# std imports
import sys
import types
import asyncio

# 3rd party
import pytest

# local
from telnetlib3 import slc as slc_mod
from telnetlib3 import client_shell as cs
from telnetlib3 import guard_shells as gs
from telnetlib3 import server_shell as ss
from telnetlib3._session_context import TelnetSessionContext


class DummyWriter:
    is_binary_writer = False

    def __init__(self, slctab=None):
        self.echos = []
        self.slctab = slctab or slc_mod.generate_slctab()
        self.local_option = types.SimpleNamespace(enabled=lambda opt: False)
        self.outbinary = False
        self.inbinary = False
        self.xon_any = False
        self.lflow = True

    def echo(self, data):
        self.echos.append(data)


def _run_readline(sequence, max_visible_width=0):
    w = DummyWriter()
    gen = ss.readline(None, w, max_visible_width=max_visible_width)
    gen.send(None)
    cmds = []
    for ch in sequence:
        out = gen.send(ch)
        if out is not None:
            cmds.append(out)
    return cmds, w.echos


class MockReader:
    is_binary_reader = False

    def __init__(self, data):
        self._data = list(data)
        self._idx = 0

    async def read(self, n):
        if self._idx >= len(self._data):
            return ""
        result = self._data[self._idx]
        self._idx += 1
        return result


class SlowReader:
    is_binary_reader = False

    async def read(self, n):
        await asyncio.sleep(1.0)
        return ""


class _MockProtocol:
    def __init__(self, never_send_ga=False):
        self.never_send_ga = never_send_ga


class MockWriter:
    is_binary_writer = False

    def __init__(self, protocol=None):
        self.written = []
        self._closing = False
        self._extra = {"peername": ("127.0.0.1", 12345)}
        self.protocol = protocol or _MockProtocol()
        self.ga_calls = []

    def write(self, data):
        self.written.append(data)

    async def drain(self):
        pass

    def get_extra_info(self, key, default=None):
        return self._extra.get(key, default)

    def is_closing(self):
        return self._closing

    def echo(self, data):
        self.written.append(data)

    def close(self):
        self._closing = True

    def send_ga(self):
        self.ga_calls.append(True)
        return True


@pytest.mark.parametrize(
    "input_data, expected_cmds, check_echos",
    [
        ("foo\r", ["foo"], lambda e: "".join(e).endswith("foo")),
        ("bar\r\n", ["bar"], None),
        ("baz\n", ["baz"], None),
        ("zip\r\x00zap\r\n", ["zip", "zap"], None),
        ("\bhel\blp\r", ["help"], lambda e: "\b \b" in "".join(e)),
    ],
    ids=["cr", "crlf", "lf", "crnul_multi", "backspace"],
)
def test_readline_basic(input_data, expected_cmds, check_echos):
    cmds, echos = _run_readline(input_data)
    assert cmds == expected_cmds
    if check_echos is not None:
        assert check_echos(echos)


def test_character_dump_yields_patterns_and_summary():
    it = ss.character_dump(1)
    assert next(it).startswith("/" * 80)
    assert next(it).startswith("\\" * 80)
    assert list(ss.character_dump(0))[-1].endswith("wrote 0 bytes")


def test_get_slcdata_contains_expected_sections():
    out = ss.get_slcdata(DummyWriter(slctab=slc_mod.generate_slctab()))
    assert "Special Line Characters:" in out
    assert "SLC_EC" in out
    assert "Unset by client:" in out and "SLC_BRK" in out
    assert "Not supported by server:" in out


@pytest.mark.asyncio
@pytest.mark.skipif(sys.platform == "win32", reason="requires termios")
async def test_terminal_determine_mode(monkeypatch):
    monkeypatch.setattr(sys, "stdin", types.SimpleNamespace(fileno=lambda: 0))
    _mock_opt = types.SimpleNamespace(enabled=lambda key: False)
    tw = types.SimpleNamespace(
        will_echo=False,
        client=True,
        remote_option=_mock_opt,
        local_option=_mock_opt,
        log=types.SimpleNamespace(debug=lambda *a, **k: None),
        ctx=TelnetSessionContext(),
    )
    term = cs.Terminal(tw)
    mode = cs.Terminal.ModeDef(0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 38400, 38400, [0] * 32)
    assert term.determine_mode(mode) is mode

