import re
from functools import partial, reduce
from math import gcd
from operator import itemgetter
from typing import (
    TYPE_CHECKING,
    Any,
    Callable,
    Dict,
    Iterable,
    List,
    NamedTuple,
    Optional,
    Tuple,
    Union,
)

from ._loop import loop_last
from ._pick import pick_bool
from ._wrap import divide_line
from .align import AlignMethod
from .cells import cell_len, set_cell_size
from .containers import Lines
from .control import strip_control_codes
from .emoji import EmojiVariant
from .jupyter import JupyterMixin
from .measure import Measurement
from .segment import Segment
from .style import Style, StyleType

if TYPE_CHECKING:  # pragma: no cover
    from .console import Console, ConsoleOptions, JustifyMethod, OverflowMethod

DEFAULT_JUSTIFY: "JustifyMethod" = "default"
DEFAULT_OVERFLOW: "OverflowMethod" = "fold"


_re_whitespace = re.compile(r"\s+$")

TextType = Union[str, "Text"]
"""A plain string or a :class:`Text` instance."""

GetStyleCallable = Callable[[str], Optional[StyleType]]


class Span(NamedTuple):
    """A marked up region in some text."""

    start: int
    """Span start index."""
    end: int
    """Span end index."""
    style: Union[str, Style]
    """Style associated with the span."""

    def __repr__(self) -> str:
        return f"Span({self.start}, {self.end}, {self.style!r})"

    def __bool__(self) -> bool:
        return self.end > self.start

    def split(self, offset: int) -> Tuple["Span", Optional["Span"]]:
        """Split a span in to 2 from a given offset."""

        if offset < self.start:
            return self, None
        if offset >= self.end:
            return self, None

        start, end, style = self
        span1 = Span(start, min(end, offset), style)
        span2 = Span(span1.end, end, style)
        return span1, span2

    def move(self, offset: int) -> "Span":
        """Move start and end by a given offset.

        Args:
            offset (int): Number of characters to add to start and end.

        Returns:
            TextSpan: A new TextSpan with adjusted position.
        """
        start, end, style = self
        return Span(start + offset, end + offset, style)

    def right_crop(self, offset: int) -> "Span":
        """Crop the span at the given offset.

        Args:
            offset (int): A value between start and end.

        Returns:
            Span: A new (possibly smaller) span.
        """
        start, end, style = self
        if offset >= end:
            return self
        return Span(start, min(offset, end), style)

    def extend(self, cells: int) -> "Span":
        """Extend the span by the given number of cells.

        Args:
            cells (int): Additional space to add to end of span.

        Returns:
            Span: A span.
        """
        if cells:
            start, end, style = self
            return Span(start, end + cells, style)
        else:
            return self


class Text(JupyterMixin):
    """Text with color / style.

    Args:
        text (str, optional): Default unstyled text. Defaults to "".
        style (Union[str, Style], optional): Base style for text. Defaults to "".
        justify (str, optional): Justify method: "left", "center", "full", "right". Defaults to None.
        overflow (str, optional): Overflow method: "crop", "fold", "ellipsis". Defaults to None.
        no_wrap (bool, optional): Disable text wrapping, or None for default. Defaults to None.
        end (str, optional): Character to end text with. Defaults to "\\\\n".
        tab_size (int): Number of spaces per tab, or ``None`` to use ``console.tab_size``. Defaults to None.
        spans (List[Span], optional). A list of predefined style spans. Defaults to None.
    """

    __slots__ = [
        "_text",
        "style",
        "justify",
        "overflow",
        "no_wrap",
        "end",
        "tab_size",
        "_spans",
        "_length",
    ]

    def __init__(
        self,
        text: str = "",
        style: Union[str, Style] = "",
        *,
        justify: Optional["JustifyMethod"] = None,
        overflow: Optional["OverflowMethod"] = None,
        no_wrap: Optional[bool] = None,
        end: str = "\n",
        tab_size: Optional[int] = None,
        spans: Optional[List[Span]] = None,
    ) -> None:
        sanitized_text = strip_control_codes(text)
        self._text = [sanitized_text]
        self.style = style
        self.justify: Optional["JustifyMethod"] = justify
        self.overflow: Optional["OverflowMethod"] = overflow
        self.no_wrap = no_wrap
        self.end = end
        self.tab_size = tab_size
        self._spans: List[Span] = spans or []
        self._length: int = len(sanitized_text)

    def __len__(self) -> int:
        return self._length

    def __bool__(self) -> bool:
        return bool(self._length)

    def __str__(self) -> str:
        return self.plain

    def __repr__(self) -> str:
        return f"<text {self.plain!r} {self._spans!r}>"

    def __add__(self, other: Any) -> "Text":
        if isinstance(other, (str, Text)):
            result = self.copy()
            result.append(other)
            return result
        return NotImplemented

    def __eq__(self, other: object) -> bool:
        if not isinstance(other, Text):
            return NotImplemented
        return self.plain == other.plain and self._spans == other._spans

    def __contains__(self, other: object) -> bool:
        if isinstance(other, str):
            return other in self.plain
        elif isinstance(other, Text):
            return other.plain in self.plain
        return False

    def __getitem__(self, slice: Union[int, slice]) -> "Text":
        def get_text_at(offset: int) -> "Text":
            _Span = Span
            text = Text(
                self.plain[offset],
                spans=[
                    _Span(0, 1, style)
                    for start, end, style in self._spans
                    if end > offset >= start
                ],
                end="",
            )
            return text

        if isinstance(slice, int):
            return get_text_at(slice)
        else:
            start, stop, step = slice.indices(len(self.plain))
            if step == 1:
                lines = self.divide([start, stop])
                return lines[1]
            else:
                # This would be a bit of work to implement efficiently
                # For now, its not required
                raise TypeError("slices with step!=1 are not supported")

    @property
    def cell_len(self) -> int:
        """Get the number of cells required to render this text."""
        return cell_len(self.plain)

    @property
    def markup(self) -> str:
        """Get console markup to render this Text.

        Returns:
            str: A string potentially creating markup tags.
        """
        from .markup import escape

        output: List[str] = []

        plain = self.plain
        markup_spans = [
            (0, False, self.style),
            *((span.start, False, span.style) for span in self._spans),
            *((span.end, True, span.style) for span in self._spans),
            (len(plain), True, self.style),
        ]
        markup_spans.sort(key=itemgetter(0, 1))
        position = 0
        append = output.append
        for offset, closing, style in markup_spans:
            if offset > position:
                append(escape(plain[position:offset]))
                position = offset
            if style:
                append(f"[/{style}]" if closing else f"[{style}]")
        markup = "".join(output)
        return markup

    @classmethod
    def from_markup(
        cls,
        text: str,
        *,
        style: Union[str, Style] = "",
        emoji: bool = True,
        emoji_variant: Optional[EmojiVariant] = None,
        justify: Optional["JustifyMethod"] = None,
        overflow: Optional["OverflowMethod"] = None,
        end: str = "\n",
    ) -> "Text":
        """Create Text instance from markup.

        Args:
            text (str): A string containing console markup.
            style (Union[str, Style], optional): Base style for text. Defaults to "".
            emoji (bool, optional): Also render emoji code. Defaults to True.
            emoji_variant (str, optional): Optional emoji variant, either "text" or "emoji". Defaults to None.
            justify (str, optional): Justify method: "left", "center", "full", "right". Defaults to None.
            overflow (str, optional): Overflow method: "crop", "fold", "ellipsis". Defaults to None.
            end (str, optional): Character to end text with. Defaults to "\\\\n".

        Returns:
            Text: A Text instance with markup rendered.
        """
        from .markup import render

        rendered_text = render(text, style, emoji=emoji, emoji_variant=emoji_variant)
        rendered_text.justify = justify
        rendered_text.overflow = overflow
        rendered_text.end = end
        return rendered_text

    @classmethod
    def from_ansi(
        cls,
        text: str,
        *,
        style: Union[str, Style] = "",
        justify: Optional["JustifyMethod"] = None,
        overflow: Optional["OverflowMethod"] = None,
        no_wrap: Optional[bool] = None,
        end: str = "\n",
        tab_size: Optional[int] = 8,
    ) -> "Text":
        """Create a Text object from a string containing ANSI escape codes.

        Args:
            text (str): A string containing escape codes.
            style (Union[str, Style], optional): Base style for text. Defaults to "".
            justify (str, optional): Justify method: "left", "center", "full", "right". Defaults to None.
            overflow (str, optional): Overflow method: "crop", "fold", "ellipsis". Defaults to None.
            no_wrap (bool, optional): Disable text wrapping, or None for default. Defaults to None.
            end (str, optional): Character to end text with. Defaults to "\\\\n".
            tab_size (int): Number of spaces per tab, or ``None`` to use ``console.tab_size``. Defaults to None.
        """
        from .ansi import AnsiDecoder

        joiner = Text(
            "\n",
            justify=justify,
            overflow=overflow,
            no_wrap=no_wrap,
            end=end,
            tab_size=tab_size,
            style=style,
        )
        decoder = AnsiDecoder()
        result = joiner.join(line for line in decoder.decode(text))
        return result

    @classmethod
    def styled(
        cls,
        text: str,
        style: StyleType = "",
        *,
        justify: Optional["JustifyMethod"] = None,
        overflow: Optional["OverflowMethod"] = None,
    ) -> "Text":
        """Construct a Text instance with a pre-applied styled. A style applied in this way won't be used
        to pad the text when it is justified.

        Args:
            text (str): A string containing console markup.
            style (Union[str, Style]): Style to apply to the text. Defaults to "".
            justify (str, optional): Justify method: "left", "center", "full", "right". Defaults to None.
            overflow (str, optional): Overflow method: "crop", "fold", "ellipsis". Defaults to None.

        Returns:
            Text: A text instance with a style applied to the entire string.
        """
        styled_text = cls(text, justify=justify, overflow=overflow)
        styled_text.stylize(style)
        return styled_text

    @classmethod
    def assemble(
        cls,
        *parts: Union[str, "Text", Tuple[str, StyleType]],
        style: Union[str, Style] = "",
        justify: Optional["JustifyMethod"] = None,
        overflow: Optional["OverflowMethod"] = None,
        no_wrap: Optional[bool] = None,
        end: str = "\n",
        tab_size: int = 8,
        meta: Optional[Dict[str, Any]] = None,
    ) -> "Text":
        """Construct a text instance by combining a sequence of strings with optional styles.
        The positional arguments should be either strings, or a tuple of string + style.

        Args:
            style (Union[str, Style], optional): Base style for text. Defaults to "".
            justify (str, optional): Justify method: "left", "center", "full", "right". Defaults to None.
            overflow (str, optional): Overflow method: "crop", "fold", "ellipsis". Defaults to None.
            no_wrap (bool, optional): Disable text wrapping, or None for default. Defaults to None.
            end (str, optional): Character to end text with. Defaults to "\\\\n".
            tab_size (int): Number of spaces per tab, or ``None`` to use ``console.tab_size``. Defaults to None.
            meta (Dict[str, Any], optional). Meta data to apply to text, or None for no meta data. Default to None

        Returns:
            Text: A new text instance.
        """
        text = cls(
            style=style,
            justify=justify,
            overflow=overflow,
            no_wrap=no_wrap,
            end=end,
            tab_size=tab_size,
        )
        append = text.append
        _Text = Text
        for part in parts:
            if isinstance(part, (_Text, str)):
                append(part)
            else:
                append(*part)
        if meta:
            text.apply_meta(meta)
        return text

    @property
    def plain(self) -> str:
        """Get the text as a single string."""
        if len(self._text) != 1:
            self._text[:] = ["".join(self._text)]
        return self._text[0]

    @plain.setter
    def plain(self, new_text: str) -> None:
        """Set the text to a new value."""
        if new_text != self.plain:
            sanitized_text = strip_control_codes(new_text)
            self._text[:] = [sanitized_text]
            old_length = self._length
            self._length = len(sanitized_text)
            if old_length > self._length:
                self._trim_spans()

    @property
    def spans(self) -> List[Span]:
        """Get a reference to the internal list of spans."""
        return self._spans

    @spans.setter
    def spans(self, spans: List[Span]) -> None:
        """Set spans."""
        self._spans = spans[:]

    def blank_copy(self, plain: str = "") -> "Text":
        """Return a new Text instance with copied metadata (but not the string or spans)."""
        copy_self = Text(
            plain,
            style=self.style,
            justify=self.justify,
            overflow=self.overflow,
            no_wrap=self.no_wrap,
            end=self.end,
            tab_size=self.tab_size,
        )
        return copy_self

    def copy(self) -> "Text":
        """Return a copy of this instance."""
        copy_self = Text(
            self.plain,
            style=self.style,
            justify=self.justify,
            overflow=self.overflow,
            no_wrap=self.no_wrap,
            end=self.end,
            tab_size=self.tab_size,
        )
        copy_self._spans[:] = self._spans
        return copy_self

    def stylize(
        self,
        style: Union[str, Style],
        start: int = 0,
        end: Optional[int] = None,
    ) -> None:
        """Apply a style to the text, or a portion of the text.

