"""Thread assembly (server/threads.py) — pure, stub-safe."""
from server.threads import format_thread, rolling_thread


def test_format_thread_skips_empty():
    msgs = [
        {"sender": "Alex", "text": "dinner 7pm?"},
        {"sender": "Me", "text": ""},
        {"sender": "Me", "text": "works"},
    ]
    assert format_thread(msgs) == "Alex: dinner 7pm?\nMe: works"


def test_rolling_thread_filters_by_chat():
    feed = [
        {"chat": "Mom", "sender": "Mom", "text": "a", "timestamp": "2026-06-05T10:00:00"},
        {"chat": "Work", "sender": "Boss", "text": "b", "timestamp": "2026-06-05T10:01:00"},
        {"chat": "Mom", "sender": "Mom", "text": "c", "timestamp": "2026-06-05T10:02:00"},
    ]
    out = rolling_thread(feed, "Mom")
    assert "a" in out and "c" in out and "b" not in out


def test_rolling_thread_window_limit():
    feed = [
        {"chat": "Mom", "sender": "Mom", "text": str(i), "timestamp": f"2026-06-05T10:{i:02d}:00"}
        for i in range(10)
    ]
    out = rolling_thread(feed, "Mom", window=3)
    assert out.splitlines() == ["Mom: 7", "Mom: 8", "Mom: 9"]


def test_rolling_thread_drops_old_messages():
    feed = [
        {"chat": "Mom", "sender": "Mom", "text": "old", "timestamp": "2026-06-05T00:00:00"},
        {"chat": "Mom", "sender": "Mom", "text": "new", "timestamp": "2026-06-05T23:00:00"},
    ]
    out = rolling_thread(feed, "Mom", minutes=60)
    assert "new" in out and "old" not in out


def test_rolling_thread_empty_for_unknown_chat():
    assert rolling_thread([], "Nobody") == ""