"""field classes for form construction

:organization: Logilab

:copyright: 2009 LOGILAB S.A. (Paris, FRANCE), all rights reserved.

:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr

"""

__docformat__ = "restructuredtext en"

from datetime import datetime

from logilab.mtconverter import html_escape

from yams.constraints import SizeConstraint, StaticVocabularyConstraint

from cubicweb.schema import FormatConstraint

from cubicweb.utils import ustrftime

from cubicweb.common import tags, uilib

from cubicweb.web import INTERNAL_FIELD_VALUE

from cubicweb.web.formwidgets import (HiddenInput, TextInput, FileInput, PasswordInput,

                                      TextArea, FCKEditor, Radio, Select,

                                      DateTimePicker) 

class Field(object):

    """field class is introduced to control what's displayed in edition form

    """

    widget = TextInput

    needs_multipart = False

    creation_rank = 0

    def __init__(self, name=None, id=None, label=None,

                 widget=None, required=False, initial=None,

                 choices=None, help=None, eidparam=False, role='subject'):

        self.required = required

        if widget is not None:

            self.widget = widget

        if isinstance(self.widget, type):

            self.widget = self.widget()

        self.name = name

        self.label = label or name

        self.id = id or name

        self.initial = initial

        self.choices = choices

        self.help = help

        self.eidparam = eidparam

        self.role = role

        # global fields ordering in forms

        self.creation_rank = Field.creation_rank

        Field.creation_rank += 1

    def __unicode__(self):

        return u'<%s name=%r label=%r id=%r initial=%r @%x>' % (

            self.__class__.__name__, self.name, self.label,

            self.id, self.initial, id(self))

    def __repr__(self):

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

    def set_name(self, name):

        assert name

        self.name = name

        if not self.id:

            self.id = name

        if not self.label:

            self.label = name

    def is_visible(self):

        return not isinstance(self.widget, HiddenInput)

    def actual_fields(self, form):

        yield self

    def format_value(self, req, value):

        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):

        if value is None:

            return u''

        return unicode(value)

    def get_widget(self, form):

        return self.widget

    def example_format(self, req):

        return u''

    def render(self, form, renderer):

        return self.get_widget(form).render(form, self)

    def vocabulary(self, form):

        if self.choices is not None:

        return form.form_field_vocabulary(self)

class StringField(Field):

    def __init__(self, max_length=None, **kwargs):

        super(StringField, self).__init__(**kwargs)

        self.max_length = max_length

class TextField(Field):

    widget = TextArea

    def __init__(self, rows=10, cols=80, **kwargs):

        super(TextField, self).__init__(**kwargs)

        self.rows = rows

        self.cols = cols

class RichTextField(TextField):

    widget = None

    def __init__(self, format_field=None, **kwargs):

        super(RichTextField, self).__init__(**kwargs)

        self.format_field = format_field

    def get_widget(self, form):

        if self.widget is None:

            if self.use_fckeditor(form):

                return FCKEditor()

            return TextArea()

        return self.widget

    def get_format_field(self, form):

        if self.format_field:

            return self.format_field

        # we have to cache generated field since it's use as key in the

        # context dictionnary

        req = form.req

        try:

            return req.data[self]

        except KeyError:

            if self.use_fckeditor(form):

                # if fckeditor is used and format field isn't explicitly

                # deactivated, we want an hidden field for the format

                widget = HiddenInput()

                choices = None

            else:

                # else we want a format selector

                # XXX compute vocabulary

                widget = Select

                fcstr = FormatConstraint()

                choices = [(req._(fmt), fmt) for fmt in fcstr.vocabulary(req=req)]

            field = StringField(name=self.name + '_format', widget=widget,

                                choices=choices)

            req.data[self] = field

            return field

    def actual_fields(self, form):

        yield self

        format_field = self.get_format_field(form)

        if format_field:

            yield format_field

    def use_fckeditor(self, form):

        """return True if fckeditor should be used to edit entity's attribute named

        `attr`, according to user preferences

        """

        if form.req.use_fckeditor():

            return form.form_field_format(self) == 'text/html'

        return False

    def render(self, form, renderer):

        format_field = self.get_format_field(form)

        if format_field:

            result = format_field.render(form, renderer)

        else:

            result = u''

        return result + self.get_widget(form).render(form, self)

class FileField(StringField):

    widget = FileInput

    needs_multipart = True

    def __init__(self, format_field=None, encoding_field=None, **kwargs):

        super(FileField, self).__init__(**kwargs)

        self.format_field = format_field

        self.encoding_field = encoding_field

    def actual_fields(self, form):

        yield self

        if self.format_field:

            yield self.format_field

        if self.encoding_field:

            yield self.encoding_field

    def render(self, form, renderer):

        wdgs = [self.get_widget(form).render(form, self)]

        if self.format_field or self.encoding_field:

            divid = '%s-advanced' % form.context[self]['name']

            wdgs.append(u'<a href="%s" title="%s"><img src="%s" alt="%s"/></a>' %

                        (html_escape(uilib.toggle_action(divid)),

                         form.req._('show advanced fields'),

                         html_escape(form.req.build_url('data/puce_down.png')),

                         form.req._('show advanced fields')))

            wdgs.append(u'<div id="%s" class="hidden">' % divid)

            if self.format_field:

                wdgs.append(self.render_subfield(form, self.format_field, renderer))

            if self.encoding_field:

                wdgs.append(self.render_subfield(form, self.encoding_field, renderer))

            wdgs.append(u'</div>')            

        if not self.required and form.context[self]['value']:

