forms.py

import re
from django import forms
from askbot import models
from askbot import const
from django.utils.translation import ugettext_lazy as _
from django.utils.translation import ungettext_lazy
from django.contrib.auth.models import User
from django.contrib.contenttypes.models import ContentType
from django_countries import countries
from askbot.utils.forms import NextUrlField, UserNameField
from askbot.utils.mail import extract_first_email_address
from askbot.deps.recaptcha_django import ReCaptchaField
from askbot.conf import settings as askbot_settings
import logging

def cleanup_dict(dictionary, key, empty_value):
    """deletes key from dictionary if it exists
    and the corresponding value equals the empty_value
    """
    if key in dictionary and dictionary[key] == empty_value:
        del dictionary[key]

def clean_marked_tagnames(tagnames):
    """return two strings - one containing tagnames
    that are straight names of tags, and the second one
    containing names of wildcard tags,
    wildcard tags are those that have an asterisk at the end
    the function does not verify that the tag names are valid
    """
    if askbot_settings.USE_WILDCARD_TAGS == False:
        return tagnames, list()

    pure_tags = list()
    wildcards = list()
    for tagname in tagnames:
        if tagname == '':
            continue
        if tagname.endswith('*'):
            if tagname.count('*') > 1:
                continue
            else:
                wildcards.append(tagname)
        else:
            pure_tags.append(tagname)
    
    return pure_tags, wildcards

def filter_choices(remove_choices = None, from_choices = None):
    """a utility function that will remove choice tuples
    usable for the forms.ChoicesField from
    ``from_choices``, the removed ones will be those given
    by the ``remove_choice`` list

    there is no error checking, ``from_choices`` tuple must be as expected
    to work with the forms.ChoicesField
    """

    if not isinstance(remove_choices, list):
        raise TypeError('remove_choices must be a list')

    filtered_choices = tuple()
    for choice_to_test in from_choices:
        remove = False
        for choice in remove_choices:
            if choice == choice_to_test[0]:
                remove = True
                break
        if remove == False:
            filtered_choices += ( choice_to_test, )

    return filtered_choices

COUNTRY_CHOICES = (('unknown',_('select country')),) + countries.COUNTRIES

class CountryField(forms.ChoiceField):
    """this is better placed into the django_coutries app"""
    
    def __init__(self, *args, **kwargs):
        """sets label and the country choices
        """
        kwargs['choices'] = kwargs.pop('choices', COUNTRY_CHOICES)
        kwargs['label'] = kwargs.pop('label', _('Country'))
        super(CountryField, self).__init__(*args, **kwargs)

    def clean(self, value):
        """Handles case of 'unknown' country selection
        """
        if self.required:
            if value == 'unknown':
                raise forms.ValidationError(_('Country field is required'))
        if value == 'unknown':
            return None
        return value

class TitleField(forms.CharField):
    def __init__(self, *args, **kwargs):
        super(TitleField, self).__init__(*args, **kwargs)
        self.required = True
        self.widget = forms.TextInput(
                                attrs={'size' : 70, 'autocomplete' : 'off'}
                            )
        self.max_length = 255
        self.label  = _('title')
        self.help_text = _('please enter a descriptive title for your question')
        self.initial = ''

    def clean(self, value):
        if len(value) < 10:
            raise forms.ValidationError(_('title must be > 10 characters'))

        return value

class EditorField(forms.CharField):
    def __init__(self, *args, **kwargs):
        super(EditorField, self).__init__(*args, **kwargs)
        self.required = True
        self.widget = forms.Textarea(attrs={'id':'editor'})
        self.label  = _('content')
        self.help_text = u''
        self.initial = ''

    def clean(self, value):
        if len(value) < 10:
            raise forms.ValidationError(_('question content must be > 10 characters'))
        return value

class TagNamesField(forms.CharField):
    def __init__(self, *args, **kwargs):
        super(TagNamesField, self).__init__(*args, **kwargs)
        self.required = True
        self.widget = forms.TextInput(attrs={'size' : 50, 'autocomplete' : 'off'})
        self.max_length = 255
        self.label  = _('tags')
        #self.help_text = _('please use space to separate tags (this enables autocomplete feature)')
        self.help_text = _('Tags are short keywords, with no spaces within. Up to five tags can be used.')
        self.initial = ''

    def clean(self, value):
        value = super(TagNamesField, self).clean(value)
        data = value.strip()
        if len(data) < 1:
            raise forms.ValidationError(_('tags are required'))

