_win32_console.py

"""Light wrapper around the Win32 Console API - this module should only be imported on Windows

The API that this module wraps is documented at https://docs.microsoft.com/en-us/windows/console/console-functions
"""
import ctypes
import sys
from typing import Any

windll: Any = None
if sys.platform == "win32":
    windll = ctypes.LibraryLoader(ctypes.WinDLL)
else:
    raise ImportError(f"{__name__} can only be imported on Windows")

import time
from ctypes import Structure, byref, wintypes
from typing import IO, NamedTuple, Type, cast

from rich.color import ColorSystem
from rich.style import Style

STDOUT = -11
ENABLE_VIRTUAL_TERMINAL_PROCESSING = 4

COORD = wintypes._COORD


class LegacyWindowsError(Exception):
    pass


class WindowsCoordinates(NamedTuple):
    """Coordinates in the Windows Console API are (y, x), not (x, y).
    This class is intended to prevent that confusion.
    Rows and columns are indexed from 0.
    This class can be used in place of wintypes._COORD in arguments and argtypes.
    """

    row: int
    col: int

    @classmethod
    def from_param(cls, value: "WindowsCoordinates") -> COORD:
        """Converts a WindowsCoordinates into a wintypes _COORD structure.
        This classmethod is internally called by ctypes to perform the conversion.

        Args:
            value (WindowsCoordinates): The input coordinates to convert.

        Returns:
            wintypes._COORD: The converted coordinates struct.
        """
        return COORD(value.col, value.row)


class CONSOLE_SCREEN_BUFFER_INFO(Structure):
    _fields_ = [
        ("dwSize", COORD),
        ("dwCursorPosition", COORD),
        ("wAttributes", wintypes.WORD),
        ("srWindow", wintypes.SMALL_RECT),
        ("dwMaximumWindowSize", COORD),
    ]


class CONSOLE_CURSOR_INFO(ctypes.Structure):
    _fields_ = [("dwSize", wintypes.DWORD), ("bVisible", wintypes.BOOL)]


_GetStdHandle = windll.kernel32.GetStdHandle
_GetStdHandle.argtypes = [
    wintypes.DWORD,
]
_GetStdHandle.restype = wintypes.HANDLE


def GetStdHandle(handle: int = STDOUT) -> wintypes.HANDLE:
    """Retrieves a handle to the specified standard device (standard input, standard output, or standard error).

    Args:
        handle (int): Integer identifier for the handle. Defaults to -11 (stdout).

    Returns:
        wintypes.HANDLE: The handle
    """
    return cast(wintypes.HANDLE, _GetStdHandle(handle))


_GetConsoleMode = windll.kernel32.GetConsoleMode
_GetConsoleMode.argtypes = [wintypes.HANDLE, wintypes.LPDWORD]
_GetConsoleMode.restype = wintypes.BOOL


def GetConsoleMode(std_handle: wintypes.HANDLE) -> int:
    """Retrieves the current input mode of a console's input buffer
    or the current output mode of a console screen buffer.

    Args:
        std_handle (wintypes.HANDLE): A handle to the console input buffer or the console screen buffer.

    Raises:
        LegacyWindowsError: If any error occurs while calling the Windows console API.

    Returns:
        int: Value representing the current console mode as documented at
            https://docs.microsoft.com/en-us/windows/console/getconsolemode#parameters
    """

    console_mode = wintypes.DWORD()
    success = bool(_GetConsoleMode(std_handle, console_mode))
    if not success:
        raise LegacyWindowsError("Unable to get legacy Windows Console Mode")
    return console_mode.value


_FillConsoleOutputCharacterW = windll.kernel32.FillConsoleOutputCharacterW
_FillConsoleOutputCharacterW.argtypes = [
    wintypes.HANDLE,
    ctypes.c_char,
    wintypes.DWORD,
    cast(Type[COORD], WindowsCoordinates),
    ctypes.POINTER(wintypes.DWORD),
]
_FillConsoleOutputCharacterW.restype = wintypes.BOOL


def FillConsoleOutputCharacter(
    std_handle: wintypes.HANDLE,
    char: str,
    length: int,
    start: WindowsCoordinates,
) -> int:
    """Writes a character to the console screen buffer a specified number of times, beginning at the specified coordinates.

    Args:
        std_handle (wintypes.HANDLE): A handle to the console input buffer or the console screen buffer.
        char (str): The character to write. Must be a string of length 1.
        length (int): The number of times to write the character.
        start (WindowsCoordinates): The coordinates to start writing at.