        Args:
            style (Union[str, Style]): Style instance or style definition to apply.
            start (int): Start offset (negative indexing is supported). Defaults to 0.
            end (Optional[int], optional): End offset (negative indexing is supported), or None for end of text. Defaults to None.
        """
        if style:
            length = len(self)
            if start < 0:
                start = length + start
            if end is None:
                end = length
            if end < 0:
                end = length + end
            if start >= length or end <= start:
                # Span not in text or not valid
                return
            self._spans.append(Span(start, min(length, end), style))

    def stylize_before(
        self,
        style: Union[str, Style],
        start: int = 0,
        end: Optional[int] = None,
    ) -> None:
        """Apply a style to the text, or a portion of the text. Styles will be applied before other styles already present.

        Args:
            style (Union[str, Style]): Style instance or style definition to apply.
            start (int): Start offset (negative indexing is supported). Defaults to 0.
            end (Optional[int], optional): End offset (negative indexing is supported), or None for end of text. Defaults to None.
        """
        if style:
            length = len(self)
            if start < 0:
                start = length + start
            if end is None:
                end = length
            if end < 0:
                end = length + end
            if start >= length or end <= start:
                # Span not in text or not valid
                return
            self._spans.insert(0, Span(start, min(length, end), style))

    def apply_meta(
        self, meta: Dict[str, Any], start: int = 0, end: Optional[int] = None
    ) -> None:
        """Apply metadata to the text, or a portion of the text.

        Args:
            meta (Dict[str, Any]): A dict of meta information.
            start (int): Start offset (negative indexing is supported). Defaults to 0.
            end (Optional[int], optional): End offset (negative indexing is supported), or None for end of text. Defaults to None.

        """
        style = Style.from_meta(meta)
        self.stylize(style, start=start, end=end)

    def on(self, meta: Optional[Dict[str, Any]] = None, **handlers: Any) -> "Text":
        """Apply event handlers (used by Textual project).

        Example:
            >>> from rich.text import Text
            >>> text = Text("hello world")
            >>> text.on(click="view.toggle('world')")

        Args:
            meta (Dict[str, Any]): Mapping of meta information.
            **handlers: Keyword args are prefixed with "@" to defined handlers.

        Returns:
            Text: Self is returned to method may be chained.
        """
        meta = {} if meta is None else meta
        meta.update({f"@{key}": value for key, value in handlers.items()})
        self.stylize(Style.from_meta(meta))
        return self

    def remove_suffix(self, suffix: str) -> None:
        """Remove a suffix if it exists.

        Args:
            suffix (str): Suffix to remove.
        """
        if self.plain.endswith(suffix):
            self.right_crop(len(suffix))

    def get_style_at_offset(self, console: "Console", offset: int) -> Style:
        """Get the style of a character at give offset.

        Args:
            console (~Console): Console where text will be rendered.
            offset (int): Offset in to text (negative indexing supported)

        Returns:
            Style: A Style instance.
        """
        # TODO: This is a little inefficient, it is only used by full justify
        if offset < 0:
            offset = len(self) + offset
        get_style = console.get_style
        style = get_style(self.style).copy()
        for start, end, span_style in self._spans:
            if end > offset >= start:
                style += get_style(span_style, default="")
        return style

    def extend_style(self, spaces: int) -> None:
        """Extend the Text given number of spaces where the spaces have the same style as the last character.

        Args:
            spaces (int): Number of spaces to add to the Text.
        """
        if spaces <= 0:
            return
        spans = self.spans
        new_spaces = " " * spaces
        if spans:
            end_offset = len(self)
            self._spans[:] = [
                span.extend(spaces) if span.end >= end_offset else span
                for span in spans
            ]
            self._text.append(new_spaces)
            self._length += spaces
        else:
            self.plain += new_spaces

    def highlight_regex(
        self,
        re_highlight: str,
        style: Optional[Union[GetStyleCallable, StyleType]] = None,
        *,
        style_prefix: str = "",
    ) -> int:
        """Highlight text with a regular expression, where group names are
        translated to styles.

        Args:
            re_highlight (str): A regular expression.
            style (Union[GetStyleCallable, StyleType]): Optional style to apply to whole match, or a callable
                which accepts the matched text and returns a style. Defaults to None.
            style_prefix (str, optional): Optional prefix to add to style group names.

        Returns:
            int: Number of regex matches
        """
        count = 0
        append_span = self._spans.append
        _Span = Span
        plain = self.plain
        for match in re.finditer(re_highlight, plain):
            get_span = match.span
            if style:
                start, end = get_span()
                match_style = style(plain[start:end]) if callable(style) else style
                if match_style is not None and end > start:
                    append_span(_Span(start, end, match_style))

            count += 1
            for name in match.groupdict().keys():
                start, end = get_span(name)
                if start != -1 and end > start:
                    append_span(_Span(start, end, f"{style_prefix}{name}"))
        return count

    def highlight_words(
        self,
        words: Iterable[str],
        style: Union[str, Style],
        *,
        case_sensitive: bool = True,
    ) -> int:
        """Highlight words with a style.

        Args:
            words (Iterable[str]): Words to highlight.
            style (Union[str, Style]): Style to apply.
            case_sensitive (bool, optional): Enable case sensitive matching. Defaults to True.

        Returns:
            int: Number of words highlighted.
        """
        re_words = "|".join(re.escape(word) for word in words)
        add_span = self._spans.append
        count = 0
        _Span = Span
        for match in re.finditer(
            re_words, self.plain, flags=0 if case_sensitive else re.IGNORECASE
        ):
            start, end = match.span(0)
            add_span(_Span(start, end, style))
            count += 1
        return count

    def rstrip(self) -> None:
        """Strip whitespace from end of text."""
        self.plain = self.plain.rstrip()

    def rstrip_end(self, size: int) -> None:
        """Remove whitespace beyond a certain width at the end of the text.

        Args:
            size (int): The desired size of the text.
        """
        text_length = len(self)
        if text_length > size:
            excess = text_length - size
            whitespace_match = _re_whitespace.search(self.plain)
            if whitespace_match is not None:
                whitespace_count = len(whitespace_match.group(0))
                self.right_crop(min(whitespace_count, excess))

    def set_length(self, new_length: int) -> None:
        """Set new length of the text, clipping or padding is required."""
        length = len(self)
        if length != new_length:
            if length < new_length:
                self.pad_right(new_length - length)
            else:
                self.right_crop(length - new_length)

    def __rich_console__(
        self, console: "Console", options: "ConsoleOptions"
    ) -> Iterable[Segment]:
        tab_size: int = console.tab_size if self.tab_size is None else self.tab_size
        justify = self.justify or options.justify or DEFAULT_JUSTIFY

        overflow = self.overflow or options.overflow or DEFAULT_OVERFLOW

        lines = self.wrap(
            console,
            options.max_width,
            justify=justify,
            overflow=overflow,
            tab_size=tab_size or 8,
            no_wrap=pick_bool(self.no_wrap, options.no_wrap, False),
        )
        all_lines = Text("\n").join(lines)
        yield from all_lines.render(console, end=self.end)

    def __rich_measure__(
        self, console: "Console", options: "ConsoleOptions"
    ) -> Measurement:
        text = self.plain
        lines = text.splitlines()
        max_text_width = max(cell_len(line) for line in lines) if lines else 0
        words = text.split()
        min_text_width = (
            max(cell_len(word) for word in words) if words else max_text_width
        )
        return Measurement(min_text_width, max_text_width)

    def render(self, console: "Console", end: str = "") -> Iterable["Segment"]:
        """Render the text as Segments.

        Args:
            console (Console): Console instance.
            end (Optional[str], optional): Optional end character.

        Returns:
            Iterable[Segment]: Result of render that may be written to the console.
        """
        _Segment = Segment
        text = self.plain
        if not self._spans:
            yield Segment(text)
            if end:
                yield _Segment(end)
            return
        get_style = partial(console.get_style, default=Style.null())

        enumerated_spans = list(enumerate(self._spans, 1))
        style_map = {index: get_style(span.style) for index, span in enumerated_spans}
        style_map[0] = get_style(self.style)

        spans = [
            (0, False, 0),
            *((span.start, False, index) for index, span in enumerated_spans),
            *((span.end, True, index) for index, span in enumerated_spans),
            (len(text), True, 0),
        ]
        spans.sort(key=itemgetter(0, 1))

        stack: List[int] = []
        stack_append = stack.append
        stack_pop = stack.remove

        style_cache: Dict[Tuple[Style, ...], Style] = {}
        style_cache_get = style_cache.get
        combine = Style.combine

        def get_current_style() -> Style:
            """Construct current style from stack."""
            styles = tuple(style_map[_style_id] for _style_id in sorted(stack))
            cached_style = style_cache_get(styles)
            if cached_style is not None:
                return cached_style
            current_style = combine(styles)
            style_cache[styles] = current_style
            return current_style

        for (offset, leaving, style_id), (next_offset, _, _) in zip(spans, spans[1:]):
            if leaving:
                stack_pop(style_id)
            else:
                stack_append(style_id)
            if next_offset > offset:
                yield _Segment(text[offset:next_offset], get_current_style())
        if end:
            yield _Segment(end)

    def join(self, lines: Iterable["Text"]) -> "Text":
        """Join text together with this instance as the separator.

        Args:
            lines (Iterable[Text]): An iterable of Text instances to join.

        Returns:
            Text: A new text instance containing join text.
        """

        new_text = self.blank_copy()

        def iter_text() -> Iterable["Text"]:
            if self.plain:
                for last, line in loop_last(lines):
                    yield line
                    if not last:
                        yield self
            else:
                yield from lines

        extend_text = new_text._text.extend
        append_span = new_text._spans.append
        extend_spans = new_text._spans.extend
        offset = 0
        _Span = Span

        for text in iter_text():
            extend_text(text._text)
            if text.style:
                append_span(_Span(offset, offset + len(text), text.style))
            extend_spans(
                _Span(offset + start, offset + end, style)
                for start, end, style in text._spans
            )
            offset += len(text)
        new_text._length = offset
        return new_text

    def expand_tabs(self, tab_size: Optional[int] = None) -> None:
        """Converts tabs to spaces.

        Args:
            tab_size (int, optional): Size of tabs. Defaults to 8.

        """
        if "\t" not in self.plain:
            return
        if tab_size is None:
            tab_size = self.tab_size
        if tab_size is None:
            tab_size = 8

        new_text: List[Text] = []
        append = new_text.append

        for line in self.split("\n", include_separator=True):
            if "\t" not in line.plain:
                append(line)
            else:
                cell_position = 0
                parts = line.split("\t", include_separator=True)
                for part in parts:
                    if part.plain.endswith("\t"):
                        part._text[-1] = part._text[-1][:-1] + " "
                        cell_position += part.cell_len
                        tab_remainder = cell_position % tab_size
                        if tab_remainder:
                            spaces = tab_size - tab_remainder
                            part.extend_style(spaces)
                            cell_position += spaces
                    else:
                        cell_position += part.cell_len
                    append(part)

        result = Text("").join(new_text)

        self._text = [result.plain]
        self._length = len(self.plain)
        self._spans[:] = result._spans

    def truncate(
        self,
        max_width: int,
        *,
        overflow: Optional["OverflowMethod"] = None,
        pad: bool = False,
    ) -> None:
        """Truncate text if it is longer that a given width.

        Args:
            max_width (int): Maximum number of characters in text.
            overflow (str, optional): Overflow method: "crop", "fold", or "ellipsis". Defaults to None, to use self.overflow.
            pad (bool, optional): Pad with spaces if the length is less than max_width. Defaults to False.
        """
        _overflow = overflow or self.overflow or DEFAULT_OVERFLOW
        if _overflow != "ignore":
            length = cell_len(self.plain)
            if length > max_width:
                if _overflow == "ellipsis":
                    self.plain = set_cell_size(self.plain, max_width - 1) + "…"
                else:
                    self.plain = set_cell_size(self.plain, max_width)
            if pad and length < max_width:
                spaces = max_width - length
                self._text = [f"{self.plain}{' ' * spaces}"]
                self._length = len(self.plain)

    def _trim_spans(self) -> None:
        """Remove or modify any spans that are over the end of the text."""
        max_offset = len(self.plain)
        _Span = Span
        self._spans[:] = [
            (
                span
                if span.end < max_offset
                else _Span(span.start, min(max_offset, span.end), span.style)
            )
            for span in self._spans
            if span.start < max_offset
        ]

    def pad(self, count: int, character: str = " ") -> None:
        """Pad left and right with a given number of characters.

        Args:
            count (int): Width of padding.
            character (str): The character to pad with. Must be a string of length 1.
        """
        assert len(character) == 1, "Character must be a string of length 1"
        if count:
            pad_characters = character * count
            self.plain = f"{pad_characters}{self.plain}{pad_characters}"
            _Span = Span
            self._spans[:] = [
                _Span(start + count, end + count, style)
                for start, end, style in self._spans
            ]

    def pad_left(self, count: int, character: str = " ") -> None:
        """Pad the left with a given character.

