"""--rollback: a rip-up that loses connections is undone, leaving no trace."""

from __future__ import annotations

from pathlib import Path

import pytest

from rpmroute.board import build_board
from rpmroute.dsn import parse_dsn
from rpmroute.route.grid_router import GridRouter
from rpmroute.route.pipeline import _rule_clearance_dsn, _rule_width_dsn, route_dsn_board

FIXTURES = Path(__file__).resolve().parent.parent / "dsn" / "fixtures"


def _routed_router(name):
    dsn = parse_dsn((FIXTURES / name).read_text())
    s = dsn.resolution.value
    router = GridRouter(
        build_board(dsn),
        trace_width=round(_rule_width_dsn(dsn) * s),
        clearance=round(_rule_clearance_dsn(dsn) * s),
        rollback=True,
    )
    return router, router.route()


@pytest.mark.parametrize("name", ["ripup_needed.dsn", "true_density.dsn", "kicad_routable.dsn"])
def test_occupancy_only_holds_routed_connections(name):
    router, _ = _routed_router(name)
    conns = router._conns
    assert all(conns[i].routed for i in router._cell_owner.values())
    assert all(conns[i].routed for claims in router._via_claims.values() for i in claims)
    assert all(conns[i].routed for claims in router._halo.values() for i in claims)


@pytest.mark.parametrize("name", ["ripup_needed.dsn", "true_density.dsn", "kicad_routable.dsn"])
def test_rollback_never_routes_fewer_than_plain_rip_up(name):
    text = (FIXTURES / name).read_text()
    plain, _, _ = route_dsn_board(parse_dsn(text), rollback=False)
    undo, _, _ = route_dsn_board(parse_dsn(text))
    assert undo.unrouted <= plain.unrouted