    Returns:
        int: The number of characters written.
    """
    character = ctypes.c_char(char.encode())
    num_characters = wintypes.DWORD(length)
    num_written = wintypes.DWORD(0)
    _FillConsoleOutputCharacterW(
        std_handle,
        character,
        num_characters,
        start,
        byref(num_written),
    )
    return num_written.value


_FillConsoleOutputAttribute = windll.kernel32.FillConsoleOutputAttribute
_FillConsoleOutputAttribute.argtypes = [
    wintypes.HANDLE,
    wintypes.WORD,
    wintypes.DWORD,
    cast(Type[COORD], WindowsCoordinates),
    ctypes.POINTER(wintypes.DWORD),
]
_FillConsoleOutputAttribute.restype = wintypes.BOOL


def FillConsoleOutputAttribute(
    std_handle: wintypes.HANDLE,
    attributes: int,
    length: int,
    start: WindowsCoordinates,
) -> int:
    """Sets the character attributes for a specified number of character cells,
    beginning at the specified coordinates in a screen buffer.

    Args:
        std_handle (wintypes.HANDLE): A handle to the console input buffer or the console screen buffer.
        attributes (int): Integer value representing the foreground and background colours of the cells.
        length (int): The number of cells to set the output attribute of.
        start (WindowsCoordinates): The coordinates of the first cell whose attributes are to be set.

    Returns:
        int: The number of cells whose attributes were actually set.
    """
    num_cells = wintypes.DWORD(length)
    style_attrs = wintypes.WORD(attributes)
    num_written = wintypes.DWORD(0)
    _FillConsoleOutputAttribute(
        std_handle, style_attrs, num_cells, start, byref(num_written)
    )
    return num_written.value


_SetConsoleTextAttribute = windll.kernel32.SetConsoleTextAttribute
_SetConsoleTextAttribute.argtypes = [
    wintypes.HANDLE,
    wintypes.WORD,
]
_SetConsoleTextAttribute.restype = wintypes.BOOL


def SetConsoleTextAttribute(
    std_handle: wintypes.HANDLE, attributes: wintypes.WORD
) -> bool:
    """Set the colour attributes for all text written after this function is called.

    Args:
        std_handle (wintypes.HANDLE): A handle to the console input buffer or the console screen buffer.
        attributes (int): Integer value representing the foreground and background colours.


    Returns:
        bool: True if the attribute was set successfully, otherwise False.
    """
    return bool(_SetConsoleTextAttribute(std_handle, attributes))


_GetConsoleScreenBufferInfo = windll.kernel32.GetConsoleScreenBufferInfo
_GetConsoleScreenBufferInfo.argtypes = [
    wintypes.HANDLE,
    ctypes.POINTER(CONSOLE_SCREEN_BUFFER_INFO),
]
_GetConsoleScreenBufferInfo.restype = wintypes.BOOL


def GetConsoleScreenBufferInfo(
    std_handle: wintypes.HANDLE,
) -> CONSOLE_SCREEN_BUFFER_INFO:
    """Retrieves information about the specified console screen buffer.

    Args:
        std_handle (wintypes.HANDLE): A handle to the console input buffer or the console screen buffer.

    Returns:
        CONSOLE_SCREEN_BUFFER_INFO: A CONSOLE_SCREEN_BUFFER_INFO ctype struct contain information about
            screen size, cursor position, colour attributes, and more."""
    console_screen_buffer_info = CONSOLE_SCREEN_BUFFER_INFO()
    _GetConsoleScreenBufferInfo(std_handle, byref(console_screen_buffer_info))
    return console_screen_buffer_info


_SetConsoleCursorPosition = windll.kernel32.SetConsoleCursorPosition
_SetConsoleCursorPosition.argtypes = [
    wintypes.HANDLE,
    cast(Type[COORD], WindowsCoordinates),
]
_SetConsoleCursorPosition.restype = wintypes.BOOL


def SetConsoleCursorPosition(
    std_handle: wintypes.HANDLE, coords: WindowsCoordinates
) -> bool:
    """Set the position of the cursor in the console screen

    Args:
        std_handle (wintypes.HANDLE): A handle to the console input buffer or the console screen buffer.
        coords (WindowsCoordinates): The coordinates to move the cursor to.

