import time

from nova_plan.contracts import PlanDelta, crdt_merge_deltas


def test_crdt_merge_deltas_basic():
    # Create two independent deltas with overlapping keys
    d1 = PlanDelta(
        agent_id="agent-A",
        delta={"task1": 1.0, "task2": 2.0},
        timestamp=time.time(),
        parent_version=1,
        sequence=1,
        contract_id="c1",
        signature=None,
    )

    time.sleep(0.001)
    d2 = PlanDelta(
        agent_id="agent-B",
        delta={"task3": 3.0, "task2": 2.5},  # note overlapping key 'task2'
        timestamp=time.time(),
        parent_version=2,
        sequence=2,
        contract_id="c2",
        signature=None,
    )

    merged = crdt_merge_deltas(d1, d2)

    # merged should contain the union of keys; task2 should come from d2 due to last-writer-wins style
    assert merged.delta["task1"] == 1.0
    assert merged.delta["task3"] == 3.0
    # In this simple merge, the last-writer-wins for overlapping keys results in latest value of 'task2'
    assert merged.delta["task2"] == 2.5
    # timestamp should be the max of both
    assert merged.timestamp >= d1.timestamp and merged.timestamp >= d2.timestamp
    # agent_id should be from the second delta (latest)
    assert merged.agent_id == d2.agent_id