    from telnetlib3.telopt import SGA

    tw.will_echo = True
    tw.remote_option = types.SimpleNamespace(enabled=lambda key: key == SGA)
    t = cs.termios
    cc = [0] * 32
    cc[t.VMIN] = 0
    cc[t.VTIME] = 1
    mode = cs.Terminal.ModeDef(
        t.BRKINT | t.ICRNL | t.INPCK | t.ISTRIP | t.IXON,
        t.OPOST | getattr(t, "ONLCR", 0),
        t.PARENB | getattr(t, "CS7", 0),
        t.ICANON | t.IEXTEN | t.ISIG | t.ECHO,
        38400,
        38400,
        list(cc),
    )
    new = term.determine_mode(mode)
    for flag in (t.BRKINT, t.ICRNL, t.INPCK, t.ISTRIP, t.IXON):
        assert not new.iflag & flag
    assert not new.oflag & t.OPOST
    assert not new.cflag & t.PARENB
    assert new.cflag & t.CS8
    for flag in (t.ICANON, t.IEXTEN, t.ISIG, t.ECHO):
        assert not new.lflag & flag
    assert new.cc[t.VMIN] == 1
    assert new.cc[t.VTIME] == 0


@pytest.mark.parametrize(
    "limit,acquires,expected_count,expected_results",
    [
        pytest.param(1, 1, 1, [True], id="single_acquire"),
        pytest.param(1, 2, 1, [True, False], id="over_limit"),
        pytest.param(3, 3, 3, [True, True, True], id="at_limit"),
        pytest.param(2, 3, 2, [True, True, False], id="over_limit_by_one"),
    ],
)
def test_connection_counter_acquire(limit, acquires, expected_count, expected_results):
    counter = gs.ConnectionCounter(limit)
    results = [counter.try_acquire() for _ in range(acquires)]
    assert results == expected_results
    assert counter.count == expected_count


def test_connection_counter_release():
    counter = gs.ConnectionCounter(2)
    assert counter.try_acquire()
    assert counter.try_acquire()
    assert counter.count == 2
    counter.release()
    assert counter.count == 1
    counter.release()
    counter.release()
    assert counter.count == 0


@pytest.mark.parametrize(
    "input_data,max_len,expected",
    [
        pytest.param("hi\r", 100, "hi", id="cr_terminator"),
        pytest.param("hi\n", 100, "hi", id="lf_terminator"),
        pytest.param("ab", 100, "ab", id="eof_no_terminator"),
        pytest.param("", 100, "", id="empty_input"),
        pytest.param("abcdefgh", 5, "abcde", id="truncated_at_max_len"),
    ],
)
@pytest.mark.asyncio
async def test_read_line_inner(input_data, max_len, expected):
    assert await gs._read_line_inner(MockReader(list(input_data)), max_len) == expected


@pytest.mark.asyncio
async def test_read_line_with_timeout():
    assert await gs._read_line(MockReader(list("hello\r")), timeout=5.0) == "hello"
    assert await gs._read_line(SlowReader(), timeout=0.01) is None


@pytest.mark.asyncio
async def test_robot_shell_full_conversation():
    writer = MockWriter()
    await gs.robot_shell(MockReader(["y", "\r", "n", "o", "\r"]), writer)
    written = "".join(writer.written)
    assert "Do robots dream of electric sheep?" in written
    assert "windowmakers" in written


@pytest.mark.asyncio
async def test_busy_shell_full_conversation():
    writer = MockWriter()
    await gs.busy_shell(MockReader(["h", "i", "\r", "x", "\r"]), writer)
    written = "".join(writer.written)
    assert "Machine is busy" in written
    assert "distant explosion" in written


@pytest.mark.parametrize(
    "input_chars,expected",
    [
        pytest.param(["\x1b", "[", "A", "x"], "x", id="csi_sequence"),
        pytest.param(["\x1b", "!", "x"], "!", id="esc_non_sequence"),
        pytest.param(["a"], "a", id="normal_char"),
        pytest.param([""], "", id="eof"),
        pytest.param(["\x1b", "[", "1", ";", "2", "H", "z"], "z", id="csi_with_params"),
        pytest.param(["\x1b", "[", ""], "", id="csi_no_final_byte"),
        pytest.param(["\x1b", "O", "P", "x"], "x", id="ss3_f1"),
        pytest.param(["\x1b", "O", "A", "y"], "y", id="ss3_arrow_up"),
        pytest.param(["\x1b", "O", "p", "z"], "z", id="ss3_kp0"),
        pytest.param(["\x1b", "O", ""], "", id="ss3_eof"),
    ],
)
@pytest.mark.asyncio
async def test_filter_ansi(input_chars, expected):
    assert await ss.filter_ansi(MockReader(input_chars), MockWriter()) == expected


@pytest.mark.parametrize(
    "input_chars,expected",
    [
        pytest.param(["h", "e", "l", "l", "o", "\r"], "hello", id="basic"),
        pytest.param(["h", "x", "\x7f", "i", "\r"], "hi", id="with_backspace"),
        pytest.param(["\n", "\x00", "a", "\r"], "a", id="ignores_initial_lf_nul"),
        pytest.param(["a", ""], None, id="returns_none_on_eof"),
        pytest.param(["\x7f", "a", "\r"], "a", id="backspace_on_empty"),
        pytest.param(["\b", "\b", "x", "\r"], "x", id="multiple_backspace_on_empty"),
    ],
)
@pytest.mark.asyncio
async def test_readline2(input_chars, expected):
    assert await ss.readline2(MockReader(input_chars), MockWriter()) == expected


