from deltax_forge_cross.core.delta_sync import DeltaCRDT, DeltaAction, deterministic_merge, merge_snapshots


def test_gen_and_snapshot_merge():
    a = DeltaCRDT("VENUE_A")
    b = DeltaCRDT("VENUE_B")

    act_a = a.gen_action(asset="AAPL", delta=5.0)
    act_b = b.gen_action(asset="AAPL", delta=3.0)

    # Local snapshots
    snap_a = a.snapshot()
    snap_b = b.snapshot()

    merged = merge_snapshots([snap_a, snap_b])
    assert "AAPL" in merged
    # Conservative policy selects smaller absolute delta (3.0)
    assert merged["AAPL"].delta == 3.0
    # Merged version should include both counters
    assert "VENUE_A" in merged["AAPL"].version and "VENUE_B" in merged["AAPL"].version


def test_deterministic_merge_tie_break():
    # Two equal magnitude deltas: tie breaks by venue id lexicographically
    a1 = DeltaAction(venue="B", asset="MSFT", delta=2.0, version={"B": 1})
    a2 = DeltaAction(venue="A", asset="MSFT", delta=2.0, version={"A": 1})
    merged = deterministic_merge([a1, a2])
    assert merged is not None
    # tie-break picks venue 'A' because ('abs', 'venue') sorts to ('2.0','A') first
    assert merged.venue == "A"
    assert merged.delta == 2.0