    Returns:
        bool: True if the function succeeds, otherwise False.
    """
    return bool(_SetConsoleCursorPosition(std_handle, coords))


_GetConsoleCursorInfo = windll.kernel32.GetConsoleCursorInfo
_GetConsoleCursorInfo.argtypes = [
    wintypes.HANDLE,
    ctypes.POINTER(CONSOLE_CURSOR_INFO),
]
_GetConsoleCursorInfo.restype = wintypes.BOOL


def GetConsoleCursorInfo(
    std_handle: wintypes.HANDLE, cursor_info: CONSOLE_CURSOR_INFO
) -> bool:
    """Get the cursor info - used to get cursor visibility and width

    Args:
        std_handle (wintypes.HANDLE): A handle to the console input buffer or the console screen buffer.
        cursor_info (CONSOLE_CURSOR_INFO): CONSOLE_CURSOR_INFO ctype struct that receives information
            about the console's cursor.

    Returns:
          bool: True if the function succeeds, otherwise False.
    """
    return bool(_GetConsoleCursorInfo(std_handle, cursor_info))


_SetConsoleCursorInfo = windll.kernel32.SetConsoleCursorInfo
_SetConsoleCursorInfo.argtypes = [
    wintypes.HANDLE,
    ctypes.POINTER(CONSOLE_CURSOR_INFO),
]
_SetConsoleCursorInfo.restype = wintypes.BOOL


def SetConsoleCursorInfo(
    std_handle: wintypes.HANDLE, cursor_info: CONSOLE_CURSOR_INFO
) -> bool:
    """Set the cursor info - used for adjusting cursor visibility and width

    Args:
        std_handle (wintypes.HANDLE): A handle to the console input buffer or the console screen buffer.
        cursor_info (CONSOLE_CURSOR_INFO): CONSOLE_CURSOR_INFO ctype struct containing the new cursor info.

    Returns:
          bool: True if the function succeeds, otherwise False.
    """
    return bool(_SetConsoleCursorInfo(std_handle, byref(cursor_info)))


_SetConsoleTitle = windll.kernel32.SetConsoleTitleW
_SetConsoleTitle.argtypes = [wintypes.LPCWSTR]
_SetConsoleTitle.restype = wintypes.BOOL


def SetConsoleTitle(title: str) -> bool:
    """Sets the title of the current console window

    Args:
        title (str): The new title of the console window.

    Returns:
        bool: True if the function succeeds, otherwise False.
    """
    return bool(_SetConsoleTitle(title))


class LegacyWindowsTerm:
    """This class allows interaction with the legacy Windows Console API. It should only be used in the context
    of environments where virtual terminal processing is not available. However, if it is used in a Windows environment,
    the entire API should work.

    Args:
        file (IO[str]): The file which the Windows Console API HANDLE is retrieved from, defaults to sys.stdout.
    """

    BRIGHT_BIT = 8

    # Indices are ANSI color numbers, values are the corresponding Windows Console API color numbers
    ANSI_TO_WINDOWS = [
        0,  # black                      The Windows colours are defined in wincon.h as follows:
        4,  # red                         define FOREGROUND_BLUE            0x0001 -- 0000 0001
        2,  # green                       define FOREGROUND_GREEN           0x0002 -- 0000 0010
        6,  # yellow                      define FOREGROUND_RED             0x0004 -- 0000 0100
        1,  # blue                        define FOREGROUND_INTENSITY       0x0008 -- 0000 1000
        5,  # magenta                     define BACKGROUND_BLUE            0x0010 -- 0001 0000
        3,  # cyan                        define BACKGROUND_GREEN           0x0020 -- 0010 0000
        7,  # white                       define BACKGROUND_RED             0x0040 -- 0100 0000
        8,  # bright black (grey)         define BACKGROUND_INTENSITY       0x0080 -- 1000 0000
        12,  # bright red
        10,  # bright green
        14,  # bright yellow
        9,  # bright blue
        13,  # bright magenta
        11,  # bright cyan
        15,  # bright white
    ]

    def __init__(self, file: "IO[str]") -> None:
        handle = GetStdHandle(STDOUT)
        self._handle = handle
        default_text = GetConsoleScreenBufferInfo(handle).wAttributes
        self._default_text = default_text
        
        # Store the current cursor size
        # @link https://docs.microsoft.com/en-us/windows/console/console-cursor-info-str
        initial_cursor_info = CONSOLE_CURSOR_INFO()
        GetConsoleCursorInfo(self._handle, cursor_info=initial_cursor_info)
        self._initial_cursor_size = initial_cursor_info.dwSize

        self._default_fore = default_text & 7
        self._default_back = (default_text >> 4) & 7
        self._default_attrs = self._default_fore | (self._default_back << 4)

        self._file = file
        self.write = file.write
        self.flush = file.flush

    @property
    def cursor_position(self) -> WindowsCoordinates:
        """Returns the current position of the cursor (0-based)

