# -*- coding: utf-8 -*-
# -----------------------------------------------------------------------------
# Copyright (C) 2009 Tim Dumol <tim@timdumol.com>
# Copyright (C) 2010- Spyder Project Contributors
#
# Distributed under the terms of the Modified BSD License
# (BSD 3-clause; see NOTICE.txt in the Spyder root directory for details).
# -----------------------------------------------------------------------------

"""
Process docstrings with Sphinx.

**AUTHORS**:

* Tim Joseph Dumol (2009-09-29): Initial version.
* The Spyder Project Contributors: Several changes to make it work with Spyder.

Originally based on sagenb/misc/sphinxify.py from the
`Sage Notebook project <https://github.com/sagemath/sagenb>`_,
part of the `SageMath <https://www.sagemath.org/>`_ system.
"""

# Standard library imports
import codecs
import os
import os.path as osp
import pathlib
import shutil
import sys
from tempfile import mkdtemp
from xml.sax.saxutils import escape

# Third party imports
from docutils.utils import SystemMessage as SystemMessage
from jinja2 import Environment, FileSystemLoader
import sphinx
from sphinx.application import Sphinx

# Local imports
from spyder.api.translations import _
from spyder.config.base import get_module_data_path, get_module_source_path
from spyder.utils import encoding


#-----------------------------------------------------------------------------
# Globals and constants
#-----------------------------------------------------------------------------

# Note: we do not use __file__ because it won't be working in the stand-alone
# version of Spyder (i.e. the py2exe or cx_Freeze build)
CONFDIR_PATH = get_module_source_path('spyder.plugins.help.utils')
CSS_PATH = osp.join(CONFDIR_PATH, 'static', 'css')
DARK_CSS_PATH = osp.join(CONFDIR_PATH, 'static', 'dark_css')
BASE_CSS_PATH = osp.join(CONFDIR_PATH, 'static', 'base_css')
JS_PATH = osp.join(CONFDIR_PATH, 'js')

# To let Debian packagers redefine the MathJax and JQuery locations so they can
# use their own packages for them. See spyder-ide/spyder#1230, comment #7.
MATHJAX_PATH = get_module_data_path('spyder',
                                    relpath=osp.join('utils', 'help',
                                                     JS_PATH, 'mathjax'),
                                    attr_name='MATHJAXPATH')

JQUERY_PATH = get_module_data_path('spyder',
                                   relpath=osp.join('utils', 'help',
                                                    JS_PATH),
                                   attr_name='JQUERYPATH')

#-----------------------------------------------------------------------------
# Utility functions
#-----------------------------------------------------------------------------

def is_sphinx_markup(docstring):
    """Returns whether a string contains Sphinx-style ReST markup."""
    # this could be made much more clever
    return ("`" in docstring or "::" in docstring)


def warning(message, css_path=CSS_PATH):
    """Print a warning message on the rich text view"""
    env = Environment()
    env.loader = FileSystemLoader(osp.join(CONFDIR_PATH, 'templates'))
    warning = env.get_template("warning.html")
    return warning.render(css_path=css_path, text=message)


def usage(title, message, tutorial_message, tutorial, css_path=CSS_PATH):
    """Print a usage message on the rich text view"""
    env = Environment()
    env.loader = FileSystemLoader(osp.join(CONFDIR_PATH, 'templates'))
    usage = env.get_template("usage.html")
    return usage.render(css_path=css_path, title=title, intro_message=message,
                        tutorial_message=tutorial_message, tutorial=tutorial)


def loading(message, loading_img, css_path=CSS_PATH):
    """Print loading message on the rich text view."""
    env = Environment()
    env.loader = FileSystemLoader(osp.join(CONFDIR_PATH, 'templates'))
    loading = env.get_template("loading.html")
    return loading.render(
        css_path=css_path, loading_img=loading_img, message=message)


def generate_context(name='', argspec='', note='', math=False, collapse=False,
                     img_path='', css_path=CSS_PATH):
    """
    Generate the html_context dictionary for our Sphinx conf file.

    This is a set of variables to be passed to the Jinja template engine and
    that are used to control how the webpage is rendered in connection with
    Sphinx

    Parameters
    ----------
    name : str
        Object's name.
    note : str
        A note describing what type has the function or method being
        introspected
    argspec : str
        Argspec of the the function or method being introspected
    math : bool
        Turn on/off Latex rendering on the OI. If False, Latex will be shown in
        plain text.
    collapse : bool
        Collapse sections
    img_path : str
        Path for images relative to the file containing the docstring

    Returns
    -------
    A dict of strings to be used by Jinja to generate the webpage
    """

    if img_path and os.name == 'nt':
        img_path = img_path.replace('\\', '/')

    context = \
    {
      # Arg dependent variables
      'math_on': 'true' if math else '',
      'name': name,
      'argspec': argspec,
      'note': note,
      'collapse': collapse,
      'img_path': img_path,
      # Static variables
      'base_css_path': BASE_CSS_PATH,
      'css_path': css_path,
      'js_path': JS_PATH,
      'jquery_path': JQUERY_PATH,
      'mathjax_path': MATHJAX_PATH,
      'right_sphinx_version': '' if sphinx.__version__ < "1.1" else 'true',
      'sphinx_version_2': '' if sphinx.__version__ < "2.0" else 'true',
      'platform': sys.platform
    }

    return context


def sphinxify(docstring, context, buildername='html'):
    """
    Runs Sphinx on a docstring and outputs the processed documentation.

