11:13:32')

        # Create order to be billed.
        order = Order.objects.create(
                owner=self.user,
                starting_date=starting_date,
                ending_date=ending_date,
                recurring_period=RecurringPeriod.PER_HOUR)
        order.add_record(one_time_price, recurring_price, description)

        # Generate & check bill for first month: recurring_price + setup.
        first_month_bills = order.bills
        self.assertEqual(len(first_month_bills), 1)
        self.assertEqual(float(first_month_bills[0].total),
                round(16 * recurring_price, AMOUNT_DECIMALS) + one_time_price)

        # Generate & check bill for first month: recurring_price.
        second_month_bills = Bill.generate_for(2020, 4, self.user)
        self.assertEqual(len(second_month_bills), 1)
        self.assertEqual(float(second_month_bills[0].total),
                round(12 * recurring_price, AMOUNT_DECIMALS))