"""Cursor pagination + request id + exception handler (API-STANDARD.md §4-§7)."""

import pytest
from django.http import HttpResponse
from django.test import RequestFactory
from rest_framework.exceptions import ValidationError

from infrasynth.api.exceptions import envelope_exception_handler
from infrasynth.api.middleware import RequestIdMiddleware
from infrasynth.api.pagination import CursorPagination
from infrasynth.shared.exceptions import EntitlementError


class TestCursorPagination:
    def test_configuration(self):
        pagination = CursorPagination()
        assert pagination.page_size == 25
        assert pagination.max_page_size == 100
        assert pagination.page_size_query_param == "pageSize"
        assert pagination.ordering == "-pk"

    def test_response_shape(self):
        # get_paginated_response depends on cursor state set during pagination;
        # the envelope renderer test covers the wire shape end-to-end.
        pagination = CursorPagination()
        assert callable(pagination.get_paginated_response)


class TestRequestIdMiddleware:
    def test_generates_request_id(self):
        request = RequestFactory().get("/")
        response = RequestIdMiddleware(lambda r: HttpResponse("ok"))(request)
        assert response["X-Request-Id"] == request.request_id
        assert request.request_id.startswith("req_")

    def test_echoes_supplied_request_id(self):
        request = RequestFactory().get("/", HTTP_X_REQUEST_ID="req_abc")
        response = RequestIdMiddleware(lambda r: HttpResponse("ok"))(request)
        assert response["X-Request-Id"] == "req_abc"
        assert request.request_id == "req_abc"


class TestEnvelopeExceptionHandler:
    def test_app_error_maps_to_code_and_status(self):
        response = envelope_exception_handler(
            EntitlementError(code="ENTITLEMENT_PLAN_UPGRADE_REQUIRED", app="helpdesk", feature="tickets"),
            {},
        )
        assert response.status_code == 402
        assert response.data["code"] == "ENTITLEMENT_PLAN_UPGRADE_REQUIRED"
        assert response.data["details"][0]["app"] == "helpdesk"
        assert response.data["details"][0]["feature"] == "tickets"

    def test_drf_validation_error_flattens_details(self):
        response = envelope_exception_handler(ValidationError({"name": ["required"]}), {})
        assert response.status_code == 400
        assert response.data["code"] == "VALIDATION_ERROR"
        assert response.data["details"] == [{"field": "name", "issue": "required"}]

    def test_unexpected_exception_is_not_masked(self):
        assert envelope_exception_handler(RuntimeError("boom"), {}) is None


@pytest.mark.django_db
class TestIdempotency:
    def test_replays_first_successful_response(self):
        from django.core.cache import cache
        from rest_framework.response import Response

        from infrasynth.api.idempotency import idempotent

        cache.clear()

        class _View:
            def __init__(self):
                self.calls = 0

            @idempotent
            def post(self, request):
                self.calls += 1
                return Response({"n": self.calls})

        class _Request:
            method = "POST"
            path = "/api/v1/billing/checkout/"
            headers = {"Idempotency-Key": "key-1"}

        view = _View()
        first = view.post(_Request())
        second = view.post(_Request())
        assert first.data == {"n": 1}
        assert second.data == {"n": 1}
        assert second["Idempotent-Replay"] == "true"
        assert view.calls == 1