"""

__docformat__ = "restructuredtext en"

from warnings import warn

from datetime import datetime

from logilab.mtconverter import xml_escape

from logilab.common import nullobject

from logilab.common.date import ustrftime

from yams.schema import KNOWN_METAATTRIBUTES, role_name

from yams.constraints import (SizeConstraint, StaticVocabularyConstraint,

                              FormatConstraint)

from cubicweb import Binary, tags, uilib

from cubicweb.web import INTERNAL_FIELD_VALUE, ProcessFormError, eid_param, \

     formwidgets as fw, uicfg

class UnmodifiedField(Exception):

    """raise this when a field has not actually been edited and you want to skip

    it

    """

def vocab_sort(vocab):

    """sort vocabulary, considering option groups"""

    result = []

    partresult = []

    for label, value in vocab:

        if value is None: # opt group start

            if partresult:

                result += sorted(partresult)

                partresult = []

            result.append( (label, value) )

        else:

            partresult.append( (label, value) )

    result += sorted(partresult)

    return result

_MARKER = nullobject()

class Field(object):

    """This class is the abstract base class for all fields. It hold a bunch

    of attributes which may be used for fine control of the behaviour of a

    concret field.

    All the attributes described below have sensible default value which may be

       a form.

       label of the field (default to the same value as `name`).

       help message about this field.

       widget associated to the field. Each field class has a default widget

       class which may be overriden per instance.

       bool flag telling if the field is required or not.

       bool flag telling if the vocabulary (either static vocabulary specified

       in `choices` or dynamic vocabulary fetched from the form) should be

       sorted on label.

       bool flag telling if the vocabulary labels should be translated using the

       current request language.

       bool flag telling if this field is linked to a specific entity

       when the field is linked to an entity attribute or relation, tells the

       role of the entity in the relation (eg 'subject' or 'object')

       optional fieldset to which this field belongs to

       key used by automatic forms to sort fields

       when true, this field won't consider value potentialy specified using

       request's form parameters (eg you won't be able to specify a value using for

       instance url like http://mywebsite.com/form?field=value)

    """

    # default widget associated to this class of fields. May be overriden per

    # instance

    widget = fw.TextInput

    # does this field requires a multipart form

    needs_multipart = False

    # class attribute used for ordering of fields in a form

    __creation_rank = 0

    eidparam = False

    role = None

    id = None

    help = None

    required = False

    choices = None

    sort = True

    internationalizable = False

    fieldset = None

    order = None

    value = _MARKER

    fallback_on_none_attribute = False

    ignore_req_params = False

    def __init__(self, name=None, label=_MARKER, widget=None, **kwargs):

        for key, val in kwargs.items():

            if key == 'initial':

                warn('[3.6] use value instead of initial', DeprecationWarning,

                     stacklevel=3)

                key = 'value'

            assert hasattr(self.__class__, key) and not key[0] == '_', key

            setattr(self, key, val)

        self.name = name

        if label is _MARKER:

            label = name or _MARKER

        self.label = label

        # has to be done after other attributes initialization

        self.init_widget(widget)

        # ordering number for this field instance

        self.creation_rank = Field.__creation_rank

        Field.__creation_rank += 1

    def __unicode__(self):

        return u'<%s name=%r eidparam=%s role=%r id=%r value=%r visible=%r @%x>' % (

            self.__class__.__name__, self.name, self.eidparam, self.role,

            self.id, self.value, self.is_visible(), id(self))

    def __repr__(self):

        return self.__unicode__().encode('utf-8')

    def init_widget(self, widget):

        if widget is not None:

            self.widget = widget

        elif self.choices and not self.widget.vocabulary_widget:

            self.widget = fw.Select()

        if isinstance(self.widget, type):

            self.widget = self.widget()

    def set_name(self, name):

        """automatically set .label when name is set"""

        assert name

        self.name = name

        if self.label is _MARKER:

            self.label = name

    def is_visible(self):

        """return true if the field is not an hidden field"""

        return not isinstance(self.widget, fw.HiddenInput)

    def actual_fields(self, form):

        """

        yield self

    def format_value(self, req, value):

        """return value suitable for display where value may be a list or tuple

        of values

        """

        if isinstance(value, (list, tuple)):

            return [self.format_single_value(req, val) for val in value]

        return self.format_single_value(req, value)

    def format_single_value(self, req, value):

        """return value suitable for display"""

        if value is None or value is False:

            return u''

        if value is True:

            return u'1'

        return unicode(value)

    def get_widget(self, form):

