"""
    sphinx.parsers
    ~~~~~~~~~~~~~~

    A Base class for additional parsers.

    :copyright: Copyright 2007-2020 by the Sphinx team, see AUTHORS.
    :license: BSD, see LICENSE for details.
"""

from typing import Any, Dict, List, Union

import docutils.parsers
import docutils.parsers.rst
from docutils import nodes
from docutils.parsers.rst import states
from docutils.statemachine import StringList
from docutils.transforms.universal import SmartQuotes

from sphinx.util.rst import append_epilog, prepend_prolog

if False:
    # For type annotation
    from docutils.transforms import Transform  # NOQA
    from typing import Type  # NOQA # for python3.5.1
    from sphinx.application import Sphinx


class Parser(docutils.parsers.Parser):
    """
    A base class of source parsers.  The additional parsers should inherit this class instead
    of ``docutils.parsers.Parser``.  Compared with ``docutils.parsers.Parser``, this class
    improves accessibility to Sphinx APIs.

    The subclasses can access following objects and functions:

    self.app
        The application object (:class:`sphinx.application.Sphinx`)
    self.config
        The config object (:class:`sphinx.config.Config`)
    self.env
        The environment object (:class:`sphinx.environment.BuildEnvironment`)
    self.warn()
        Emit a warning. (Same as :meth:`sphinx.application.Sphinx.warn()`)
    self.info()
        Emit a informational message. (Same as :meth:`sphinx.application.Sphinx.info()`)

    .. deprecated:: 1.6
       ``warn()`` and ``info()`` is deprecated.  Use :mod:`sphinx.util.logging` instead.
    """

    def set_application(self, app: "Sphinx") -> None:
        """set_application will be called from Sphinx to set app and other instance variables

        :param sphinx.application.Sphinx app: Sphinx application object
        """
        self.app = app
        self.config = app.config
        self.env = app.env


class RSTParser(docutils.parsers.rst.Parser, Parser):
    """A reST parser for Sphinx."""

    def get_transforms(self) -> List["Type[Transform]"]:
        """Sphinx's reST parser replaces a transform class for smart-quotes by own's

        refs: sphinx.io.SphinxStandaloneReader
        """
        transforms = super().get_transforms()
        transforms.remove(SmartQuotes)
        return transforms

    def parse(self, inputstring: Union[str, StringList], document: nodes.document) -> None:
        """Parse text and generate a document tree."""
        self.setup_parse(inputstring, document)  # type: ignore
        self.statemachine = states.RSTStateMachine(
            state_classes=self.state_classes,
            initial_state=self.initial_state,
            debug=document.reporter.debug_flag)

        # preprocess inputstring
        if isinstance(inputstring, str):
            lines = docutils.statemachine.string2lines(
                inputstring, tab_width=document.settings.tab_width,
                convert_whitespace=True)

            inputlines = StringList(lines, document.current_source)
        else:
            inputlines = inputstring

        self.decorate(inputlines)
        self.statemachine.run(inputlines, document, inliner=self.inliner)
        self.finish_parse()

    def decorate(self, content: StringList) -> None:
        """Preprocess reST content before parsing."""
        prepend_prolog(content, self.config.rst_prolog)
        append_epilog(content, self.config.rst_epilog)


def setup(app: "Sphinx") -> Dict[str, Any]:
    app.add_source_parser(RSTParser)

    return {
        'version': 'builtin',
        'parallel_read_safe': True,
        'parallel_write_safe': True,
    }