        Args:
            count (int): Number of characters to pad.
            character (str, optional): Character to pad with. Defaults to " ".
        """
        assert len(character) == 1, "Character must be a string of length 1"
        if count:
            self.plain = f"{character * count}{self.plain}"
            _Span = Span
            self._spans[:] = [
                _Span(start + count, end + count, style)
                for start, end, style in self._spans
            ]

    def pad_right(self, count: int, character: str = " ") -> None:
        """Pad the right with a given character.

        Args:
            count (int): Number of characters to pad.
            character (str, optional): Character to pad with. Defaults to " ".
        """
        assert len(character) == 1, "Character must be a string of length 1"
        if count:
            self.plain = f"{self.plain}{character * count}"

    def align(self, align: AlignMethod, width: int, character: str = " ") -> None:
        """Align text to a given width.

        Args:
            align (AlignMethod): One of "left", "center", or "right".
            width (int): Desired width.
            character (str, optional): Character to pad with. Defaults to " ".
        """
        self.truncate(width)
        excess_space = width - cell_len(self.plain)
        if excess_space:
            if align == "left":
                self.pad_right(excess_space, character)
            elif align == "center":
                left = excess_space // 2
                self.pad_left(left, character)
                self.pad_right(excess_space - left, character)
            else:
                self.pad_left(excess_space, character)

    def append(
        self, text: Union["Text", str], style: Optional[Union[str, "Style"]] = None
    ) -> "Text":
        """Add text with an optional style.

        Args:
            text (Union[Text, str]): A str or Text to append.
            style (str, optional): A style name. Defaults to None.

        Returns:
            Text: Returns self for chaining.
        """

        if not isinstance(text, (str, Text)):
            raise TypeError("Only str or Text can be appended to Text")

        if len(text):
            if isinstance(text, str):
                sanitized_text = strip_control_codes(text)
                self._text.append(sanitized_text)
                offset = len(self)
                text_length = len(sanitized_text)
                if style:
                    self._spans.append(Span(offset, offset + text_length, style))
                self._length += text_length
            elif isinstance(text, Text):
                _Span = Span
                if style is not None:
                    raise ValueError(
                        "style must not be set when appending Text instance"
                    )
                text_length = self._length
                if text.style:
                    self._spans.append(
                        _Span(text_length, text_length + len(text), text.style)
                    )
                self._text.append(text.plain)
                self._spans.extend(
                    _Span(start + text_length, end + text_length, style)
                    for start, end, style in text._spans
                )
                self._length += len(text)
        return self

    def append_text(self, text: "Text") -> "Text":
        """Append another Text instance. This method is more performant that Text.append, but
        only works for Text.

        Args:
            text (Text): The Text instance to append to this instance.

        Returns:
            Text: Returns self for chaining.
        """
        _Span = Span
        text_length = self._length
        if text.style:
            self._spans.append(_Span(text_length, text_length + len(text), text.style))
        self._text.append(text.plain)
        self._spans.extend(
            _Span(start + text_length, end + text_length, style)
            for start, end, style in text._spans
        )
        self._length += len(text)
        return self

    def append_tokens(
        self, tokens: Iterable[Tuple[str, Optional[StyleType]]]
    ) -> "Text":
        """Append iterable of str and style. Style may be a Style instance or a str style definition.

        Args:
            tokens (Iterable[Tuple[str, Optional[StyleType]]]): An iterable of tuples containing str content and style.

        Returns:
            Text: Returns self for chaining.
        """
        append_text = self._text.append
        append_span = self._spans.append
        _Span = Span
        offset = len(self)
        for content, style in tokens:
            append_text(content)
            if style:
                append_span(_Span(offset, offset + len(content), style))
            offset += len(content)
        self._length = offset
        return self

    def copy_styles(self, text: "Text") -> None:
        """Copy styles from another Text instance.

        Args:
            text (Text): A Text instance to copy styles from, must be the same length.
        """
        self._spans.extend(text._spans)

    def split(
        self,
        separator: str = "\n",
        *,
        include_separator: bool = False,
        allow_blank: bool = False,
    ) -> Lines:
        """Split rich text in to lines, preserving styles.

        Args:
            separator (str, optional): String to split on. Defaults to "\\\\n".
            include_separator (bool, optional): Include the separator in the lines. Defaults to False.
            allow_blank (bool, optional): Return a blank line if the text ends with a separator. Defaults to False.

        Returns:
            List[RichText]: A list of rich text, one per line of the original.
        """
        assert separator, "separator must not be empty"

        text = self.plain
        if separator not in text:
            return Lines([self.copy()])

        if include_separator:
            lines = self.divide(
                match.end() for match in re.finditer(re.escape(separator), text)
            )
        else:

            def flatten_spans() -> Iterable[int]:
                for match in re.finditer(re.escape(separator), text):
                    start, end = match.span()
                    yield start
                    yield end

            lines = Lines(
                line for line in self.divide(flatten_spans()) if line.plain != separator
            )

        if not allow_blank and text.endswith(separator):
            lines.pop()

        return lines

    def divide(self, offsets: Iterable[int]) -> Lines:
        """Divide text in to a number of lines at given offsets.

        Args:
            offsets (Iterable[int]): Offsets used to divide text.

        Returns:
            Lines: New RichText instances between offsets.
        """
        _offsets = list(offsets)

        if not _offsets:
            return Lines([self.copy()])

        text = self.plain
        text_length = len(text)
        divide_offsets = [0, *_offsets, text_length]
        line_ranges = list(zip(divide_offsets, divide_offsets[1:]))

        style = self.style
        justify = self.justify
        overflow = self.overflow
        _Text = Text
        new_lines = Lines(
            _Text(
                text[start:end],
                style=style,
                justify=justify,
                overflow=overflow,
            )
            for start, end in line_ranges
        )
        if not self._spans:
            return new_lines

        _line_appends = [line._spans.append for line in new_lines._lines]
        line_count = len(line_ranges)
        _Span = Span

        for span_start, span_end, style in self._spans:
            lower_bound = 0
            upper_bound = line_count
            start_line_no = (lower_bound + upper_bound) // 2

            while True:
                line_start, line_end = line_ranges[start_line_no]
                if span_start < line_start:
                    upper_bound = start_line_no - 1
                elif span_start > line_end:
                    lower_bound = start_line_no + 1
                else:
                    break
                start_line_no = (lower_bound + upper_bound) // 2

            if span_end < line_end:
                end_line_no = start_line_no
            else:
                end_line_no = lower_bound = start_line_no
                upper_bound = line_count

                while True:
                    line_start, line_end = line_ranges[end_line_no]
                    if span_end < line_start:
                        upper_bound = end_line_no - 1
                    elif span_end > line_end:
                        lower_bound = end_line_no + 1
                    else:
                        break
                    end_line_no = (lower_bound + upper_bound) // 2

            for line_no in range(start_line_no, end_line_no + 1):
                line_start, line_end = line_ranges[line_no]
                new_start = max(0, span_start - line_start)
                new_end = min(span_end - line_start, line_end - line_start)
                if new_end > new_start:
                    _line_appends[line_no](_Span(new_start, new_end, style))

        return new_lines

    def right_crop(self, amount: int = 1) -> None:
        """Remove a number of characters from the end of the text."""
        max_offset = len(self.plain) - amount
        _Span = Span
        self._spans[:] = [
            (
                span
                if span.end < max_offset
                else _Span(span.start, min(max_offset, span.end), span.style)
            )
            for span in self._spans
            if span.start < max_offset
        ]
        self._text = [self.plain[:-amount]]
        self._length -= amount

    def wrap(
        self,
        console: "Console",
        width: int,
        *,
        justify: Optional["JustifyMethod"] = None,
        overflow: Optional["OverflowMethod"] = None,
        tab_size: int = 8,
        no_wrap: Optional[bool] = None,
    ) -> Lines:
        """Word wrap the text.

        Args:
            console (Console): Console instance.
            width (int): Number of cells available per line.
            justify (str, optional): Justify method: "default", "left", "center", "full", "right". Defaults to "default".
            overflow (str, optional): Overflow method: "crop", "fold", or "ellipsis". Defaults to None.
            tab_size (int, optional): Default tab size. Defaults to 8.
            no_wrap (bool, optional): Disable wrapping, Defaults to False.

        Returns:
            Lines: Number of lines.
        """
        wrap_justify = justify or self.justify or DEFAULT_JUSTIFY
        wrap_overflow = overflow or self.overflow or DEFAULT_OVERFLOW

        no_wrap = pick_bool(no_wrap, self.no_wrap, False) or overflow == "ignore"

        lines = Lines()
        for line in self.split(allow_blank=True):
            if "\t" in line:
                line.expand_tabs(tab_size)
            if no_wrap:
                new_lines = Lines([line])
            else:
                offsets = divide_line(str(line), width, fold=wrap_overflow == "fold")
                new_lines = line.divide(offsets)
            for line in new_lines:
                line.rstrip_end(width)
            if wrap_justify:
                new_lines.justify(
                    console, width, justify=wrap_justify, overflow=wrap_overflow
                )
            for line in new_lines:
                line.truncate(width, overflow=wrap_overflow)
            lines.extend(new_lines)
        return lines

    def fit(self, width: int) -> Lines:
        """Fit the text in to given width by chopping in to lines.

        Args:
            width (int): Maximum characters in a line.

        Returns:
            Lines: Lines container.
        """
        lines: Lines = Lines()
        append = lines.append
        for line in self.split():
            line.set_length(width)
            append(line)
        return lines

    def detect_indentation(self) -> int:
        """Auto-detect indentation of code.

        Returns:
            int: Number of spaces used to indent code.
        """

        _indentations = {
            len(match.group(1))
            for match in re.finditer(r"^( *)(.*)$", self.plain, flags=re.MULTILINE)
        }

        try:
            indentation = (
                reduce(gcd, [indent for indent in _indentations if not indent % 2]) or 1
            )
        except TypeError:
            indentation = 1

        return indentation

    def with_indent_guides(
        self,
        indent_size: Optional[int] = None,
        *,
        character: str = "│",
        style: StyleType = "dim green",
    ) -> "Text":
        """Adds indent guide lines to text.

        Args:
            indent_size (Optional[int]): Size of indentation, or None to auto detect. Defaults to None.
            character (str, optional): Character to use for indentation. Defaults to "│".
            style (Union[Style, str], optional): Style of indent guides.

        Returns:
            Text: New text with indentation guides.
        """

        _indent_size = self.detect_indentation() if indent_size is None else indent_size

        text = self.copy()
        text.expand_tabs()
        indent_line = f"{character}{' ' * (_indent_size - 1)}"

        re_indent = re.compile(r"^( *)(.*)$")
        new_lines: List[Text] = []
        add_line = new_lines.append
        blank_lines = 0
        for line in text.split(allow_blank=True):
            match = re_indent.match(line.plain)
            if not match or not match.group(2):
                blank_lines += 1
                continue
            indent = match.group(1)
            full_indents, remaining_space = divmod(len(indent), _indent_size)
            new_indent = f"{indent_line * full_indents}{' ' * remaining_space}"
            line.plain = new_indent + line.plain[len(new_indent) :]
            line.stylize(style, 0, len(new_indent))
            if blank_lines:
                new_lines.extend([Text(new_indent, style=style)] * blank_lines)
                blank_lines = 0
            add_line(line)
        if blank_lines:
            new_lines.extend([Text("", style=style)] * blank_lines)

        new_text = text.blank_copy("\n").join(new_lines)
        return new_text


if __name__ == "__main__":  # pragma: no cover
    from pip._vendor.rich.console import Console

    text = Text(
        """\nLorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.\n"""
    )
    text.highlight_words(["Lorem"], "bold")
    text.highlight_words(["ipsum"], "italic")

    console = Console()

    console.rule("justify='left'")
    console.print(text, style="red")
    console.print()

    console.rule("justify='center'")
    console.print(text, style="green", justify="center")
    console.print()

    console.rule("justify='right'")
    console.print(text, style="blue", justify="right")
    console.print()

    console.rule("justify='full'")
    console.print(text, style="magenta", justify="full")
    console.print()

from collections.abc import Mapping
from typing import TYPE_CHECKING, Any, Optional, Tuple

from .highlighter import ReprHighlighter
from .panel import Panel
from .pretty import Pretty
from .table import Table
from .text import Text, TextType

if TYPE_CHECKING:
    from .console import ConsoleRenderable


def render_scope(
    scope: "Mapping[str, Any]",
    *,
    title: Optional[TextType] = None,
    sort_keys: bool = True,
    indent_guides: bool = False,
    max_length: Optional[int] = None,
    max_string: Optional[int] = None,
) -> "ConsoleRenderable":
    """Render python variables in a given scope.

    Args:
        scope (Mapping): A mapping containing variable names and values.
        title (str, optional): Optional title. Defaults to None.
        sort_keys (bool, optional): Enable sorting of items. Defaults to True.
        indent_guides (bool, optional): Enable indentation guides. Defaults to False.
        max_length (int, optional): Maximum length of containers before abbreviating, or None for no abbreviation.
            Defaults to None.
        max_string (int, optional): Maximum length of string before truncating, or None to disable. Defaults to None.

