"""
Integration tests for Paddle webhook handling.
Covers signature verification, event parsing, subscription lifecycle transitions, and Hypothesis fuzzing.
"""
import json

import pytest
from conftest import make_webhook_payload, sign_payload
from hypothesis import HealthCheck, given
from hypothesis import settings as h_settings
from hypothesis import strategies as st
from padelnomics.billing.routes import get_subscription

WEBHOOK_PATH = "/billing/webhook/paddle"
SIG_HEADER = "Paddle-Signature"


# ════════════════════════════════════════════════════════════
# Signature Verification
# ════════════════════════════════════════════════════════════

class TestWebhookSignature:
    async def test_missing_signature_rejected(self, client, db):
        payload = make_webhook_payload("subscription.activated")
        payload_bytes = json.dumps(payload).encode()

        response = await client.post(
            WEBHOOK_PATH,
            data=payload_bytes,
            headers={"Content-Type": "application/json"},
        )
        assert response.status_code in (400, 401)

    async def test_invalid_signature_rejected(self, client, db):
        payload = make_webhook_payload("subscription.activated")
        payload_bytes = json.dumps(payload).encode()

        response = await client.post(
            WEBHOOK_PATH,
            data=payload_bytes,
            headers={SIG_HEADER: "invalid_signature", "Content-Type": "application/json"},
        )
        assert response.status_code in (400, 401)

    async def test_valid_signature_accepted(self, client, db, test_user):
        payload = make_webhook_payload("subscription.activated", user_id=str(test_user["id"]))
        payload_bytes = json.dumps(payload).encode()
        sig = sign_payload(payload_bytes)

        response = await client.post(
            WEBHOOK_PATH,
            data=payload_bytes,
            headers={SIG_HEADER: sig, "Content-Type": "application/json"},
        )
        assert response.status_code in (200, 204)

    async def test_modified_payload_rejected(self, client, db, test_user):
        payload = make_webhook_payload("subscription.activated", user_id=str(test_user["id"]))
        payload_bytes = json.dumps(payload).encode()
        sig = sign_payload(payload_bytes)
        tampered = payload_bytes + b"extra"

        response = await client.post(
            WEBHOOK_PATH,
            data=tampered,
            headers={SIG_HEADER: sig, "Content-Type": "application/json"},
        )
        assert response.status_code in (400, 401)

    async def test_empty_payload_rejected(self, client, db):
        sig = sign_payload(b"")

        response = await client.post(
            WEBHOOK_PATH,
            data=b"",
            headers={SIG_HEADER: sig, "Content-Type": "application/json"},
        )
        assert response.status_code == 400

    async def test_null_custom_data_does_not_crash(self, client, db):
        """Paddle sends null custom_data on lifecycle events like subscription.updated."""
        payload = {
            "event_type": "subscription.updated",
            "data": {
                "id": "sub_test456",
                "status": "active",
                "customer_id": "ctm_test123",
                "custom_data": None,
                "current_billing_period": {
                    "starts_at": "2025-02-01T00:00:00.000000Z",
                    "ends_at": "2025-03-01T00:00:00.000000Z",
                },
            },
        }
        payload_bytes = json.dumps(payload).encode()
        sig = sign_payload(payload_bytes)

        response = await client.post(
            WEBHOOK_PATH,
            data=payload_bytes,
            headers={SIG_HEADER: sig, "Content-Type": "application/json"},
        )
        assert response.status_code == 200

    async def test_null_custom_data_activated_does_not_crash(self, client, db):
        """subscription.activated with null custom_data must not FK-violate on user_id=0."""
        payload = {
            "event_type": "subscription.activated",
            "data": {
                "id": "sub_test456",
                "status": "active",
                "customer_id": "ctm_test123",
                "custom_data": None,
                "current_billing_period": {
                    "starts_at": "2025-02-01T00:00:00.000000Z",
                    "ends_at": "2025-03-01T00:00:00.000000Z",
                },
            },
        }
        payload_bytes = json.dumps(payload).encode()
        sig = sign_payload(payload_bytes)

        response = await client.post(
            WEBHOOK_PATH,
            data=payload_bytes,
            headers={SIG_HEADER: sig, "Content-Type": "application/json"},
        )
        assert response.status_code == 200

    async def test_null_data_does_not_crash(self, client, db):
        """Guard against data being null in the event payload."""
        payload = {
            "event_type": "subscription.updated",
            "data": None,
        }
        payload_bytes = json.dumps(payload).encode()
        sig = sign_payload(payload_bytes)

        response = await client.post(
            WEBHOOK_PATH,
            data=payload_bytes,
            headers={SIG_HEADER: sig, "Content-Type": "application/json"},
        )
        assert response.status_code == 200


