"""mckicad selects freeroute's best *available* engine, not its grid default.

freeroute's CLI exits 2 on an unsupported (engine, flag) combination rather than
ignoring it, and older freeroute builds don't advertise the flags at all — so the
command has to be built from both the CLI's probed capabilities and the engine's
own option matrix.
"""

from __future__ import annotations

from unittest.mock import MagicMock, patch

from mckicad.utils.freerouting import FreeRoutingEngine

ALL_FLAGS = {"--engine", "--pack", "--shove", "--diagonal"}


def _run_capturing(captured):
    def _run(cmd, **_kwargs):
        captured.append(cmd)
        out = cmd[cmd.index("-do") + 1]
        with open(out, "w") as f:
            f.write("(session board)")
        return MagicMock(returncode=0, stdout="", stderr="")

    return _run


def _route(tmp_path, supported, config=None):
    engine = FreeRoutingEngine()
    dsn = tmp_path / "board.dsn"
    dsn.write_text("(pcb)")
    captured: list[list[str]] = []
    with (
        patch("mckicad.utils.freerouting.freeroute_supported_flags", return_value=supported),
        patch("mckicad.utils.freerouting.subprocess.run", side_effect=_run_capturing(captured)),
    ):
        ok, ses = engine._run_freeroute_cli(
            "/usr/bin/freeroute", str(dsn), str(tmp_path), config
        )
    assert ok and ses
    return captured[0]


def test_defaults_to_room_engine_with_packing(tmp_path):
    cmd = _route(tmp_path, ALL_FLAGS)
    assert "--engine" in cmd and cmd[cmd.index("--engine") + 1] == "room"
    assert "--pack" in cmd
    # 45-degree routing is an exact-track feature; sending it with room would
    # make freeroute exit 2.
    assert "--diagonal" not in cmd


def test_older_freeroute_gets_the_bare_invocation(tmp_path):
    cmd = _route(tmp_path, set())  # a build that advertises no optional flags
    assert "--engine" not in cmd
    assert "--pack" not in cmd
    assert cmd[1] == "-de"  # still the plain JAR-compatible drop-in call


def test_incompatible_flag_is_skipped_not_sent(tmp_path):
    cmd = _route(
        tmp_path,
        ALL_FLAGS,
        {"freeroute_engine": "room", "freeroute_diagonal": True},
    )
    assert "--diagonal" not in cmd  # room does not implement it


def test_exact_engine_can_use_diagonal(tmp_path):
    cmd = _route(
        tmp_path,
        ALL_FLAGS,
        {
            "freeroute_engine": "exact",
            "freeroute_pack": False,
            "freeroute_diagonal": True,
        },
    )
    assert cmd[cmd.index("--engine") + 1] == "exact"
    assert "--diagonal" in cmd
    assert "--pack" not in cmd  # exact does not implement packing