"""Tests for the freeroute CLI (Specctra DSN in, SES out).

Covers the engine selection contract: every engine must route a fixture from the
command line, and every option the selected engine does not implement must fail
loudly rather than being silently dropped.
"""

from __future__ import annotations

from pathlib import Path

import pytest

from freeroute.cli import ENGINE_OPTIONS, main

FIXTURES = Path(__file__).parent / "dsn" / "fixtures"
FIXTURE = FIXTURES / "simple_2net.dsn"
CHANNEL_PACK = FIXTURES / "channel_pack.dsn"
SHOVE_NEEDED = FIXTURES / "shove_needed.dsn"
DIAGONAL_WIN = FIXTURES / "diagonal_win.dsn"


def test_cli_jar_compatible_flags_write_ses(tmp_path):
    out = tmp_path / "out.ses"
    rc = main(["-de", str(FIXTURE), "-do", str(out)])
    assert rc == 0
    text = out.read_text()
    assert text.startswith("(session")
    assert "(net" in text and "(wire" in text


def test_cli_positional_input_to_stdout(capsys):
    rc = main([str(FIXTURE)])
    assert rc == 0
    assert "(session" in capsys.readouterr().out


def test_cli_missing_input_errors():
    with pytest.raises(SystemExit):
        main([])


def test_cli_unreadable_input_returns_2(capsys):
    rc = main(["/nonexistent/board.dsn"])
    assert rc == 2
    assert "cannot read" in capsys.readouterr().err


def test_cli_bad_layers_errors(capsys):
    with pytest.raises(SystemExit):
        main([str(FIXTURE), "--layers", "top,bottom"])
    assert "--layers must be comma-separated integers" in capsys.readouterr().err


# --- engine selection -------------------------------------------------------


@pytest.mark.parametrize("engine", sorted(ENGINE_OPTIONS))
def test_cli_every_engine_routes_a_fixture(engine, tmp_path):
    out = tmp_path / f"{engine}.ses"
    rc = main([str(FIXTURE), "--engine", engine, "-do", str(out)])
    assert rc == 0
    text = out.read_text()
    assert text.startswith("(session")
    assert "(wire" in text


def test_cli_default_engine_is_grid(tmp_path):
    """The default must stay grid — the drop-in JAR replacement behaviour."""
    default = tmp_path / "default.ses"
    grid = tmp_path / "grid.ses"
    assert main([str(FIXTURE), "-do", str(default)]) == 0
    assert main([str(FIXTURE), "--engine", "grid", "-do", str(grid)]) == 0
    assert default.read_text() == grid.read_text()


def test_cli_room_pack_routes(tmp_path):
    out = tmp_path / "pack.ses"
    rc = main([str(CHANNEL_PACK), "--engine", "room", "--pack", "-do", str(out)])
    assert rc == 0
    assert "(wire" in out.read_text()


def test_cli_room_shove_routes(tmp_path):
    out = tmp_path / "shove.ses"
    rc = main([str(SHOVE_NEEDED), "--engine", "room", "--shove", "-do", str(out)])
    assert rc == 0
    assert "(wire" in out.read_text()


def test_cli_exact_shove_routes(tmp_path):
    out = tmp_path / "shove.ses"
    rc = main([str(SHOVE_NEEDED), "--engine", "exact", "--shove", "-do", str(out)])
    assert rc == 0
    assert "(wire" in out.read_text()


def test_cli_exact_diagonal_routes(tmp_path):
    out = tmp_path / "diag.ses"
    rc = main([str(DIAGONAL_WIN), "--engine", "exact", "--diagonal", "-do", str(out)])
    assert rc == 0
    assert "(wire" in out.read_text()


def test_cli_max_passes_is_honoured_not_advisory(tmp_path):
    out = tmp_path / "mp.ses"
    rc = main([str(FIXTURE), "--engine", "exact", "-mp", "3", "-do", str(out)])
    assert rc == 0
    assert "(wire" in out.read_text()


# --- unsupported combinations must error, never be silently ignored ---------


@pytest.mark.parametrize(
    ("argv", "flag"),
    [
        (["--engine", "grid", "--pack"], "--pack"),
        (["--engine", "grid", "--shove"], "--shove"),
        (["--engine", "grid", "--diagonal"], "--diagonal"),
        (["--engine", "exact", "--pack"], "--pack"),
        (["--engine", "room", "--diagonal"], "--diagonal"),
        (["--engine", "room", "--no-rip-up"], "--no-rip-up"),
        (["--engine", "room", "-mp", "5"], "-mp/--max-passes"),
    ],
)
def test_cli_unsupported_option_errors(argv, flag, capsys):
    with pytest.raises(SystemExit) as excinfo:
        main([str(FIXTURE), *argv])
    assert excinfo.value.code == 2
    err = capsys.readouterr().err
    assert flag in err
    assert "not supported by --engine" in err
    assert "supported by:" in err


def test_cli_unknown_engine_errors(capsys):
    with pytest.raises(SystemExit):
        main([str(FIXTURE), "--engine", "quantum"])
    assert "invalid choice" in capsys.readouterr().err


def test_cli_supported_combinations_are_accepted(tmp_path):
    """Every (engine, flag) pair the matrix claims to support must actually run."""
    argv_for = {
        "pack": ["--pack"],
        "shove": ["--shove"],
        "diagonal": ["--diagonal"],
        "rip_up": ["--no-rip-up"],
        "max_passes": ["-mp", "4"],
    }
    for engine, options in ENGINE_OPTIONS.items():
        for option in options:
            out = tmp_path / f"{engine}-{option}.ses"
            rc = main([str(FIXTURE), "--engine", engine, *argv_for[option], "-do", str(out)])
            assert rc == 0, f"{engine} + {option} failed"
            assert out.read_text().startswith("(session")