"""Regression tests for the ChromaDB singleton client (issue #326).

Covers the fast-fail preflight (so an unreachable ChromaDB doesn't block
startup for the full OS connection timeout) and the rule that a failed
connection must not poison the cached singleton.
"""
import socket
import time

import pytest

import src.chroma_client as cc


@pytest.fixture
def closed_port():
    """Reserve a port without listening, so another worker cannot take it."""
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as reserved:
        reserved.bind(("127.0.0.1", 0))
        yield reserved.getsockname()[1]


def test_port_open_false_for_closed_port_and_is_fast(closed_port):
    t0 = time.monotonic()
    assert cc._port_open("127.0.0.1", closed_port, timeout=1.0) is False
    # The whole point: we fail fast, nowhere near the 30-60s OS timeout.
    assert time.monotonic() - t0 < 5.0


def test_port_open_true_for_listening_socket():
    srv = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    srv.bind(("127.0.0.1", 0))
    srv.listen(1)
    host, port = srv.getsockname()
    try:
        assert cc._port_open(host, port, timeout=1.0) is True
    finally:
        srv.close()


def test_get_chroma_client_does_not_cache_when_unreachable(monkeypatch, closed_port):
    pytest.importorskip("chromadb")
    cc.reset_client()
    monkeypatch.setenv("CHROMADB_HOST", "127.0.0.1")
    monkeypatch.setenv("CHROMADB_PORT", str(closed_port))
    with pytest.raises(RuntimeError):
        cc.get_chroma_client()
    # A failed connection must leave the singleton unset so a later call
    # (once ChromaDB is up) can succeed.
    assert cc._client is None