    Returns:
        ConsoleRenderable: A renderable object.
    """
    highlighter = ReprHighlighter()
    items_table = Table.grid(padding=(0, 1), expand=False)
    items_table.add_column(justify="right")

    def sort_items(item: Tuple[str, Any]) -> Tuple[bool, str]:
        """Sort special variables first, then alphabetically."""
        key, _ = item
        return (not key.startswith("__"), key.lower())

    items = sorted(scope.items(), key=sort_items) if sort_keys else scope.items()
    for key, value in items:
        key_text = Text.assemble(
            (key, "scope.key.special" if key.startswith("__") else "scope.key"),
            (" =", "scope.equals"),
        )
        items_table.add_row(
            key_text,
            Pretty(
                value,
                highlighter=highlighter,
                indent_guides=indent_guides,
                max_length=max_length,
                max_string=max_string,
            ),
        )
    return Panel.fit(
        items_table,
        title=title,
        border_style="scope.border",
        padding=(0, 1),
    )


if __name__ == "__main__":  # pragma: no cover
    from pip._vendor.rich import print

    print()

    def test(foo: float, bar: float) -> None:
        list_of_things = [1, 2, 3, None, 4, True, False, "Hello World"]
        dict_of_things = {
            "version": "1.1",
            "method": "confirmFruitPurchase",
            "params": [["apple", "orange", "mangoes", "pomelo"], 1.123],
            "id": "194521489",
        }
        print(render_scope(locals(), title="[i]locals", sort_keys=False))

    test(20.3423, 3.1427)
    print()

from typing import Dict

from .style import Style

DEFAULT_STYLES: Dict[str, Style] = {
    "none": Style.null(),
    "reset": Style(
        color="default",
        bgcolor="default",
        dim=False,
        bold=False,
        italic=False,
        underline=False,
        blink=False,
        blink2=False,
        reverse=False,
        conceal=False,
        strike=False,
    ),
    "dim": Style(dim=True),
    "bright": Style(dim=False),
    "bold": Style(bold=True),
    "strong": Style(bold=True),
    "code": Style(reverse=True, bold=True),
    "italic": Style(italic=True),
    "emphasize": Style(italic=True),
    "underline": Style(underline=True),
    "blink": Style(blink=True),
    "blink2": Style(blink2=True),
    "reverse": Style(reverse=True),
    "strike": Style(strike=True),
    "black": Style(color="black"),
    "red": Style(color="red"),
    "green": Style(color="green"),
    "yellow": Style(color="yellow"),
    "magenta": Style(color="magenta"),
    "cyan": Style(color="cyan"),
    "white": Style(color="white"),
    "inspect.attr": Style(color="yellow", italic=True),
    "inspect.attr.dunder": Style(color="yellow", italic=True, dim=True),
    "inspect.callable": Style(bold=True, color="red"),
    "inspect.async_def": Style(italic=True, color="bright_cyan"),
    "inspect.def": Style(italic=True, color="bright_cyan"),
    "inspect.class": Style(italic=True, color="bright_cyan"),
    "inspect.error": Style(bold=True, color="red"),
    "inspect.equals": Style(),
    "inspect.help": Style(color="cyan"),
    "inspect.doc": Style(dim=True),
    "inspect.value.border": Style(color="green"),
    "live.ellipsis": Style(bold=True, color="red"),
    "layout.tree.row": Style(dim=False, color="red"),
    "layout.tree.column": Style(dim=False, color="blue"),
    "logging.keyword": Style(bold=True, color="yellow"),
    "logging.level.notset": Style(dim=True),
    "logging.level.debug": Style(color="green"),
    "logging.level.info": Style(color="blue"),
    "logging.level.warning": Style(color="red"),
    "logging.level.error": Style(color="red", bold=True),
    "logging.level.critical": Style(color="red", bold=True, reverse=True),
    "log.level": Style.null(),
    "log.time": Style(color="cyan", dim=True),
    "log.message": Style.null(),
    "log.path": Style(dim=True),
    "repr.ellipsis": Style(color="yellow"),
    "repr.indent": Style(color="green", dim=True),
    "repr.error": Style(color="red", bold=True),
    "repr.str": Style(color="green", italic=False, bold=False),
    "repr.brace": Style(bold=True),
    "repr.comma": Style(bold=True),
    "repr.ipv4": Style(bold=True, color="bright_green"),
    "repr.ipv6": Style(bold=True, color="bright_green"),
    "repr.eui48": Style(bold=True, color="bright_green"),
    "repr.eui64": Style(bold=True, color="bright_green"),
    "repr.tag_start": Style(bold=True),
    "repr.tag_name": Style(color="bright_magenta", bold=True),
    "repr.tag_contents": Style(color="default"),
    "repr.tag_end": Style(bold=True),
    "repr.attrib_name": Style(color="yellow", italic=False),
    "repr.attrib_equal": Style(bold=True),
    "repr.attrib_value": Style(color="magenta", italic=False),
    "repr.number": Style(color="cyan", bold=True, italic=False),
    "repr.number_complex": Style(color="cyan", bold=True, italic=False),  # same
    "repr.bool_true": Style(color="bright_green", italic=True),
    "repr.bool_false": Style(color="bright_red", italic=True),
    "repr.none": Style(color="magenta", italic=True),
    "repr.url": Style(underline=True, color="bright_blue", italic=False, bold=False),
    "repr.uuid": Style(color="bright_yellow", bold=False),
    "repr.call": Style(color="magenta", bold=True),
    "repr.path": Style(color="magenta"),
    "repr.filename": Style(color="bright_magenta"),
    "rule.line": Style(color="bright_green"),
    "rule.text": Style.null(),
    "json.brace": Style(bold=True),
    "json.bool_true": Style(color="bright_green", italic=True),
    "json.bool_false": Style(color="bright_red", italic=True),
    "json.null": Style(color="magenta", italic=True),
    "json.number": Style(color="cyan", bold=True, italic=False),
    "json.str": Style(color="green", italic=False, bold=False),
    "json.key": Style(color="blue", bold=True),
    "prompt": Style.null(),
    "prompt.choices": Style(color="magenta", bold=True),
    "prompt.default": Style(color="cyan", bold=True),
    "prompt.invalid": Style(color="red"),
    "prompt.invalid.choice": Style(color="red"),
    "pretty": Style.null(),
    "scope.border": Style(color="blue"),
    "scope.key": Style(color="yellow", italic=True),
    "scope.key.special": Style(color="yellow", italic=True, dim=True),
    "scope.equals": Style(color="red"),
    "table.header": Style(bold=True),
    "table.footer": Style(bold=True),
    "table.cell": Style.null(),
    "table.title": Style(italic=True),
    "table.caption": Style(italic=True, dim=True),
    "traceback.error": Style(color="red", italic=True),
    "traceback.border.syntax_error": Style(color="bright_red"),
    "traceback.border": Style(color="red"),
    "traceback.text": Style.null(),
    "traceback.title": Style(color="red", bold=True),
    "traceback.exc_type": Style(color="bright_red", bold=True),
    "traceback.exc_value": Style.null(),
    "traceback.offset": Style(color="bright_red", bold=True),
    "bar.back": Style(color="grey23"),
    "bar.complete": Style(color="rgb(249,38,114)"),
    "bar.finished": Style(color="rgb(114,156,31)"),
    "bar.pulse": Style(color="rgb(249,38,114)"),
    "progress.description": Style.null(),
    "progress.filesize": Style(color="green"),
    "progress.filesize.total": Style(color="green"),
    "progress.download": Style(color="green"),
    "progress.elapsed": Style(color="yellow"),
    "progress.percentage": Style(color="magenta"),
    "progress.remaining": Style(color="cyan"),
    "progress.data.speed": Style(color="red"),
    "progress.spinner": Style(color="green"),
    "status.spinner": Style(color="green"),
    "tree": Style(),
    "tree.line": Style(),
    "markdown.paragraph": Style(),
    "markdown.text": Style(),
    "markdown.em": Style(italic=True),
    "markdown.emph": Style(italic=True),  # For commonmark backwards compatibility
    "markdown.strong": Style(bold=True),
    "markdown.code": Style(bold=True, color="cyan", bgcolor="black"),
    "markdown.code_block": Style(color="cyan", bgcolor="black"),
    "markdown.block_quote": Style(color="magenta"),
    "markdown.list": Style(color="cyan"),
    "markdown.item": Style(),
    "markdown.item.bullet": Style(color="yellow", bold=True),
    "markdown.item.number": Style(color="yellow", bold=True),
    "markdown.hr": Style(color="yellow"),
    "markdown.h1.border": Style(),
    "markdown.h1": Style(bold=True),
    "markdown.h2": Style(bold=True, underline=True),
    "markdown.h3": Style(bold=True),
    "markdown.h4": Style(bold=True, dim=True),
    "markdown.h5": Style(underline=True),
    "markdown.h6": Style(italic=True),
    "markdown.h7": Style(italic=True, dim=True),
    "markdown.link": Style(color="bright_blue"),
    "markdown.link_url": Style(color="blue", underline=True),
    "markdown.s": Style(strike=True),
    "iso8601.date": Style(color="blue"),
    "iso8601.time": Style(color="magenta"),
    "iso8601.timezone": Style(color="yellow"),
}


if __name__ == "__main__":  # pragma: no cover
    import argparse
    import io

    from pip._vendor.rich.console import Console
    from pip._vendor.rich.table import Table
    from pip._vendor.rich.text import Text

    parser = argparse.ArgumentParser()
    parser.add_argument("--html", action="store_true", help="Export as HTML table")
    args = parser.parse_args()
    html: bool = args.html
    console = Console(record=True, width=70, file=io.StringIO()) if html else Console()

    table = Table("Name", "Styling")

    for style_name, style in DEFAULT_STYLES.items():
        table.add_row(Text(style_name, style=style), str(style))

    console.print(table)
    if html:
        print(console.export_html(inline_styles=True))

import sys
from itertools import chain
from typing import TYPE_CHECKING, Iterable, Optional

if sys.version_info >= (3, 8):
    from typing import Literal
else:
    from pip._vendor.typing_extensions import Literal  # pragma: no cover

from .constrain import Constrain
from .jupyter import JupyterMixin
from .measure import Measurement
from .segment import Segment
from .style import StyleType

if TYPE_CHECKING:
    from .console import Console, ConsoleOptions, RenderableType, RenderResult

AlignMethod = Literal["left", "center", "right"]
VerticalAlignMethod = Literal["top", "middle", "bottom"]


class Align(JupyterMixin):
    """Align a renderable by adding spaces if necessary.

    Args:
        renderable (RenderableType): A console renderable.
        align (AlignMethod): One of "left", "center", or "right""
        style (StyleType, optional): An optional style to apply to the background.
        vertical (Optional[VerticalAlignMethod], optional): Optional vertical align, one of "top", "middle", or "bottom". Defaults to None.
        pad (bool, optional): Pad the right with spaces. Defaults to True.
        width (int, optional): Restrict contents to given width, or None to use default width. Defaults to None.
        height (int, optional): Set height of align renderable, or None to fit to contents. Defaults to None.