        """return the widget instance associated to this field"""

        return self.widget

    def input_name(self, form, suffix=None):

        # caching is necessary else we get some pb on entity creation :

        # entity.eid is modified from creation mark (eg 'X') to its actual eid

        # (eg 123), and then `field.input_name()` won't return the right key

        # anymore if not cached (first call to input_name done *before* eventual

        # eid affectation).

        #

        # note that you should NOT use @cached else it will create a memory leak

        # on persistent fields (eg created once for all on a form class) because

        # of the 'form' appobject argument: the cache will keep growing as new

        # form are created...

        try:

            return form.formvalues[(self, 'input_name', suffix)]

        except KeyError:

            name = self.role_name()

            if suffix is not None:

                name += suffix

            if self.eidparam:

                name = eid_param(name, form.edited_entity.eid)

            form.formvalues[(self, 'input_name', suffix)] = name

            return name

    def role_name(self):

        """return <field.name>-<field.role> if role is specified, else field.name"""

        if self.role is not None:

            return role_name(self.name, self.role)

        return self.name

    def dom_id(self, form, suffix=None):

        id = self.id or self.role_name()

        if suffix is not None:

            id += suffix

        if self.eidparam:

            return eid_param(id, form.edited_entity.eid)

        return id

    def typed_value(self, form, load_bytes=False):

        if self.eidparam and self.role is not None:

            entity = form.edited_entity

            if form._cw.vreg.schema.rschema(self.name).final:

                if entity.has_eid() or self.name in entity:

                    value = getattr(entity, self.name)

                    if value is not None or not self.fallback_on_none_attribute:

                        return value

            elif entity.has_eid() or entity.relation_cached(self.name, self.role):

                value = [r[0] for r in entity.related(self.name, self.role)]

                if value or not self.fallback_on_none_attribute:

                    return value

        return self.initial_typed_value(form, load_bytes)

    def initial_typed_value(self, form, load_bytes):

        if self.value is not _MARKER:

            if callable(self.value):

                return self.value(form)

            return self.value

        formattr = '%s_%s_default' % (self.role, self.name)

        if hasattr(form, formattr):

            warn('[3.6] %s.%s deprecated, use field.value' % (

                form.__class__.__name__, formattr), DeprecationWarning)

            return getattr(form, formattr)()

        if self.eidparam and self.role is not None:

            if form._cw.vreg.schema.rschema(self.name).final:

                return form.edited_entity.e_schema.default(self.name)

            return ()

        return None

    def example_format(self, req):

        """return a sample string describing what can be given as input for this

        field

        """

        return u''

    def render(self, form, renderer):

        """render this field, which is part of form, using the given form

        renderer

        """

        widget = self.get_widget(form)

        return widget.render(form, self, renderer)

    def vocabulary(self, form, **kwargs):

        """return vocabulary for this field. This method will be called by

        widgets which requires a vocabulary.

        """

        assert self.choices is not None

        if callable(self.choices):

            try:

                if getattr(self.choices, 'im_self', None) is self:

                    vocab = self.choices(form=form, **kwargs)

                else:

                    vocab = self.choices(form=form, field=self, **kwargs)

            except TypeError:

                try:

                    vocab = self.choices(form=form, **kwargs)

                    warn('[3.6]  %s: choices should now take '

                         'the form and field as named arguments' % self,

                         DeprecationWarning)

                except TypeError:

                    warn('[3.3]  %s: choices should now take '

                         'the form and field as named arguments' % self,

                         DeprecationWarning)

                    vocab = self.choices(req=form._cw, **kwargs)

        else:

            vocab = self.choices

        if vocab and not isinstance(vocab[0], (list, tuple)):

            vocab = [(x, x) for x in vocab]

        if self.internationalizable:

            # the short-cirtcuit 'and' boolean operator is used here to permit

            # a valid empty string in vocabulary without attempting to translate

            # it by gettext (which can lead to weird strings display)

            vocab = [(label and form._cw._(label), value) for label, value in vocab]

        if self.sort:

            vocab = vocab_sort(vocab)

        return vocab

    def format(self, form):

        """return MIME type used for the given (text or bytes) field"""

        if self.eidparam and self.role == 'subject':

            entity = form.edited_entity

            if entity.e_schema.has_metadata(self.name, 'format') and (

                entity.has_eid() or '%s_format' % self.name in entity):

                return form.edited_entity.attr_metadata(self.name, 'format')

        return form._cw.property_value('ui.default-text-format')

    def encoding(self, form):

        """return encoding used for the given (text) field"""

        if self.eidparam: