import re

class TypogrifyError(Exception): pass

class Typogrify(object):
    """
    Wrapping the utilities in a class to avoid namespace clashes.
    """

    @staticmethod
    def amp(text):
        """Wraps apersands in HTML with ``<span class="amp">`` so they can be
        styled with CSS. Apersands are also normalized to ``&amp;``. Requires
        ampersands to have whitespace or an ``&nbsp;`` on both sides.

        >>> Typogrify.amp('One & two')
        'One <span class="amp">&amp;</span> two'
        >>> Typogrify.amp('One &amp; two')
        'One <span class="amp">&amp;</span> two'
        >>> Typogrify.amp('One &#38; two')
        'One <span class="amp">&amp;</span> two'

        >>> Typogrify.amp('One&nbsp;&amp;&nbsp;two')
        'One&nbsp;<span class="amp">&amp;</span>&nbsp;two'

        It won't mess up & that are already wrapped, in entities or URLs

        >>> Typogrify.amp('One <span class="amp">&amp;</span> two')
        'One <span class="amp">&amp;</span> two'
        >>> Typogrify.amp('&ldquo;this&rdquo; & <a href="/?that&amp;test">that</a>')
        '&ldquo;this&rdquo; <span class="amp">&amp;</span> <a href="/?that&amp;test">that</a>'

        It should ignore standalone amps that are in attributes
        >>> Typogrify.amp('<link href="xyz.html" title="One & Two">xyz</link>')
        '<link href="xyz.html" title="One & Two">xyz</link>'
        """
        # tag_pattern from http://haacked.com/archive/2004/10/25/usingregularexpressionstomatchhtml.aspx
        # it kinda sucks but it fixes the standalone amps in attributes bug
        tag_pattern = '</?\w+((\s+\w+(\s*=\s*(?:".*?"|\'.*?\'|[^\'">\s]+))?)+\s*|\s*)/?>'
        amp_finder = re.compile(r"(\s|&nbsp;)(&|&amp;|&\#38;)(\s|&nbsp;)")
        intra_tag_finder = re.compile(r'(?P<prefix>(%s)?)(?P<text>([^<]*))(?P<suffix>(%s)?)' % (tag_pattern, tag_pattern))
        def _amp_process(groups):
            prefix = groups.group('prefix') or ''
            text = amp_finder.sub(r"""\1<span class="amp">&amp;</span>\3""", groups.group('text'))
            suffix = groups.group('suffix') or ''
            return prefix + text + suffix
        output = intra_tag_finder.sub(_amp_process, text)
        return output

    @staticmethod
    def caps(text):
        """Wraps multiple capital letters in ``<span class="caps">``
        so they can be styled with CSS.

        >>> Typogrify.caps("A message from KU")
        'A message from <span class="caps">KU</span>'

        Uses the smartypants tokenizer to not screw with HTML or with tags it shouldn't.

        >>> Typogrify.caps("<PRE>CAPS</pre> more CAPS")
        '<PRE>CAPS</pre> more <span class="caps">CAPS</span>'

        >>> Typogrify.caps("A message from 2KU2 with digits")
        'A message from <span class="caps">2KU2</span> with digits'

        >>> Typogrify.caps("Dotted caps followed by spaces should never include them in the wrap D.O.T.   like so.")
        'Dotted caps followed by spaces should never include them in the wrap <span class="caps">D.O.T.</span>  like so.'

        All caps with with apostrophes in them shouldn't break. Only handles dump apostrophes though.
        >>> Typogrify.caps("JIMMY'S")
        '<span class="caps">JIMMY\\'S</span>'

        >>> Typogrify.caps("<i>D.O.T.</i>HE34T<b>RFID</b>")
        '<i><span class="caps">D.O.T.</span></i><span class="caps">HE34T</span><b><span class="caps">RFID</span></b>'
        """
        try:
            import smartypants
        except ImportError:
            raise TypogrifyError, "Error in {% caps %} filter: The Python SmartyPants library isn't installed."