        split_re = re.compile(const.TAG_SPLIT_REGEX)
        tag_strings = split_re.split(data)
        entered_tags = []
        tag_count = len(tag_strings)
        if tag_count > askbot_settings.MAX_TAGS_PER_POST:
            max_tags = askbot_settings.MAX_TAGS_PER_POST
            msg = ungettext_lazy(
                        'please use %(tag_count)d tag or less',
                        'please use %(tag_count)d tags or less',
                        tag_count) % {'tag_count':max_tags}
            raise forms.ValidationError(msg)
        for tag in tag_strings:
            tag_length = len(tag)
            if tag_length > askbot_settings.MAX_TAG_LENGTH:
                #singular form is odd in english, but required for pluralization
                #in other languages
                msg = ungettext_lazy('each tag must be shorter than %(max_chars)d character',#odd but added for completeness
                                'each tag must be shorter than %(max_chars)d characters',
                                tag_length) % {'max_chars':tag_length}
                raise forms.ValidationError(msg)

            #todo - this needs to come from settings
            tagname_re = re.compile(const.TAG_REGEX, re.UNICODE)
            if not tagname_re.search(tag):
                raise forms.ValidationError(_('use-these-chars-in-tags'))
            #only keep unique tags
            if tag not in entered_tags:
                entered_tags.append(tag)

        #normalize character case of tags
        cleaned_entered_tags = list()
        if askbot_settings.FORCE_LOWERCASE_TAGS:
            #a simpler way to handle tags - just lowercase thew all
            for name in entered_tags:
                lowercased_name = name.lower()
                if lowercased_name not in cleaned_entered_tags:
                    cleaned_entered_tags.append(lowercased_name)
        else:
            #make names of tags in the input to agree with the database
            for entered_tag in entered_tags:
                try:
                    #looks like we have to load tags one-by one
                    #because we need tag name cases to be the same
                    #as those stored in the database
                    stored_tag = models.Tag.objects.get(
                                            name__iexact = entered_tag
                                        )
                    if stored_tag.name not in cleaned_entered_tags:
                        cleaned_entered_tags.append(stored_tag.name)
                except models.Tag.DoesNotExist:
                    cleaned_entered_tags.append(entered_tag)

        return u' '.join(cleaned_entered_tags)

class WikiField(forms.BooleanField):
    def __init__(self, *args, **kwargs):
        super(WikiField, self).__init__(*args, **kwargs)
        self.required = False
        self.initial = False
        self.label  = _('community wiki (karma is not awarded & many others can edit wiki post)')
        self.help_text = _('if you choose community wiki option, the question and answer do not generate points and name of author will not be shown')
    def clean(self, value):
        return value and askbot_settings.WIKI_ON

class EmailNotifyField(forms.BooleanField):
    def __init__(self, *args, **kwargs):
        super(EmailNotifyField, self).__init__(*args, **kwargs)
        self.required = False
        self.widget.attrs['class'] = 'nomargin'

class SummaryField(forms.CharField):
    def __init__(self, *args, **kwargs):
        super(SummaryField, self).__init__(*args, **kwargs)
        self.required = False
        self.widget = forms.TextInput(attrs={'size' : 50, 'autocomplete' : 'off'})
        self.max_length = 300
        self.label  = _('update summary:')
        self.help_text = _('enter a brief summary of your revision (e.g. fixed spelling, grammar, improved style, this field is optional)')


class DumpUploadForm(forms.Form):
    """This form handles importing
    data into the forum. At the moment it only 
    supports stackexchange import.
    """
    dump_file = forms.FileField()

class ShowQuestionForm(forms.Form):
    answer = forms.IntegerField(required = False)
    comment = forms.IntegerField(required = False)
    page = forms.IntegerField(required = False)
    sort = forms.CharField(required = False)

    def __init__(self, data, default_sort_method):
        super(ShowQuestionForm, self).__init__(data)
        self.default_sort_method = default_sort_method

    def get_pruned_data(self):
        nones = ('answer', 'comment', 'page')
        for key in nones:
            if self.cleaned_data[key] is None:
                del self.cleaned_data[key]
        if self.cleaned_data['sort'] == '':
            del self.cleaned_data['sort']
        return self.cleaned_data

    def clean(self):
        """this form must always be valid
        should use defaults if the data is incomplete
        or invalid"""
        in_data = self.get_pruned_data()
        out_data = dict()
        if ('answer' in in_data) ^ ('comment' in in_data):
            out_data['is_permalink'] = True
            out_data['show_page'] = None
            out_data['answer_sort_method'] = 'votes'
            out_data['show_comment'] = in_data.get('comment', None)
            out_data['show_answer'] = in_data.get('answer', None)
        else:
            out_data['is_permalink'] = False
            out_data['show_page'] = in_data.get('page', 1)
            out_data['answer_sort_method'] = in_data.get(
                                                    'sort',
                                                    self.default_sort_method
                                                )
            out_data['show_comment'] = None
            out_data['show_answer'] = None
        self.cleaned_data = out_data
        return out_data

class ChangeUserReputationForm(forms.Form):
    """Form that allows moderators and site administrators
    to adjust reputation of users.

