class _GetError(object):

    """Get error from form_errors, and represent it as span wrapped error

    message

    :param field_name: field to fetch errors for

    :param form_errors: form errors dict

    """

    def __call__(self, field_name, form_errors):

        tmpl = """<span class="error_msg">%s</span>"""

        if form_errors and form_errors.has_key(field_name):

            return literal(tmpl % form_errors.get(field_name))

get_error = _GetError()

class _ToolTip(object):

    def __call__(self, tooltip_title, trim_at=50):

        """Special function just to wrap our text into nice formatted

        autowrapped text

        :param tooltip_title:

        """

    def activate(self):

        """Adds tooltip mechanism to the given Html all tooltips have to have

        set class `tooltip` and set attribute `tooltip_title`.

        Then a tooltip will be generated based on that. All with yui js tooltip

        """

        js = '''

        YAHOO.util.Event.onDOMReady(function(){

            function toolTipsId(){

                var ids = [];

                var tts = YAHOO.util.Dom.getElementsByClassName('tooltip');

                for (var i = 0; i < tts.length; i++) {

                    //if element doesn't not have and id autogenerate one for tooltip

                    if (!tts[i].id){

                        tts[i].id='tt'+i*100;

                    }

                    ids.push(tts[i].id);

                }

                return ids

            };

            var myToolTips = new YAHOO.widget.Tooltip("tooltip", {

        :returns: RGB tuple

        """

        import colorsys

        golden_ratio = 0.618033988749895

        h = 0.22717784590367374

        for _ in xrange(n):

            h += golden_ratio

            h %= 1

            HSV_tuple = [h, 0.95, 0.95]

            RGB_tuple = colorsys.hsv_to_rgb(*HSV_tuple)

            yield map(lambda x:str(int(x * 256)), RGB_tuple)

    cgenerator = gen_color()

    def get_color_string(cs):

        if color_dict.has_key(cs):

            col = color_dict[cs]

        else:

            col = color_dict[cs] = cgenerator.next()

        return "color: rgb(%s)! important;" % (', '.join(col))

    def url_func(repo_name):

        def _url_func(changeset):

            lnk_format = '%5s:%s' % ('r%s' % changeset.revision,

                                     short_id(changeset.raw_id))

            uri = link_to(

                    lnk_format,

                    url('changeset_home', repo_name=repo_name,

                        revision=changeset.raw_id),

                    style=get_color_string(changeset.raw_id),

                    class_='tooltip',

                    title=tooltip_html

                  )

            uri += '\n'

            return uri

        return _url_func

    return literal(annotate_highlight(filenode, url_func(repo_name), **kwargs))

def get_changeset_safe(repo, rev):

    from vcs.backends.base import BaseRepository

    from vcs.exceptions import RepositoryError

    if not isinstance(repo, BaseRepository):

        raise Exception('You must pass an Repository '

                        'object as first argument got %s', type(repo))