@pytest.mark.parametrize(
    "input_data,expected",
    [
        pytest.param([b"\x1b", b"[", b"1", b"0", b";", b"2", b"0", b"R"], (10, 20), id="valid"),
        pytest.param([b"\x1b", b"[", b"1", b";", b"1", b"R"], (1, 1), id="single_digit"),
        pytest.param([b"\x1b", b"[", b"2", b"5", b";", b"8", b"0", b"R"], (25, 80), id="typical"),
        pytest.param([b""], None, id="eof"),
        pytest.param(
            [b"g", b"a", b"r", b"\x1b", b"[", b"5", b";", b"3", b"R"], (5, 3), id="garbage_prefix"
        ),
        pytest.param([b"R", b"\x1b", b"[", b"3", b";", b"7", b"R"], (3, 7), id="R_without_match"),
        pytest.param(list("\x1b[5;10R"), (5, 10), id="string_input"),
    ],
)
@pytest.mark.asyncio
async def test_read_cpr_response(input_data, expected):
    assert await gs._read_cpr_response(MockReader(input_data)) == expected


@pytest.mark.asyncio
async def test_read_cpr_response_unicode_decode_error():
    class BadReader:
        def __init__(self):
            self._call = 0

        async def read(self, n):
            self._call += 1
            if self._call == 1:
                raise UnicodeDecodeError("utf-8", b"\xff", 0, 1, "invalid")
            return b""

    assert await gs._read_cpr_response(BadReader()) is None


@pytest.mark.asyncio
async def test_get_cursor_position_success():
    reader = MockReader([b"\x1b", b"[", b"1", b"0", b";", b"2", b"0", b"R"])
    writer = MockWriter()
    assert await gs._get_cursor_position(reader, writer, timeout=1.0) == (10, 20)
    assert "\x1b[6n" in writer.written


@pytest.mark.asyncio
async def test_get_cursor_position_timeout():
    assert await gs._get_cursor_position(SlowReader(), MockWriter(), timeout=0.01) == (None, None)


@pytest.mark.asyncio
async def test_get_cursor_position_eof():
    assert await gs._get_cursor_position(MockReader([b""]), MockWriter(), timeout=1.0) == (
        None,
        None,
    )


@pytest.mark.parametrize(
    "responses,expected",
    [
        pytest.param([(1, 5), (1, 7)], 2, id="success"),
        pytest.param([(None, None)], None, id="first_cpr_fails"),
        pytest.param([(1, 5), (None, None)], None, id="second_cpr_fails"),
    ],
)
@pytest.mark.asyncio
async def test_measure_width(monkeypatch, responses, expected):
    responses_iter = iter(responses)

    async def mock_gcp(reader, writer, timeout):
        return next(responses_iter)

    monkeypatch.setattr(gs, "_get_cursor_position", mock_gcp)
    assert await gs._measure_width(None, MockWriter(), "ab", timeout=1.0) == expected


@pytest.mark.parametrize(
    "width,expected",
    [
        pytest.param(1, True, id="width_1"),
        pytest.param(2, False, id="width_2"),
        pytest.param(None, False, id="width_none"),
    ],
)
@pytest.mark.asyncio
async def test_robot_check(monkeypatch, width, expected):
    async def mock_measure(r, w, text, timeout):
        return width

    monkeypatch.setattr(gs, "_measure_width", mock_measure)
    assert await gs.robot_check(None, None, timeout=1.0) is expected


@pytest.mark.asyncio
async def test_readline_with_echo_timeout():
    assert await gs._readline_with_echo(SlowReader(), MockWriter(), timeout=0.01) is None


@pytest.mark.parametrize(
    "timeout_at", [pytest.param(1, id="first_question"), pytest.param(2, id="second_question")]
)
@pytest.mark.asyncio
async def test_robot_shell_timeout(monkeypatch, timeout_at):
    call_count = [0]

    async def mock_readline_with_echo(reader, writer, timeout):
        call_count[0] += 1
        if call_count[0] == timeout_at:
            return None
        return "y"

    monkeypatch.setattr(gs, "_readline_with_echo", mock_readline_with_echo)
    await gs.robot_shell(MockReader([]), MockWriter())
    assert call_count[0] == timeout_at


