"""The router prefers the native freeroute CLI and falls back to the JAR."""

from __future__ import annotations

import os
from unittest.mock import MagicMock, patch

import pytest

from mckicad.utils.freerouting import FreeRoutingEngine, FreeRoutingError


def _jar_run_writes_ses(cmd, **_kwargs):
    """Simulate the FreeRouting JAR: write a .ses into the -do output directory."""
    outdir = cmd[cmd.index("-do") + 1]
    with open(os.path.join(outdir, "board.ses"), "w") as f:
        f.write("(session board)")
    return MagicMock(returncode=0, stdout="", stderr="")


def test_prefers_freeroute_when_available(tmp_path):
    eng = FreeRoutingEngine(freerouting_jar_path="/fake/freerouting.jar")
    with (
        patch("mckicad.utils.freerouting.find_freeroute_cli", return_value="/usr/bin/freeroute"),
        patch.object(eng, "_run_freeroute_cli", return_value=(True, "/out/board.ses")) as fr,
        patch("mckicad.utils.freerouting.subprocess.run") as jar_run,
    ):
        ok, ses = eng.run_freerouting("/tmp/board.dsn", "/out")

    assert ok and ses == "/out/board.ses"
    fr.assert_called_once()
    jar_run.assert_not_called()  # the JAR is never invoked when freeroute succeeds


def test_falls_back_to_jar_when_freeroute_fails(tmp_path):
    jar = tmp_path / "freerouting.jar"
    jar.write_text("x")
    eng = FreeRoutingEngine(freerouting_jar_path=str(jar))
    with (
        patch("mckicad.utils.freerouting.find_freeroute_cli", return_value="/usr/bin/freeroute"),
        patch.object(eng, "_run_freeroute_cli", return_value=(False, None)),
        patch("mckicad.utils.freerouting.subprocess.run", side_effect=_jar_run_writes_ses),
    ):
        ok, ses = eng.run_freerouting("/tmp/board.dsn", str(tmp_path))

    assert ok and ses.endswith("board.ses")


def test_uses_jar_when_freeroute_absent(tmp_path):
    jar = tmp_path / "freerouting.jar"
    jar.write_text("x")
    eng = FreeRoutingEngine(freerouting_jar_path=str(jar))
    with (
        patch("mckicad.utils.freerouting.find_freeroute_cli", return_value=None),
        patch("mckicad.utils.freerouting.subprocess.run", side_effect=_jar_run_writes_ses),
    ):
        ok, ses = eng.run_freerouting("/tmp/board.dsn", str(tmp_path))

    assert ok


def test_raises_when_no_router_available(tmp_path):
    eng = FreeRoutingEngine()
    with (
        patch("mckicad.utils.freerouting.find_freeroute_cli", return_value=None),
        patch.object(eng, "find_freerouting_jar", return_value=None),
        pytest.raises(FreeRoutingError),
    ):
        eng.run_freerouting("/tmp/board.dsn", str(tmp_path))