    this form internally verifies that user who claims to
    be a moderator acually is
    """

    user_reputation_delta = forms.IntegerField(
                                    min_value = 1,
                                    label = _('Enter number of points to add or subtract')
                                )
    comment = forms.CharField(max_length = 128)

    def clean_comment(self):
        if 'comment' in  self.cleaned_data:
            comment = self.cleaned_data['comment'].strip()
            if comment == '':
                del self.cleaned_data['comment']
                raise forms.ValidationError('Please enter non-empty comment')
            self.cleaned_data['comment'] = comment
            return comment

MODERATOR_STATUS_CHOICES = (
                                ('a', _('approved')),
                                ('w', _('watched')),
                                ('s', _('suspended')),
                                ('b', _('blocked')),
                           )
ADMINISTRATOR_STATUS_CHOICES = (('m', _('moderator')), ) \
                               + MODERATOR_STATUS_CHOICES


class ChangeUserStatusForm(forms.Form):
    """form that allows moderators to change user's status

    the type of options displayed depend on whether user
    is a moderator or a site administrator as well as
    what is the current status of the moderated user

    for example moderators cannot moderate other moderators
    and admins. Admins can take away admin status, but cannot
    add it (that can be done through the Django Admin interface

    this form is to be displayed in the user profile under
    "moderation" tab
    """

    user_status = forms.ChoiceField(
                            label = _('Change status to'),
                        )

    def __init__(self, *arg, **kwarg):

        moderator = kwarg.pop('moderator')
        subject = kwarg.pop('subject')

        super(ChangeUserStatusForm, self).__init__(*arg, **kwarg)

        #select user_status_choices depending on status of the moderator
        if moderator.is_administrator():
            user_status_choices = ADMINISTRATOR_STATUS_CHOICES
        elif moderator.is_moderator():
            user_status_choices = MODERATOR_STATUS_CHOICES
            if subject.is_moderator() and subject != moderator:
                raise ValueError('moderator cannot moderate another moderator')
        else:
            raise ValueError('moderator or admin expected from "moderator"')

        #remove current status of the "subject" user from choices
        user_status_choices = filter_choices(
                                        remove_choices = [subject.status, ],
                                        from_choices = user_status_choices
                                    )

        #add prompt option
        user_status_choices = ( ('select', _('which one?')), ) \
                                + user_status_choices

        self.fields['user_status'].choices = user_status_choices

        #set prompt option as default
        self.fields['user_status'].default = 'select' 
        self.moderator = moderator
        self.subject = subject

    def clean(self):
        #if moderator is looking at own profile - do not
        #let change status
        if 'user_status' in self.cleaned_data:

            user_status = self.cleaned_data['user_status']

            #does not make sense to change own user status
            #if necessary, this can be done from the Django admin interface
            if self.moderator == self.subject:
                del self.cleaned_data['user_status']
                raise forms.ValidationError(_('Cannot change own status'))

            #do not let moderators turn other users into moderators
            if self.moderator.is_moderator() and user_status == 'moderator':
                del self.cleanded_data['user_status']
                raise forms.ValidationError(
                                _('Cannot turn other user to moderator')
                            )

            #do not allow moderator to change status of other moderators
            if self.moderator.is_moderator() and self.subject.is_moderator():
                del self.cleaned_data['user_status']
                raise forms.ValidationError(
                                _('Cannot change status of another moderator')
                            )

            if user_status == 'select':
                del self.cleaned_data['user_status']
                msg = _(
                        'If you wish to change %(username)s\'s status, '
                        'please make a meaningful selection.'
                    ) % {'username': self.subject.username }
                raise forms.ValidationError(msg)

        return self.cleaned_data

class SendMessageForm(forms.Form):
    subject_line = forms.CharField(
                            label = _('Subject line'),
                            max_length = 64,
                            widget = forms.TextInput(
                                            attrs = {'size':64},
                                        )
                        )
    body_text = forms.CharField(
                            label = _('Message text'),
                            max_length = 1600,
                            widget = forms.Textarea(
                                            attrs = {'cols':64}
                                        )
                        )