@pytest.mark.asyncio
async def test_busy_shell_timeout(monkeypatch):
    call_count = [0]

    async def mock_read_line(reader, timeout, max_len=gs._MAX_INPUT):
        call_count[0] += 1
        return None if call_count[0] == 1 else "hi"

    monkeypatch.setattr(gs, "_read_line", mock_read_line)
    await gs.busy_shell(MockReader([]), MockWriter())
    assert call_count[0] == 2


@pytest.mark.asyncio
async def test_ask_question_blank_then_answer(monkeypatch):
    call_count = [0]

    async def mock_readline_with_echo(reader, writer, timeout):
        call_count[0] += 1
        return "   " if call_count[0] == 1 else "answer"

    monkeypatch.setattr(gs, "_readline_with_echo", mock_readline_with_echo)
    assert await gs._ask_question(None, MockWriter(), "q? ", timeout=5.0) == "answer"
    assert call_count[0] == 2


@pytest.mark.parametrize(
    "never_send_ga,expect_ga",
    [pytest.param(False, True, id="ga_sent"), pytest.param(True, False, id="ga_suppressed")],
)
@pytest.mark.asyncio
async def test_telnet_server_shell_ga(never_send_ga, expect_ga):
    reader = MockReader(list("quit\r"))
    writer = MockWriter(protocol=_MockProtocol(never_send_ga=never_send_ga))
    await ss.telnet_server_shell(reader, writer)
    assert (len(writer.ga_calls) >= 1) == expect_ga


@pytest.mark.asyncio
async def test_telnet_server_shell_dump_with_delay(monkeypatch):
    slept = []
    _real_sleep = asyncio.sleep
    monkeypatch.setattr(asyncio, "sleep", lambda d: slept.append(d) or _real_sleep(0))
    reader = MockReader(list("dump 0 1000\r") + list("quit\r"))
    writer = MockWriter()
    await ss.telnet_server_shell(reader, writer)
    written = "".join(writer.written)
    assert "kb_limit=0" in written
    assert "delay=1" in written


@pytest.mark.asyncio
async def test_telnet_server_shell_dump_with_explicit_kb():
    writer = MockWriter()
    await ss.telnet_server_shell(MockReader(list("dump 0\r") + list("quit\r")), writer)
    written = "".join(writer.written)
    assert "kb_limit=0" in written
    assert "wrote 0 bytes" in written


@pytest.mark.asyncio
async def test_telnet_server_shell_dump_closing():
    class _ClosingWriter(MockWriter):
        def write(self, data):
            super().write(data)
            if "kb_limit=" in data:
                self._closing = True

    w1 = _ClosingWriter()
    await ss.telnet_server_shell(MockReader(list("dump\r") + list("quit\r")), w1)
    assert "kb_limit=1000" in "".join(w1.written)

    w2 = _ClosingWriter()
    await ss.telnet_server_shell(MockReader(list("dump 1\r") + list("quit\r")), w2)
    assert "1 OK" not in "".join(w2.written)


def test_readline2_is_readline_async():
    assert ss.readline2 is ss.readline_async


@pytest.mark.parametrize(
    "chars,expected_cmds",
    [
        pytest.param("a\r", ["a"], id="cr_terminates"),
        pytest.param("b\n", ["b"], id="lf_terminates"),
        pytest.param("c\r\n", ["c"], id="crlf_single_cmd"),
        pytest.param("d\r\x00", ["d"], id="crnul_single_cmd"),
        pytest.param("x\ry\r", ["x", "y"], id="two_commands_cr"),
        pytest.param("x\r\ny\r\n", ["x", "y"], id="two_commands_crlf"),
    ],
)
def test_line_editor_crlf(chars, expected_cmds):
    editor = ss._LineEditor()
    cmds = []
    for ch in chars:
        _, cmd = editor.feed(ch)
        if cmd is not None:
            cmds.append(cmd)
    assert cmds == expected_cmds


def test_line_editor_backspace():
    editor = ss._LineEditor()
    editor.feed("a")
    editor.feed("b")
    echo, cmd = editor.feed("\b")
    assert cmd is None
    assert "\b \b" in echo
    _, cmd = editor.feed("\r")
    assert cmd == "a"


def test_line_editor_backspace_on_empty():
    editor = ss._LineEditor()
    echo, cmd = editor.feed("\x7f")
    assert cmd is None
    assert not echo


def test_line_editor_maxvis_ascii():
    editor = ss._LineEditor(max_visible_width=3)
    for ch in "abc":
        echo, _ = editor.feed(ch)
        assert echo == ch
    echo, _ = editor.feed("d")
    assert not echo
    _, cmd = editor.feed("\r")
    assert cmd == "abc"


