"""
Output for vt100 terminals.

A lot of thanks, regarding outputting of colors, goes to the Pygments project:
(We don't rely on Pygments anymore, because many things are very custom, and
everything has been highly optimized.)
http://pygments.org/
"""
import array
import errno
import sys
from typing import (
    IO,
    Callable,
    Dict,
    Hashable,
    Iterable,
    List,
    Optional,
    Sequence,
    Set,
    TextIO,
    Tuple,
)

from prot.prompt.data_structures import Size
from prot.prompt.output import Output
from prot.prompt.styles import ANSI_COLOR_NAMES, Attrs

from .color_depth import ColorDepth

__all__ = [
    "Vt100_Output",
]


FG_ANSI_COLORS = {
    "ansidefault": 39,
    # Low intensity.
    "ansiblack": 30,
    "ansired": 31,
    "ansigreen": 32,
    "ansiyellow": 33,
    "ansiblue": 34,
    "ansimagenta": 35,
    "ansicyan": 36,
    "ansigray": 37,
    # High intensity.
    "ansibrightblack": 90,
    "ansibrightred": 91,
    "ansibrightgreen": 92,
    "ansibrightyellow": 93,
    "ansibrightblue": 94,
    "ansibrightmagenta": 95,
    "ansibrightcyan": 96,
    "ansiwhite": 97,
}

BG_ANSI_COLORS = {
    "ansidefault": 49,
    # Low intensity.
    "ansiblack": 40,
    "ansired": 41,
    "ansigreen": 42,
    "ansiyellow": 43,
    "ansiblue": 44,
    "ansimagenta": 45,
    "ansicyan": 46,
    "ansigray": 47,
    # High intensity.
    "ansibrightblack": 100,
    "ansibrightred": 101,
    "ansibrightgreen": 102,
    "ansibrightyellow": 103,
    "ansibrightblue": 104,
    "ansibrightmagenta": 105,
    "ansibrightcyan": 106,
    "ansiwhite": 107,
}


ANSI_COLORS_TO_RGB = {
    "ansidefault": (
        0x00,
        0x00,
        0x00,
    ),  # Don't use, 'default' doesn't really have a value.
    "ansiblack": (0x00, 0x00, 0x00),
    "ansigray": (0xE5, 0xE5, 0xE5),
    "ansibrightblack": (0x7F, 0x7F, 0x7F),
    "ansiwhite": (0xFF, 0xFF, 0xFF),
    # Low intensity.
    "ansired": (0xCD, 0x00, 0x00),
    "ansigreen": (0x00, 0xCD, 0x00),
    "ansiyellow": (0xCD, 0xCD, 0x00),
    "ansiblue": (0x00, 0x00, 0xCD),
    "ansimagenta": (0xCD, 0x00, 0xCD),
    "ansicyan": (0x00, 0xCD, 0xCD),
    # High intensity.
    "ansibrightred": (0xFF, 0x00, 0x00),
    "ansibrightgreen": (0x00, 0xFF, 0x00),
    "ansibrightyellow": (0xFF, 0xFF, 0x00),
    "ansibrightblue": (0x00, 0x00, 0xFF),
    "ansibrightmagenta": (0xFF, 0x00, 0xFF),
    "ansibrightcyan": (0x00, 0xFF, 0xFF),
}


assert set(FG_ANSI_COLORS) == set(ANSI_COLOR_NAMES)
assert set(BG_ANSI_COLORS) == set(ANSI_COLOR_NAMES)
assert set(ANSI_COLORS_TO_RGB) == set(ANSI_COLOR_NAMES)


def _get_closest_ansi_color(r: int, g: int, b: int, exclude: Sequence[str] = ()) -> str:
    """
    Find closest ANSI color. Return it by name.

    :param r: Red (Between 0 and 255.)
    :param g: Green (Between 0 and 255.)
    :param b: Blue (Between 0 and 255.)
    :param exclude: A tuple of color names to exclude. (E.g. ``('ansired', )``.)
    """
    exclude = list(exclude)

    # When we have a bit of saturation, avoid the gray-like colors, otherwise,
    # too often the distance to the gray color is less.
    saturation = abs(r - g) + abs(g - b) + abs(b - r)  # Between 0..510

    if saturation > 30:
        exclude.extend(["ansilightgray", "ansidarkgray", "ansiwhite", "ansiblack"])

    # Take the closest color.
    # (Thanks to Pygments for this part.)
    distance = 257 * 257 * 3  # "infinity" (>distance from #000000 to #ffffff)
    match = "ansidefault"

    for name, (r2, g2, b2) in ANSI_COLORS_TO_RGB.items():
        if name != "ansidefault" and name not in exclude:
            d = (r - r2) ** 2 + (g - g2) ** 2 + (b - b2) ** 2

            if d < distance:
                match = name
                distance = d

    return match


_ColorCodeAndName = Tuple[int, str]


class _16ColorCache:
    """
    Cache which maps (r, g, b) tuples to 16 ansi colors.

