"""Shared pytest fixtures for the kernbench test suite.

Session-scoped topology caching: ``resolve_topology("topology.yaml")`` is
pure (no side effects), so we cache the result across all tests in a
worker process. Each test still builds its own ``GraphEngine`` (which is
stateful/SimPy-event-consuming and MUST NOT be shared).
"""
from __future__ import annotations

import os

import pytest

from kernbench.topology.builder import resolve_topology


def pytest_sessionfinish(session, exitstatus):
    """Aggregate parametrized sweep rows into combined CSV + PNG plots.

    Runs on the controller node only (xdist worker processes set
    ``PYTEST_XDIST_WORKER``; we skip those). Idempotent — does nothing
    if no sweep rows are present (e.g., when the sweep was filtered out).
    """
    if os.environ.get("PYTEST_XDIST_WORKER"):
        return
    import importlib.util
    import sys
    from pathlib import Path

    mod_path = Path(__file__).parent / "test_allreduce_multidevice.py"
    if not mod_path.exists():
        return
    spec = importlib.util.spec_from_file_location(
        "_test_allreduce_multidevice_for_aggregate", mod_path,
    )
    if spec is None or spec.loader is None:
        return
    mod = importlib.util.module_from_spec(spec)
    sys.modules[spec.name] = mod
    try:
        spec.loader.exec_module(mod)
        agg = getattr(mod, "_aggregate_sweep_plots", None)
        if agg is not None:
            agg()
    except Exception as e:
        print(f"[conftest] sweep aggregation failed: {e}")


@pytest.fixture(scope="session")
def topology():
    """Session-scoped parsed topology (immutable graph + spec).

    Usage in tests::

        def test_foo(topology):
            engine = GraphEngine(topology.topology_obj, enable_data=True)
    """
    return resolve_topology("topology.yaml")


@pytest.fixture(scope="session")
def topology_obj(topology):
    """The TopologyGraph inside the handle (convenience shortcut)."""
    return topology.topology_obj


@pytest.fixture(scope="session")
def spec(topology):
    """Topology spec dict (convenience shortcut)."""
    return topology.topology_obj.spec