@pytest.mark.parametrize(
    "command,expected_cmd,expected_echo",
    [
        pytest.param("hello", "hell", "\b \b", id="ascii"),
        pytest.param("", "", "", id="empty"),
        pytest.param("a", "", "\b \b", id="single"),
    ],
)
def test_backspace_grapheme_ascii(command, expected_cmd, expected_echo):
    cmd, echo = ss._backspace_grapheme(command)
    assert cmd == expected_cmd
    assert echo == expected_echo


@pytest.mark.parametrize(
    "command,expected_cmd,expected_echo",
    [
        pytest.param("ab\u30b3", "ab", "\b \b\b \b", id="wide_cjk"),
        pytest.param("\u30b3", "", "\b \b\b \b", id="single_wide"),
        pytest.param("cafe\u0301", "caf", "\b \b", id="combining_accent"),
        pytest.param(
            "ab\U0001f468\u200d\U0001f469\u200d\U0001f467", "ab", "\b \b\b \b", id="family_emoji"
        ),
        pytest.param("x\U0001f1fa\U0001f1f8", "x", "\b \b\b \b", id="flag_emoji"),
    ],
)
def test_backspace_grapheme_wcwidth(command, expected_cmd, expected_echo):
    cmd, echo = ss._backspace_grapheme(command)
    assert cmd == expected_cmd
    assert echo == expected_echo


@pytest.mark.parametrize(
    "text,expected", [pytest.param("hello", 5, id="ascii"), pytest.param("", 0, id="empty")]
)
def test_visible_width_ascii(text, expected):
    assert ss._visible_width(text) == expected


@pytest.mark.parametrize(
    "text,expected",
    [
        pytest.param("\u30b3\u30f3\u30cb\u30c1\u30cf", 10, id="cjk"),
        pytest.param("a\u30b3b", 4, id="mixed"),
        pytest.param("cafe\u0301", 4, id="combining"),
    ],
)
def test_visible_width_wcwidth(text, expected):
    assert ss._visible_width(text) == expected


def test_readline_backspace_wide():
    cmds, echos = _run_readline("a\u30b3\b\r")
    assert cmds == ["a"]
    echo_str = "".join(echos)
    assert echo_str.count("\b \b") == 2


def test_readline_backspace_emoji():
    family = "\U0001f468\u200d\U0001f469\u200d\U0001f467"
    cmds, _ = _run_readline("x" + family + "\bq\r")
    assert cmds == ["xq"]


def test_readline_maxvis_ascii():
    cmds, echos = _run_readline("abcdefg\r", max_visible_width=5)
    assert cmds == ["abcde"]
    echo_str = "".join(echos)
    assert "f" not in echo_str
    assert "g" not in echo_str


def test_readline_maxvis_wide():
    cmds, _ = _run_readline("a\u30b3x\r", max_visible_width=3)
    assert cmds == ["a\u30b3"]


@pytest.mark.asyncio
async def test_readline_async_backspace_wide():
    result = await ss.readline_async(
        MockReader(list("a\u30b3") + ["\x7f", "b", "\r"]), MockWriter()
    )
    assert result == "ab"


@pytest.mark.asyncio
async def test_readline_async_backspace_emoji():
    family = "\U0001f468\u200d\U0001f469\u200d\U0001f467"
    result = await ss.readline_async(
        MockReader(list("x") + list(family) + ["\x7f", "y", "\r"]), MockWriter()
    )
    assert result == "xy"


@pytest.mark.asyncio
async def test_readline_async_maxvis_ascii():
    result = await ss.readline_async(
        MockReader(list("abcdef\r")), MockWriter(), max_visible_width=4
    )
    assert result == "abcd"


@pytest.mark.asyncio
async def test_readline_async_maxvis_wide():
    result = await ss.readline_async(
        MockReader(list("a\u30b3\u30b3x\r")), MockWriter(), max_visible_width=5
    )
    assert result == "a\u30b3\u30b3"


@pytest.mark.asyncio
async def test_readline_async_lf_terminates():
    result = await ss.readline_async(MockReader(list("hello\n")), MockWriter())
    assert result == "hello"


@pytest.mark.asyncio
async def test_readline_async_ss3_filtered():
    result = await ss.readline_async(
        MockReader(list("he") + ["\x1b", "O", "P"] + list("llo\r")), MockWriter()
    )
    assert result == "hello"


@pytest.mark.parametrize(
    "input_chars,expected",
    [
        pytest.param(["\x1b", "]", "0", ";", "t", "\x07", "x"], "x", id="osc_sequence"),
        pytest.param(["\x1b", "P", "q", "\x1b", "\\", "y"], "y", id="dcs_sequence"),
        pytest.param(["\x1b", "(", "B", "z"], "z", id="charset_designation"),
        pytest.param(["\x1b", "D", "w"], "w", id="fe_sequence"),
        pytest.param(["\x1b", "X", "v"], "v", id="fe_sos_sequence"),
    ],
)
@pytest.mark.asyncio
async def test_filter_ansi_wcwidth_sequences(input_chars, expected):
    result = await ss.filter_ansi(MockReader(input_chars), MockWriter())
    assert result == expected