    :param bg: Cache for background colors, instead of foreground.
    """

    def __init__(self, bg: bool = False) -> None:
        self.bg = bg
        self._cache: Dict[Hashable, _ColorCodeAndName] = {}

    def get_code(
        self, value: Tuple[int, int, int], exclude: Sequence[str] = ()
    ) -> _ColorCodeAndName:
        """
        Return a (ansi_code, ansi_name) tuple. (E.g. ``(44, 'ansiblue')``.) for
        a given (r,g,b) value.
        """
        key: Hashable = (value, tuple(exclude))
        cache = self._cache

        if key not in cache:
            cache[key] = self._get(value, exclude)

        return cache[key]

    def _get(
        self, value: Tuple[int, int, int], exclude: Sequence[str] = ()
    ) -> _ColorCodeAndName:

        r, g, b = value
        match = _get_closest_ansi_color(r, g, b, exclude=exclude)

        # Turn color name into code.
        if self.bg:
            code = BG_ANSI_COLORS[match]
        else:
            code = FG_ANSI_COLORS[match]

        return code, match


class _256ColorCache(Dict[Tuple[int, int, int], int]):
    """
    Cache which maps (r, g, b) tuples to 256 colors.
    """

    def __init__(self) -> None:
        # Build color table.
        colors: List[Tuple[int, int, int]] = []

        # colors 0..15: 16 basic colors
        colors.append((0x00, 0x00, 0x00))  # 0
        colors.append((0xCD, 0x00, 0x00))  # 1
        colors.append((0x00, 0xCD, 0x00))  # 2
        colors.append((0xCD, 0xCD, 0x00))  # 3
        colors.append((0x00, 0x00, 0xEE))  # 4
        colors.append((0xCD, 0x00, 0xCD))  # 5
        colors.append((0x00, 0xCD, 0xCD))  # 6
        colors.append((0xE5, 0xE5, 0xE5))  # 7
        colors.append((0x7F, 0x7F, 0x7F))  # 8
        colors.append((0xFF, 0x00, 0x00))  # 9
        colors.append((0x00, 0xFF, 0x00))  # 10
        colors.append((0xFF, 0xFF, 0x00))  # 11
        colors.append((0x5C, 0x5C, 0xFF))  # 12
        colors.append((0xFF, 0x00, 0xFF))  # 13
        colors.append((0x00, 0xFF, 0xFF))  # 14
        colors.append((0xFF, 0xFF, 0xFF))  # 15

        # colors 16..232: the 6x6x6 color cube
        valuerange = (0x00, 0x5F, 0x87, 0xAF, 0xD7, 0xFF)

        for i in range(217):
            r = valuerange[(i // 36) % 6]
            g = valuerange[(i // 6) % 6]
            b = valuerange[i % 6]
            colors.append((r, g, b))

        # colors 233..253: grayscale
        for i in range(1, 22):
            v = 8 + i * 10
            colors.append((v, v, v))

        self.colors = colors

    def __missing__(self, value: Tuple[int, int, int]) -> int:
        r, g, b = value

        # Find closest color.
        # (Thanks to Pygments for this!)
        distance = 257 * 257 * 3  # "infinity" (>distance from #000000 to #ffffff)
        match = 0

        for i, (r2, g2, b2) in enumerate(self.colors):
            if i >= 16:  # XXX: We ignore the 16 ANSI colors when mapping RGB
                # to the 256 colors, because these highly depend on
                # the color scheme of the terminal.
                d = (r - r2) ** 2 + (g - g2) ** 2 + (b - b2) ** 2

                if d < distance:
                    match = i
                    distance = d

        # Turn color name into code.
        self[value] = match
        return match


_16_fg_colors = _16ColorCache(bg=False)
_16_bg_colors = _16ColorCache(bg=True)
_256_colors = _256ColorCache()


class _EscapeCodeCache(Dict[Attrs, str]):
    """
    Cache for VT100 escape codes. It maps
    (fgcolor, bgcolor, bold, underline, reverse) tuples to VT100 escape sequences.