class AdvancedSearchForm(forms.Form):
    """nothing must be required in this form
    it is used by the main questions view for input validation only
    """
    scope = forms.ChoiceField(choices=const.POST_SCOPE_LIST, required=False)
    sort = forms.ChoiceField(choices=const.POST_SORT_METHODS, required=False)
    query = forms.CharField(max_length=256, required=False)
    #search field is actually a button, used to detect manual button click
    search = forms.CharField(max_length=16, required=False)
    reset_tags = forms.BooleanField(required=False)
    reset_author = forms.BooleanField(required=False)
    reset_query = forms.BooleanField(required=False)
    start_over = forms.BooleanField(required=False)
    tags = forms.CharField(max_length=256, required=False)
    remove_tag = forms.CharField(max_length=256, required=False)
    author = forms.IntegerField(required=False)
    page_size = forms.ChoiceField(choices=const.PAGE_SIZE_CHOICES, required=False)
    page = forms.IntegerField(required=False)

    def clean_tags(self):
        if 'tags' in self.cleaned_data:
            tags_input = self.cleaned_data['tags'].strip()
            split_re = re.compile(const.TAG_SPLIT_REGEX)
            tag_strings = split_re.split(tags_input)
            tagname_re = re.compile(const.TAG_REGEX, re.UNICODE)
            out = set()
            for s in tag_strings:
                if tagname_re.search(s):
                    out.add(s)
            if len(out) > 0:
                self.cleaned_data['tags'] = out
            else:
                self.cleaned_data['tags'] = None
            return self.cleaned_data['tags']

    def clean_query(self):
        if 'query' in self.cleaned_data:
            q = self.cleaned_data['query'].strip()
            if q == '':
                q = None
            self.cleaned_data['query'] = q
            return self.cleaned_data['query']

    def clean_page_size(self):
        if 'page_size' in self.cleaned_data:
            if self.cleaned_data['page_size'] == '':
                self.cleaned_data['page_size'] = None
            else:
                page_size = self.cleaned_data['page_size']
                #by this time it is guaranteed to be castable as int
                self.cleaned_data['page_size'] = int(page_size)
            return self.cleaned_data['page_size']

    def clean(self):
        #todo rewrite
        data = self.cleaned_data
        cleanup_dict(data, 'scope', '')
        cleanup_dict(data, 'tags', None)
        cleanup_dict(data, 'sort', '')
        cleanup_dict(data, 'query', None)
        cleanup_dict(data, 'search', '')
        cleanup_dict(data, 'reset_tags', False)
        cleanup_dict(data, 'reset_author', False)
        cleanup_dict(data, 'reset_query', False)
        cleanup_dict(data, 'remove_tag', '')
        cleanup_dict(data, 'start_over', False)
        cleanup_dict(data, 'author', None)
        cleanup_dict(data, 'page', None)
        cleanup_dict(data, 'page_size', None)
        return data

class NotARobotForm(forms.Form):
    recaptcha = ReCaptchaField()

class FeedbackForm(forms.Form):
    name = forms.CharField(label=_('Your name:'), required=False)
    email = forms.EmailField(label=_('Email (not shared with anyone):'), required=False)
    message = forms.CharField(label=_('Your message:'), max_length=800,widget=forms.Textarea(attrs={'cols':60}))
    next = NextUrlField()

class FormWithHideableFields(object):
    """allows to swap a field widget to HiddenInput() and back"""

    def hide_field(self, name):
        """replace widget with HiddenInput()
        and save the original in the __hidden_fields dictionary
        """
        if not hasattr(self, '__hidden_fields'):
            self.__hidden_fields = dict()
        if name in self.__hidden_fields:
            return
        self.__hidden_fields[name] = self.fields[name].widget
        self.fields[name].widget = forms.HiddenInput()

    def show_field(self, name):
        """restore the original widget on the field
        if it was previously hidden
        """
        if name in self.__hidden_fields:
            self.fields[name] = self.__hidden_fields.pop(name)