@pytest.mark.asyncio
async def test_telnet_server_shell_lf_input():
    reader = MockReader(list("quit\n"))
    writer = MockWriter()
    await ss.telnet_server_shell(reader, writer)
    written = "".join(writer.written)
    assert "Goodbye." in written


@pytest.mark.asyncio
async def test_telnet_server_shell_plain_banner():
    reader = MockReader(list("quit\r"))
    writer = MockWriter()
    await ss.telnet_server_shell(reader, writer)
    written = "".join(writer.written)
    assert "Ready.\r\n" in written
    assert "secure" not in written


@pytest.mark.asyncio
async def test_telnet_server_shell_tls_banner():
    class _FakeSSL:
        def version(self):
            return "TLSv1.3"

    reader = MockReader(list("quit\r"))
    writer = MockWriter()
    writer._extra["ssl_object"] = _FakeSSL()
    await ss.telnet_server_shell(reader, writer)
    written = "".join(writer.written)
    assert "Ready (secure: TLSv1.3)." in written


@pytest.mark.asyncio
async def test_filter_ansi_esc_then_eof():
    reader = MockReader(["\x1b", ""])
    result = await ss.filter_ansi(reader, MockWriter())
    assert not result


class MockBinaryReader:
    is_binary_reader = True

    def __init__(self, data):
        self._data = [d.encode("latin-1") if isinstance(d, str) else d for d in data]
        self._idx = 0

    async def read(self, n):
        if self._idx >= len(self._data):
            return b""
        result = self._data[self._idx]
        self._idx += 1
        return result


class MockBinaryWriter:
    is_binary_writer = True

    def __init__(self):
        self.written = []

    def write(self, data):
        assert isinstance(data, bytes), f"expected bytes, got {type(data)}"
        self.written.append(data)

    def echo(self, data):
        assert isinstance(data, bytes), f"expected bytes, got {type(data)}"
        self.written.append(data)

    async def drain(self):
        pass

    def is_closing(self):
        return False


@pytest.mark.parametrize(
    "input_chars,expected",
    [
        pytest.param([b"\x1b", b"[", b"A", b"x"], "x", id="csi_bytes"),
        pytest.param([b"\x1b", b"!", b"x"], "!", id="esc_non_sequence_bytes"),
        pytest.param([b"a"], "a", id="normal_char_bytes"),
        pytest.param([b""], "", id="eof_bytes"),
        pytest.param([b"\x1b", b"O", b"P", b"x"], "x", id="ss3_f1_bytes"),
        pytest.param([b"\x1b", b"(", b"B", b"z"], "z", id="charset_bytes"),
        pytest.param([b"\x1b", b"[", b"1", b";", b"2", b"H", b"z"], "z", id="csi_params_bytes"),
        pytest.param([b"\x1b", b"[", b""], "", id="csi_no_final_bytes"),
        pytest.param(
            [b"\x1b", b"]", b"0", b";", b"t", b"\x07", b"x"], "x", id="osc_sequence_bytes"
        ),
        pytest.param([b"\x1b", b"D", b"w"], "w", id="fe_sequence_bytes"),
        pytest.param([b"\x1b", b"X", b"v"], "v", id="fe_sos_sequence_bytes"),
        pytest.param([b"\x1b", b"P", b"q", b"\x1b", b"\\", b"y"], "y", id="dcs_sequence_bytes"),
        pytest.param([b"\x1b", b"[", b"1", b"m", b"z"], "z", id="match_mid_buffer_bytes"),
    ],
)
@pytest.mark.asyncio
async def test_filter_ansi_binary_reader(input_chars, expected):
    result = await ss.filter_ansi(MockBinaryReader(input_chars), MockBinaryWriter())
    assert result == expected


@pytest.mark.parametrize(
    "input_chars,expected",
    [
        pytest.param([b"h", b"e", b"l", b"l", b"o", b"\r"], "hello", id="basic_bytes"),
        pytest.param([b"h", b"x", b"\x7f", b"i", b"\r"], "hi", id="backspace_bytes"),
        pytest.param([b"\n", b"\x00", b"a", b"\r"], "a", id="skip_lf_nul_bytes"),
        pytest.param([b""], None, id="eof_bytes"),
    ],
)
@pytest.mark.asyncio
async def test_readline_async_binary_reader(input_chars, expected):
    result = await ss.readline_async(MockBinaryReader(input_chars), MockBinaryWriter())
    assert result == expected


