import json
import uuid
from decimal import Decimal
from typing import override

from django.core.cache import cache
from django.test import Client, TestCase
from django.urls import reverse
from django.utils import timezone

from apps.events.tests.helpers import make_event_type, make_exposure_type
from apps.experiments.services import (
    experiment_approve,
    experiment_start,
    experiment_submit_for_review,
)
from apps.experiments.tests.helpers import add_two_variants, make_experiment
from apps.metrics.services import (
    experiment_metric_add,
    metric_definition_create,
)
from apps.reviews.services import review_settings_update
from apps.reviews.tests.helpers import make_approver, make_experimenter
from apps.users.tests.helpers import auth_header


class APIContractFlowTest(TestCase):
    @override
    def setUp(self) -> None:
        cache.clear()
        self.client = Client()

        review_settings_update(
            default_min_approvals=1,
            allow_any_approver=True,
        )

        owner = make_experimenter("_api")
        self.auth = auth_header(owner)
        approver = make_approver("_api")

        self.experiment = make_experiment(
            owner=owner,
            suffix="_api",
            traffic_allocation=Decimal("100.00"),
        )
        add_two_variants(self.experiment)

        self.metric = metric_definition_create(
            key="ctr_api",
            name="CTR",
            metric_type="ratio",
            direction="higher_is_better",
            calculation_rule={
                "numerator_event": "api_click",
                "denominator_event": "api_exposure",
            },
        )
        experiment_metric_add(
            experiment=self.experiment,
            metric=self.metric,
            is_primary=True,
        )

        make_exposure_type(name="api_exposure")
        make_event_type(
            name="api_click",
            display_name="Click",
            requires_exposure=True,
        )

        self.experiment = experiment_submit_for_review(
            experiment=self.experiment, user=owner
        )
        self.experiment = experiment_approve(
            experiment=self.experiment, approver=approver
        )
        self.experiment = experiment_start(
            experiment=self.experiment, user=owner
        )

    def test_decide_to_events_to_report_via_http(self) -> None:
        decide_resp = self.client.post(
            reverse("api-1:decide"),
            data=json.dumps(
                {
                    "subject_id": "api_user_1",
                    "flags": [self.experiment.flag.key],
                    "subject_attributes": {},
                }
            ),
            content_type="application/json",
        )
        self.assertEqual(decide_resp.status_code, 200)
        decide_data = decide_resp.json()

        self.assertEqual(len(decide_data["decisions"]), 1)
        decision = decide_data["decisions"][0]
        self.assertEqual(decision["reason"], "experiment_assigned")
        self.assertIsNotNone(decision["decision_id"])
        self.assertIsNotNone(decision["variant_id"])

        now = timezone.now().isoformat()
        events_resp = self.client.post(
            reverse("api-1:ingest_events"),
            data=json.dumps(
                {
                    "events": [
                        {
                            "event_id": "api_exp_1",
                            "event_type": "api_exposure",
                            "decision_id": decision["decision_id"],
                            "subject_id": "api_user_1",
                            "timestamp": now,
                            "properties": {},
                        },
                        {
                            "event_id": "api_click_1",
                            "event_type": "api_click",
                            "decision_id": decision["decision_id"],
                            "subject_id": "api_user_1",
                            "timestamp": now,
                            "properties": {},
                        },
                    ]
                }
            ),
            content_type="application/json",
        )
        self.assertEqual(events_resp.status_code, 200)
        events_data = events_resp.json()
        self.assertEqual(events_data["accepted"], 2)
        self.assertEqual(events_data["rejected"], 0)
        self.assertEqual(events_data["duplicates"], 0)

        report_resp = self.client.get(
            reverse(
                "api-1:get_experiment_report",
                args=[self.experiment.pk],
            ),
            HTTP_AUTHORIZATION=self.auth,
        )
        self.assertEqual(report_resp.status_code, 200)
        report = report_resp.json()

        self.assertEqual(report["experiment_id"], str(self.experiment.pk))
        total_exposures = sum(v["exposures"] for v in report["variants"])
        self.assertEqual(total_exposures, 1)
        self.assertEqual(len(report["variants"]), 2)

        for variant in report["variants"]:
            if variant["exposures"] > 0:
                self.assertEqual(len(variant["metrics"]), 1)
                self.assertEqual(
                    variant["metrics"][0]["metric_key"], "ctr_api"
                )

    def test_decide_returns_all_requested_flags(self) -> None:
        resp = self.client.post(
            reverse("api-1:decide"),
            data=json.dumps(
                {
                    "subject_id": "api_user_2",
                    "flags": [
                        self.experiment.flag.key,
                        "nonexistent_flag",
                    ],
                }
            ),
            content_type="application/json",
        )
        self.assertEqual(resp.status_code, 200)
        data = resp.json()

        self.assertEqual(len(data["decisions"]), 2)
        reasons = {d["flag"]: d["reason"] for d in data["decisions"]}
        self.assertEqual(
            reasons[self.experiment.flag.key], "experiment_assigned"
        )
        self.assertEqual(reasons["nonexistent_flag"], "flag_not_found")

    def test_events_dedup_via_http(self) -> None:
        cache.clear()
        decide_resp = self.client.post(
            reverse("api-1:decide"),
            data=json.dumps(
                {
                    "subject_id": "api_user_3",
                    "flags": [self.experiment.flag.key],
                }
            ),
            content_type="application/json",
        )
        decision = decide_resp.json()["decisions"][0]
        now = timezone.now().isoformat()

        event_payload = json.dumps(
            {
                "events": [
                    {
                        "event_id": "api_ddup_1",
                        "event_type": "api_exposure",
                        "decision_id": decision["decision_id"],
                        "subject_id": "api_user_3",
                        "timestamp": now,
                        "properties": {},
                    }
                ]
            }
        )

        r1 = self.client.post(
            reverse("api-1:ingest_events"),
            data=event_payload,
            content_type="application/json",
        )
        self.assertEqual(r1.json()["accepted"], 1)

        r2 = self.client.post(
            reverse("api-1:ingest_events"),
            data=event_payload,
            content_type="application/json",
        )
        self.assertEqual(r2.json()["duplicates"], 1)
        self.assertEqual(r2.json()["accepted"], 0)

    def test_report_404_for_unknown_experiment(self) -> None:
        resp = self.client.get(
            reverse(
                "api-1:get_experiment_report",
                args=[uuid.uuid4()],
            ),
            HTTP_AUTHORIZATION=self.auth,
        )
        self.assertEqual(resp.status_code, 404)