class AskForm(forms.Form, FormWithHideableFields):
    """the form used to askbot questions
    field ask_anonymously is shown to the user if the 
    if ALLOW_ASK_ANONYMOUSLY live setting is True
    however, for simplicity, the value will always be present
    in the cleaned data, and will evaluate to False if the
    settings forbids anonymous asking
    """
    title  = TitleField()
    text   = EditorField()
    tags   = TagNamesField()
    wiki = WikiField()
    ask_anonymously = forms.BooleanField(
        label = _('ask anonymously'),
        help_text = _(
            'Check if you do not want to reveal your name '
            'when asking this question'
        ),
        required = False,
    )
    openid = forms.CharField(required=False, max_length=255, widget=forms.TextInput(attrs={'size' : 40, 'class':'openid-input'}))
    user   = forms.CharField(required=False, max_length=255, widget=forms.TextInput(attrs={'size' : 35}))
    email  = forms.CharField(required=False, max_length=255, widget=forms.TextInput(attrs={'size' : 35}))

    def __init__(self, *args, **kwargs):
        super(AskForm, self).__init__(*args, **kwargs)
        #hide ask_anonymously field
        if askbot_settings.ALLOW_ASK_ANONYMOUSLY == False:
            self.hide_field('ask_anonymously')

    def clean_ask_anonymously(self):
        """returns false if anonymous asking is not allowed
        """
        if askbot_settings.ALLOW_ASK_ANONYMOUSLY == False:
            self.cleaned_data['ask_anonymously'] = False
        return self.cleaned_data['ask_anonymously'] 


class AskByEmailForm(forms.Form):
    """:class:`~askbot.forms.AskByEmailForm`
    validates question data, where question was posted
    by email.

    It is ivoked by the management command
    :mod:`~askbot.management.commands.post_emailed_questions`

    Input is text data with attributes:

    * :attr:`~askbot.forms.AskByEmailForm.sender` - unparsed "from" data
    * :attr:`~askbot.forms.AskByEmailForm.subject` - subject line
    * :attr:`~askbot.forms.AskByEmailForm.body_text` - body text of the email

    Cleaned values are:
    * ``email`` - email address
    * ``title`` - question title
    * ``tagnames`` - tag names all in one string
    * ``body_text`` - body of question text - a pass-through, no extra validation
    """
    sender = forms.CharField(max_length = 255)
    subject = forms.CharField(max_length = 255)
    body_text = EditorField()

    def clean_sender(self):
        """Cleans the :attr:`~askbot.forms.AskByEmail.sender` attribute

        If the field is valid, cleaned data will receive value ``email``
        """
        raw_email = self.cleaned_data['sender']
        email = extract_first_email_address(raw_email)
        if email is None:
            raise forms.ValidationError('Could not extract email address')
        self.cleaned_data['email'] = email
        return self.cleaned_data['sender']

    def clean_subject(self):
        """Cleans the :attr:`~askbot.forms.AskByEmail.subject` attribute

        If the field is valid, cleaned data will receive values
        ``tagnames`` and ``title``
        """
        raw_subject = self.cleaned_data['subject'].strip()
        subject_re = re.compile(r'^\[([^]]+)\](.*)$')
        match = subject_re.match(raw_subject)
        if match:
            #make raw tags comma-separated
            tagnames = match.group(1).replace(';',',')

            #pre-process tags
            tag_list = [tag.strip() for tag in tagnames.split(',')]
            tag_list = [re.sub(r'\s+', ' ', tag) for tag in tag_list]
            if askbot_settings.REPLACE_SPACE_WITH_DASH_IN_EMAILED_TAGS:
                tag_list = [tag.replace(' ', '-') for tag in tag_list]
            tagnames = ' '.join(tag_list)#todo: use tag separator char here

            #clean tags - may raise ValidationError
            self.cleaned_data['tagnames'] = TagNamesField().clean(tagnames)

            #clean title - may raise ValidationError
            title = match.group(2).strip()
            self.cleaned_data['title'] = TitleField().clean(title)
        else:
            raise forms.ValidationError('could not parse subject line')
        return self.cleaned_data['subject']

class AnswerForm(forms.Form):
    text   = EditorField()
    wiki   = WikiField()
    openid = forms.CharField(required=False, max_length=255, widget=forms.TextInput(attrs={'size' : 40, 'class':'openid-input'}))
    user   = forms.CharField(required=False, max_length=255, widget=forms.TextInput(attrs={'size' : 35}))
    email  = forms.CharField(required=False, max_length=255, widget=forms.TextInput(attrs={'size' : 35}))
    email_notify = EmailNotifyField()
    def __init__(self, question, user, *args, **kwargs):
        super(AnswerForm, self).__init__(*args, **kwargs)
        self.fields['email_notify'].widget.attrs['id'] = 'question-subscribe-updates'
        if question.wiki and askbot_settings.WIKI_ON:
            self.fields['wiki'].initial = True
        if user.is_authenticated():
            if user in question.followed_by.all():
                self.fields['email_notify'].initial = True
                return
        self.fields['email_notify'].initial = False


