#!/usr/bin/python2.5

#

# Copyright 2009 the Melange authors.

#

# Licensed under the Apache License, Version 2.0 (the "License");

# you may not use this file except in compliance with the License.

# You may obtain a copy of the License at

#

#   http://www.apache.org/licenses/LICENSE-2.0

#

# Unless required by applicable law or agreed to in writing, software

# distributed under the License is distributed on an "AS IS" BASIS,

# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

# See the License for the specific language governing permissions and

# limitations under the License.

"""Custom widgets used for Survey form fields, plus the SurveyContent form.

"""

__authors__ = [

  '"Daniel Diniz" <ajaksu@gmail.com>',

  '"James Levy" <jamesalexanderlevy@gmail.com>',

  '"Lennard de Rijk" <ljvderijk@gmail.com>',

  ]

from itertools import chain

import datetime

import logging

from google.appengine.ext.db import djangoforms

from django import forms

from django.forms import widgets

from django.forms.fields import CharField

from django.template import loader

from django.utils.encoding import force_unicode

from django.utils.html import escape

from django.utils.safestring import mark_safe

from soc.logic import dicts

from soc.logic.lists import Lists

from soc.models.survey import SurveyContent

class SurveyForm(djangoforms.ModelForm):

  """Main SurveyContent form.

  This class is used to produce survey forms for several circumstances:

    - Admin creating survey from scratch

    - Admin updating existing survey

    - User taking survey

    - User updating already taken survey

  Using dynamic properties of the survey model (if passed as an arg) the

  survey form is dynamically formed.

  """

  def __init__(self, *args, **kwargs):

    """Store special kwargs as attributes.

      read_only: controls whether the survey taking UI allows data entry.

      editing: controls whether to show the edit or show form.

    """

    self.kwargs = kwargs

    self.survey_content = self.kwargs.pop('survey_content', None)

    self.this_user = self.kwargs.pop('this_user', None)

    self.project = self.kwargs.pop('project', None)

    self.survey_record = self.kwargs.pop('survey_record', None)

    self.read_only = self.kwargs.pop('read_only', None)

    self.editing = self.kwargs.pop('editing', None)

    self.fields_map = dict(

        long_answer=self.addLongField,

        short_answer=self.addShortField,

        selection=self.addSingleField,

        pick_multi=self.addMultiField,

        pick_quant=self.addQuantField,

        )

    super(SurveyForm, self).__init__(*args, **self.kwargs)

  def getFields(self):

    """Build the SurveyContent (questions) form fields.

    Populates self.survey_fields, which will be ordered in self.insert_fields.

    """

    if not self.survey_content:

      return

    self.survey_fields = {}

    schema = SurveyContentSchema(self.survey_content.schema)

    has_record = (not self.editing) and self.survey_record

    extra_attrs = {}

    # figure out whether we want a read-only view

    if not self.editing:

      # only survey taking can be read-only

      read_only = self.read_only

      if not read_only:

        read_only =  deadline and (datetime.datetime.now() > deadline)

      else:

        extra_attrs['disabled'] = 'disabled'

    # add unordered fields to self.survey_fields

    for field in self.survey_content.dynamic_properties():

      # a comment made by the user

      comment = ''

      if has_record and hasattr(self.survey_record, field):

        # previously entered value

        value = getattr(self.survey_record, field)

        if hasattr(self.survey_record, 'comment_for_' + field):

          comment = getattr(self.survey_record, 'comment_for_' + field)

      else:

        # use prompts set by survey creator

        value = getattr(self.survey_content, field)

      label = schema.getLabel(field)

      if label is None:

        continue

      # dispatch to field-specific methods

      addField = self.fields_map[schema.getType(field)]

      addField(field, value, extra_attrs, schema, label=label, comment=comment)

    return self.insertFields()

  def insertFields(self):

    """Add ordered fields to self.fields.

    """

    survey_order = self.survey_content.getSurveyOrder()

    # first, insert dynamic survey fields

    for position, property in survey_order.items():

      position = position * 2

      self.fields.insert(position, property, self.survey_fields[property])

      if not self.editing:

        property = 'comment_for_' + property

        self.fields.insert(position - 1, property,

                           self.survey_fields[property])

    return self.fields

  def addLongField(self, field, value, attrs, schema, req=False, label='', tip='',

                   comment=''):

    """Add a long answer fields to this form.

    params:

      field: the current field

      value: the initial value for this field

      attrs: additional attributes for field

      schema: schema for survey

      req: required bool

      label: label for field

      tip: tooltip text for field

      comment: initial comment value for field

    """

    widget = widgets.Textarea(attrs=attrs)

    if not tip:

      tip = 'Please provide a long answer to this question.'

    question = CharField(help_text=tip, required=req, label=label,

                         widget=widget, initial=value)

    self.survey_fields[field] = question

    self.addCommentField(field, comment, attrs, tip)

  def addShortField(self, field, value, attrs, schema, req=False, label='', tip='',

                    comment=''):