        Returns:
            WindowsCoordinates: The current cursor position.
        """
        coord: COORD = GetConsoleScreenBufferInfo(self._handle).dwCursorPosition
        return WindowsCoordinates(row=cast(int, coord.Y), col=cast(int, coord.X))

    @property
    def screen_size(self) -> WindowsCoordinates:
        """Returns the current size of the console screen buffer, in character columns and rows

        Returns:
            WindowsCoordinates: The width and height of the screen as WindowsCoordinates.
        """
        screen_size: COORD = GetConsoleScreenBufferInfo(self._handle).dwSize
        return WindowsCoordinates(
            row=cast(int, screen_size.Y), col=cast(int, screen_size.X)
        )

    def write_text(self, text: str) -> None:
        """Write text directly to the terminal without any modification of styles

        Args:
            text (str): The text to write to the console
        """
        self.write(text)
        self.flush()

    def write_styled(self, text: str, style: Style) -> None:
        """Write styled text to the terminal.

        Args:
            text (str): The text to write
            style (Style): The style of the text
        """
        color = style.color
        bgcolor = style.bgcolor
        if style.reverse:
            color, bgcolor = bgcolor, color

        if color:
            fore = color.downgrade(ColorSystem.WINDOWS).number
            fore = fore if fore is not None else 7  # Default to ANSI 7: White
            if style.bold:
                fore = fore | self.BRIGHT_BIT
            if style.dim:
                fore = fore & ~self.BRIGHT_BIT
            fore = self.ANSI_TO_WINDOWS[fore]
        else:
            fore = self._default_fore

        if bgcolor:
            back = bgcolor.downgrade(ColorSystem.WINDOWS).number
            back = back if back is not None else 0  # Default to ANSI 0: Black
            back = self.ANSI_TO_WINDOWS[back]
        else:
            back = self._default_back

        assert fore is not None
        assert back is not None

        SetConsoleTextAttribute(
            self._handle, attributes=ctypes.c_ushort(fore | (back << 4))
        )
        self.write_text(text)
        SetConsoleTextAttribute(self._handle, attributes=self._default_text)

    def move_cursor_to(self, new_position: WindowsCoordinates) -> None:
        """Set the position of the cursor

        Args:
            new_position (WindowsCoordinates): The WindowsCoordinates representing the new position of the cursor.
        """
        if new_position.col < 0 or new_position.row < 0:
            return
        SetConsoleCursorPosition(self._handle, coords=new_position)

    def erase_line(self) -> None:
        """Erase all content on the line the cursor is currently located at"""
        screen_size = self.screen_size
        cursor_position = self.cursor_position
        cells_to_erase = screen_size.col
        start_coordinates = WindowsCoordinates(row=cursor_position.row, col=0)
        FillConsoleOutputCharacter(
            self._handle, " ", length=cells_to_erase, start=start_coordinates
        )
        FillConsoleOutputAttribute(
            self._handle,
            self._default_attrs,
            length=cells_to_erase,
            start=start_coordinates,
        )

    def erase_end_of_line(self) -> None:
        """Erase all content from the cursor position to the end of that line"""
        cursor_position = self.cursor_position
        cells_to_erase = self.screen_size.col - cursor_position.col
        FillConsoleOutputCharacter(
            self._handle, " ", length=cells_to_erase, start=cursor_position
        )
        FillConsoleOutputAttribute(
            self._handle,
            self._default_attrs,
            length=cells_to_erase,
            start=cursor_position,
        )

    def erase_start_of_line(self) -> None:
        """Erase all content from the cursor position to the start of that line"""
        row, col = self.cursor_position
        start = WindowsCoordinates(row, 0)
        FillConsoleOutputCharacter(self._handle, " ", length=col, start=start)
        FillConsoleOutputAttribute(
            self._handle, self._default_attrs, length=col, start=start
        )

    def move_cursor_up(self) -> None:
        """Move the cursor up a single cell"""
        cursor_position = self.cursor_position
        SetConsoleCursorPosition(
            self._handle,
            coords=WindowsCoordinates(
                row=cursor_position.row - 1, col=cursor_position.col
            ),
        )

    def move_cursor_down(self) -> None:
        """Move the cursor down a single cell"""
        cursor_position = self.cursor_position
        SetConsoleCursorPosition(
            self._handle,
            coords=WindowsCoordinates(
                row=cursor_position.row + 1,
                col=cursor_position.col,
            ),
        )

    def move_cursor_forward(self) -> None:
        """Move the cursor forward a single cell. Wrap to the next line if required."""
        row, col = self.cursor_position
        if col == self.screen_size.col - 1:
            row += 1
            col = 0
        else:
            col += 1
        SetConsoleCursorPosition(
            self._handle, coords=WindowsCoordinates(row=row, col=col)
        )

    def move_cursor_to_column(self, column: int) -> None:
        """Move cursor to the column specified by the zero-based column index, staying on the same row