    Parameters
    ----------
    docstring : str
        a ReST-formatted docstring

    context : dict
        Variables to be passed to the layout template to control how its
        rendered (through the Sphinx variable *html_context*).

    buildername:  str
        It can be either `html` or `text`.

    Returns
    -------
    An Sphinx-processed string, in either HTML or plain text format, depending
    on the value of `buildername`
    """

    confdir = osp.join(get_module_source_path('spyder.plugins.help.utils'))
    srcdir = mkdtemp()
    srcdir = encoding.to_unicode_from_fs(srcdir)
    destdir = osp.join(srcdir, '_build')
    temp_confdir_needed = False

    if os.name == 'nt':
        # Check if confdir and srcdir are in the same drive
        # See spyder-ide/spyder#11762
        drive_confdir = pathlib.Path(confdir).parts[0]
        drive_srcdir = pathlib.Path(srcdir).parts[0]
        temp_confdir_needed = drive_confdir != drive_srcdir

        if temp_confdir_needed:
            # TODO: This may be inefficient. Find a faster way to do it.
            confdir = mkdtemp()
            confdir = encoding.to_unicode_from_fs(confdir)
            generate_configuration(confdir)

    rst_name = osp.join(srcdir, 'docstring.rst')
    if buildername == 'html':
        suffix = '.html'
    else:
        suffix = '.txt'
    output_name = osp.join(destdir, 'docstring' + suffix)

    # This is needed so users can type \\ on latex eqnarray envs inside raw
    # docstrings
    if context['right_sphinx_version'] and context['math_on']:
        docstring = docstring.replace('\\\\', '\\\\\\\\')
        # Needed to prevent MathJax render the '\*' red.
        # Also the '\*' seems to actually by a simple '*'
        # See spyder-ide/spyder#9785
        docstring = docstring.replace("\\*", "*")

    # Add a class to several characters on the argspec. This way we can
    # highlight them using css, in a similar way to what IPython does.
    # NOTE: Before doing this, we escape common html chars so that they
    # don't interfere with the rest of html present in the page
    argspec = escape(context['argspec'])
    for char in ['=', ',', '(', ')', '*', '**']:
        argspec = argspec.replace(char,
                         '<span class="argspec-highlight">' + char + '</span>')
    context['argspec'] = argspec

    doc_file = codecs.open(rst_name, 'w', encoding='utf-8')
    doc_file.write(docstring)
    doc_file.close()

    confoverrides = {'html_context': context}

    doctreedir = osp.join(srcdir, 'doctrees')

    sphinx_app = Sphinx(srcdir, confdir, destdir, doctreedir, buildername,
                        confoverrides, status=None, warning=None,
                        freshenv=True, warningiserror=False, tags=None)
    try:
        sphinx_app.build(None, [rst_name])
    except SystemMessage:
        output = _("It was not possible to generate rich text help for this "
                    "object.</br>"
                    "Please see it in plain text.")
        return warning(output)

    # TODO: Investigate if this is necessary/important for us
    if osp.exists(output_name):
        output = codecs.open(output_name, 'r', encoding='utf-8').read()
        output = output.replace('<pre>', '<pre class="literal-block">')
    else:
        output = _("It was not possible to generate rich text help for this "
                    "object.</br>"
                    "Please see it in plain text.")
        return warning(output)

    if temp_confdir_needed:
        shutil.rmtree(confdir, ignore_errors=True)
    shutil.rmtree(srcdir, ignore_errors=True)

    return output


def generate_configuration(directory):
    """
    Generates a Sphinx configuration in `directory`.

    Parameters
    ----------
    directory : str
        Base directory to use
    """

    # conf.py file for Sphinx
    conf = osp.join(get_module_source_path('spyder.plugins.help.utils'),
                    'conf.py')

    # Docstring layout page (in Jinja):
    layout = osp.join(osp.join(CONFDIR_PATH, 'templates'), 'layout.html')

    os.makedirs(osp.join(directory, 'templates'))
    os.makedirs(osp.join(directory, 'static'))
    shutil.copy(conf, directory)
    shutil.copy(layout, osp.join(directory, 'templates'))
    open(osp.join(directory, '__init__.py'), 'w').write('')
    open(osp.join(directory, 'static', 'empty'), 'w').write('')