def test_readline_binary_writer():
    """Readline (sync) with binary writer writes bytes for echo."""
    writer = MockBinaryWriter()
    gen = ss.readline(None, writer, max_visible_width=0)
    gen.send(None)
    for ch in "hello\r":
        out = gen.send(ch)
        if out is not None:
            assert out == "hello"
    assert len(writer.written) > 0


def test_readline_binary_writer_no_echo():
    """Readline (sync) with binary writer: terminators produce no echo."""
    writer = MockBinaryWriter()
    gen = ss.readline(None, writer)
    gen.send(None)
    out = gen.send("\r")
    assert out == ""
    assert writer.written == []


def test_write_binary_writer():
    writer = MockBinaryWriter()
    ss._write(writer, "hello")
    assert writer.written == [b"hello"]


def test_echo_non_binary_writer():
    writer = MockWriter()
    ss._echo(writer, "test")
    assert writer.written == ["test"]


def test_echo_binary_writer():
    writer = MockBinaryWriter()
    ss._echo(writer, "test")
    assert writer.written == [b"test"]


class MockWriterClosing(MockWriter):
    def __init__(self, closing=False):
        super().__init__()
        self._closing = closing


class MockWriterFull(MockWriter):
    def __init__(self):
        super().__init__()
        self.local_option = types.SimpleNamespace(enabled=lambda opt: False)
        self.remote_option = types.SimpleNamespace(enabled=lambda opt: False)
        self.outbinary = False
        self.inbinary = False
        self.xon_any = False
        self.lflow = True
        self.linemode = types.SimpleNamespace(
            edit=False, trapsig=False, soft_tab=False, lit_echo=False, ack=False
        )
        self._iac_calls = []
        self._send_lineflow_calls = []
        self._request_linemode_calls = []

    def iac(self, cmd, opt):
        self._iac_calls.append((cmd, opt))

    def send_lineflow_mode(self):
        self._send_lineflow_calls.append(True)

    def request_linemode_change(self, edit=None, trapsig=None):
        self._request_linemode_calls.append({"edit": edit, "trapsig": trapsig})


def test_do_toggle_no_option():
    writer = MockWriterFull()
    result = ss.do_toggle(writer, None)
    for opt in (
        "echo",
        "goahead",
        "outbinary",
        "inbinary",
        "binary",
        "xon-any",
        "lflow",
        "linemode",
    ):
        assert opt in result


@pytest.mark.parametrize(
    "option,expected_substrs,iac_count,lineflow_count",
    [
        pytest.param("echo", ["echo"], 1, 0, id="echo"),
        pytest.param("goahead", ["go-ahead"], 1, 0, id="goahead"),
        pytest.param("outbinary", ["outbinary"], 1, 0, id="outbinary"),
        pytest.param("inbinary", ["inbinary"], 1, 0, id="inbinary"),
        pytest.param("binary", ["outbinary", "inbinary"], 2, 0, id="binary"),
        pytest.param("xon-any", ["xon-any"], 0, 1, id="xon-any"),
        pytest.param("lflow", ["lineflow"], 0, 1, id="lflow"),
        pytest.param("linemode", ["linemode"], 1, 0, id="linemode"),
    ],
)
def test_do_toggle_option(option, expected_substrs, iac_count, lineflow_count):
    writer = MockWriterFull()
    result = ss.do_toggle(writer, option)
    for s in expected_substrs:
        assert s in result.lower()
    assert len(writer._iac_calls) == iac_count
    assert len(writer._send_lineflow_calls) == lineflow_count


@pytest.mark.parametrize(
    "option,linemode_active,expected_substr",
    [
        pytest.param("linemode-edit", False, "linemode not active", id="edit_inactive"),
        pytest.param("linemode-edit", True, "linemode-edit dis", id="edit_active"),
        pytest.param("linemode-trapsig", False, "linemode not active", id="trapsig_inactive"),
        pytest.param("linemode-trapsig", True, "linemode-trapsig dis", id="trapsig_active"),
    ],
)
def test_do_toggle_linemode_sub(option, linemode_active, expected_substr):
    writer = MockWriterFull()
    writer.remote_option = types.SimpleNamespace(enabled=lambda opt: linemode_active)
    if linemode_active:
        attr = "edit" if "edit" in option else "trapsig"
        base = {"edit": False, "trapsig": False, "soft_tab": False, "lit_echo": False, "ack": False}
        base[attr] = True
        writer.linemode = types.SimpleNamespace(**base)
    result = ss.do_toggle(writer, option)
    assert expected_substr in result.lower()


def test_do_toggle_unknown_option():
    writer = MockWriterFull()
    result = ss.do_toggle(writer, "nonexistent")
    assert "not an option" in result


def test_do_toggle_all():
    writer = MockWriterFull()
    result = ss.do_toggle(writer, "all")
    for s in ("echo", "go-ahead", "outbinary", "inbinary", "xon-any", "lineflow"):
        assert s in result.lower()
    assert len(writer._iac_calls) >= 4


