Module livekit.agents.cli.readchar

def _posix_readchar() -> str:
    """Read a single character from standard input on POSIX systems.

    This function blocks until a character is available.  It uses
    ``termios`` to disable canonical input processing and echo so
    characters are returned immediately and without being echoed to
    the terminal.  The implementation closely follows the upstream
    ``_posix_read.readchar`` function.
    """
    import termios
    import tty

    fd = sys.stdin.fileno()
    old_settings = termios.tcgetattr(fd)
    term = termios.tcgetattr(fd)
    try:
        term[3] &= ~(termios.ICANON | termios.ECHO)
        term[3] |= termios.ISIG
        termios.tcsetattr(fd, termios.TCSAFLUSH, term)

        ch = sys.stdin.read(1)
    finally:
        try:
            termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
        except Exception:
            try:
                tty.setcbreak(fd)
                cur = termios.tcgetattr(fd)
                cur[3] |= termios.ICANON | termios.ECHO | termios.ISIG
                termios.tcsetattr(fd, termios.TCSADRAIN, cur)
            except Exception:
                pass
    return ch

def _posix_readkey() -> str:
    """Read the next keypress on POSIX systems.

    If a multi‑byte escape sequence is encountered (for example, an arrow
    key or function key), the entire sequence is read and returned.
    ``KeyboardInterrupt`` is raised when a key listed in
    :data:`config.INTERRUPT_KEYS` is pressed.
    """
    c1 = _posix_readchar()

    if c1 in INTERRUPT_KEYS:
        raise KeyboardInterrupt

    # Not an escape sequence; return immediately
    if c1 != "\x1b":
        return c1

    # Escape sequence – read second byte
    c2 = _posix_readchar()
    if c2 not in "\x4f\x5b":
        return c1 + c2

    # Third byte distinguishes between simple arrows and multi‑byte
    c3 = _posix_readchar()
    if c3 not in "\x31\x32\x33\x35\x36":
        return c1 + c2 + c3

    # Fourth byte for multi‑byte function/navigation keys
    c4 = _posix_readchar()
    if c4 not in "\x30\x31\x33\x34\x35\x37\x38\x39":
        return c1 + c2 + c3 + c4

    # Fifth byte for the remainder of the sequence
    c5 = _posix_readchar()
    return c1 + c2 + c3 + c4 + c5

class _PosixKey(_BaseKey):
    """Namespace of key codes specific to POSIX platforms (Linux, macOS, BSD).

    These values mirror those defined in the upstream ``_posix_key.py``
    module.  All attributes from :class:`_BaseKey` are inherited.
    """

    # Common additional control character
    BACKSPACE: ClassVar[str] = "\x7f"

    # Cursor movement (escape sequences)
    UP: ClassVar[str] = "\x1b\x5b\x41"
    DOWN: ClassVar[str] = "\x1b\x5b\x42"
    LEFT: ClassVar[str] = "\x1b\x5b\x44"
    RIGHT: ClassVar[str] = "\x1b\x5b\x43"

    # Navigation keys
    INSERT: ClassVar[str] = "\x1b\x5b\x32\x7e"
    SUPR: ClassVar[str] = "\x1b\x5b\x33\x7e"
    HOME: ClassVar[str] = "\x1b\x5b\x48"
    END: ClassVar[str] = "\x1b\x5b\x46"
    PAGE_UP: ClassVar[str] = "\x1b\x5b\x35\x7e"
    PAGE_DOWN: ClassVar[str] = "\x1b\x5b\x36\x7e"

    # Function keys
    F1: ClassVar[str] = "\x1b\x4f\x50"
    F2: ClassVar[str] = "\x1b\x4f\x51"
    F3: ClassVar[str] = "\x1b\x4f\x52"
    F4: ClassVar[str] = "\x1b\x4f\x53"
    F5: ClassVar[str] = "\x1b\x5b\x31\x35\x7e"
    F6: ClassVar[str] = "\x1b\x5b\x31\x37\x7e"
    F7: ClassVar[str] = "\x1b\x5b\x31\x38\x7e"
    F8: ClassVar[str] = "\x1b\x5b\x31\x39\x7e"
    F9: ClassVar[str] = "\x1b\x5b\x32\x30\x7e"
    F10: ClassVar[str] = "\x1b\x5b\x32\x31\x7e"
    F11: ClassVar[str] = "\x1b\x5b\x32\x33\x7e"
    F12: ClassVar[str] = "\x1b\x5b\x32\x34\x7e"

    # Shift/other combinations
    SHIFT_TAB: ClassVar[str] = "\x1b\x5b\x5a"
    CTRL_ALT_SUPR: ClassVar[str] = "\x1b\x5b\x33\x5e"

    # ALT combinations
    ALT_A: ClassVar[str] = "\x1b\x61"

    # CTRL+ALT combinations
    CTRL_ALT_A: ClassVar[str] = "\x1b\x01"

    # Aliases to improve readability
    ENTER: ClassVar[str] = _BaseKey.LF
    DELETE: ClassVar[str] = SUPR