# -*- coding: utf8 -*-
#
# Copyright (c) 2006-2019  Andrey Golovigin
# Copyright (c) 2014  Jorrit Wronski
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
# CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
# TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.


r"""
Markdown output backend.

>>> from pybtex.richtext import Tag, HRef
>>> markdown = Backend()
>>> print(Tag('em', '').render(markdown))
<BLANKLINE>
>>> print(Tag('em', 'Non-', 'empty').render(markdown))
*Non\-empty*
>>> print(HRef('/', '').render(markdown))
<BLANKLINE>
>>> print(HRef('/', 'Non-', 'empty').render(markdown))
[Non\-empty](/)
"""
from __future__ import unicode_literals

from xml.sax.saxutils import escape

from pybtex.backends import BaseBackend

SPECIAL_CHARS = [
    u'\\',  # backslash
    u'`',   # backtick
    u'*',   # asterisk
    u'_',   # underscore
    u'{',   # curly braces
    u'}',   # curly braces
    u'[',   # square brackets
    u']',   # square brackets
    u'(',   # parentheses
    u')',   # parentheses
    u'#',   # hash mark
    u'+',   # plus sign
    u'-',   # minus sign (hyphen)
    u'.',   # dot
    u'!',   # exclamation mark
]


class Backend(BaseBackend):
    u""" A backend to support markdown output. It implements the same
    features as the HTML backend.

    In addition to that, you can use the keyword php_extra=True to enable
    the definition list extension of php-markdown. The default is not to use
    it, since we cannot be sure that this feature is implemented on all
    systems.

    More information:
    http://www.michelf.com/projects/php-markdown/extra/#def-list

    """

    def __init__(self, encoding=None, php_extra=False):
        super(Backend, self).__init__(encoding=encoding)
        self.php_extra = php_extra

    default_suffix = '.md'
    symbols = {
        'ndash': u'&ndash;',# or 'ndash': u'–',
        'newblock': u'\n',
        'nbsp': u' '
    }
    tags = {
        'em'    : u'*',  # emphasize text
        'strong': u'**', # emphasize text even more
        'i'     : u'*',  # italicize text: be careful, i is not semantic
        'b'     : u'**', # embolden text: be careful, b is not semantic
        'tt'    : u'`',  # make text appear as code (typically typewriter text), a little hacky
    }

    def format_str(self, text):
        """Format the given string *str_*.
        Escapes special markdown control characters.
        """
        text = escape(text)
        for special_char in SPECIAL_CHARS:
            text = text.replace(special_char, u'\\' + special_char)
        return text

    def format_tag(self, tag_name, text):
        tag = self.tags.get(tag_name)
        if tag is None:
            return text
        else:
            return r'{0}{1}{0}'.format(tag, text) if text else u''

    def format_href(self, url, text):
        return r'[%s](%s)' % (text, url) if text else u''

    def write_entry(self, key, label, text):
        # Support http://www.michelf.com/projects/php-markdown/extra/#def-list
        if self.php_extra:
            self.output(u'%s\n' % label)
            self.output(u':   %s\n\n' % text)
        else:
            self.output(u'[%s] ' % label)
            self.output(u'%s  \n' % text)