    """Add a short answer fields to this form.

    params:

      field: the current field

      value: the initial value for this field

      attrs: additional attributes for field

      schema: schema for survey

      req: required bool

      label: label for field

      tip: tooltip text for field

      comment: initial comment value for field

    """

    attrs['class'] = "text_question"

    widget = widgets.TextInput(attrs=attrs)

    if not tip:

      tip = 'Please provide a short answer to this question.'

    question = CharField(help_text=tip, required=req, label=label,

                         widget=widget, max_length=140, initial=value)

    self.survey_fields[field] = question

    self.addCommentField(field, comment, attrs, tip)

  def addSingleField(self, field, value, attrs, schema, req=False, label='',

                     tip='', comment=''):

    """Add a selection field to this form.

    params:

      field: the current field

      value: the initial value for this field

      attrs: additional attributes for field

      schema: schema for survey

      req: required bool

      label: label for field

      tip: tooltip text for field

      comment: initial comment value for field

    """

    widget = schema.getWidget(field, self.editing, attrs)

    these_choices = []

    # add all properties, but select chosen one

    options = getattr(self.survey_content, field)

    has_record = not self.editing and self.survey_record

    if has_record and hasattr(self.survey_record, field):

      these_choices.append((value, value))

      if value in options:

        options.remove(value)

    for option in options:

      these_choices.append((option, option))

    if not tip:

      tip = 'Please select an answer this question.'

    question = PickOneField(help_text=tip, required=req, label=label,

                            choices=tuple(these_choices), widget=widget)

    self.survey_fields[field] = question

    self.addCommentField(field, comment, attrs, tip)

  def addMultiField(self, field, value, attrs, schema, req=False, label='',

                    tip='', comment=''):

    """Add a pick_multi field to this form.

    params:

      field: the current field

      value: the initial value for this field

      attrs: additional attributes for field

      schema: schema for survey

      req: required bool

      label: label for field

      tip: tooltip text for field

      comment: initial comment value for field

    """

    widget = schema.getWidget(field, self.editing, attrs)

    # TODO(ajaksu) need to allow checking checkboxes by default

    if self.survey_record and isinstance(value, basestring):

      # pass value as 'initial' so MultipleChoiceField renders checked boxes

      value = value.split(',')

    else:

      value = None

    these_choices = [(v,v) for v in getattr(self.survey_content, field)]

    if not tip:

      tip = 'Please select one or more of these choices.'

    question = PickManyField(help_text=tip, required=req, label=label,

                             choices=tuple(these_choices), widget=widget,

                             initial=value)

    self.survey_fields[field] = question

    self.addCommentField(field, comment, attrs, tip)

  def addQuantField(self, field, value, attrs, schema, req=False, label='',

                    tip='', comment=''):

    """Add a pick_quant field to this form.

    params:

      field: the current field

      value: the initial value for this field

      attrs: additional attributes for field

      schema: schema for survey

      req: required bool

      label: label for field

      tip: tooltip text for field

      comment: initial comment value for field

    """

    widget = schema.getWidget(field, self.editing, attrs)

    if self.survey_record:

      value = value

    else:

      value = None

    these_choices = [(v,v) for v in getattr(self.survey_content, field)]

    if not tip:

      tip = 'Please select one of these choices.'

    question = PickQuantField(help_text=tip, required=req, label=label,

                             choices=tuple(these_choices), widget=widget,

                             initial=value)

    self.survey_fields[field] = question

    self.addCommentField(field, comment, attrs, tip)

  def addCommentField(self, field, comment, attrs, tip):

    if not self.editing:

      widget = widgets.Textarea(attrs=attrs)

      comment = CharField(help_text=tip, required=False, label='Comments',

                          widget=widget, initial=comment)

      self.survey_fields['comment_for_' + field] = comment

  class Meta(object):

    model = SurveyContent

    exclude = ['schema']

class SurveyContentSchema(object):

  """Abstract question metadata handling.

  """

  def __init__(self, schema):

    self.schema = eval(schema)

  def getType(self, field):

    return self.schema[field]["type"]

  def getRender(self, field):

    return self.schema[field]["render"]

  def getWidget(self, field, editing, attrs):

    """Get survey editing or taking widget for choice questions.

    """

    if editing:

      kind = self.getType(field)

      render = self.getRender(field)

      widget = UniversalChoiceEditor(kind, render)

    else:

      widget = WIDGETS[self.schema[field]['render']](attrs=attrs)

    return widget

  def getLabel(self, field):

    """Fetch the free text 'question' or use field name as label.

    """

    if field not in self.schema:

      logging.error('field %s not found in schema %s' %

                    (field, str(self.schema)))

      return

    elif 'question' in self.schema[field]:

      label = self.schema[field].get('question') or field

    else:

      label = field

    return label

class UniversalChoiceEditor(widgets.Widget):

  """Edit interface for choice questions.

