import re

from webhelpers2.html import HTML, literal

    def _pagerlink(self, page, text):

        """hack to mimic old webhelpers.paginate internals"""

        return literal('''<li><a class="pager_link" href="%s">%s</a></li>''') % (self.url_maker(page), text)

    def _get_pos(self, cur_page, max_page, items):

        edge = (items / 2) + 1

        if (cur_page <= edge):

            radius = max(items / 2, items - cur_page)

        elif (max_page - cur_page) < edge:

            radius = (items - 1) - (max_page - cur_page)

        else:

            radius = items / 2

        left = max(1, (cur_page - (radius)))

        right = min(max_page, cur_page + (radius))

        return left, cur_page, right

    def _range(self, regexp_match):

        """

        Return range of linked pages (e.g. '1 2 [3] 4 5 6 7 8').

        Arguments:

        regexp_match

            A "re" (regular expressions) match object containing the

            radius of linked pages around the current page in

            regexp_match.group(1) as a string

        This function is supposed to be called as a callable in

        re.sub.

        """

        radius = int(regexp_match.group(1))

        # Compute the first and last page number within the radius

        # e.g. '1 .. 5 6 [7] 8 9 .. 12'

        # -> leftmost_page  = 5

        # -> rightmost_page = 9

        leftmost_page, _cur, rightmost_page = self._get_pos(self.page,

                                                            self.last_page,

                                                            (radius * 2) + 1)

        nav_items = []

        # Create a link to the first page (unless we are on the first page

        # or there would be no need to insert '..' spacers)

        if self.page != self.first_page and self.first_page < leftmost_page:

            nav_items.append(HTML.li(self._pagerlink(self.first_page, self.first_page)))

        # Insert dots if there are pages between the first page

        # and the currently displayed page range

        if leftmost_page - self.first_page > 1:

            # Wrap in a SPAN tag if nolink_attr is set

            text_ = '..'

            if self.dotdot_attr:

                text_ = HTML.span(c=text_, **self.dotdot_attr)

            nav_items.append(HTML.li(text_))

        for thispage in xrange(leftmost_page, rightmost_page + 1):

            # Highlight the current page number and do not use a link

            text_ = str(thispage)

            if thispage == self.page:

                # Wrap in a SPAN tag if nolink_attr is set

                if self.curpage_attr:

                    text_ = HTML.li(HTML.span(c=text_), **self.curpage_attr)

                nav_items.append(text_)

            # Otherwise create just a link to that page

                nav_items.append(HTML.li(self._pagerlink(thispage, text_)))

        # Insert dots if there are pages between the displayed

        # page numbers and the end of the page range

        if self.last_page - rightmost_page > 1:

            text_ = '..'

            # Wrap in a SPAN tag if nolink_attr is set

            if self.dotdot_attr:

                text_ = HTML.span(c=text_, **self.dotdot_attr)

            nav_items.append(HTML.li(text_))

        # Create a link to the very last page (unless we are on the last

        # page or there would be no need to insert '..' spacers)

        if self.page != self.last_page and rightmost_page < self.last_page:

            nav_items.append(HTML.li(self._pagerlink(self.last_page, self.last_page)))

        #_page_link = url.current()

        #nav_items.append(literal('<link rel="prerender" href="%s?page=%s">' % (_page_link, str(int(self.page)+1))))

        #nav_items.append(literal('<link rel="prefetch" href="%s?page=%s">' % (_page_link, str(int(self.page)+1))))

        return self.separator.join(nav_items)

    def pager(self, format='<ul class="pagination">$link_previous ~2~ $link_next</ul>', page_param='page', partial_param='partial',

        show_if_single_page=False, separator=' ', onclick=None,

        symbol_first='<<', symbol_last='>>',

        symbol_previous='<', symbol_next='>',

        link_attr=None,

        curpage_attr=None,

        dotdot_attr=None, **kwargs

    ):

        self.curpage_attr = curpage_attr or {'class': 'active'}

        self.separator = separator

        self.pager_kwargs = kwargs

        self.page_param = page_param

        self.partial_param = partial_param

        self.onclick = onclick

        self.link_attr = link_attr or {'class': 'pager_link', 'rel': 'prerender'}

        self.dotdot_attr = dotdot_attr or {'class': 'pager_dotdot'}

        # Don't show navigator if there is no more than one page

        if self.page_count == 0 or (self.page_count == 1 and not show_if_single_page):

            return ''

        from string import Template

        # Replace ~...~ in token format by range of pages

        result = re.sub(r'~(\d+)~', self._range, format)

        # Interpolate '%' variables

        result = Template(result).safe_substitute({

            'first_page': self.first_page,

            'last_page': self.last_page,

            'page': self.page,

            'page_count': self.page_count,

            'items_per_page': self.items_per_page,

            'first_item': self.first_item,

            'last_item': self.last_item,

            'item_count': self.item_count,

            'link_first': self.page > self.first_page and

                    self._pagerlink(self.first_page, symbol_first) or '',

            'link_last': self.page < self.last_page and

                    self._pagerlink(self.last_page, symbol_last) or '',

            'link_previous': HTML.li(self.previous_page and

                    self._pagerlink(self.previous_page, symbol_previous)

                    or HTML.a(symbol_previous)),

            'link_next': HTML.li(self.next_page and

                    self._pagerlink(self.next_page, symbol_next)

                    or HTML.a(symbol_next)),

        })

        return literal(result)