class CloseForm(forms.Form):
    reason = forms.ChoiceField(choices=const.CLOSE_REASONS)

class RetagQuestionForm(forms.Form):
    tags = TagNamesField()
    # initialize the default values
    def __init__(self, question, *args, **kwargs):
        super(RetagQuestionForm, self).__init__(*args, **kwargs)
        self.fields['tags'].initial = question.tagnames

class RevisionForm(forms.Form):
    """
    Lists revisions of a Question or Answer
    """
    revision = forms.ChoiceField(widget=forms.Select(attrs={'style' : 'width:520px'}))

    def __init__(self, post, latest_revision, *args, **kwargs):
        super(RevisionForm, self).__init__(*args, **kwargs)
        revisions = post.revisions.all().values_list(
            'revision', 'author__username', 'revised_at', 'summary')
        date_format = '%c'
        self.fields['revision'].choices = [
            (r[0], u'%s - %s (%s) %s' % (r[0], r[1], r[2].strftime(date_format), r[3]))
            for r in revisions]
        self.fields['revision'].initial = latest_revision.revision

class EditQuestionForm(forms.Form, FormWithHideableFields):
    title  = TitleField()
    text   = EditorField()
    tags   = TagNamesField()
    summary = SummaryField()
    wiki = WikiField()
    reveal_identity = forms.BooleanField(
        help_text = _(
            'You have asked this question anonymously, '
            'if you decide to reveal your identity, please check '
            'this box.'
        ),
        label = _('reveal identity'),
        required = False,
    )

    #todo: this is odd that this form takes question as an argument
    def __init__(self, *args, **kwargs):
        """populate EditQuestionForm with initial data"""
        self.question = kwargs.pop('question')
        self.user = kwargs.pop('user')
        revision = kwargs.pop('revision')
        super(EditQuestionForm, self).__init__(*args, **kwargs)
        self.fields['title'].initial = revision.title
        self.fields['text'].initial = revision.text
        self.fields['tags'].initial = revision.tagnames
        self.fields['wiki'].initial = self.question.wiki
        #hide the reveal identity field
        if not self.can_stay_anonymous():
            self.hide_field('reveal_identity')

    def can_stay_anonymous(self):
        """determines if the user cat keep editing the question
        anonymously"""
        return (askbot_settings.ALLOW_ASK_ANONYMOUSLY \
            and self.question.is_anonymous \
            and self.user.is_owner_of(self.question)
        )

    def clean_reveal_identity(self):
        """cleans the reveal_identity field
        which determines whether previous anonymous
        edits must be rewritten as not anonymous
        this does not necessarily mean that the edit will be anonymous

        only does real work when question is anonymous
        based on the following truth table:

        is_anon  can  owner  checked  cleaned data
        -        *     *        *        False (ignore choice in checkbox)
        +        +     +        +        True
        +        +     +        -        False
        +        +     -        +        Raise(Not owner)
        +        +     -        -        False
        +        -     +        +        True (setting "can" changed, say yes)
        +        -     +        -        False, warn (but prev edits stay anon)
        +        -     -        +        Raise(Not owner)
        +        -     -        -        False
        """
        value = self.cleaned_data['reveal_identity']
        if self.question.is_anonymous:
            if value == True:
                if self.user.is_owner_of(self.question):
                    #regardless of the ALLOW_ASK_ANONYMOUSLY
                    return True
                else:
                    self.show_field('reveal_identity')
                    del self.cleaned_data['reveal_identity']
                    raise forms.ValidationError(
                                _(
                                    'Sorry, only owner of the anonymous '
                                    'question can reveal his or her '
                                    'identity, please uncheck the '
                                    'box'
                                 )
                             )
            else:
                can_ask_anon = askbot_settings.ALLOW_ASK_ANONYMOUSLY
                is_owner = self.user.is_owner_of(self.question)
                if can_ask_anon == False and is_owner:
                    self.show_field('reveal_identity')
                    raise forms.ValidationError(
                        _(
                            'Sorry, apparently rules have just changed - '
                            'it is no longer possible to ask anonymously. '
                            'Please either check the "reveal identity" box '
                            'or reload this page and try editing the question '
                            'again.'
                        )
                    )
                return False
        else:
            #takes care of 8 possibilities - first row of the table
            return False

