"""Tests for the prune_stale_peers use case."""

from neotalk.core.entities.peer import Peer
from neotalk.core.use_cases.roster.prune_stale_peers import (
    prune_stale_peers_use_case,
)


def _peer(peer_id: str, last_seen: float) -> Peer:
    return Peer(peer_id, peer_id, "host", 1, b"k", last_seen)


def test_prune_keeps_recent_peers_and_drops_old_ones():
    # Given a roster with one fresh and one stale peer
    roster = {"fresh": _peer("fresh", 95.0), "stale": _peer("stale", 80.0)}

    # When pruning at t=100 with a 10s timeout
    response = prune_stale_peers_use_case(roster, now=100.0, timeout=10.0)

    # Then only the fresh peer survives
    assert set(response["data"]["roster"]) == {"fresh"}
    assert response["data"]["removed"] == ["stale"]


def test_prune_keeps_a_peer_exactly_on_the_boundary():
    # Given a peer seen exactly timeout seconds ago
    roster = {"edge": _peer("edge", 90.0)}

    # When pruning at the boundary
    response = prune_stale_peers_use_case(roster, now=100.0, timeout=10.0)

    # Then it is kept
    assert set(response["data"]["roster"]) == {"edge"}


def test_prune_on_empty_roster_returns_empty():
    # Given no peers
    # When pruning
    response = prune_stale_peers_use_case({}, now=1.0, timeout=1.0)

    # Then nothing is removed
    assert response["data"]["roster"] == {}
    assert response["data"]["removed"] == []