"""form renderers, responsible to layout a form to html

:organization: Logilab

:copyright: 2009-2010 LOGILAB S.A. (Paris, FRANCE), license is LGPL v2.

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

:license: GNU Lesser General Public License, v2.1 - http://www.gnu.org/licenses

"""

__docformat__ = "restructuredtext en"

from warnings import warn

from logilab.common import dictattr

from logilab.mtconverter import xml_escape

from simplejson import dumps

from cubicweb import tags

from cubicweb.appobject import AppObject

from cubicweb.selectors import implements, yes

from cubicweb.web import eid_param, formwidgets as fwdgs

def checkbox(name, value, attrs='', checked=None):

    if checked is None:

        checked = value

    checked = checked and 'checked="checked"' or ''

    return u'<input type="checkbox" name="%s" value="%s" %s %s />' % (

        name, value, checked, attrs)

def field_label(form, field):

    # XXX with 3.6 we can now properly rely on 'if field.role is not None' and

    # stop having a tuple for label

    if isinstance(field.label, tuple): # i.e. needs contextual translation

        return form._cw.pgettext(*field.label)

    return form._cw._(field.label)

class FormRenderer(AppObject):

    """basic renderer displaying fields in a two columns table label | value

    +--------------+--------------+

    | field1 label | field1 input |

    +--------------+--------------+

    | field1 label | field2 input |

    +--------------+--------------+

    +---------+

    | buttons |

    +---------+

    """

    __registry__ = 'formrenderers'

    __regid__ = 'default'

    _options = ('display_label', 'display_help',

                'display_progress_div', 'table_class', 'button_bar_class',

                # add entity since it may be given to select the renderer

                'entity')

    display_label = True

    display_help = True

    display_progress_div = True

    table_class = u'attributeForm'

    button_bar_class = u'formButtonBar'

    def __init__(self, req=None, rset=None, row=None, col=None, **kwargs):

        super(FormRenderer, self).__init__(req, rset=rset, row=row, col=col)

        if self._set_options(kwargs):

            raise ValueError('unconsumed arguments %s' % kwargs)

    def _set_options(self, kwargs):

        for key in self._options:

            try:

                setattr(self, key, kwargs.pop(key))

            except KeyError:

                continue

        return kwargs

    # renderer interface ######################################################

    def render(self, form, values):

        self._set_options(values)

        form.add_media()

        data = []

        w = data.append

        w(self.open_form(form, values))

        if self.display_progress_div:

            w(u'<div id="progress">%s</div>' % self._cw._('validating...'))

        w(u'<fieldset>')

        self.render_fields(w, form, values)

        self.render_buttons(w, form)

        w(u'</fieldset>')

        w(self.close_form(form, values))

        errormsg = self.error_message(form)

        if errormsg:

            data.insert(0, errormsg)

        return '\n'.join(data)

    def render_label(self, form, field):

        if field.label is None:

            return u''

        label = field_label(form, field)

        attrs = {'for': field.dom_id(form)}

        if field.required:

            attrs['class'] = 'required'

        return tags.label(label, **attrs)

    def render_help(self, form, field):

        help = []

        descr = field.help

        if callable(descr):

            descr = descr(form)

        if descr:

            help.append('<div class="helper">%s</div>' % self._cw._(descr))

        example = field.example_format(self._cw)

        if example:

            help.append('<div class="helper">(%s: %s)</div>'

                        % (self._cw._('sample format'), example))

        return u' '.join(help)

    # specific methods (mostly to ease overriding) #############################

    def error_message(self, form):

        """return formatted error message

        This method should be called once inlined field errors has been consumed

        """

        req = self._cw

        errex = form.form_valerror

        # get extra errors

        if errex is not None:

            errormsg = req._('please correct the following errors:')

            errors = form.remaining_errors()

            if errors:

                if len(errors) > 1:

                    templstr = u'<li>%s</li>\n'

                else:

                    templstr = u' %s\n'

                for field, err in errors:

                    if field is None:

                        errormsg += templstr % err

                    else:

                        errormsg += templstr % '%s: %s' % (req._(field), err)

                if len(errors) > 1:

                    errormsg = '<ul>%s</ul>' % errormsg

            return u'<div class="errorMessage">%s</div>' % errormsg

        return u''

    def open_form(self, form, values):

        if form.needs_multipart:

            enctype = 'multipart/form-data'

        else:

            enctype = 'application/x-www-form-urlencoded'

        if form.action is None:

            action = self._cw.build_url('edit')

        else:

            action = form.action

        tag = ('<form action="%s" method="post" enctype="%s"' % (

            xml_escape(action or '#'), enctype))

        if form.domid:

            tag += ' id="%s"' % form.domid

        if form.onsubmit:

            tag += ' onsubmit="%s"' % xml_escape(form.onsubmit % dictattr(form))

        if form.cssstyle:

            tag += ' style="%s"' % xml_escape(form.cssstyle)

        if form.cssclass:

            tag += ' class="%s"' % xml_escape(form.cssclass)

        if form.cwtarget:

            tag += ' cubicweb:target="%s"' % xml_escape(form.cwtarget)

        return tag + '>'

    def close_form(self, form, values):

        """seems dumb but important for consistency w/ close form, and necessary

        for form renderers overriding open_form to use something else or more than

        and <form>

        """

        return '</form>'

    def render_fields(self, w, form, values):

        fields = self._render_hidden_fields(w, form)

        if fields:

            self._render_fields(fields, w, form)

        self.render_child_forms(w, form, values)

    def render_child_forms(self, w, form, values):