    def clean(self):
        """Purpose of this function is to determine whether
        it is ok to apply edit anonymously in the synthetic
        field edit_anonymously. It relies on correct cleaning
        if the "reveal_identity" field
        """
        reveal_identity = self.cleaned_data.get('reveal_identity', False)
        stay_anonymous = False
        if reveal_identity == False and self.can_stay_anonymous():
            stay_anonymous = True
        self.cleaned_data['stay_anonymous'] = stay_anonymous
        return self.cleaned_data

class EditAnswerForm(forms.Form):
    text = EditorField()
    summary = SummaryField()
    wiki = WikiField()

    def __init__(self, answer, revision, *args, **kwargs):
        super(EditAnswerForm, self).__init__(*args, **kwargs)
        self.fields['text'].initial = revision.text
        self.fields['wiki'].initial = answer.wiki

class EditUserForm(forms.Form):
    email = forms.EmailField(
                    label=u'Email',
                    help_text=_('this email will be linked to gravatar'),
                    required=True,
                    max_length=255,
                    widget=forms.TextInput(attrs={'size' : 35})
                )

    realname = forms.CharField(
                        label=_('Real name'), 
                        required=False, 
                        max_length=255, 
                        widget=forms.TextInput(attrs={'size' : 35})
                    )

    website = forms.URLField(
                        label=_('Website'), 
                        required=False, 
                        max_length=255, 
                        widget=forms.TextInput(attrs={'size' : 35})
                    )

    city = forms.CharField(
                        label=_('City'),
                        required=False,
                        max_length=255,
                        widget=forms.TextInput(attrs={'size' : 35})
                    )

    country = CountryField(required = False)

    show_country = forms.BooleanField(
                        label=_('Show country'),
                        required=False
                    )

    birthday = forms.DateField(
                        label=_('Date of birth'),
                        help_text=_('will not be shown, used to calculate age, format: YYYY-MM-DD'),
                        required=False,
                        widget=forms.TextInput(attrs={'size' : 35})
                    )

    about = forms.CharField(
                        label=_('Profile'),
                        required=False,
                        widget=forms.Textarea(attrs={'cols' : 60})
                    )

    def __init__(self, user, *args, **kwargs):
        super(EditUserForm, self).__init__(*args, **kwargs)
        logging.debug('initializing the form')
        if askbot_settings.EDITABLE_SCREEN_NAME:
            self.fields['username'] = UserNameField(label=_('Screen name'))
            self.fields['username'].initial = user.username
            self.fields['username'].user_instance = user
        self.fields['email'].initial = user.email
        self.fields['realname'].initial = user.real_name
        self.fields['website'].initial = user.website
        self.fields['city'].initial = user.location
        if user.country == None:
            country = 'unknown'
        else:
            country = user.country
        self.fields['country'].initial = country
        self.fields['show_country'].initial = user.show_country

        if user.date_of_birth is not None:
            self.fields['birthday'].initial = user.date_of_birth

        self.fields['about'].initial = user.about
        self.user = user

    def clean_email(self):
        """For security reason one unique email in database"""
        if self.user.email != self.cleaned_data['email']:
            #todo dry it, there is a similar thing in openidauth
            if askbot_settings.EMAIL_UNIQUE == True:
                if 'email' in self.cleaned_data:
                    try:
                        User.objects.get(email = self.cleaned_data['email'])
                    except User.DoesNotExist:
                        return self.cleaned_data['email']
                    except User.MultipleObjectsReturned:
                        raise forms.ValidationError(_('this email has already been registered, please use another one'))
                    raise forms.ValidationError(_('this email has already been registered, please use another one'))
        return self.cleaned_data['email']

class TagFilterSelectionForm(forms.ModelForm):
    email_tag_filter_strategy = forms.ChoiceField(
        choices = const.TAG_FILTER_STRATEGY_CHOICES,
        initial = const.EXCLUDE_IGNORED,
        label = _('Choose email tag filter'),
        widget = forms.RadioSelect
    )
    class Meta:
        model = User
        fields = ('email_tag_filter_strategy',)

    def save(self):
        before = self.instance.email_tag_filter_strategy
        super(TagFilterSelectionForm, self).save()
        after = self.instance.email_tag_filter_strategy
        if before != after:
            return True
        return False
        