    :param true_color: When True, use 24bit colors instead of 256 colors.
    """

    def __init__(self, color_depth: ColorDepth) -> None:
        self.color_depth = color_depth

    def __missing__(self, attrs: Attrs) -> str:
        fgcolor, bgcolor, bold, underline, italic, blink, reverse, hidden = attrs
        parts: List[str] = []

        parts.extend(self._colors_to_code(fgcolor or "", bgcolor or ""))

        if bold:
            parts.append("1")
        if italic:
            parts.append("3")
        if blink:
            parts.append("5")
        if underline:
            parts.append("4")
        if reverse:
            parts.append("7")
        if hidden:
            parts.append("8")

        if parts:
            result = "\x1b[0;" + ";".join(parts) + "m"
        else:
            result = "\x1b[0m"

        self[attrs] = result
        return result

    def _color_name_to_rgb(self, color: str) -> Tuple[int, int, int]:
        " Turn 'ffffff', into (0xff, 0xff, 0xff). "
        try:
            rgb = int(color, 16)
        except ValueError:
            raise
        else:
            r = (rgb >> 16) & 0xFF
            g = (rgb >> 8) & 0xFF
            b = rgb & 0xFF
            return r, g, b

    def _colors_to_code(self, fg_color: str, bg_color: str) -> Iterable[str]:
        """
        Return a tuple with the vt100 values  that represent this color.
        """
        # When requesting ANSI colors only, and both fg/bg color were converted
        # to ANSI, ensure that the foreground and background color are not the
        # same. (Unless they were explicitly defined to be the same color.)
        fg_ansi = ""

        def get(color: str, bg: bool) -> List[int]:
            nonlocal fg_ansi

            table = BG_ANSI_COLORS if bg else FG_ANSI_COLORS

            if not color or self.color_depth == ColorDepth.DEPTH_1_BIT:
                return []

            # 16 ANSI colors. (Given by name.)
            elif color in table:
                return [table[color]]

            # RGB colors. (Defined as 'ffffff'.)
            else:
                try:
                    rgb = self._color_name_to_rgb(color)
                except ValueError:
                    return []

                # When only 16 colors are supported, use that.
                if self.color_depth == ColorDepth.DEPTH_4_BIT:
                    if bg:  # Background.
                        if fg_color != bg_color:
                            exclude = [fg_ansi]
                        else:
                            exclude = []
                        code, name = _16_bg_colors.get_code(rgb, exclude=exclude)
                        return [code]
                    else:  # Foreground.
                        code, name = _16_fg_colors.get_code(rgb)
                        fg_ansi = name
                        return [code]

                # True colors. (Only when this feature is enabled.)
                elif self.color_depth == ColorDepth.DEPTH_24_BIT:
                    r, g, b = rgb
                    return [(48 if bg else 38), 2, r, g, b]

                # 256 RGB colors.
                else:
                    return [(48 if bg else 38), 5, _256_colors[rgb]]

        result: List[int] = []
        result.extend(get(fg_color, False))
        result.extend(get(bg_color, True))

        return map(str, result)


def _get_size(fileno: int) -> Tuple[int, int]:
    # Thanks to fabric (fabfile.org), and
    # http://sqizit.bartletts.id.au/2011/02/14/pseudo-terminals-in-python/
    """
    Get the size of this pseudo terminal.

    :param fileno: stdout.fileno()
    :returns: A (rows, cols) tuple.
    """
    # Inline imports, because these modules are not available on Windows.
    # (This file is used by ConEmuOutput, which is used on Windows.)
    import fcntl
    import termios

    # Buffer for the C call
    buf = array.array("h", [0, 0, 0, 0])

    # Do TIOCGWINSZ (Get)
    # Note: We should not pass 'True' as a fourth parameter to 'ioctl'. (True
    #       is the default.) This causes segmentation faults on some systems.
    #       See: https://github.com/jonathanslenders/python-prompt-toolkit/pull/364
    fcntl.ioctl(fileno, termios.TIOCGWINSZ, buf)  # type: ignore

    # Return rows, cols
    return buf[0], buf[1]


class Vt100_Output(Output):
    """
    :param get_size: A callable which returns the `Size` of the output terminal.
    :param stdout: Any object with has a `write` and `flush` method + an 'encoding' property.
    :param term: The terminal environment variable. (xterm, xterm-256color, linux, ...)
    :param write_binary: Encode the output before writing it. If `True` (the
        default), the `stdout` object is supposed to expose an `encoding` attribute.
    """