    Raises:
        ValueError: if ``align`` is not one of the expected values.
    """

    def __init__(
        self,
        renderable: "RenderableType",
        align: AlignMethod = "left",
        style: Optional[StyleType] = None,
        *,
        vertical: Optional[VerticalAlignMethod] = None,
        pad: bool = True,
        width: Optional[int] = None,
        height: Optional[int] = None,
    ) -> None:
        if align not in ("left", "center", "right"):
            raise ValueError(
                f'invalid value for align, expected "left", "center", or "right" (not {align!r})'
            )
        if vertical is not None and vertical not in ("top", "middle", "bottom"):
            raise ValueError(
                f'invalid value for vertical, expected "top", "middle", or "bottom" (not {vertical!r})'
            )
        self.renderable = renderable
        self.align = align
        self.style = style
        self.vertical = vertical
        self.pad = pad
        self.width = width
        self.height = height

    def __repr__(self) -> str:
        return f"Align({self.renderable!r}, {self.align!r})"

    @classmethod
    def left(
        cls,
        renderable: "RenderableType",
        style: Optional[StyleType] = None,
        *,
        vertical: Optional[VerticalAlignMethod] = None,
        pad: bool = True,
        width: Optional[int] = None,
        height: Optional[int] = None,
    ) -> "Align":
        """Align a renderable to the left."""
        return cls(
            renderable,
            "left",
            style=style,
            vertical=vertical,
            pad=pad,
            width=width,
            height=height,
        )

    @classmethod
    def center(
        cls,
        renderable: "RenderableType",
        style: Optional[StyleType] = None,
        *,
        vertical: Optional[VerticalAlignMethod] = None,
        pad: bool = True,
        width: Optional[int] = None,
        height: Optional[int] = None,
    ) -> "Align":
        """Align a renderable to the center."""
        return cls(
            renderable,
            "center",
            style=style,
            vertical=vertical,
            pad=pad,
            width=width,
            height=height,
        )

    @classmethod
    def right(
        cls,
        renderable: "RenderableType",
        style: Optional[StyleType] = None,
        *,
        vertical: Optional[VerticalAlignMethod] = None,
        pad: bool = True,
        width: Optional[int] = None,
        height: Optional[int] = None,
    ) -> "Align":
        """Align a renderable to the right."""
        return cls(
            renderable,
            "right",
            style=style,
            vertical=vertical,
            pad=pad,
            width=width,
            height=height,
        )

    def __rich_console__(
        self, console: "Console", options: "ConsoleOptions"
    ) -> "RenderResult":
        align = self.align
        width = console.measure(self.renderable, options=options).maximum
        rendered = console.render(
            Constrain(
                self.renderable, width if self.width is None else min(width, self.width)
            ),
            options.update(height=None),
        )
        lines = list(Segment.split_lines(rendered))
        width, height = Segment.get_shape(lines)
        lines = Segment.set_shape(lines, width, height)
        new_line = Segment.line()
        excess_space = options.max_width - width
        style = console.get_style(self.style) if self.style is not None else None

        def generate_segments() -> Iterable[Segment]:
            if excess_space <= 0:
                # Exact fit
                for line in lines:
                    yield from line
                    yield new_line

            elif align == "left":
                # Pad on the right
                pad = Segment(" " * excess_space, style) if self.pad else None
                for line in lines:
                    yield from line
                    if pad:
                        yield pad
                    yield new_line

            elif align == "center":
                # Pad left and right
                left = excess_space // 2
                pad = Segment(" " * left, style)
                pad_right = (
                    Segment(" " * (excess_space - left), style) if self.pad else None
                )
                for line in lines:
                    if left:
                        yield pad
                    yield from line
                    if pad_right:
                        yield pad_right
                    yield new_line

            elif align == "right":
                # Padding on left
                pad = Segment(" " * excess_space, style)
                for line in lines:
                    yield pad
                    yield from line
                    yield new_line

        blank_line = (
            Segment(f"{' ' * (self.width or options.max_width)}\n", style)
            if self.pad
            else Segment("\n")
        )

        def blank_lines(count: int) -> Iterable[Segment]:
            if count > 0:
                for _ in range(count):
                    yield blank_line

        vertical_height = self.height or options.height
        iter_segments: Iterable[Segment]
        if self.vertical and vertical_height is not None:
            if self.vertical == "top":
                bottom_space = vertical_height - height
                iter_segments = chain(generate_segments(), blank_lines(bottom_space))
            elif self.vertical == "middle":
                top_space = (vertical_height - height) // 2
                bottom_space = vertical_height - top_space - height
                iter_segments = chain(
                    blank_lines(top_space),
                    generate_segments(),
                    blank_lines(bottom_space),
                )
            else:  #  self.vertical == "bottom":
                top_space = vertical_height - height
                iter_segments = chain(blank_lines(top_space), generate_segments())
        else:
            iter_segments = generate_segments()
        if self.style:
            style = console.get_style(self.style)
            iter_segments = Segment.apply_style(iter_segments, style)
        yield from iter_segments

    def __rich_measure__(
        self, console: "Console", options: "ConsoleOptions"
    ) -> Measurement:
        measurement = Measurement.get(console, options, self.renderable)
        return measurement


class VerticalCenter(JupyterMixin):
    """Vertically aligns a renderable.

    Warn:
        This class is deprecated and may be removed in a future version. Use Align class with
        `vertical="middle"`.

    Args:
        renderable (RenderableType): A renderable object.
    """

    def __init__(
        self,
        renderable: "RenderableType",
        style: Optional[StyleType] = None,
    ) -> None:
        self.renderable = renderable
        self.style = style

    def __repr__(self) -> str:
        return f"VerticalCenter({self.renderable!r})"

    def __rich_console__(
        self, console: "Console", options: "ConsoleOptions"
    ) -> "RenderResult":
        style = console.get_style(self.style) if self.style is not None else None
        lines = console.render_lines(
            self.renderable, options.update(height=None), pad=False
        )
        width, _height = Segment.get_shape(lines)
        new_line = Segment.line()
        height = options.height or options.size.height
        top_space = (height - len(lines)) // 2
        bottom_space = height - top_space - len(lines)
        blank_line = Segment(f"{' ' * width}", style)

        def blank_lines(count: int) -> Iterable[Segment]:
            for _ in range(count):
                yield blank_line
                yield new_line

        if top_space > 0:
            yield from blank_lines(top_space)
        for line in lines:
            yield from line
            yield new_line
        if bottom_space > 0:
            yield from blank_lines(bottom_space)

    def __rich_measure__(
        self, console: "Console", options: "ConsoleOptions"
    ) -> Measurement:
        measurement = Measurement.get(console, options, self.renderable)
        return measurement


if __name__ == "__main__":  # pragma: no cover
    from pip._vendor.rich.console import Console, Group
    from pip._vendor.rich.highlighter import ReprHighlighter
    from pip._vendor.rich.panel import Panel

    highlighter = ReprHighlighter()
    console = Console()

    panel = Panel(
        Group(
            Align.left(highlighter("align='left'")),
            Align.center(highlighter("align='center'")),
            Align.right(highlighter("align='right'")),
        ),
        width=60,
        style="on dark_blue",
        title="Align",
    )

    console.print(
        Align.center(panel, vertical="middle", style="on red", height=console.height)
    )

import sys
from typing import TYPE_CHECKING, Iterable, List

if sys.version_info >= (3, 8):
    from typing import Literal
else:
    from pip._vendor.typing_extensions import Literal  # pragma: no cover


from ._loop import loop_last

if TYPE_CHECKING:
    from pip._vendor.rich.console import ConsoleOptions


class Box:
    """Defines characters to render boxes.

    ┌─┬┐ top
    │ ││ head
    ├─┼┤ head_row
    │ ││ mid
    ├─┼┤ row
    ├─┼┤ foot_row
    │ ││ foot
    └─┴┘ bottom

    Args:
        box (str): Characters making up box.
        ascii (bool, optional): True if this box uses ascii characters only. Default is False.
    """

    def __init__(self, box: str, *, ascii: bool = False) -> None:
        self._box = box
        self.ascii = ascii
        line1, line2, line3, line4, line5, line6, line7, line8 = box.splitlines()
        # top
        self.top_left, self.top, self.top_divider, self.top_right = iter(line1)
        # head
        self.head_left, _, self.head_vertical, self.head_right = iter(line2)
        # head_row
        (
            self.head_row_left,
            self.head_row_horizontal,
            self.head_row_cross,
            self.head_row_right,
        ) = iter(line3)

        # mid
        self.mid_left, _, self.mid_vertical, self.mid_right = iter(line4)
        # row
        self.row_left, self.row_horizontal, self.row_cross, self.row_right = iter(line5)
        # foot_row
        (
            self.foot_row_left,
            self.foot_row_horizontal,
            self.foot_row_cross,
            self.foot_row_right,
        ) = iter(line6)
        # foot
        self.foot_left, _, self.foot_vertical, self.foot_right = iter(line7)
        # bottom
        self.bottom_left, self.bottom, self.bottom_divider, self.bottom_right = iter(
            line8
        )

    def __repr__(self) -> str:
        return "Box(...)"

    def __str__(self) -> str:
        return self._box

    def substitute(self, options: "ConsoleOptions", safe: bool = True) -> "Box":
        """Substitute this box for another if it won't render due to platform issues.

        Args:
            options (ConsoleOptions): Console options used in rendering.
            safe (bool, optional): Substitute this for another Box if there are known problems
                displaying on the platform (currently only relevant on Windows). Default is True.

        Returns:
            Box: A different Box or the same Box.
        """
        box = self
        if options.legacy_windows and safe:
            box = LEGACY_WINDOWS_SUBSTITUTIONS.get(box, box)
        if options.ascii_only and not box.ascii:
            box = ASCII
        return box

    def get_plain_headed_box(self) -> "Box":
        """If this box uses special characters for the borders of the header, then
        return the equivalent box that does not.

        Returns:
            Box: The most similar Box that doesn't use header-specific box characters.
                If the current Box already satisfies this criterion, then it's returned.
        """
        return PLAIN_HEADED_SUBSTITUTIONS.get(self, self)

    def get_top(self, widths: Iterable[int]) -> str:
        """Get the top of a simple box.

        Args:
            widths (List[int]): Widths of columns.

        Returns:
            str: A string of box characters.
        """

        parts: List[str] = []
        append = parts.append
        append(self.top_left)
        for last, width in loop_last(widths):
            append(self.top * width)
            if not last:
                append(self.top_divider)
        append(self.top_right)
        return "".join(parts)

    def get_row(
        self,
        widths: Iterable[int],
        level: Literal["head", "row", "foot", "mid"] = "row",
        edge: bool = True,
    ) -> str:
        """Get the top of a simple box.

        Args:
            width (List[int]): Widths of columns.

        Returns:
            str: A string of box characters.
        """
        if level == "head":
            left = self.head_row_left
            horizontal = self.head_row_horizontal
            cross = self.head_row_cross
            right = self.head_row_right
        elif level == "row":
            left = self.row_left
            horizontal = self.row_horizontal
            cross = self.row_cross
            right = self.row_right
        elif level == "mid":
            left = self.mid_left
            horizontal = " "
            cross = self.mid_vertical
            right = self.mid_right
        elif level == "foot":
            left = self.foot_row_left
            horizontal = self.foot_row_horizontal
            cross = self.foot_row_cross
            right = self.foot_row_right
        else:
            raise ValueError("level must be 'head', 'row' or 'foot'")

        parts: List[str] = []
        append = parts.append
        if edge:
            append(left)
        for last, width in loop_last(widths):
            append(horizontal * width)
            if not last:
                append(cross)
        if edge:
            append(right)
        return "".join(parts)

    def get_bottom(self, widths: Iterable[int]) -> str:
        """Get the bottom of a simple box.

        Args:
            widths (List[int]): Widths of columns.

        Returns:
            str: A string of box characters.
        """

        parts: List[str] = []
        append = parts.append
        append(self.bottom_left)
        for last, width in loop_last(widths):
            append(self.bottom * width)
            if not last:
                append(self.bottom_divider)
        append(self.bottom_right)
        return "".join(parts)


# fmt: off
ASCII: Box = Box(
    "+--+\n"
    "| ||\n"
    "|-+|\n"
    "| ||\n"
    "|-+|\n"
    "|-+|\n"
    "| ||\n"
    "+--+\n",
    ascii=True,
)

ASCII2: Box = Box(
    "+-++\n"
    "| ||\n"
    "+-++\n"
    "| ||\n"
    "+-++\n"
    "+-++\n"
    "| ||\n"
    "+-++\n",
    ascii=True,
)

ASCII_DOUBLE_HEAD: Box = Box(
    "+-++\n"
    "| ||\n"
    "+=++\n"
    "| ||\n"
    "+-++\n"
    "+-++\n"
    "| ||\n"
    "+-++\n",
    ascii=True,
)

SQUARE: Box = Box(
    "┌─┬┐\n"
    "│ ││\n"
    "├─┼┤\n"
    "│ ││\n"
    "├─┼┤\n"
    "├─┼┤\n"
    "│ ││\n"
    "└─┴┘\n"
)

SQUARE_DOUBLE_HEAD: Box = Box(
    "┌─┬┐\n"
    "│ ││\n"
    "╞═╪╡\n"
    "│ ││\n"
    "├─┼┤\n"
    "├─┼┤\n"
    "│ ││\n"
    "└─┴┘\n"
)

MINIMAL: Box = Box(
    "  ╷ \n"
    "  │ \n"
    "╶─┼╴\n"
    "  │ \n"
    "╶─┼╴\n"
    "╶─┼╴\n"
    "  │ \n"
    "  ╵ \n"
)


MINIMAL_HEAVY_HEAD: Box = Box(
    "  ╷ \n"
    "  │ \n"
    "╺━┿╸\n"
    "  │ \n"
    "╶─┼╴\n"
    "╶─┼╴\n"
    "  │ \n"
    "  ╵ \n"
)

MINIMAL_DOUBLE_HEAD: Box = Box(
    "  ╷ \n"
    "  │ \n"
    " ═╪ \n"
    "  │ \n"
    " ─┼ \n"
    " ─┼ \n"
    "  │ \n"
    "  ╵ \n"
)


SIMPLE: Box = Box(
    "    \n"
    "    \n"
    " ── \n"
    "    \n"
    "    \n"
    " ── \n"
    "    \n"
    "    \n"
)

SIMPLE_HEAD: Box = Box(
    "    \n"
    "    \n"
    " ── \n"
    "    \n"
    "    \n"
    "    \n"
    "    \n"
    "    \n"
)


SIMPLE_HEAVY: Box = Box(
    "    \n"
    "    \n"
    " ━━ \n"
    "    \n"
    "    \n"
    " ━━ \n"
    "    \n"
    "    \n"
)