class EmailFeedSettingField(forms.ChoiceField):
    def __init__(self, *arg, **kwarg):
        kwarg['choices'] = const.NOTIFICATION_DELIVERY_SCHEDULE_CHOICES
        kwarg['initial'] = askbot_settings.DEFAULT_NOTIFICATION_DELIVERY_SCHEDULE
        kwarg['widget'] = forms.RadioSelect
        super(EmailFeedSettingField, self).__init__(*arg, **kwarg)

class EditUserEmailFeedsForm(forms.Form):
    FORM_TO_MODEL_MAP = {
                    'all_questions':'q_all',
                    'asked_by_me':'q_ask',
                    'answered_by_me':'q_ans',
                    'individually_selected':'q_sel',
                    'mentions_and_comments':'m_and_c',
                }
    NO_EMAIL_INITIAL = {
                    'all_questions':'n',
                    'asked_by_me':'n',
                    'answered_by_me':'n',
                    'individually_selected':'n',
                    'mentions_and_comments':'n',
                }

    asked_by_me = EmailFeedSettingField(
                            label=_('Asked by me')
                        )
    answered_by_me = EmailFeedSettingField(
                            label=_('Answered by me')
                        )
    individually_selected = EmailFeedSettingField(
                            label=_('Individually selected')
                        )
    all_questions = EmailFeedSettingField(
                            label=_('Entire forum (tag filtered)'),
                        )

    mentions_and_comments = EmailFeedSettingField(
                            label=_('Comments and posts mentioning me'),
                        )

    def set_initial_values(self, user=None):
        KEY_MAP = dict([(v, k) for k, v in self.FORM_TO_MODEL_MAP.iteritems()])
        if user != None:
            settings = models.EmailFeedSetting.objects.filter(subscriber=user)
            initial_values = {}
            for setting in settings:
                feed_type = setting.feed_type
                form_field = KEY_MAP[feed_type]
                frequency = setting.frequency
                initial_values[form_field] = frequency
            self.initial = initial_values
        return self

    def reset(self):
        """equivalent to set_frequency('n')
        but also returns self due to some legacy requirement
        todo: clean up use of this function
        """
        if self.is_bound:
            self.cleaned_data = self.NO_EMAIL_INITIAL
        self.initial = self.NO_EMAIL_INITIAL
        return self

    def set_frequency(self, frequency = 'n'):
        data = {
            'all_questions': frequency,
            'asked_by_me': frequency,
            'answered_by_me': frequency,
            'individually_selected': frequency,
            'mentions_and_comments': frequency
        }
        if self.is_bound:
            self.cleaned_data = data
        self.initial = data

    def save(self,user,save_unbound=False):
        """
            with save_unbound==True will bypass form validation and save initial values
        """
        changed = False
        for form_field, feed_type in self.FORM_TO_MODEL_MAP.items():
            s, created = models.EmailFeedSetting.objects.get_or_create(
                                                    subscriber=user,
                                                    feed_type=feed_type
                                                )
            if save_unbound:
                #just save initial values instead
                if form_field in self.initial:
                    new_value = self.initial[form_field]
                else:
                    new_value = self.fields[form_field].initial
            else:
                new_value = self.cleaned_data[form_field]
            if s.frequency != new_value:
                s.frequency = new_value
                s.save()
                changed = True
            else:
                if created:
                    s.save()
            if form_field == 'individually_selected':
                feed_type = ContentType.objects.get_for_model(models.Question)
                user.followed_questions.clear()
        return changed

class SimpleEmailSubscribeForm(forms.Form):
    SIMPLE_SUBSCRIBE_CHOICES = (
        ('y',_('okay, let\'s try!')),
        ('n',_('no community email please, thanks'))
    )
    subscribe = forms.ChoiceField(
            widget=forms.widgets.RadioSelect, 
            error_messages={'required':_('please choose one of the options above')},
            choices=SIMPLE_SUBSCRIBE_CHOICES
        )

    def __init__(self, *args, **kwargs):
        self.frequency = kwargs.pop('frequency', 'w') 
        super(SimpleEmailSubscribeForm, self).__init__(*args, **kwargs)

    def save(self, user=None):
        EFF = EditUserEmailFeedsForm
        #here we have kind of an anomaly - the value 'y' is redundant
        #with the frequency variable - needs to be fixed
        if self.is_bound and self.cleaned_data['subscribe'] == 'y':
            email_settings_form = EFF()
            email_settings_form.set_frequency(self.frequency)
            logging.debug('%s wants to subscribe' % user.username)
        else:
            email_settings_form = EFF(initial=EFF.NO_EMAIL_INITIAL)
        email_settings_form.save(user, save_unbound=True)