            # trick to be able to delete an uploaded file

            wdgs.append(u'<br/>')

            wdgs.append(tags.input(name=u'%s__detach' % form.context[self]['name'],

                                   type=u'checkbox'))

            wdgs.append(form.req._('detach attached file'))

        return u'\n'.join(wdgs)

    def render_subfield(self, form, field, renderer):

        return (renderer.render_label(form, field)

                + field.render(form, renderer)

                + renderer.render_help(form, field)

                + u'<br/>')

class EditableFileField(FileField):

    editable_formats = ('text/plain', 'text/html', 'text/rest')

    def render(self, form, renderer):

        wdgs = [super(EditableFileField, self).render(form, renderer)]

        if form.form_field_format(self) in self.editable_formats:

            data = form.form_field_value(self, {}, load_bytes=True)

            if data:

                encoding = form.form_field_encoding(self)

                try:

                    form.context[self]['value'] = unicode(data.getvalue(), encoding)

                except UnicodeError:

                    pass

                else:

                    if not self.required:

                        msg = form.req._(

                            'You can either submit a new file using the browse button above'

                            ', or choose to remove already uploaded file by checking the '

                            '"detach attached file" check-box, or edit file content online '

                            'with the widget below.')

                    else:

                        msg = form.req._(

                            'You can either submit a new file using the browse button above'

                            ', or edit file content online with the widget below.')

                    wdgs.append(u'<p><b>%s</b></p>' % msg)

                    wdgs.append(TextArea(setdomid=False).render(form, self))

                    # XXX restore form context?

        return '\n'.join(wdgs)

class IntField(Field):

    def __init__(self, min=None, max=None, **kwargs):

        super(IntField, self).__init__(**kwargs)

        self.min = min

        self.max = max

class BooleanField(Field):

    widget = Radio

    def vocabulary(self, form):

        if self.choices:

            return self.choices

        return [(form.req._('yes'), '1'), (form.req._('no'), '')]

class FloatField(IntField):    

    def format_single_value(self, req, value):

        formatstr = req.property_value('ui.float-format')

        if value is None:

            return u''

        return formatstr % float(value)

    def render_example(self, req):

        return self.format_value(req, 1.234)

class DateField(StringField):

    format_prop = 'ui.date-format'

    widget = DateTimePicker

    def format_single_value(self, req, value):

        return value and ustrftime(value, req.property_value(self.format_prop)) or u''

    def render_example(self, req):

        return self.format_value(req, datetime.now())

class DateTimeField(DateField):

    format_prop = 'ui.datetime-format'

class TimeField(DateField):

    format_prop = 'ui.datetime-format'

class HiddenInitialValueField(Field):

    def __init__(self, visible_field, name):

        super(HiddenInitialValueField, self).__init__(name=name,

                                                      widget=HiddenInput,

                                                      eidparam=True)

        self.visible_field = visible_field

class RelationField(Field):

    def __init__(self, **kwargs):

        super(RelationField, self).__init__(**kwargs)

    @staticmethod

    def fromcardinality(card, **kwargs):

        return RelationField(widget=Select(multiple=card in '*+'), **kwargs)

    def vocabulary(self, form):

        entity = form.edited_entity

        req = entity.req

        # first see if its specified by __linkto form parameters

        linkedto = entity.linked_to(self.name, self.role)

        if linkedto:

            entities = (req.eid_rset(eid).get_entity(0, 0) for eid in linkedto)

            return [(entity.view('combobox'), entity.eid) for entity in entities]

        # it isn't, check if the entity provides a method to get correct values

        res = []

        if not self.required:

            res.append(('', INTERNAL_FIELD_VALUE))

        # vocabulary doesn't include current values, add them

        if entity.has_eid():

            rset = entity.related(self.name, self.role)

            relatedvocab = [(e.view('combobox'), e.eid) for e in rset.entities()]

        else:

            relatedvocab = []

        return res + form.form_field_vocabulary(self) + relatedvocab

    def format_single_value(self, req, value):

        return value

def stringfield_from_constraints(constraints, **kwargs):

    field = None

    for cstr in constraints:

        if isinstance(cstr, StaticVocabularyConstraint):

        if isinstance(cstr, SizeConstraint) and cstr.max is not None:

            if cstr.max > 257:

                rows_cols_from_constraint(cstr, kwargs)

                field = TextField(**kwargs)

            else:

                field = StringField(max_length=cstr.max, **kwargs)

    return field or TextField(**kwargs)

def rows_cols_from_constraint(constraint, kwargs):

    if constraint.max < 513:

        rows, cols = 5, 60

    else:

        rows, cols = 10, 80

    kwargs.setdefault('rows', rows)

    kwargs.setdefault('cols', cols)

def guess_field(eclass, rschema, role='subject', skip_meta_attr=True, **kwargs):

    """return the most adapated widget to edit the relation

    'subjschema rschema objschema' according to information found in the schema

    """

    fieldclass = None

    eschema = eclass.e_schema

    if role == 'subject':

        targetschema = rschema.objects(eschema)[0]

        card = rschema.rproperty(eschema, targetschema, 'cardinality')[0]

    else:

        targetschema = rschema.subjects(eschema)[0]

        card = rschema.rproperty(targetschema, eschema, 'cardinality')[1]

    kwargs['required'] = card in '1+'

    kwargs['name'] = rschema.type

    if rschema.is_final():

        if skip_meta_attr and rschema in eschema.meta_attributes():

            return None