HORIZONTALS: Box = Box(
    " ── \n"
    "    \n"
    " ── \n"
    "    \n"
    " ── \n"
    " ── \n"
    "    \n"
    " ── \n"
)

ROUNDED: Box = Box(
    "╭─┬╮\n"
    "│ ││\n"
    "├─┼┤\n"
    "│ ││\n"
    "├─┼┤\n"
    "├─┼┤\n"
    "│ ││\n"
    "╰─┴╯\n"
)

HEAVY: Box = Box(
    "┏━┳┓\n"
    "┃ ┃┃\n"
    "┣━╋┫\n"
    "┃ ┃┃\n"
    "┣━╋┫\n"
    "┣━╋┫\n"
    "┃ ┃┃\n"
    "┗━┻┛\n"
)

HEAVY_EDGE: Box = Box(
    "┏━┯┓\n"
    "┃ │┃\n"
    "┠─┼┨\n"
    "┃ │┃\n"
    "┠─┼┨\n"
    "┠─┼┨\n"
    "┃ │┃\n"
    "┗━┷┛\n"
)

HEAVY_HEAD: Box = Box(
    "┏━┳┓\n"
    "┃ ┃┃\n"
    "┡━╇┩\n"
    "│ ││\n"
    "├─┼┤\n"
    "├─┼┤\n"
    "│ ││\n"
    "└─┴┘\n"
)

DOUBLE: Box = Box(
    "╔═╦╗\n"
    "║ ║║\n"
    "╠═╬╣\n"
    "║ ║║\n"
    "╠═╬╣\n"
    "╠═╬╣\n"
    "║ ║║\n"
    "╚═╩╝\n"
)

DOUBLE_EDGE: Box = Box(
    "╔═╤╗\n"
    "║ │║\n"
    "╟─┼╢\n"
    "║ │║\n"
    "╟─┼╢\n"
    "╟─┼╢\n"
    "║ │║\n"
    "╚═╧╝\n"
)

MARKDOWN: Box = Box(
    "    \n"
    "| ||\n"
    "|-||\n"
    "| ||\n"
    "|-||\n"
    "|-||\n"
    "| ||\n"
    "    \n",
    ascii=True,
)
# fmt: on

# Map Boxes that don't render with raster fonts on to equivalent that do
LEGACY_WINDOWS_SUBSTITUTIONS = {
    ROUNDED: SQUARE,
    MINIMAL_HEAVY_HEAD: MINIMAL,
    SIMPLE_HEAVY: SIMPLE,
    HEAVY: SQUARE,
    HEAVY_EDGE: SQUARE,
    HEAVY_HEAD: SQUARE,
}

# Map headed boxes to their headerless equivalents
PLAIN_HEADED_SUBSTITUTIONS = {
    HEAVY_HEAD: SQUARE,
    SQUARE_DOUBLE_HEAD: SQUARE,
    MINIMAL_DOUBLE_HEAD: MINIMAL,
    MINIMAL_HEAVY_HEAD: MINIMAL,
    ASCII_DOUBLE_HEAD: ASCII2,
}


if __name__ == "__main__":  # pragma: no cover
    from pip._vendor.rich.columns import Columns
    from pip._vendor.rich.panel import Panel

    from . import box as box
    from .console import Console
    from .table import Table
    from .text import Text

    console = Console(record=True)

    BOXES = [
        "ASCII",
        "ASCII2",
        "ASCII_DOUBLE_HEAD",
        "SQUARE",
        "SQUARE_DOUBLE_HEAD",
        "MINIMAL",
        "MINIMAL_HEAVY_HEAD",
        "MINIMAL_DOUBLE_HEAD",
        "SIMPLE",
        "SIMPLE_HEAD",
        "SIMPLE_HEAVY",
        "HORIZONTALS",
        "ROUNDED",
        "HEAVY",
        "HEAVY_EDGE",
        "HEAVY_HEAD",
        "DOUBLE",
        "DOUBLE_EDGE",
        "MARKDOWN",
    ]

    console.print(Panel("[bold green]Box Constants", style="green"), justify="center")
    console.print()

    columns = Columns(expand=True, padding=2)
    for box_name in sorted(BOXES):
        table = Table(
            show_footer=True, style="dim", border_style="not dim", expand=True
        )
        table.add_column("Header 1", "Footer 1")
        table.add_column("Header 2", "Footer 2")
        table.add_row("Cell", "Cell")
        table.add_row("Cell", "Cell")
        table.box = getattr(box, box_name)
        table.title = Text(f"box.{box_name}", style="magenta")
        columns.add_renderable(table)
    console.print(columns)

    # console.save_svg("box.svg")

# -*- coding: utf-8 -*-
#
# Copyright (C) 2012 The Python Software Foundation.
# See LICENSE.txt and CONTRIBUTORS.txt.
#
"""Implementation of the Metadata for Python packages PEPs.

Supports all metadata formats (1.0, 1.1, 1.2, 1.3/2.1 and 2.2).
"""
from __future__ import unicode_literals

import codecs
from email import message_from_file
import json
import logging
import re

from . import DistlibException, __version__
from .compat import StringIO, string_types, text_type
from .markers import interpret
from .util import extract_by_key, get_extras
from .version import get_scheme, PEP440_VERSION_RE

logger = logging.getLogger(__name__)


class MetadataMissingError(DistlibException):
    """A required metadata is missing"""


class MetadataConflictError(DistlibException):
    """Attempt to read or write metadata fields that are conflictual."""


class MetadataUnrecognizedVersionError(DistlibException):
    """Unknown metadata version number."""


class MetadataInvalidError(DistlibException):
    """A metadata value is invalid"""


# public API of this module
__all__ = ['Metadata', 'PKG_INFO_ENCODING', 'PKG_INFO_PREFERRED_VERSION']

# Encoding used for the PKG-INFO files
PKG_INFO_ENCODING = 'utf-8'

# preferred version. Hopefully will be changed
# to 1.2 once PEP 345 is supported everywhere
PKG_INFO_PREFERRED_VERSION = '1.1'

_LINE_PREFIX_1_2 = re.compile('\n       \\|')
_LINE_PREFIX_PRE_1_2 = re.compile('\n        ')
_241_FIELDS = ('Metadata-Version', 'Name', 'Version', 'Platform', 'Summary', 'Description', 'Keywords', 'Home-page',
               'Author', 'Author-email', 'License')

_314_FIELDS = ('Metadata-Version', 'Name', 'Version', 'Platform', 'Supported-Platform', 'Summary', 'Description',
               'Keywords', 'Home-page', 'Author', 'Author-email', 'License', 'Classifier', 'Download-URL', 'Obsoletes',
               'Provides', 'Requires')

_314_MARKERS = ('Obsoletes', 'Provides', 'Requires', 'Classifier', 'Download-URL')

_345_FIELDS = ('Metadata-Version', 'Name', 'Version', 'Platform', 'Supported-Platform', 'Summary', 'Description',
               'Keywords', 'Home-page', 'Author', 'Author-email', 'Maintainer', 'Maintainer-email', 'License',
               'Classifier', 'Download-URL', 'Obsoletes-Dist', 'Project-URL', 'Provides-Dist', 'Requires-Dist',
               'Requires-Python', 'Requires-External')

_345_MARKERS = ('Provides-Dist', 'Requires-Dist', 'Requires-Python', 'Obsoletes-Dist', 'Requires-External',
                'Maintainer', 'Maintainer-email', 'Project-URL')

_426_FIELDS = ('Metadata-Version', 'Name', 'Version', 'Platform', 'Supported-Platform', 'Summary', 'Description',
               'Keywords', 'Home-page', 'Author', 'Author-email', 'Maintainer', 'Maintainer-email', 'License',
               'Classifier', 'Download-URL', 'Obsoletes-Dist', 'Project-URL', 'Provides-Dist', 'Requires-Dist',
               'Requires-Python', 'Requires-External', 'Private-Version', 'Obsoleted-By', 'Setup-Requires-Dist',
               'Extension', 'Provides-Extra')

_426_MARKERS = ('Private-Version', 'Provides-Extra', 'Obsoleted-By', 'Setup-Requires-Dist', 'Extension')

# See issue #106: Sometimes 'Requires' and 'Provides' occur wrongly in
# the metadata. Include them in the tuple literal below to allow them
# (for now).
# Ditto for Obsoletes - see issue #140.
_566_FIELDS = _426_FIELDS + ('Description-Content-Type', 'Requires', 'Provides', 'Obsoletes')

_566_MARKERS = ('Description-Content-Type', )

_643_MARKERS = ('Dynamic', 'License-File')

_643_FIELDS = _566_FIELDS + _643_MARKERS

_ALL_FIELDS = set()
_ALL_FIELDS.update(_241_FIELDS)
_ALL_FIELDS.update(_314_FIELDS)
_ALL_FIELDS.update(_345_FIELDS)
_ALL_FIELDS.update(_426_FIELDS)
_ALL_FIELDS.update(_566_FIELDS)
_ALL_FIELDS.update(_643_FIELDS)

EXTRA_RE = re.compile(r'''extra\s*==\s*("([^"]+)"|'([^']+)')''')


def _version2fieldlist(version):
    if version == '1.0':
        return _241_FIELDS
    elif version == '1.1':
        return _314_FIELDS
    elif version == '1.2':
        return _345_FIELDS
    elif version in ('1.3', '2.1'):
        # avoid adding field names if already there
        return _345_FIELDS + tuple(f for f in _566_FIELDS if f not in _345_FIELDS)
    elif version == '2.0':
        raise ValueError('Metadata 2.0 is withdrawn and not supported')
        # return _426_FIELDS
    elif version == '2.2':
        return _643_FIELDS
    raise MetadataUnrecognizedVersionError(version)


def _best_version(fields):
    """Detect the best version depending on the fields used."""

    def _has_marker(keys, markers):
        return any(marker in keys for marker in markers)

    keys = [key for key, value in fields.items() if value not in ([], 'UNKNOWN', None)]
    possible_versions = ['1.0', '1.1', '1.2', '1.3', '2.1', '2.2']  # 2.0 removed

    # first let's try to see if a field is not part of one of the version
    for key in keys:
        if key not in _241_FIELDS and '1.0' in possible_versions:
            possible_versions.remove('1.0')
            logger.debug('Removed 1.0 due to %s', key)
        if key not in _314_FIELDS and '1.1' in possible_versions:
            possible_versions.remove('1.1')
            logger.debug('Removed 1.1 due to %s', key)
        if key not in _345_FIELDS and '1.2' in possible_versions:
            possible_versions.remove('1.2')
            logger.debug('Removed 1.2 due to %s', key)
        if key not in _566_FIELDS and '1.3' in possible_versions:
            possible_versions.remove('1.3')
            logger.debug('Removed 1.3 due to %s', key)
        if key not in _566_FIELDS and '2.1' in possible_versions:
            if key != 'Description':  # In 2.1, description allowed after headers
                possible_versions.remove('2.1')
                logger.debug('Removed 2.1 due to %s', key)
        if key not in _643_FIELDS and '2.2' in possible_versions:
            possible_versions.remove('2.2')
            logger.debug('Removed 2.2 due to %s', key)
        # if key not in _426_FIELDS and '2.0' in possible_versions:
        # possible_versions.remove('2.0')
        # logger.debug('Removed 2.0 due to %s', key)

    # possible_version contains qualified versions
    if len(possible_versions) == 1:
        return possible_versions[0]  # found !
    elif len(possible_versions) == 0:
        logger.debug('Out of options - unknown metadata set: %s', fields)
        raise MetadataConflictError('Unknown metadata set')

    # let's see if one unique marker is found
    is_1_1 = '1.1' in possible_versions and _has_marker(keys, _314_MARKERS)
    is_1_2 = '1.2' in possible_versions and _has_marker(keys, _345_MARKERS)
    is_2_1 = '2.1' in possible_versions and _has_marker(keys, _566_MARKERS)
    # is_2_0 = '2.0' in possible_versions and _has_marker(keys, _426_MARKERS)
    is_2_2 = '2.2' in possible_versions and _has_marker(keys, _643_MARKERS)
    if int(is_1_1) + int(is_1_2) + int(is_2_1) + int(is_2_2) > 1:
        raise MetadataConflictError('You used incompatible 1.1/1.2/2.1/2.2 fields')

    # we have the choice, 1.0, or 1.2, 2.1 or 2.2
    #   - 1.0 has a broken Summary field but works with all tools
    #   - 1.1 is to avoid
    #   - 1.2 fixes Summary but has little adoption
    #   - 2.1 adds more features
    #   - 2.2 is the latest
    if not is_1_1 and not is_1_2 and not is_2_1 and not is_2_2:
        # we couldn't find any specific marker
        if PKG_INFO_PREFERRED_VERSION in possible_versions:
            return PKG_INFO_PREFERRED_VERSION
    if is_1_1:
        return '1.1'
    if is_1_2:
        return '1.2'
    if is_2_1:
        return '2.1'
    # if is_2_2:
    # return '2.2'

    return '2.2'


# This follows the rules about transforming keys as described in
# https://www.python.org/dev/peps/pep-0566/#id17
_ATTR2FIELD = {name.lower().replace("-", "_"): name for name in _ALL_FIELDS}
_FIELD2ATTR = {field: attr for attr, field in _ATTR2FIELD.items()}

_PREDICATE_FIELDS = ('Requires-Dist', 'Obsoletes-Dist', 'Provides-Dist')
_VERSIONS_FIELDS = ('Requires-Python', )
_VERSION_FIELDS = ('Version', )
_LISTFIELDS = ('Platform', 'Classifier', 'Obsoletes', 'Requires', 'Provides', 'Obsoletes-Dist', 'Provides-Dist',
               'Requires-Dist', 'Requires-External', 'Project-URL', 'Supported-Platform', 'Setup-Requires-Dist',
               'Provides-Extra', 'Extension', 'License-File')
_LISTTUPLEFIELDS = ('Project-URL', )

_ELEMENTSFIELD = ('Keywords', )

_UNICODEFIELDS = ('Author', 'Maintainer', 'Summary', 'Description')

_MISSING = object()

_FILESAFE = re.compile('[^A-Za-z0-9.]+')


def _get_name_and_version(name, version, for_filename=False):
    """Return the distribution name with version.

