"""OpenTelemetry wiring tests.

The actual OpenTelemetry packages are an optional extra (``kca-app[otel]``),
so the kaya-otel mixin is stubbed here. Provider-dependent tests live in
``test_telemetry.py``.
"""
from __future__ import annotations

import os
import sys
import types
import unittest
from unittest.mock import patch

from kca.app import otel_mixin_from_settings
from kca.config import Settings
from kca.telemetry import session_tag_hook


def _settings(env: dict) -> Settings:
    with patch.dict(os.environ, env, clear=True):
        return Settings.from_env()


class _StubOTelMixin:
    def __init__(self, **kwargs):
        self.kwargs = kwargs


def _stub_kaya_otel():
    module = types.ModuleType("kaya.otel")
    module.OTelMixin = _StubOTelMixin  # type: ignore[attr-defined]
    return patch.dict(sys.modules, {"kaya.otel": module})


class OTelMixinFromSettingsTests(unittest.TestCase):
    def test_disabled_by_default(self):
        self.assertIsNone(otel_mixin_from_settings(_settings({})))

    def test_enabled_by_otel_enabled(self):
        with _stub_kaya_otel():
            mixin = otel_mixin_from_settings(_settings({"OTEL_ENABLED": "1"}))
        self.assertIsNotNone(mixin)

    def test_settings_are_passed_through(self):
        with _stub_kaya_otel():
            mixin = otel_mixin_from_settings(
                _settings(
                    {
                        "OTEL_ENABLED": "true",
                        "OTEL_SERVICE_NAME": "kca-test",
                        "OTEL_EXPORTER_OTLP_ENDPOINT": "http://collector:4318",
                        "OTEL_EXPORTER_OTLP_HEADERS": "Authorization=Bearer t, X-Tenant=one",
                        "OTEL_METRIC_EXPORT_INTERVAL_MILLIS": "15000",
                    }
                )
            )
        assert isinstance(mixin, _StubOTelMixin)
        self.assertEqual("kca-test", mixin.kwargs["service_name"])
        self.assertEqual("http://collector:4318", mixin.kwargs["endpoint"])
        self.assertEqual(
            {"Authorization": "Bearer t", "X-Tenant": "one"},
            mixin.kwargs["headers"],
        )
        self.assertEqual(("/api/health",), mixin.kwargs["excluded_paths"])
        self.assertEqual(15000, mixin.kwargs["metric_export_interval_millis"])
        self.assertIs(session_tag_hook, mixin.kwargs["server_response_hook"])
        self.assertIs(session_tag_hook, mixin.kwargs["websocket_close_hook"])

    def test_defaults_when_only_enabled(self):
        with _stub_kaya_otel():
            mixin = otel_mixin_from_settings(_settings({"OTEL_ENABLED": "on"}))
        assert isinstance(mixin, _StubOTelMixin)
        self.assertEqual("kca", mixin.kwargs["service_name"])
        self.assertIsNone(mixin.kwargs["endpoint"])
        self.assertIsNone(mixin.kwargs["headers"])
        self.assertEqual(("/api/health",), mixin.kwargs["excluded_paths"])

    def test_providers_are_passed_through(self):
        with _stub_kaya_otel():
            meter = object()
            tracer = object()
            mixin = otel_mixin_from_settings(
                _settings({"OTEL_ENABLED": "1"}),
                meter_provider=meter,
                tracer_provider=tracer,
            )
        assert isinstance(mixin, _StubOTelMixin)
        self.assertIs(meter, mixin.kwargs["meter_provider"])
        self.assertIs(tracer, mixin.kwargs["tracer_provider"])

    def test_excluded_paths_are_passed_through(self):
        with _stub_kaya_otel():
            mixin = otel_mixin_from_settings(
                _settings(
                    {
                        "OTEL_ENABLED": "1",
                        "OTEL_EXCLUDED_PATHS": "/api/health,/api/docs",
                    }
                )
            )
        assert isinstance(mixin, _StubOTelMixin)
        self.assertEqual(("/api/health", "/api/docs"), mixin.kwargs["excluded_paths"])

    def test_missing_extra_raises_runtime_error(self):
        with patch.dict(sys.modules, {"kaya.otel": None}):
            with self.assertRaises(RuntimeError):
                otel_mixin_from_settings(_settings({"OTEL_ENABLED": "1"}))


if __name__ == "__main__":
    unittest.main()