  Allows adding and removing options, re-ordering and editing option text.

  """

  def __init__(self, kind, render, attrs=None, choices=()):

    self.attrs = attrs or {}

    # Choices can be any iterable, but we may need to render this widget

    # multiple times. Thus, collapse it into a list so it can be consumed

    # more than once.

    self.choices = list(choices)

    self.kind = kind

    self.render_as = render

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

    """ renders UCE widget

    """

    if value is None:

      value = ''

    final_attrs = self.build_attrs(attrs, name=name)

    # find out which options should be selected in type and render drop-downs.

    selected = 'selected="selected"'

    context =  dict(

        name=name,

        is_selection=selected * (self.kind == 'selection'),

        is_pick_multi=selected * (self.kind == 'pick_multi'),

        is_pick_quant=selected * (self.kind == 'pick_quant'),

        is_select=selected * (self.render_as == 'single_select'),

        is_checkboxes=selected * (self.render_as == 'multi_checkbox'),

        is_radio_buttons=selected * (self.render_as == 'quant_radio'),

        )

    str_value = forms.util.smart_unicode(value) # normalize to string.

    chained_choices = enumerate(chain(self.choices, choices))

    choices = {}

    for i, (option_value, option_label) in chained_choices:

      option_value = escape(forms.util.smart_unicode(option_value))

      choices[i] = option_value

    context['choices'] = choices

    template = 'soc/survey/universal_choice_editor.html'

    return loader.render_to_string(template, context)

class PickOneField(forms.ChoiceField):

  """Stub for customizing the single choice field.

  """

  #TODO(james): Ensure that more than one option cannot be selected

  def __init__(self, *args, **kwargs):

    super(PickOneField, self).__init__(*args, **kwargs)

class PickManyField(forms.MultipleChoiceField):

  """Stub for customizing the multiple choice field.

  """

  def __init__(self, *args, **kwargs):

    super(PickManyField, self).__init__(*args, **kwargs)

class PickQuantField(forms.MultipleChoiceField):

  """Stub for customizing the multiple choice field.

  """

  #TODO(james): Ensure that more than one quant cannot be selected

  def __init__(self, *args, **kwargs):

    super(PickQuantField, self).__init__(*args, **kwargs)

class PickOneSelect(forms.Select):

  """Stub for customizing the single choice select widget.

  """

  def __init__(self, *args, **kwargs):

    super(PickOneSelect, self).__init__(*args, **kwargs)

class PickManyCheckbox(forms.CheckboxSelectMultiple):

  """Customized multiple choice checkbox widget.

  """

  def __init__(self, *args, **kwargs):

    super(PickManyCheckbox, self).__init__(*args, **kwargs)

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

    """Render checkboxes as list items grouped in a fieldset.

    This is the pick_multi widget for survey taking

    """

    if value is None:

      value = []

    has_id = attrs and attrs.has_key('id')

    final_attrs = self.build_attrs(attrs, name=name)

    # normalize to strings.

    str_values = set([forms.util.smart_unicode(v) for v in value])

    is_checked = lambda value: value in str_values

    smart_unicode = forms.util.smart_unicode

    # set container fieldset and list

    output = [u'<fieldset id="id_%s">\n  <ul class="pick_multi">' % name]

    # add numbered checkboxes wrapped in list items

    chained_choices = enumerate(chain(self.choices, choices))

    for i, (option_value, option_label) in chained_choices:

      option_label = escape(smart_unicode(option_label))

      # If an ID attribute was given, add a numeric index as a suffix,

      # so that the checkboxes don't all have the same ID attribute.

      if has_id:

        final_attrs = dict(final_attrs, id='%s_%s' % (attrs['id'], i))

      cb = widgets.CheckboxInput(final_attrs, check_test=is_checked)

      rendered_cb = cb.render(name, option_value)

      cb_label = (rendered_cb, option_label)

      output.append(u'    <li><label>%s %s</label></li>' % cb_label)

    output.append(u'  </ul>\n</fieldset>')

    return u'\n'.join(output)

  def id_for_label(self, id_):

    # see the comment for RadioSelect.id_for_label()

    if id_:

      id_ += '_fieldset'

    return id_

  id_for_label = classmethod(id_for_label)

class PickQuantRadioRenderer(widgets.RadioFieldRenderer):

  """Used by PickQuantRadio to enable customization of radio widgets.

  """

  def __init__(self, *args, **kwargs):

    super(PickQuantRadioRenderer, self).__init__(*args, **kwargs)

  def render(self):

    """Outputs set of radio fields in a div.

    """

    return mark_safe(u'<div class="quant_radio">\n%s\n</div>'

                     % u'\n'.join([u'%s' % force_unicode(w) for w in self]))

class PickQuantRadio(forms.RadioSelect):

  """TODO(James,Ajaksu) Fix Docstring

  """