        # render

        for childform in getattr(form, 'forms', []):

            self.render_fields(w, childform, values)

    def _render_hidden_fields(self, w, form):

        fields = form.fields[:]

        for field in form.fields:

            if not field.is_visible():

                w(field.render(form, self))

                fields.remove(field)

        return fields

    def _render_fields(self, fields, w, form):

        byfieldset = {}

        for field in fields:

            byfieldset.setdefault(field.fieldset, []).append(field)

        if form.fieldsets_in_order:

            fieldsets = form.fieldsets_in_order

        else:

            fieldsets = byfieldset.keys()

        for fieldset in fieldsets:

            try:

                fields = byfieldset.pop(fieldset)

            except KeyError:

                self.warning('no such fieldset: %s (%s)', fieldset, form)

                continue

            w(u'<fieldset class="%s">' % (fieldset or u'default'))

            if fieldset:

                w(u'<legend>%s</legend>' % self._cw._(fieldset))

            w(u'<table class="%s">' % self.table_class)

            for field in fields:

                w(u'<tr class="%s_%s_row">' % (field.name, field.role))

                if self.display_label and field.label is not None:

                    w(u'<th class="labelCol">%s</th>' % self.render_label(form, field))

                w('<td')

                if field.label is None:

                    w(' colspan="2"')

                error = form.field_error(field)

                if error:

                    w(u' class="error"')

                w(u'>')

                w(field.render(form, self))

                if self.display_help:

                    w(self.render_help(form, field))

                w(u'</td></tr>')

            w(u'</table></fieldset>')

        if byfieldset:

            self.warning('unused fieldsets: %s', ', '.join(byfieldset))

    def render_buttons(self, w, form):

        if not form.form_buttons:

            return

        w(u'<table class="%s">\n<tr>\n' % self.button_bar_class)

        for button in form.form_buttons:

            w(u'<td>%s</td>\n' % button.render(form))

        w(u'</tr></table>')

    def render_error(self, w, err):

        """return validation error for widget's field, if any"""

        w(u'<span class="error">%s</span>' % err)

class BaseFormRenderer(FormRenderer):

    """use form_renderer_id = 'base' if you want base FormRenderer layout even

    when selected for an entity

    """

    __regid__ = 'base'

class HTableFormRenderer(FormRenderer):

    """display fields horizontally in a table

    +--------------+--------------+---------+

    | field1 label | field2 label |         |

    +--------------+--------------+---------+

    +--------------+--------------+---------+

    """

    __regid__ = 'htable'

    display_help = False

    def _render_fields(self, fields, w, form):

        w(u'<table border="0" class="htableForm">')

        w(u'<tr>')

        for field in fields:

            if self.display_label:

                w(u'<th class="labelCol">%s</th>' % self.render_label(form, field))

            if self.display_help:

                w(self.render_help(form, field))

        # empty slot for buttons

        w(u'<th class="labelCol">&#160;</th>')

        w(u'</tr>')

        w(u'<tr>')

        for field in fields:

            error = form.field_error(field)

            if error:

                w(u'<td class="error">')

                self.render_error(w, error)

            else:

                w(u'<td>')

            w(field.render(form, self))

            w(u'</td>')

        w(u'<td>')

        for button in form.form_buttons:

            w(button.render(form))

        w(u'</td>')

        w(u'</tr>')

        w(u'</table>')

    def render_buttons(self, w, form):

        pass

class EntityCompositeFormRenderer(FormRenderer):

    """specific renderer for multiple entities edition form (muledit)"""

    __regid__ = 'composite'

    _main_display_fields = None

    def render_fields(self, w, form, values):

        if form.parent_form is None:

            w(u'<table class="listing">')

            subfields = [field for field in form.forms[0].fields

                         if field.is_visible()]

            if subfields:

                # main form, display table headers

                w(u'<tr class="header">')

                w(u'<th align="left">%s</th>' %

                  tags.input(type='checkbox',

                             title=self._cw._('toggle check boxes'),

                             onclick="setCheckboxesState('eid', this.checked)"))

                for field in subfields:

                    w(u'<th>%s</th>' % field_label(form, field))

                w(u'</tr>')

        super(EntityCompositeFormRenderer, self).render_fields(w, form, values)

        if form.parent_form is None:

            w(u'</table>')

            if self._main_display_fields:

                super(EntityCompositeFormRenderer, self)._render_fields(

                    self._main_display_fields, w, form)

    def _render_fields(self, fields, w, form):

        if form.parent_form is not None:

            entity = form.edited_entity

            values = form.form_previous_values

            qeid = eid_param('eid', entity.eid)

            cbsetstate = "setCheckboxesState2('eid', %s, 'checked')" % \

                         xml_escape(dumps(entity.eid))

            w(u'<tr class="%s">' % (entity.cw_row % 2 and u'even' or u'odd'))

            # XXX turn this into a widget used on the eid field

            w(u'<td>%s</td>' % checkbox('eid', entity.eid,

                                        checked=qeid in values))

            for field in fields:

                error = form.field_error(field)

                if error:

                    w(u'<td class="error">')

                    self.render_error(w, error)

                else:

                    w(u'<td>')

                if isinstance(field.widget, (fwdgs.Select, fwdgs.CheckBox,

                                             fwdgs.Radio)):

                    field.widget.attrs['onchange'] = cbsetstate

                elif isinstance(field.widget, fwdgs.Input):

                    field.widget.attrs['onkeypress'] = cbsetstate

                # XXX else

                w(u'<div>%s</div>' % field.render(form, self))

                w(u'</td>\n')

            w(u'</tr>')

        else:

            self._main_display_fields = fields

class EntityFormRenderer(BaseFormRenderer):

    """specific renderer for entity edition form (edition)"""

    __regid__ = 'default'

    # needs some additional points in some case (XXX explain cases)

    __select__ = implements('Any') & yes()

    _options = FormRenderer._options + ('main_form_title',)

    main_form_title = _('main informations')