        Args:
            column (int): The zero-based column index to move the cursor to.
        """
        row, _ = self.cursor_position
        SetConsoleCursorPosition(self._handle, coords=WindowsCoordinates(row, column))

    def move_cursor_backward(self) -> None:
        """Move the cursor backward a single cell. Wrap to the previous line if required."""
        row, col = self.cursor_position
        if col == 0:
            row -= 1
            col = self.screen_size.col - 1
        else:
            col -= 1
        SetConsoleCursorPosition(
            self._handle, coords=WindowsCoordinates(row=row, col=col)
        )

    def hide_cursor(self) -> None:
        """Hide the cursor"""
        invisible_cursor = CONSOLE_CURSOR_INFO(dwSize=self._initial_cursor_size, bVisible=0)
        SetConsoleCursorInfo(self._handle, cursor_info=invisible_cursor)

    def show_cursor(self) -> None:
        """Show the cursor"""
        visible_cursor = CONSOLE_CURSOR_INFO(dwSize=self._initial_cursor_size, bVisible=1)
        SetConsoleCursorInfo(self._handle, cursor_info=visible_cursor)

    def set_title(self, title: str) -> None:
        """Set the title of the terminal window

        Args:
            title (str): The new title of the console window
        """
        assert len(title) < 255, "Console title must be less than 255 characters"
        SetConsoleTitle(title)


if __name__ == "__main__":
    handle = GetStdHandle()

    from rich.console import Console

    console = Console()

    term = LegacyWindowsTerm(sys.stdout)
    term.set_title("Win32 Console Examples")

    style = Style(color="black", bgcolor="red")

    heading = Style.parse("black on green")

    # Check colour output
    console.rule("Checking colour output")
    console.print("[on red]on red!")
    console.print("[blue]blue!")
    console.print("[yellow]yellow!")
    console.print("[bold yellow]bold yellow!")
    console.print("[bright_yellow]bright_yellow!")
    console.print("[dim bright_yellow]dim bright_yellow!")
    console.print("[italic cyan]italic cyan!")
    console.print("[bold white on blue]bold white on blue!")
    console.print("[reverse bold white on blue]reverse bold white on blue!")
    console.print("[bold black on cyan]bold black on cyan!")
    console.print("[black on green]black on green!")
    console.print("[blue on green]blue on green!")
    console.print("[white on black]white on black!")
    console.print("[black on white]black on white!")
    console.print("[#1BB152 on #DA812D]#1BB152 on #DA812D!")

    # Check cursor movement
    console.rule("Checking cursor movement")
    console.print()
    term.move_cursor_backward()
    term.move_cursor_backward()
    term.write_text("went back and wrapped to prev line")
    time.sleep(1)
    term.move_cursor_up()
    term.write_text("we go up")
    time.sleep(1)
    term.move_cursor_down()
    term.write_text("and down")
    time.sleep(1)
    term.move_cursor_up()
    term.move_cursor_backward()
    term.move_cursor_backward()
    term.write_text("we went up and back 2")
    time.sleep(1)
    term.move_cursor_down()
    term.move_cursor_backward()
    term.move_cursor_backward()
    term.write_text("we went down and back 2")
    time.sleep(1)

    # Check erasing of lines
    term.hide_cursor()
    console.print()
    console.rule("Checking line erasing")
    console.print("\n...Deleting to the start of the line...")
    term.write_text("The red arrow shows the cursor location, and direction of erase")
    time.sleep(1)
    term.move_cursor_to_column(16)
    term.write_styled("<", Style.parse("black on red"))
    term.move_cursor_backward()
    time.sleep(1)
    term.erase_start_of_line()
    time.sleep(1)

    console.print("\n\n...And to the end of the line...")
    term.write_text("The red arrow shows the cursor location, and direction of erase")
    time.sleep(1)

    term.move_cursor_to_column(16)
    term.write_styled(">", Style.parse("black on red"))
    time.sleep(1)
    term.erase_end_of_line()
    time.sleep(1)

    console.print("\n\n...Now the whole line will be erased...")
    term.write_styled("I'm going to disappear!", style=Style.parse("black on cyan"))
    time.sleep(1)
    term.erase_line()

    term.show_cursor()
    print("\n")