@pytest.mark.asyncio
async def test_telnet_server_shell_already_closing():
    writer = MockWriterClosing(closing=True)
    reader = MockReader([])
    await ss.telnet_server_shell(reader, writer)
    written = "".join(writer.written)
    assert "Ready" in written


@pytest.mark.asyncio
async def test_telnet_server_shell_eof():
    writer = MockWriter()
    reader = MockReader([""])
    await ss.telnet_server_shell(reader, writer)
    written = "".join(writer.written)
    assert "Ready" in written


@pytest.mark.asyncio
async def test_telnet_server_shell_unknown_command():
    writer = MockWriter()
    reader = MockReader(list("bogus\r") + list("quit\r"))
    await ss.telnet_server_shell(reader, writer)
    written = "".join(writer.written)
    assert "no such command" in written


@pytest.mark.asyncio
async def test_telnet_server_shell_dump_with_close():
    writer = MockWriter()
    reader = MockReader(list("dump 0 0 drain close\r"))
    await ss.telnet_server_shell(reader, writer)
    written = "".join(writer.written)
    assert "kb_limit=0" in written
    assert "do_close=True" in written
    assert "quit" not in written


class MockBinaryWriterShell(MockBinaryWriter):
    def __init__(self, protocol=None):
        super().__init__()
        self._closing = False
        self._extra = {"peername": ("127.0.0.1", 12345)}
        self.protocol = protocol or _MockProtocol()
        self.ga_calls = []

    def get_extra_info(self, key, default=None):
        return self._extra.get(key, default)

    def is_closing(self):
        return self._closing

    def close(self):
        self._closing = True

    def send_ga(self):
        self.ga_calls.append(True)
        return True


@pytest.mark.asyncio
async def test_telnet_server_shell_binary_writer():
    reader = MockBinaryReader([b"quit\r"])
    writer = MockBinaryWriterShell()
    await ss.telnet_server_shell(reader, writer)
    assert len(writer.written) > 0
    assert all(isinstance(w, bytes) for w in writer.written)


@pytest.mark.asyncio
async def test_readline_async_binary_writer_no_echo():
    writer = MockBinaryWriter()
    reader = MockBinaryReader([b"\r"])
    result = await ss.readline_async(reader, writer)
    assert result == ""
    assert writer.written == []


def test_readline_binary_writer_echo_backspace():
    writer = MockBinaryWriter()
    gen = ss.readline(None, writer)
    gen.send(None)
    for ch in "a\x7fb\r":
        gen.send(ch)
    assert len(writer.written) > 0
    assert all(isinstance(w, bytes) for w in writer.written)


@pytest.mark.parametrize(
    "input_data,max_len,expected",
    [
        pytest.param([b"h", b"i", b"\r"], 100, "hi", id="cr_terminated"),
        pytest.param([b"a", b"b"], 100, "ab", id="eof_no_terminator"),
    ],
)
@pytest.mark.asyncio
async def test_read_line_inner_bytes(input_data, max_len, expected):
    assert await gs._read_line_inner(MockBinaryReader(input_data), max_len) == expected


@pytest.mark.parametrize(
    "command,expected_substr,setup",
    [
        pytest.param("writer", "MockWriter", None, id="writer"),
        pytest.param("reader", "MockReader", None, id="reader"),
        pytest.param(
            "slc",
            "Special Line Characters",
            lambda w: setattr(w, "slctab", slc_mod.generate_slctab()),
            id="slc",
        ),
    ],
)
@pytest.mark.asyncio
async def test_telnet_server_shell_cmd(command, expected_substr, setup):
    writer = MockWriter()
    if setup:
        setup(writer)
    reader = MockReader(list(f"{command}\r"))
    await ss.telnet_server_shell(reader, writer)
    assert expected_substr in "".join(writer.written)


@pytest.mark.asyncio
async def test_filter_ansi_binary_long_sequence():
    reader = MockBinaryReader([b"\x1b", b"["] + [b"0"] * 254 + [b"x"])
    result = await ss.filter_ansi(reader, MockBinaryWriter())
    assert result == "x"


@pytest.mark.asyncio
async def test_busy_shell_second_timeout(monkeypatch):
    call_count = [0]

    async def mock_read_line(reader, timeout, max_len=gs._MAX_INPUT):
        call_count[0] += 1
        return "hello" if call_count[0] == 1 else None

    monkeypatch.setattr(gs, "_read_line", mock_read_line)
    writer = MockWriter()
    await gs.busy_shell(MockReader([]), writer)
    written = "".join(writer.written)
    assert "Machine is busy" in written
    assert "distant explosion" in written
    assert call_count[0] == 2