    # For the error messages. Only display "Output is not a terminal" once per
    # file descriptor.
    _fds_not_a_terminal: Set[int] = set()

    def __init__(
        self,
        stdout: TextIO,
        get_size: Callable[[], Size],
        term: Optional[str] = None,
        write_binary: bool = True,
    ) -> None:

        assert all(hasattr(stdout, a) for a in ("write", "flush"))

        if write_binary:
            assert hasattr(stdout, "encoding")

        self._buffer: List[str] = []
        self.stdout = stdout
        self.write_binary = write_binary
        self._get_size = get_size
        self.term = term or "xterm"

        # Cache for escape codes.
        self._escape_code_caches: Dict[ColorDepth, _EscapeCodeCache] = {
            ColorDepth.DEPTH_1_BIT: _EscapeCodeCache(ColorDepth.DEPTH_1_BIT),
            ColorDepth.DEPTH_4_BIT: _EscapeCodeCache(ColorDepth.DEPTH_4_BIT),
            ColorDepth.DEPTH_8_BIT: _EscapeCodeCache(ColorDepth.DEPTH_8_BIT),
            ColorDepth.DEPTH_24_BIT: _EscapeCodeCache(ColorDepth.DEPTH_24_BIT),
        }

    @classmethod
    def from_pty(cls, stdout: TextIO, term: Optional[str] = None) -> "Vt100_Output":
        """
        Create an Output class from a pseudo terminal.
        (This will take the dimensions by reading the pseudo
        terminal attributes.)
        """
        # Normally, this requires a real TTY device, but people instantiate
        # this class often during unit tests as well. For convenience, we print
        # an error message, use standard dimensions, and go on.
        fd = stdout.fileno()

        if not stdout.isatty() and fd not in cls._fds_not_a_terminal:
            msg = "Warning: Output is not a terminal (fd=%r).\n"
            sys.stderr.write(msg % fd)
            sys.stderr.flush()
            cls._fds_not_a_terminal.add(fd)

        def get_size() -> Size:
            # If terminal (incorrectly) reports its size as 0, pick a
            # reasonable default.  See
            # https://github.com/ipython/ipython/issues/10071
            rows, columns = (None, None)

            # It is possible that `stdout` is no longer a TTY device at this
            # point. In that case we get an `OSError` in the ioctl call in
            # `get_size`. See:
            # https://github.com/prompt-toolkit/python-prompt-toolkit/pull/1021
            try:
                rows, columns = _get_size(stdout.fileno())
            except OSError:
                pass
            return Size(rows=rows or 24, columns=columns or 80)

        return cls(stdout, get_size, term=term)

    def get_size(self) -> Size:
        return self._get_size()

    def fileno(self) -> int:
        " Return file descriptor. "
        return self.stdout.fileno()

    def encoding(self) -> str:
        " Return encoding used for stdout. "
        return self.stdout.encoding

    def write_raw(self, data: str) -> None:
        """
        Write raw data to output.
        """
        self._buffer.append(data)

    def write(self, data: str) -> None:
        """
        Write text to output.
        (Removes vt100 escape codes. -- used for safely writing text.)
        """
        self._buffer.append(data.replace("\x1b", "?"))

    def set_title(self, title: str) -> None:
        """
        Set terminal title.
        """
        if self.term not in (
            "linux",
            "eterm-color",
        ):  # Not supported by the Linux console.
            self.write_raw(
                "\x1b]2;%s\x07" % title.replace("\x1b", "").replace("\x07", "")
            )

    def clear_title(self) -> None:
        self.set_title("")

    def erase_screen(self) -> None:
        """
        Erases the screen with the background colour and moves the cursor to
        home.
        """
        self.write_raw("\x1b[2J")

    def enter_alternate_screen(self) -> None:
        self.write_raw("\x1b[?1049h\x1b[H")

    def quit_alternate_screen(self) -> None:
        self.write_raw("\x1b[?1049l")

    def enable_mouse_support(self) -> None:
        self.write_raw("\x1b[?1000h")

