"""Integration tests for API endpoints."""

from importlib import metadata
from typing import cast
from unittest.mock import AsyncMock

import pytest
from fastapi.testclient import TestClient
from sqlalchemy.exc import SQLAlchemyError
from sqlalchemy.ext.asyncio import AsyncSession

from backend.main import app, compatibility_status, get_api_session

client = TestClient(app)


class TestAPIIntegration:
    """Integration tests for API endpoints."""

    def test_health_check(self) -> None:
        """Test API health check endpoint."""
        healthy_session = cast("AsyncSession", AsyncMock(spec=AsyncSession))
        healthy_session.execute = AsyncMock(return_value=1)

        async def override_get_session():
            """Provide a healthy session dependency override for tests."""
            yield healthy_session

        app.dependency_overrides[get_api_session] = override_get_session
        try:
            with TestClient(app) as local_client:
                response = local_client.get("/health")

            assert response.status_code == 200
            assert response.json() == {"status": "healthy", "database": "connected"}
        finally:
            app.dependency_overrides.clear()

    def test_health_check_db_unavailable(self) -> None:
        """Health endpoint should return unavailable when DB probe fails."""
        unhealthy_session = cast("AsyncSession", AsyncMock(spec=AsyncSession))
        unhealthy_session.execute = AsyncMock(
            side_effect=SQLAlchemyError("database unavailable")
        )

        async def override_get_session():
            """Provide an unhealthy session dependency override for tests."""
            yield unhealthy_session

        app.dependency_overrides[get_api_session] = override_get_session
        try:
            with TestClient(app) as local_client:
                response = local_client.get("/health")

            assert response.status_code == 503
            assert response.json() == {
                "status": "unhealthy",
                "database": "disconnected",
            }
        finally:
            app.dependency_overrides.clear()

    def test_root_endpoint(self) -> None:
        """Test root endpoint."""
        response = client.get("/")
        assert response.status_code == 200
        assert response.json() == {"message": "Plex Playlist Backend API"}

    def test_startup_rejects_invalid_runtime_policy(
        self, monkeypatch: pytest.MonkeyPatch
    ) -> None:
        """Startup should fail fast when compatibility policy is invalid."""
        monkeypatch.setenv("BACKEND_REQUIRED_PYTHON", "99.0")

        with pytest.raises(RuntimeError), TestClient(app):
            pass

        monkeypatch.delenv("BACKEND_REQUIRED_PYTHON", raising=False)

    def test_compatibility_endpoint_reports_policy_status(
        self, monkeypatch: pytest.MonkeyPatch
    ) -> None:
        """Compatibility endpoint should expose runtime and pinning policy status."""
        monkeypatch.setenv("BACKEND_REQUIRED_PYTHON", "3.14")

        with TestClient(app) as local_client:
            response = local_client.get("/compatibility")

        assert response.status_code == 200
        payload = response.json()
        assert payload["ok"] is True
        assert payload["required_python"] == "3.14"
        assert "current_python" in payload
        assert payload["python_policy_valid"] is True
        assert "required_packages" in payload
        assert payload["required_packages"]["fastapi"] == "0.120.2"
        assert payload["required_packages"]["uvicorn"] == "0.38.0"
        assert payload["package_errors"] == {}

        monkeypatch.delenv("BACKEND_REQUIRED_PYTHON", raising=False)

    def test_startup_rejects_malformed_required_python(
        self, monkeypatch: pytest.MonkeyPatch
    ) -> None:
        """Startup should fail fast when Python policy is not strict major.minor."""
        monkeypatch.setenv("BACKEND_REQUIRED_PYTHON", "3.14.1")

        with pytest.raises(RuntimeError), TestClient(app):
            pass

        monkeypatch.delenv("BACKEND_REQUIRED_PYTHON", raising=False)

    def test_compatibility_status_handles_missing_package_metadata(
        self, monkeypatch: pytest.MonkeyPatch
    ) -> None:
        """Compatibility checks should handle missing package metadata gracefully."""

        def raise_not_found(_: str) -> str:
            raise metadata.PackageNotFoundError("fake")

        monkeypatch.setattr("backend.main._installed_version", raise_not_found)
        status = compatibility_status()
        package_checks = status["package_checks"]
        package_errors = status["package_errors"]

        assert status["ok"] is False
        assert isinstance(package_checks, dict)
        assert isinstance(package_errors, dict)
        assert package_checks["fastapi"] is False
        assert package_checks["uvicorn"] is False
        assert "fastapi" in package_errors
        assert "uvicorn" in package_errors