        tokens = smartypants._tokenize(text)
        result = []
        in_skipped_tag = False

        cap_finder = re.compile(r"""(
                                (\b[A-Z\d]*        # Group 2: Any amount of caps and digits
                                [A-Z]\d*[A-Z]      # A cap string much at least include two caps (but they can have digits between them)
                                [A-Z\d']*\b)       # Any amount of caps and digits or dumb apostsrophes
                                | (\b[A-Z]+\.\s?   # OR: Group 3: Some caps, followed by a '.' and an optional space
                                (?:[A-Z]+\.\s?)+)  # Followed by the same thing at least once more
                                (?:\s|\b|$))
                                """, re.VERBOSE)

        def _cap_wrapper(matchobj):
            """This is necessary to keep dotted cap strings to pick up extra spaces"""
            if matchobj.group(2):
                return """<span class="caps">%s</span>""" % matchobj.group(2)
            else:
                if matchobj.group(3)[-1] == " ":
                    caps = matchobj.group(3)[:-1]
                    tail = ' '
                else:
                    caps = matchobj.group(3)
                    tail = ''
                return """<span class="caps">%s</span>%s""" % (caps, tail)

        tags_to_skip_regex = re.compile("<(/)?(?:pre|code|kbd|script|math)[^>]*>", re.IGNORECASE)


        for token in tokens:
            if token[0] == "tag":
                # Don't mess with tags.
                result.append(token[1])
                close_match = tags_to_skip_regex.match(token[1])
                if close_match and close_match.group(1) == None:
                    in_skipped_tag = True
                else:
                    in_skipped_tag = False
            else:
                if in_skipped_tag:
                    result.append(token[1])
                else:
                    result.append(cap_finder.sub(_cap_wrapper, token[1]))
        output = "".join(result)
        return output


    @staticmethod
    def initial_quotes(text):
        """Wraps initial quotes in ``class="dquo"`` for double quotes or
        ``class="quo"`` for single quotes. Works in these block tags ``(h1-h6, p, li, dt, dd)``
        and also accounts for potential opening inline elements ``a, em, strong, span, b, i``

        >>> Typogrify.initial_quotes('"With primes"')
        '<span class="dquo">"</span>With primes"'
        >>> Typogrify.initial_quotes("'With single primes'")
        '<span class="quo">\\'</span>With single primes\\''

        >>> Typogrify.initial_quotes('<a href="#">"With primes and a link"</a>')
        '<a href="#"><span class="dquo">"</span>With primes and a link"</a>'

        >>> Typogrify.initial_quotes('&#8220;With smartypanted quotes&#8221;')
        '<span class="dquo">&#8220;</span>With smartypanted quotes&#8221;'
        """
        quote_finder = re.compile(r"""((<(p|h[1-6]|li|dt|dd)[^>]*>|^)              # start with an opening p, h1-6, li, dd, dt or the start of the string
                                      \s*                                          # optional white space!
                                      (<(a|em|span|strong|i|b)[^>]*>\s*)*)         # optional opening inline tags, with more optional white space for each.
                                      (("|&ldquo;|&\#8220;)|('|&lsquo;|&\#8216;))  # Find me a quote! (only need to find the left quotes and the primes)
                                                                                   # double quotes are in group 7, singles in group 8
                                      """, re.VERBOSE)
        def _quote_wrapper(matchobj):
            if matchobj.group(7):
                classname = "dquo"
                quote = matchobj.group(7)
            else:
                classname = "quo"
                quote = matchobj.group(8)
            return """%s<span class="%s">%s</span>""" % (matchobj.group(1), classname, quote)
        output = quote_finder.sub(_quote_wrapper, text)
        return output

    @staticmethod
    def smartypants(text):
        """Applies smarty pants to curl quotes.

