from captcha.conf import settings
from captcha.models import CaptchaStore, get_safe_now
from django.core.exceptions import ImproperlyConfigured
from django.core.urlresolvers import reverse, NoReverseMatch
from django.forms import ValidationError
from django.forms.fields import CharField, MultiValueField
from django.forms.widgets import TextInput, MultiWidget, HiddenInput
from django.utils.translation import ugettext, ugettext_lazy
from six import u


class BaseCaptchaTextInput(MultiWidget):
    """
    Base class for Captcha widgets
    """
    def __init__(self, attrs=None):
        widgets = (
            HiddenInput(attrs),
            TextInput(attrs),
        )
        super(BaseCaptchaTextInput, self).__init__(widgets, attrs)

    def decompress(self, value):
        if value:
            return value.split(',')
        return [None, None]

    def fetch_captcha_store(self, name, value, attrs=None):
        """
        Fetches a new CaptchaStore
        This has to be called inside render
        """
        try:
            reverse('captcha-image', args=('dummy',))
        except NoReverseMatch:
            raise ImproperlyConfigured('Make sure you\'ve included captcha.urls as explained in the INSTALLATION section on http://readthedocs.org/docs/django-simple-captcha/en/latest/usage.html#installation')

        key = CaptchaStore.generate_key()

        # these can be used by format_output and render
        self._value = [key, u('')]
        self._key = key
        self.id_ = self.build_attrs(attrs).get('id', None)

    def id_for_label(self, id_):
        if id_:
            return id_ + '_1'
        return id_

    def image_url(self):
        return reverse('captcha-image', kwargs={'key': self._key})

    def audio_url(self):
        return reverse('captcha-audio', kwargs={'key': self._key}) if settings.CAPTCHA_FLITE_PATH else None

    def refresh_url(self):
        return reverse('captcha-refresh')


class CaptchaTextInput(BaseCaptchaTextInput):
    def __init__(self, attrs=None, **kwargs):
        self._args = kwargs
        self._args['output_format'] = self._args.get('output_format') or settings.CAPTCHA_OUTPUT_FORMAT

        for key in ('image', 'hidden_field', 'text_field'):
            if '%%(%s)s' % key not in self._args['output_format']:
                raise ImproperlyConfigured('All of %s must be present in your CAPTCHA_OUTPUT_FORMAT setting. Could not find %s' % (
                    ', '.join(['%%(%s)s' % k for k in ('image', 'hidden_field', 'text_field')]),
                    '%%(%s)s' % key
                ))
        super(CaptchaTextInput, self).__init__(attrs)

    def format_output(self, rendered_widgets):
        hidden_field, text_field = rendered_widgets
        text_field = text_field.replace('<input', '<input autocomplete="off"')
        return self._args['output_format'] % {
            'image': self.image_and_audio,
            'hidden_field': hidden_field,
            'text_field': text_field
        }

    def render(self, name, value, attrs=None):
        self.fetch_captcha_store(name, value, attrs)

        self.image_and_audio = '<img src="%s" alt="captcha" class="captcha" />' % self.image_url()
        if settings.CAPTCHA_FLITE_PATH:
            self.image_and_audio = '<a href="%s" title="%s">%s</a>' % (self.audio_url(), ugettext('Play CAPTCHA as audio file'), self.image_and_audio)
        return super(CaptchaTextInput, self).render(name, self._value, attrs=attrs)


class CaptchaField(MultiValueField):
    def __init__(self, *args, **kwargs):
        fields = (
            CharField(show_hidden_initial=True),
            CharField(),
        )
        if 'error_messages' not in kwargs or 'invalid' not in kwargs.get('error_messages'):
            if 'error_messages' not in kwargs:
                kwargs['error_messages'] = {}
            kwargs['error_messages'].update({'invalid': ugettext_lazy('Invalid CAPTCHA')})

        kwargs['widget'] = kwargs.pop('widget', CaptchaTextInput(output_format=kwargs.pop('output_format', None)))

        super(CaptchaField, self).__init__(fields, *args, **kwargs)

    def compress(self, data_list):
        if data_list:
            return ','.join(data_list)
        return None

    def clean(self, value):
        super(CaptchaField, self).clean(value)
        response, value[1] = (value[1] or '').strip().lower(), ''
        CaptchaStore.remove_expired()
        if settings.CAPTCHA_TEST_MODE and response.lower() == 'passed':
            # automatically pass the test
            try:
                # try to delete the captcha based on its hash
                CaptchaStore.objects.get(hashkey=value[0]).delete()
            except CaptchaStore.DoesNotExist:
                # ignore errors
                pass
        elif not self.required and not response:
            pass
        else:
            try:
                CaptchaStore.objects.get(response=response, hashkey=value[0], expiration__gt=get_safe_now()).delete()
            except CaptchaStore.DoesNotExist:
                raise ValidationError(getattr(self, 'error_messages', {}).get('invalid', ugettext_lazy('Invalid CAPTCHA')))
        return value