from decimal import Decimal

from django.test import TestCase

from apps.pricing.engine import PricingEngine
from apps.pricing.models import PricingRule
from apps.workflows.models import Workflow, WorkflowStep, WorkflowVersion


class PricingEngineTests(TestCase):
    def setUp(self):
        wf = Workflow.objects.create(name="P", slug="p")
        self.version = WorkflowVersion.objects.create(workflow=wf, version=1)
        self.washing = WorkflowStep.objects.create(version=self.version, key="washing", name="Washing")
        self.drying = WorkflowStep.objects.create(version=self.version, key="drying", name="Drying")

    def test_per_kg(self):
        PricingRule.objects.create(step=self.washing, name="Wash", rule_type="per_kg", amount=Decimal("5000"))
        result = PricingEngine().calculate(850, [self.washing])
        self.assertEqual(result["total"], "4250000.00")

    def test_tiered(self):
        PricingRule.objects.create(step=self.washing, name="Tiered", rule_type="tiered", config={
            "tiers": [{"from": 0, "price": "5000"}, {"from": 100, "price": "4000"}, {"from": 500, "price": "3000"}],
        })
        result = PricingEngine().calculate(600, [self.washing])
        self.assertEqual(result["total"], "1800000.00")

    def test_discount_and_tax(self):
        PricingRule.objects.create(step=self.washing, name="Wash", rule_type="per_kg", amount=Decimal("1000"))
        PricingRule.objects.create(step=self.washing, name="Disc", rule_type="discount", amount=Decimal("10"), config={"percentage": True})
        PricingRule.objects.create(step=self.washing, name="Tax", rule_type="tax", amount=Decimal("9"))
        result = PricingEngine().calculate(100, [self.washing])
        # subtotal 100000, discount 10% => 10000, taxable 90000, tax 9% => 8100, total 98100
        self.assertEqual(result["total"], "98100.00")

    def test_multiple_steps(self):
        PricingRule.objects.create(step=self.washing, name="Wash", rule_type="per_kg", amount=Decimal("5000"))
        PricingRule.objects.create(step=self.drying, name="Dry", rule_type="per_kg", amount=Decimal("8000"))
        result = PricingEngine().calculate(100, [self.washing, self.drying])
        self.assertEqual(result["total"], "1300000.00")