import math
from decimal import Decimal

from django.db.models import DecimalField
from django.db.models.functions import Cot
from django.test import TestCase
from django.test.utils import register_lookup

from ..models import DecimalModel, FloatModel, IntegerModel


class CotTests(TestCase):

    def test_null(self):
        IntegerModel.objects.create()
        obj = IntegerModel.objects.annotate(null_cot=Cot('normal')).first()
        self.assertIsNone(obj.null_cot)

    def test_decimal(self):
        DecimalModel.objects.create(n1=Decimal('-12.9'), n2=Decimal('0.6'))
        obj = DecimalModel.objects.annotate(n1_cot=Cot('n1'), n2_cot=Cot('n2')).first()
        self.assertIsInstance(obj.n1_cot, Decimal)
        self.assertIsInstance(obj.n2_cot, Decimal)
        self.assertAlmostEqual(obj.n1_cot, Decimal(1 / math.tan(obj.n1)))
        self.assertAlmostEqual(obj.n2_cot, Decimal(1 / math.tan(obj.n2)))

    def test_float(self):
        FloatModel.objects.create(f1=-27.5, f2=0.33)
        obj = FloatModel.objects.annotate(f1_cot=Cot('f1'), f2_cot=Cot('f2')).first()
        self.assertIsInstance(obj.f1_cot, float)
        self.assertIsInstance(obj.f2_cot, float)
        self.assertAlmostEqual(obj.f1_cot, 1 / math.tan(obj.f1))
        self.assertAlmostEqual(obj.f2_cot, 1 / math.tan(obj.f2))

    def test_integer(self):
        IntegerModel.objects.create(small=-5, normal=15, big=-1)
        obj = IntegerModel.objects.annotate(
            small_cot=Cot('small'),
            normal_cot=Cot('normal'),
            big_cot=Cot('big'),
        ).first()
        self.assertIsInstance(obj.small_cot, float)
        self.assertIsInstance(obj.normal_cot, float)
        self.assertIsInstance(obj.big_cot, float)
        self.assertAlmostEqual(obj.small_cot, 1 / math.tan(obj.small))
        self.assertAlmostEqual(obj.normal_cot, 1 / math.tan(obj.normal))
        self.assertAlmostEqual(obj.big_cot, 1 / math.tan(obj.big))

    def test_transform(self):
        with register_lookup(DecimalField, Cot):
            DecimalModel.objects.create(n1=Decimal('12.0'), n2=Decimal('0'))
            DecimalModel.objects.create(n1=Decimal('1.0'), n2=Decimal('0'))
            objs = DecimalModel.objects.filter(n1__cot__gt=0)
            self.assertQuerysetEqual(objs, [Decimal('1.0')], lambda a: a.n1)