"""
    sphinxcontrib.jsmath
    ~~~~~~~~~~~~~~~~~~~~

    Set up everything for use of JSMath to display math in HTML
    via JavaScript.

    :copyright: Copyright 2007-2019 by the Sphinx team, see AUTHORS.
    :license: BSD, see LICENSE for details.
"""

from os import path
from typing import Any, Dict, cast

from docutils import nodes
from sphinx.application import Sphinx
from sphinx.builders.html import StandaloneHTMLBuilder
from sphinx.domains.math import MathDomain
from sphinx.environment import BuildEnvironment
from sphinx.errors import ExtensionError
from sphinx.locale import get_translation
from sphinx.util.math import get_node_equation_number
from sphinx.writers.html import HTMLTranslator

from sphinxcontrib.jsmath.version import __version__

package_dir = path.abspath(path.dirname(__file__))

_ = get_translation(__name__)


def html_visit_math(self: HTMLTranslator, node: nodes.math) -> None:
    self.body.append(self.starttag(node, 'span', '', CLASS='math notranslate nohighlight'))
    self.body.append(self.encode(node.astext()) + '</span>')
    raise nodes.SkipNode


def html_visit_displaymath(self: HTMLTranslator, node: nodes.math_block) -> None:
    if node['nowrap']:
        self.body.append(self.starttag(node, 'div', CLASS='math notranslate nohighlight'))
        self.body.append(self.encode(node.astext()))
        self.body.append('</div>')
        raise nodes.SkipNode
    for i, part in enumerate(node.astext().split('\n\n')):
        part = self.encode(part)
        if i == 0:
            # necessary to e.g. set the id property correctly
            if node['number']:
                number = get_node_equation_number(self, node)
                self.body.append('<span class="eqno">(%s)' % number)
                self.add_permalink_ref(node, _('Permalink to this equation'))
                self.body.append('</span>')
            self.body.append(self.starttag(node, 'div', CLASS='math notranslate nohighlight'))
        else:
            # but only once!
            self.body.append('<div class="math">')
        if '&' in part or '\\\\' in part:
            self.body.append('\\begin{split}' + part + '\\end{split}')
        else:
            self.body.append(part)
        self.body.append('</div>\n')
    raise nodes.SkipNode


def install_jsmath(app: Sphinx, env: BuildEnvironment) -> None:
    if app.builder.format != 'html' or app.builder.math_renderer_name != 'jsmath':  # type: ignore  # NOQA
        return
    if not app.config.jsmath_path:
        raise ExtensionError('jsmath_path config value must be set for the '
                             'jsmath extension to work')

    builder = cast(StandaloneHTMLBuilder, app.builder)
    domain = cast(MathDomain, env.get_domain('math'))
    if domain.has_equations():
        # Enable jsmath only if equations exists
        builder.add_js_file(app.config.jsmath_path)


def setup(app: Sphinx) -> Dict[str, Any]:
    app.require_sphinx('2.0')
    app.add_message_catalog(__name__, path.join(package_dir, 'locales'))
    app.add_html_math_renderer('jsmath',
                               (html_visit_math, None),
                               (html_visit_displaymath, None))

    app.add_config_value('jsmath_path', '', False)
    app.connect('env-updated', install_jsmath)
    return {
        'version': __version__,
        'parallel_read_safe': True,
        'parallel_write_safe': True,
    }