# ════════════════════════════════════════════════════════════
# Subscription Lifecycle Events
# ════════════════════════════════════════════════════════════

class TestWebhookSubscriptionActivated:
    async def test_creates_subscription(self, client, db, test_user):
        payload = make_webhook_payload(
            "subscription.activated",
            user_id=str(test_user["id"]),
            plan="starter",
        )
        payload_bytes = json.dumps(payload).encode()
        sig = sign_payload(payload_bytes)

        response = await client.post(
            WEBHOOK_PATH,
            data=payload_bytes,
            headers={SIG_HEADER: sig, "Content-Type": "application/json"},
        )
        assert response.status_code in (200, 204)

        sub = await get_subscription(test_user["id"])
        assert sub is not None
        assert sub["plan"] == "starter"
        assert sub["status"] == "active"


class TestWebhookSubscriptionUpdated:
    async def test_updates_subscription_status(self, client, db, test_user, create_subscription):
        await create_subscription(test_user["id"], status="active", provider_subscription_id="sub_test456")

        payload = make_webhook_payload(
            "subscription.updated",
            subscription_id="sub_test456",
            status="paused",
        )
        payload_bytes = json.dumps(payload).encode()
        sig = sign_payload(payload_bytes)

        response = await client.post(
            WEBHOOK_PATH,
            data=payload_bytes,
            headers={SIG_HEADER: sig, "Content-Type": "application/json"},
        )
        assert response.status_code in (200, 204)

        sub = await get_subscription(test_user["id"])
        assert sub["status"] == "paused"


class TestWebhookSubscriptionCanceled:
    async def test_marks_subscription_cancelled(self, client, db, test_user, create_subscription):
        await create_subscription(test_user["id"], status="active", provider_subscription_id="sub_test456")

        payload = make_webhook_payload(
            "subscription.canceled",
            subscription_id="sub_test456",
        )
        payload_bytes = json.dumps(payload).encode()
        sig = sign_payload(payload_bytes)

        response = await client.post(
            WEBHOOK_PATH,
            data=payload_bytes,
            headers={SIG_HEADER: sig, "Content-Type": "application/json"},
        )
        assert response.status_code in (200, 204)

        sub = await get_subscription(test_user["id"])
        assert sub["status"] == "cancelled"


class TestWebhookSubscriptionPastDue:
    async def test_marks_subscription_past_due(self, client, db, test_user, create_subscription):
        await create_subscription(test_user["id"], status="active", provider_subscription_id="sub_test456")

        payload = make_webhook_payload(
            "subscription.past_due",
            subscription_id="sub_test456",
        )
        payload_bytes = json.dumps(payload).encode()
        sig = sign_payload(payload_bytes)

        response = await client.post(
            WEBHOOK_PATH,
            data=payload_bytes,
            headers={SIG_HEADER: sig, "Content-Type": "application/json"},
        )
        assert response.status_code in (200, 204)

        sub = await get_subscription(test_user["id"])
        assert sub["status"] == "past_due"


# ════════════════════════════════════════════════════════════
# Parameterized: event -> status transitions
# ════════════════════════════════════════════════════════════

@pytest.mark.parametrize("event_type,expected_status", [
    ("subscription.activated", "active"),
    ("subscription.updated", "active"),
    ("subscription.canceled", "cancelled"),
    ("subscription.past_due", "past_due"),
])
async def test_event_status_transitions(client, db, test_user, create_subscription, event_type, expected_status):
    if event_type != "subscription.activated":
        await create_subscription(test_user["id"], provider_subscription_id="sub_test456")

    payload = make_webhook_payload(event_type, user_id=str(test_user["id"]))
    payload_bytes = json.dumps(payload).encode()
    sig = sign_payload(payload_bytes)

    response = await client.post(
        WEBHOOK_PATH,
        data=payload_bytes,
        headers={SIG_HEADER: sig, "Content-Type": "application/json"},
    )
    assert response.status_code in (200, 204)

    sub = await get_subscription(test_user["id"])
    assert sub["status"] == expected_status


# ════════════════════════════════════════════════════════════
# Hypothesis: fuzz webhook payloads
# ════════════════════════════════════════════════════════════

fuzz_event_type = st.sampled_from([
    "subscription.activated",
    "subscription.updated",
    "subscription.canceled",
    "subscription.past_due",
])
fuzz_status = st.sampled_from(["active", "paused", "past_due", "canceled"])


@st.composite
def fuzz_payload(draw):
    event_type = draw(fuzz_event_type)
    return make_webhook_payload(
        event_type=event_type,
        subscription_id=f"sub_{draw(st.integers(min_value=100, max_value=999999))}",
        user_id=str(draw(st.integers(min_value=1, max_value=999999))),
        status=draw(fuzz_status),
    )


class TestWebhookHypothesis:
    @given(payload_dict=fuzz_payload())
    @h_settings(max_examples=50, deadline=5000, suppress_health_check=[HealthCheck.function_scoped_fixture])
    async def test_webhook_never_500s(self, client, db, test_user, payload_dict):
        # Pin user_id to the test user so subscription_created/activated events don't hit FK violations
        payload_dict["data"]["custom_data"]["user_id"] = str(test_user["id"])
        payload_bytes = json.dumps(payload_dict).encode()
        sig = sign_payload(payload_bytes)

        response = await client.post(
            WEBHOOK_PATH,
            data=payload_bytes,
            headers={SIG_HEADER: sig, "Content-Type": "application/json"},
        )
        assert response.status_code < 500