    If for_filename is true, return a filename-escaped form."""
    if for_filename:
        # For both name and version any runs of non-alphanumeric or '.'
        # characters are replaced with a single '-'.  Additionally any
        # spaces in the version string become '.'
        name = _FILESAFE.sub('-', name)
        version = _FILESAFE.sub('-', version.replace(' ', '.'))
    return '%s-%s' % (name, version)


class LegacyMetadata(object):
    """The legacy metadata of a release.

    Supports versions 1.0, 1.1, 1.2, 2.0 and 1.3/2.1 (auto-detected). You can
    instantiate the class with one of these arguments (or none):
    - *path*, the path to a metadata file
    - *fileobj* give a file-like object with metadata as content
    - *mapping* is a dict-like object
    - *scheme* is a version scheme name
    """

    # TODO document the mapping API and UNKNOWN default key

    def __init__(self, path=None, fileobj=None, mapping=None, scheme='default'):
        if [path, fileobj, mapping].count(None) < 2:
            raise TypeError('path, fileobj and mapping are exclusive')
        self._fields = {}
        self.requires_files = []
        self._dependencies = None
        self.scheme = scheme
        if path is not None:
            self.read(path)
        elif fileobj is not None:
            self.read_file(fileobj)
        elif mapping is not None:
            self.update(mapping)
            self.set_metadata_version()

    def set_metadata_version(self):
        self._fields['Metadata-Version'] = _best_version(self._fields)

    def _write_field(self, fileobj, name, value):
        fileobj.write('%s: %s\n' % (name, value))

    def __getitem__(self, name):
        return self.get(name)

    def __setitem__(self, name, value):
        return self.set(name, value)

    def __delitem__(self, name):
        field_name = self._convert_name(name)
        try:
            del self._fields[field_name]
        except KeyError:
            raise KeyError(name)

    def __contains__(self, name):
        return (name in self._fields or self._convert_name(name) in self._fields)

    def _convert_name(self, name):
        if name in _ALL_FIELDS:
            return name
        name = name.replace('-', '_').lower()
        return _ATTR2FIELD.get(name, name)

    def _default_value(self, name):
        if name in _LISTFIELDS or name in _ELEMENTSFIELD:
            return []
        return 'UNKNOWN'

    def _remove_line_prefix(self, value):
        if self.metadata_version in ('1.0', '1.1'):
            return _LINE_PREFIX_PRE_1_2.sub('\n', value)
        else:
            return _LINE_PREFIX_1_2.sub('\n', value)

    def __getattr__(self, name):
        if name in _ATTR2FIELD:
            return self[name]
        raise AttributeError(name)

    #
    # Public API
    #

    def get_fullname(self, filesafe=False):
        """
        Return the distribution name with version.

        If filesafe is true, return a filename-escaped form.
        """
        return _get_name_and_version(self['Name'], self['Version'], filesafe)

    def is_field(self, name):
        """return True if name is a valid metadata key"""
        name = self._convert_name(name)
        return name in _ALL_FIELDS

    def is_multi_field(self, name):
        name = self._convert_name(name)
        return name in _LISTFIELDS

    def read(self, filepath):
        """Read the metadata values from a file path."""
        fp = codecs.open(filepath, 'r', encoding='utf-8')
        try:
            self.read_file(fp)
        finally:
            fp.close()

    def read_file(self, fileob):
        """Read the metadata values from a file object."""
        msg = message_from_file(fileob)
        self._fields['Metadata-Version'] = msg['metadata-version']

        # When reading, get all the fields we can
        for field in _ALL_FIELDS:
            if field not in msg:
                continue
            if field in _LISTFIELDS:
                # we can have multiple lines
                values = msg.get_all(field)
                if field in _LISTTUPLEFIELDS and values is not None:
                    values = [tuple(value.split(',')) for value in values]
                self.set(field, values)
            else:
                # single line
                value = msg[field]
                if value is not None and value != 'UNKNOWN':
                    self.set(field, value)

        # PEP 566 specifies that the body be used for the description, if
        # available
        body = msg.get_payload()
        self["Description"] = body if body else self["Description"]
        # logger.debug('Attempting to set metadata for %s', self)
        # self.set_metadata_version()

    def write(self, filepath, skip_unknown=False):
        """Write the metadata fields to filepath."""
        fp = codecs.open(filepath, 'w', encoding='utf-8')
        try:
            self.write_file(fp, skip_unknown)
        finally:
            fp.close()

    def write_file(self, fileobject, skip_unknown=False):
        """Write the PKG-INFO format data to a file object."""
        self.set_metadata_version()

        for field in _version2fieldlist(self['Metadata-Version']):
            values = self.get(field)
            if skip_unknown and values in ('UNKNOWN', [], ['UNKNOWN']):
                continue
            if field in _ELEMENTSFIELD:
                self._write_field(fileobject, field, ','.join(values))
                continue
            if field not in _LISTFIELDS:
                if field == 'Description':
                    if self.metadata_version in ('1.0', '1.1'):
                        values = values.replace('\n', '\n        ')
                    else:
                        values = values.replace('\n', '\n       |')
                values = [values]

            if field in _LISTTUPLEFIELDS:
                values = [','.join(value) for value in values]

            for value in values:
                self._write_field(fileobject, field, value)

    def update(self, other=None, **kwargs):
        """Set metadata values from the given iterable `other` and kwargs.

        Behavior is like `dict.update`: If `other` has a ``keys`` method,
        they are looped over and ``self[key]`` is assigned ``other[key]``.
        Else, ``other`` is an iterable of ``(key, value)`` iterables.

        Keys that don't match a metadata field or that have an empty value are
        dropped.
        """

        def _set(key, value):
            if key in _ATTR2FIELD and value:
                self.set(self._convert_name(key), value)

        if not other:
            # other is None or empty container
            pass
        elif hasattr(other, 'keys'):
            for k in other.keys():
                _set(k, other[k])
        else:
            for k, v in other:
                _set(k, v)

        if kwargs:
            for k, v in kwargs.items():
                _set(k, v)

    def set(self, name, value):
        """Control then set a metadata field."""
        name = self._convert_name(name)

        if ((name in _ELEMENTSFIELD or name == 'Platform') and not isinstance(value, (list, tuple))):
            if isinstance(value, string_types):
                value = [v.strip() for v in value.split(',')]
            else:
                value = []
        elif (name in _LISTFIELDS and not isinstance(value, (list, tuple))):
            if isinstance(value, string_types):
                value = [value]
            else:
                value = []

        if logger.isEnabledFor(logging.WARNING):
            project_name = self['Name']

            scheme = get_scheme(self.scheme)
            if name in _PREDICATE_FIELDS and value is not None:
                for v in value:
                    # check that the values are valid
                    if not scheme.is_valid_matcher(v.split(';')[0]):
                        logger.warning("'%s': '%s' is not valid (field '%s')", project_name, v, name)
            # FIXME this rejects UNKNOWN, is that right?
            elif name in _VERSIONS_FIELDS and value is not None:
                if not scheme.is_valid_constraint_list(value):
                    logger.warning("'%s': '%s' is not a valid version (field '%s')", project_name, value, name)
            elif name in _VERSION_FIELDS and value is not None:
                if not scheme.is_valid_version(value):
                    logger.warning("'%s': '%s' is not a valid version (field '%s')", project_name, value, name)

        if name in _UNICODEFIELDS:
            if name == 'Description':
                value = self._remove_line_prefix(value)

        self._fields[name] = value

    def get(self, name, default=_MISSING):
        """Get a metadata field."""
        name = self._convert_name(name)
        if name not in self._fields:
            if default is _MISSING:
                default = self._default_value(name)
            return default
        if name in _UNICODEFIELDS:
            value = self._fields[name]
            return value
        elif name in _LISTFIELDS:
            value = self._fields[name]
            if value is None:
                return []
            res = []
            for val in value:
                if name not in _LISTTUPLEFIELDS:
                    res.append(val)
                else:
                    # That's for Project-URL
                    res.append((val[0], val[1]))
            return res

        elif name in _ELEMENTSFIELD:
            value = self._fields[name]
            if isinstance(value, string_types):
                return value.split(',')
        return self._fields[name]

    def check(self, strict=False):
        """Check if the metadata is compliant. If strict is True then raise if
        no Name or Version are provided"""
        self.set_metadata_version()

        # XXX should check the versions (if the file was loaded)
        missing, warnings = [], []

        for attr in ('Name', 'Version'):  # required by PEP 345
            if attr not in self:
                missing.append(attr)

        if strict and missing != []:
            msg = 'missing required metadata: %s' % ', '.join(missing)
            raise MetadataMissingError(msg)

        for attr in ('Home-page', 'Author'):
            if attr not in self:
                missing.append(attr)

        # checking metadata 1.2 (XXX needs to check 1.1, 1.0)
        if self['Metadata-Version'] != '1.2':
            return missing, warnings

        scheme = get_scheme(self.scheme)

        def are_valid_constraints(value):
            for v in value:
                if not scheme.is_valid_matcher(v.split(';')[0]):
                    return False
            return True

        for fields, controller in ((_PREDICATE_FIELDS, are_valid_constraints),
                                   (_VERSIONS_FIELDS, scheme.is_valid_constraint_list), (_VERSION_FIELDS,
                                                                                         scheme.is_valid_version)):
            for field in fields:
                value = self.get(field, None)
                if value is not None and not controller(value):
                    warnings.append("Wrong value for '%s': %s" % (field, value))

        return missing, warnings

    def todict(self, skip_missing=False):
        """Return fields as a dict.

        Field names will be converted to use the underscore-lowercase style
        instead of hyphen-mixed case (i.e. home_page instead of Home-page).
        This is as per https://www.python.org/dev/peps/pep-0566/#id17.
        """
        self.set_metadata_version()

        fields = _version2fieldlist(self['Metadata-Version'])

        data = {}

        for field_name in fields:
            if not skip_missing or field_name in self._fields:
                key = _FIELD2ATTR[field_name]
                if key != 'project_url':
                    data[key] = self[field_name]
                else:
                    data[key] = [','.join(u) for u in self[field_name]]

        return data

    def add_requirements(self, requirements):
        if self['Metadata-Version'] == '1.1':
            # we can't have 1.1 metadata *and* Setuptools requires
            for field in ('Obsoletes', 'Requires', 'Provides'):
                if field in self:
                    del self[field]
        self['Requires-Dist'] += requirements

    # Mapping API
    # TODO could add iter* variants

    def keys(self):
        return list(_version2fieldlist(self['Metadata-Version']))

    def __iter__(self):
        for key in self.keys():
            yield key

    def values(self):
        return [self[key] for key in self.keys()]

    def items(self):
        return [(key, self[key]) for key in self.keys()]

    def __repr__(self):
        return '<%s %s %s>' % (self.__class__.__name__, self.name, self.version)


METADATA_FILENAME = 'pydist.json'
WHEEL_METADATA_FILENAME = 'metadata.json'
LEGACY_METADATA_FILENAME = 'METADATA'


class Metadata(object):
    """
    The metadata of a release. This implementation uses 2.1
    metadata where possible. If not possible, it wraps a LegacyMetadata
    instance which handles the key-value metadata format.
    """

    METADATA_VERSION_MATCHER = re.compile(r'^\d+(\.\d+)*$')

    NAME_MATCHER = re.compile('^[0-9A-Z]([0-9A-Z_.-]*[0-9A-Z])?$', re.I)

    FIELDNAME_MATCHER = re.compile('^[A-Z]([0-9A-Z-]*[0-9A-Z])?$', re.I)

    VERSION_MATCHER = PEP440_VERSION_RE

    SUMMARY_MATCHER = re.compile('.{1,2047}')

    METADATA_VERSION = '2.0'

    GENERATOR = 'distlib (%s)' % __version__

    MANDATORY_KEYS = {
        'name': (),
        'version': (),
        'summary': ('legacy', ),
    }

