from __future__ import annotations

import json

from headroom.ccr import mcp_server


def test_shared_stats_work_without_fcntl(monkeypatch, tmp_path) -> None:
    monkeypatch.setattr(mcp_server, "_HAS_FCNTL", False)
    monkeypatch.setattr(mcp_server, "fcntl", None)
    monkeypatch.setattr(mcp_server, "SHARED_STATS_DIR", tmp_path)
    monkeypatch.setattr(mcp_server, "SHARED_STATS_FILE", tmp_path / "session_stats.jsonl")
    monkeypatch.setattr(mcp_server.os, "getpid", lambda: 4242)
    monkeypatch.setattr(mcp_server.time, "time", lambda: 1001.0)

    event = {"type": "compress", "timestamp": 1000.0}
    mcp_server._append_shared_event(event)

    raw_lines = mcp_server.SHARED_STATS_FILE.read_text(encoding="utf-8").splitlines()
    assert len(raw_lines) == 1
    assert json.loads(raw_lines[0]) == {"type": "compress", "timestamp": 1000.0, "pid": 4242}

    events = mcp_server._read_shared_events(window_seconds=60)
    assert events == [{"type": "compress", "timestamp": 1000.0, "pid": 4242}]