from django.forms import widgets
from django.forms.util import flatatt
from django.utils.safestring import mark_safe
from django.utils.encoding import force_unicode
from django.utils import datetime_safe

class HiddenDateDisplayInput(widgets.HiddenInput):
    format = "%Y-%m-%d"
    
    def __init__(self, attrs=None, format=None, default_display_value="No value to show"):
        super(HiddenDateDisplayInput, self).__init__(attrs)
        self.default_display_value = default_display_value
        if format:
            self.format = format
    
    def render(self, name, value, attrs=None):
        if value is None: value = ''
        display_value = self.default_display_value
        final_attrs = self.build_attrs(attrs, type=self.input_type, name=name)
        if value != '':
            # Only add the 'value' attribute if a value is non-empty.
            final_attrs['value'] = force_unicode(value)
            display_value = datetime_safe.new_datetime(value)
            display_value = value.strftime(self.format)
        return mark_safe(u'<span class="hidden-display-value">%s</span> <input%s />' % (display_value, flatatt(final_attrs)))