        # Enable urxvt Mouse mode. (For terminals that understand this.)
        self.write_raw("\x1b[?1015h")

        # Also enable Xterm SGR mouse mode. (For terminals that understand this.)
        self.write_raw("\x1b[?1006h")

        # Note: E.g. lxterminal understands 1000h, but not the urxvt or sgr
        #       extensions.

    def disable_mouse_support(self) -> None:
        self.write_raw("\x1b[?1000l")
        self.write_raw("\x1b[?1015l")
        self.write_raw("\x1b[?1006l")

    def erase_end_of_line(self) -> None:
        """
        Erases from the current cursor position to the end of the current line.
        """
        self.write_raw("\x1b[K")

    def erase_down(self) -> None:
        """
        Erases the screen from the current line down to the bottom of the
        screen.
        """
        self.write_raw("\x1b[J")

    def reset_attributes(self) -> None:
        self.write_raw("\x1b[0m")

    def set_attributes(self, attrs: Attrs, color_depth: ColorDepth) -> None:
        """
        Create new style and output.

        :param attrs: `Attrs` instance.
        """
        # Get current depth.
        escape_code_cache = self._escape_code_caches[color_depth]

        # Write escape character.
        self.write_raw(escape_code_cache[attrs])

    def disable_autowrap(self) -> None:
        self.write_raw("\x1b[?7l")

    def enable_autowrap(self) -> None:
        self.write_raw("\x1b[?7h")

    def enable_bracketed_paste(self) -> None:
        self.write_raw("\x1b[?2004h")

    def disable_bracketed_paste(self) -> None:
        self.write_raw("\x1b[?2004l")

    def cursor_goto(self, row: int = 0, column: int = 0) -> None:
        """
        Move cursor position.
        """
        self.write_raw("\x1b[%i;%iH" % (row, column))

    def cursor_up(self, amount: int) -> None:
        if amount == 0:
            pass
        elif amount == 1:
            self.write_raw("\x1b[A")
        else:
            self.write_raw("\x1b[%iA" % amount)

    def cursor_down(self, amount: int) -> None:
        if amount == 0:
            pass
        elif amount == 1:
            # Note: Not the same as '\n', '\n' can cause the window content to
            #       scroll.
            self.write_raw("\x1b[B")
        else:
            self.write_raw("\x1b[%iB" % amount)

    def cursor_forward(self, amount: int) -> None:
        if amount == 0:
            pass
        elif amount == 1:
            self.write_raw("\x1b[C")
        else:
            self.write_raw("\x1b[%iC" % amount)

    def cursor_backward(self, amount: int) -> None:
        if amount == 0:
            pass
        elif amount == 1:
            self.write_raw("\b")  # '\x1b[D'
        else:
            self.write_raw("\x1b[%iD" % amount)

    def hide_cursor(self) -> None:
        self.write_raw("\x1b[?25l")

    def show_cursor(self) -> None:
        self.write_raw("\x1b[?12l\x1b[?25h")  # Stop blinking cursor and show.

    def flush(self) -> None:
        """
        Write to output stream and flush.
        """
        if not self._buffer:
            return

        data = "".join(self._buffer)

        try:
            # (We try to encode ourself, because that way we can replace
            # characters that don't exist in the character set, avoiding
            # UnicodeEncodeError crashes. E.g. u'\xb7' does not appear in 'ascii'.)
            # My Arch Linux installation of july 2015 reported 'ANSI_X3.4-1968'
            # for sys.stdout.encoding in xterm.
            out: IO
            if self.write_binary:
                if hasattr(self.stdout, "buffer"):
                    out = self.stdout.buffer  # Py3.
                else:
                    out = self.stdout
                out.write(data.encode(self.stdout.encoding or "utf-8", "replace"))
            else:
                self.stdout.write(data)

            self.stdout.flush()
        except IOError as e:
            if e.args and e.args[0] == errno.EINTR:
                # Interrupted system call. Can happen in case of a window
                # resize signal. (Just ignore. The resize handler will render
                # again anyway.)
                pass
            elif e.args and e.args[0] == 0:
                # This can happen when there is a lot of output and the user
                # sends a KeyboardInterrupt by pressing Control-C. E.g. in
                # a Python REPL when we execute "while True: print('test')".
                # (The `ptpython` REPL uses this `Output` class instead of
                # `stdout` directly -- in order to be network transparent.)
                # So, just ignore.
                pass
            else:
                raise

        self._buffer = []

    def ask_for_cpr(self) -> None:
        """
        Asks for a cursor position report (CPR).
        """
        self.write_raw("\x1b[6n")
        self.flush()

    def bell(self) -> None:
        " Sound bell. "
        self.write_raw("\a")
        self.flush()