    INDEX_KEYS = ('name version license summary description author '
                  'author_email keywords platform home_page classifiers '
                  'download_url')

    DEPENDENCY_KEYS = ('extras run_requires test_requires build_requires '
                       'dev_requires provides meta_requires obsoleted_by '
                       'supports_environments')

    SYNTAX_VALIDATORS = {
        'metadata_version': (METADATA_VERSION_MATCHER, ()),
        'name': (NAME_MATCHER, ('legacy', )),
        'version': (VERSION_MATCHER, ('legacy', )),
        'summary': (SUMMARY_MATCHER, ('legacy', )),
        'dynamic': (FIELDNAME_MATCHER, ('legacy', )),
    }

    __slots__ = ('_legacy', '_data', 'scheme')

    def __init__(self, path=None, fileobj=None, mapping=None, scheme='default'):
        if [path, fileobj, mapping].count(None) < 2:
            raise TypeError('path, fileobj and mapping are exclusive')
        self._legacy = None
        self._data = None
        self.scheme = scheme
        # import pdb; pdb.set_trace()
        if mapping is not None:
            try:
                self._validate_mapping(mapping, scheme)
                self._data = mapping
            except MetadataUnrecognizedVersionError:
                self._legacy = LegacyMetadata(mapping=mapping, scheme=scheme)
                self.validate()
        else:
            data = None
            if path:
                with open(path, 'rb') as f:
                    data = f.read()
            elif fileobj:
                data = fileobj.read()
            if data is None:
                # Initialised with no args - to be added
                self._data = {
                    'metadata_version': self.METADATA_VERSION,
                    'generator': self.GENERATOR,
                }
            else:
                if not isinstance(data, text_type):
                    data = data.decode('utf-8')
                try:
                    self._data = json.loads(data)
                    self._validate_mapping(self._data, scheme)
                except ValueError:
                    # Note: MetadataUnrecognizedVersionError does not
                    # inherit from ValueError (it's a DistlibException,
                    # which should not inherit from ValueError).
                    # The ValueError comes from the json.load - if that
                    # succeeds and we get a validation error, we want
                    # that to propagate
                    self._legacy = LegacyMetadata(fileobj=StringIO(data), scheme=scheme)
                    self.validate()

    common_keys = set(('name', 'version', 'license', 'keywords', 'summary'))

    none_list = (None, list)
    none_dict = (None, dict)

    mapped_keys = {
        'run_requires': ('Requires-Dist', list),
        'build_requires': ('Setup-Requires-Dist', list),
        'dev_requires': none_list,
        'test_requires': none_list,
        'meta_requires': none_list,
        'extras': ('Provides-Extra', list),
        'modules': none_list,
        'namespaces': none_list,
        'exports': none_dict,
        'commands': none_dict,
        'classifiers': ('Classifier', list),
        'source_url': ('Download-URL', None),
        'metadata_version': ('Metadata-Version', None),
    }

    del none_list, none_dict

    def __getattribute__(self, key):
        common = object.__getattribute__(self, 'common_keys')
        mapped = object.__getattribute__(self, 'mapped_keys')
        if key in mapped:
            lk, maker = mapped[key]
            if self._legacy:
                if lk is None:
                    result = None if maker is None else maker()
                else:
                    result = self._legacy.get(lk)
            else:
                value = None if maker is None else maker()
                if key not in ('commands', 'exports', 'modules', 'namespaces', 'classifiers'):
                    result = self._data.get(key, value)
                else:
                    # special cases for PEP 459
                    sentinel = object()
                    result = sentinel
                    d = self._data.get('extensions')
                    if d:
                        if key == 'commands':
                            result = d.get('python.commands', value)
                        elif key == 'classifiers':
                            d = d.get('python.details')
                            if d:
                                result = d.get(key, value)
                        else:
                            d = d.get('python.exports')
                            if not d:
                                d = self._data.get('python.exports')
                            if d:
                                result = d.get(key, value)
                    if result is sentinel:
                        result = value
        elif key not in common:
            result = object.__getattribute__(self, key)
        elif self._legacy:
            result = self._legacy.get(key)
        else:
            result = self._data.get(key)
        return result

    def _validate_value(self, key, value, scheme=None):
        if key in self.SYNTAX_VALIDATORS:
            pattern, exclusions = self.SYNTAX_VALIDATORS[key]
            if (scheme or self.scheme) not in exclusions:
                m = pattern.match(value)
                if not m:
                    raise MetadataInvalidError("'%s' is an invalid value for "
                                               "the '%s' property" % (value, key))

    def __setattr__(self, key, value):
        self._validate_value(key, value)
        common = object.__getattribute__(self, 'common_keys')
        mapped = object.__getattribute__(self, 'mapped_keys')
        if key in mapped:
            lk, _ = mapped[key]
            if self._legacy:
                if lk is None:
                    raise NotImplementedError
                self._legacy[lk] = value
            elif key not in ('commands', 'exports', 'modules', 'namespaces', 'classifiers'):
                self._data[key] = value
            else:
                # special cases for PEP 459
                d = self._data.setdefault('extensions', {})
                if key == 'commands':
                    d['python.commands'] = value
                elif key == 'classifiers':
                    d = d.setdefault('python.details', {})
                    d[key] = value
                else:
                    d = d.setdefault('python.exports', {})
                    d[key] = value
        elif key not in common:
            object.__setattr__(self, key, value)
        else:
            if key == 'keywords':
                if isinstance(value, string_types):
                    value = value.strip()
                    if value:
                        value = value.split()
                    else:
                        value = []
            if self._legacy:
                self._legacy[key] = value
            else:
                self._data[key] = value

    @property
    def name_and_version(self):
        return _get_name_and_version(self.name, self.version, True)

    @property
    def provides(self):
        if self._legacy:
            result = self._legacy['Provides-Dist']
        else:
            result = self._data.setdefault('provides', [])
        s = '%s (%s)' % (self.name, self.version)
        if s not in result:
            result.append(s)
        return result

    @provides.setter
    def provides(self, value):
        if self._legacy:
            self._legacy['Provides-Dist'] = value
        else:
            self._data['provides'] = value

    def get_requirements(self, reqts, extras=None, env=None):
        """
        Base method to get dependencies, given a set of extras
        to satisfy and an optional environment context.
        :param reqts: A list of sometimes-wanted dependencies,
                      perhaps dependent on extras and environment.
        :param extras: A list of optional components being requested.
        :param env: An optional environment for marker evaluation.
        """
        if self._legacy:
            result = reqts
        else:
            result = []
            extras = get_extras(extras or [], self.extras)
            for d in reqts:
                if 'extra' not in d and 'environment' not in d:
                    # unconditional
                    include = True
                else:
                    if 'extra' not in d:
                        # Not extra-dependent - only environment-dependent
                        include = True
                    else:
                        include = d.get('extra') in extras
                    if include:
                        # Not excluded because of extras, check environment
                        marker = d.get('environment')
                        if marker:
                            include = interpret(marker, env)
                if include:
                    result.extend(d['requires'])
            for key in ('build', 'dev', 'test'):
                e = ':%s:' % key
                if e in extras:
                    extras.remove(e)
                    # A recursive call, but it should terminate since 'test'
                    # has been removed from the extras
                    reqts = self._data.get('%s_requires' % key, [])
                    result.extend(self.get_requirements(reqts, extras=extras, env=env))
        return result

    @property
    def dictionary(self):
        if self._legacy:
            return self._from_legacy()
        return self._data

    @property
    def dependencies(self):
        if self._legacy:
            raise NotImplementedError
        else:
            return extract_by_key(self._data, self.DEPENDENCY_KEYS)

    @dependencies.setter
    def dependencies(self, value):
        if self._legacy:
            raise NotImplementedError
        else:
            self._data.update(value)

    def _validate_mapping(self, mapping, scheme):
        if mapping.get('metadata_version') != self.METADATA_VERSION:
            raise MetadataUnrecognizedVersionError()
        missing = []
        for key, exclusions in self.MANDATORY_KEYS.items():
            if key not in mapping:
                if scheme not in exclusions:
                    missing.append(key)
        if missing:
            msg = 'Missing metadata items: %s' % ', '.join(missing)
            raise MetadataMissingError(msg)
        for k, v in mapping.items():
            self._validate_value(k, v, scheme)

    def validate(self):
        if self._legacy:
            missing, warnings = self._legacy.check(True)
            if missing or warnings:
                logger.warning('Metadata: missing: %s, warnings: %s', missing, warnings)
        else:
            self._validate_mapping(self._data, self.scheme)

    def todict(self):
        if self._legacy:
            return self._legacy.todict(True)
        else:
            result = extract_by_key(self._data, self.INDEX_KEYS)
            return result

    def _from_legacy(self):
        assert self._legacy and not self._data
        result = {
            'metadata_version': self.METADATA_VERSION,
            'generator': self.GENERATOR,
        }
        lmd = self._legacy.todict(True)  # skip missing ones
        for k in ('name', 'version', 'license', 'summary', 'description', 'classifier'):
            if k in lmd:
                if k == 'classifier':
                    nk = 'classifiers'
                else:
                    nk = k
                result[nk] = lmd[k]
        kw = lmd.get('Keywords', [])
        if kw == ['']:
            kw = []
        result['keywords'] = kw
        keys = (('requires_dist', 'run_requires'), ('setup_requires_dist', 'build_requires'))
        for ok, nk in keys:
            if ok in lmd and lmd[ok]:
                result[nk] = [{'requires': lmd[ok]}]
        result['provides'] = self.provides
        # author = {}
        # maintainer = {}
        return result

    LEGACY_MAPPING = {
        'name': 'Name',
        'version': 'Version',
        ('extensions', 'python.details', 'license'): 'License',
        'summary': 'Summary',
        'description': 'Description',
        ('extensions', 'python.project', 'project_urls', 'Home'): 'Home-page',
        ('extensions', 'python.project', 'contacts', 0, 'name'): 'Author',
        ('extensions', 'python.project', 'contacts', 0, 'email'): 'Author-email',
        'source_url': 'Download-URL',
        ('extensions', 'python.details', 'classifiers'): 'Classifier',
    }

    def _to_legacy(self):

        def process_entries(entries):
            reqts = set()
            for e in entries:
                extra = e.get('extra')
                env = e.get('environment')
                rlist = e['requires']
                for r in rlist:
                    if not env and not extra:
                        reqts.add(r)
                    else:
                        marker = ''
                        if extra:
                            marker = 'extra == "%s"' % extra
                        if env:
                            if marker:
                                marker = '(%s) and %s' % (env, marker)
                            else:
                                marker = env
                        reqts.add(';'.join((r, marker)))
            return reqts

        assert self._data and not self._legacy
        result = LegacyMetadata()
        nmd = self._data
        # import pdb; pdb.set_trace()
        for nk, ok in self.LEGACY_MAPPING.items():
            if not isinstance(nk, tuple):
                if nk in nmd:
                    result[ok] = nmd[nk]
            else:
                d = nmd
                found = True
                for k in nk:
                    try:
                        d = d[k]
                    except (KeyError, IndexError):
                        found = False
                        break
                if found:
                    result[ok] = d
        r1 = process_entries(self.run_requires + self.meta_requires)
        r2 = process_entries(self.build_requires + self.dev_requires)
        if self.extras:
            result['Provides-Extra'] = sorted(self.extras)
        result['Requires-Dist'] = sorted(r1)
        result['Setup-Requires-Dist'] = sorted(r2)
        # TODO: any other fields wanted
        return result

    def write(self, path=None, fileobj=None, legacy=False, skip_unknown=True):
        if [path, fileobj].count(None) != 1:
            raise ValueError('Exactly one of path and fileobj is needed')
        self.validate()
        if legacy:
            if self._legacy:
                legacy_md = self._legacy
            else:
                legacy_md = self._to_legacy()
            if path:
                legacy_md.write(path, skip_unknown=skip_unknown)
            else:
                legacy_md.write_file(fileobj, skip_unknown=skip_unknown)
        else:
            if self._legacy:
                d = self._from_legacy()
            else:
                d = self._data
            if fileobj:
                json.dump(d, fileobj, ensure_ascii=True, indent=2, sort_keys=True)
            else:
                with codecs.open(path, 'w', 'utf-8') as f:
                    json.dump(d, f, ensure_ascii=True, indent=2, sort_keys=True)

    def add_requirements(self, requirements):
        if self._legacy:
            self._legacy.add_requirements(requirements)
        else:
            run_requires = self._data.setdefault('run_requires', [])
            always = None
            for entry in run_requires:
                if 'environment' not in entry and 'extra' not in entry:
                    always = entry
                    break
            if always is None:
                always = {'requires': requirements}
                run_requires.insert(0, always)
            else:
                rset = set(always['requires']) | set(requirements)
                always['requires'] = sorted(rset)

    def __repr__(self):
        name = self.name or '(no name)'
        version = self.version or 'no version'
        return '<%s %s %s (%s)>' % (self.__class__.__name__, self.metadata_version, name, version)