        >>> Typogrify.smartypants('The "Green" man')
        'The &#8220;Green&#8221; man'
        """
        try:
            import smartypants
        except ImportError:
            raise TypogrifyError, "Error in {% smartypants %} filter: The Python smartypants library isn't installed."
        else:
            output = smartypants.smartyPants(text)
            return output

    @staticmethod
    def titlecase(text):
        """Support for titlecase.py's titlecasing

        >>> Typogrify.titlecase("this V that")
        'This v That'

        >>> Typogrify.titlecase("this is just an example.com")
        'This Is Just an example.com'
        """
        try:
            import titlecase
        except ImportError:
            raise TypogrifyError, "Error in {% titlecase %} filter: The titlecase.py library isn't installed."
        else:
            return titlecase.titlecase(text)

    @staticmethod
    def typogrify(text):
        """The super typography filter

        Applies the following filters: widont, smartypants, caps, amp, initial_quotes

        >>> Typogrify.typogrify('<h2>"Jayhawks" & KU fans act extremely obnoxiously</h2>')
        '<h2><span class="dquo">&#8220;</span>Jayhawks&#8221; <span class="amp">&amp;</span> <span class="caps">KU</span> fans act extremely&nbsp;obnoxiously</h2>'

        """
        text = Typogrify.amp(text)
        text = Typogrify.widont(text)
        text = Typogrify.smartypants(text)
        text = Typogrify.caps(text)
        text = Typogrify.initial_quotes(text)
        return text

    @staticmethod
    def widont(text):
        """Replaces the space between the last two words in a string with ``&nbsp;``
        Works in these block tags ``(h1-h6, p, li, dd, dt)`` and also accounts for
        potential closing inline elements ``a, em, strong, span, b, i``

        >>> Typogrify.widont('A very simple test')
        'A very simple&nbsp;test'

        Single word items shouldn't be changed
        >>> Typogrify.widont('Test')
        'Test'
        >>> Typogrify.widont(' Test')
        ' Test'
        >>> Typogrify.widont('<ul><li>Test</p></li><ul>')
        '<ul><li>Test</p></li><ul>'
        >>> Typogrify.widont('<ul><li> Test</p></li><ul>')
        '<ul><li> Test</p></li><ul>'

        >>> Typogrify.widont('<p>In a couple of paragraphs</p><p>paragraph two</p>')
        '<p>In a couple of&nbsp;paragraphs</p><p>paragraph&nbsp;two</p>'

        >>> Typogrify.widont('<h1><a href="#">In a link inside a heading</i> </a></h1>')
        '<h1><a href="#">In a link inside a&nbsp;heading</i> </a></h1>'

        >>> Typogrify.widont('<h1><a href="#">In a link</a> followed by other text</h1>')
        '<h1><a href="#">In a link</a> followed by other&nbsp;text</h1>'

        Empty HTMLs shouldn't error
        >>> Typogrify.widont('<h1><a href="#"></a></h1>')
        '<h1><a href="#"></a></h1>'

        >>> Typogrify.widont('<div>Divs get no love!</div>')
        '<div>Divs get no love!</div>'

        >>> Typogrify.widont('<pre>Neither do PREs</pre>')
        '<pre>Neither do PREs</pre>'

        >>> Typogrify.widont('<div><p>But divs with paragraphs do!</p></div>')
        '<div><p>But divs with paragraphs&nbsp;do!</p></div>'
        """
        widont_finder = re.compile(r"""((?:</?(?:a|em|span|strong|i|b)[^>]*>)|[^<>\s]) # must be proceeded by an approved inline opening or closing tag or a nontag/nonspace
                                       \s+                                             # the space to replace
                                       ([^<>\s]+                                       # must be flollowed by non-tag non-space characters
                                       \s*                                             # optional white space!
                                       (</(a|em|span|strong|i|b)>\s*)*                 # optional closing inline tags with optional white space after each
                                       ((</(p|h[1-6]|li|dt|dd)>)|$))                   # end with a closing p, h1-6, li or the end of the string
                                       """, re.VERBOSE)
        output = widont_finder.sub(r'\1&nbsp;\2', text)
        return output

def _test():
    import doctest
    doctest.testmod(verbose=True)

if __name__ == "__main__":
    _test()
