"""
Adaptor for building prompt_toolkit styles, starting from a Pygments style.

Usage::

    from pygments.styles.tango import TangoStyle
    style = style_from_pygments(pygments_style_cls=TangoStyle)
"""
from __future__ import unicode_literals

from .base import Style
from .from_dict import style_from_dict

__all__ = (
    'PygmentsStyle',
    'style_from_pygments',
)


# Following imports are only needed when a ``PygmentsStyle`` class is used.
try:
    from pygments.style import Style as pygments_Style
    from pygments.styles.default import DefaultStyle as pygments_DefaultStyle
except ImportError:
    pygments_Style = None
    pygments_DefaultStyle = None


def style_from_pygments(style_cls=pygments_DefaultStyle,
                        style_dict=None,
                        include_defaults=True):
    """
    Shortcut to create a :class:`.Style` instance from a Pygments style class
    and a style dictionary.

    :param style_cls: Pygments style class to start from.
    :param style_dict: Dictionary for this style. `{Token: style}`.
    :param include_defaults: (`bool`) Include prompt_toolkit extensions.
    """
    assert style_dict is None or isinstance(style_dict, dict)
    assert style_cls is None or issubclass(style_cls, pygments_Style)

    styles_dict = {}

    if style_cls is not None:
        styles_dict.update(style_cls.styles)

    if style_dict is not None:
        styles_dict.update(style_dict)

    return style_from_dict(styles_dict, include_defaults=include_defaults)


class PygmentsStyle(Style):
    " Deprecated. "
    def __new__(cls, pygments_style_cls):
        assert issubclass(pygments_style_cls, pygments_Style)
        return style_from_dict(pygments_style_cls.styles)

    def invalidation_hash(self):
        pass

    @classmethod
    def from_defaults(cls, style_dict=None,
                      pygments_style_cls=pygments_DefaultStyle,
                      include_extensions=True):
        " Deprecated. "
        return style_from_pygments(
            style_cls=pygments_style_cls,
            style_dict=style_dict,
            include_defaults=include_extensions)
