# -*- coding: utf-8 -*-
from __future__ import absolute_import, unicode_literals

from docutils import nodes
from docutils.parsers.rst import Directive, directives
from pygments import highlight
from pygments.formatters import HtmlFormatter
from pygments.lexers import TextLexer, get_lexer_by_name

# -*- coding: utf-8 -*-
"""
The Pygments reStructuredText directive
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This fragment is a Docutils_ 0.5 directive that renders source code
(to HTML only, currently) via Pygments.

To use it, adjust the options below and copy the code into a module
that you import on initialization.  The code then automatically
registers a ``sourcecode`` directive that you can use instead of
normal code blocks like this::

    .. sourcecode:: python

        My code goes here.

If you want to have different code styles, e.g. one with line numbers
and one without, add formatters with their names in the VARIANTS dict
below.  You can invoke them instead of the DEFAULT one by using a
directive option::

    .. sourcecode:: python
        :linenos:

        My code goes here.

Look at the `directive documentation`_ to get all the gory details.

.. _Docutils: http://docutils.sf.net/
.. _directive documentation:
   http://docutils.sourceforge.net/docs/howto/rst-directives.html

:copyright: Copyright 2006-2015 by the Pygments team, see AUTHORS.
:license: BSD, see LICENSE for details.
"""

# Options
# ~~~~~~~

# Set to True if you want inline CSS styles instead of classes
INLINESTYLES = False


#: The default formatter
DEFAULT = HtmlFormatter(noclasses=INLINESTYLES)

#: Add name -> formatter pairs for every variant you want to use
VARIANTS = {
    # 'linenos': HtmlFormatter(noclasses=INLINESTYLES, linenos=True),
}


class CodeBlock(Directive):
    """Source code syntax hightlighting."""

    required_arguments = 1
    optional_arguments = 0
    final_argument_whitespace = True
    option_spec = dict([(key, directives.flag) for key in VARIANTS])
    has_content = True

    def run(self):
        self.assert_has_content()
        try:
            lexer = get_lexer_by_name(self.arguments[0])
        except ValueError:
            # no lexer found - use the text one instead of an exception
            lexer = TextLexer()
        # take an arbitrary option if more than one is given
        formatter = self.options and VARIANTS[list(self.options)[0]] or DEFAULT
        parsed = highlight(u'\n'.join(self.content), lexer, formatter)
        return [nodes.raw('', parsed, format='html')]


def register_pygments_directive(directive='code-block'):
    """Register pygments directive.

    Parameters
    ----------
    directive : str
        directive name to register pygments to.

    Examples
    --------
    If you wish to use (override) code-block (default), that means::

        .. code-block::

            // will be highlighted by pygments
    """
    directives.register_directive(directive, CodeBlock)
