#!/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 csv

import datetime

import logging

import StringIO

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 COMMENT_PREFIX

from soc.models.survey import SurveyContent

# TODO(ajaksu) add this to template

REQUIRED_COMMENT_TPL = """

  <label for="required_for_{{ name }}">Required</label>

  <select id="required_for_{{ name }}" name="required_for_{{ name }}">

    <option value="True" {% if is_required %} selected='selected' {% endif %}

     >True</option>

    <option value="False" {% if not is_required %} selected='selected'

     {% endif %}>False</option>

  </select><br/>

  <label for="comment_for_{{ name }}">Allow Comments</label>

  <select id="comment_for_{{ name }}" name="comment_for_{{ name }}">

    <option value="True" {% if has_comment %} selected='selected' {% endif %}

     >True</option>

    <option value="False" {% if not has_comment %} selected='selected'

     {% endif %}>False</option>

  </select><br/>

"""

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_logic = self.kwargs.pop('survey_logic', 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,

        )

    self.kwargs['data'] = {}

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

  def getFields(self, post_dict=None):

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

    params:

      post_dict: dict with POST data that will be used for validation

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

    Also populates self.data, which will be used in form validation.

    """

    if not self.survey_content:

      return

    post_dict = post_dict or {}

    self.survey_fields = {}

    schema = SurveyContentSchema(self.survey_content.schema)

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

    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:

        survey_content = self.survey_content

        survey_entity = self.survey_logic.getSurveyForContent(survey_content)

        deadline = survey_entity.survey_end

        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 = ''

      # flag to know where the value came from

      from_content = False

      if has_record and field in post_dict:

        # entered value that is not yet saved

        value = post_dict[field]

        if COMMENT_PREFIX + field in post_dict:

          comment = post_dict[COMMENT_PREFIX + field]

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

        # previously entered value

        value = getattr(self.survey_record, field)

        if hasattr(self.survey_record, COMMENT_PREFIX + field):

          comment = getattr(self.survey_record, COMMENT_PREFIX + field)

      else:

        # use prompts set by survey creator

        value = getattr(self.survey_content, field)

        from_content = True

      label = schema.getLabel(field)

      if label is None:

        continue

      # fix validation for pick_multi fields

      is_multi = schema.getType(field) == 'pick_multi'

      if not from_content and schema.getType(field) == 'pick_multi':

        if isinstance(value, basestring):

          value = value.split(',')

      elif from_content and is_multi:

        value = []

      # record field value for validation

      if not from_content:

        self.data[field] = value

      # find correct field type

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

      # check if question is required, it's never required when editing

      required = not self.editing and schema.getRequired(field)

      kwargs = dict(label=label, req=required)

      # add new field

      addField(field, value, extra_attrs, schema, **kwargs)

      # handle comments if question allows them

      if schema.getHasComment(field):

        self.data[COMMENT_PREFIX + field] = comment

        self.addCommentField(field, comment, extra_attrs, tip='Add a 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:

        # add comment if field has one and this isn't an edit view

        property = COMMENT_PREFIX + property

        if property in self.survey_fields:

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

                             self.survey_fields[property])

    return self.fields

  def addLongField(self, field, value, attrs, schema, req=True, 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

    """

    # use a widget that allows setting required and comments

    has_comment = schema.getHasComment(field)

    is_required = schema.getRequired(field)

    widget = LongTextarea(is_required, has_comment, attrs=attrs,

                          editing=self.editing)

    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

  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"

    # use a widget that allows setting required and comments

    has_comment = schema.getHasComment(field)

    is_required = schema.getRequired(field)

    widget = ShortTextInput(is_required, has_comment, attrs=attrs,

                          editing=self.editing)

    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

  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

  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(',')

    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

  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

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

    if not self.editing:

      widget = widgets.Textarea(attrs=attrs)

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

                          widget=widget, initial=comment)

      self.survey_fields[COMMENT_PREFIX + field] = comment_field

  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 getRequired(self, field):

    """Check whether survey question is required.

    """

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

  def getHasComment(self, field):

    """Check whether survey question allows adding a comment.

    """

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

  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)

      is_required = self.getRequired(field)

      has_comment = self.getHasComment(field)

      widget = UniversalChoiceEditor(kind, render, is_required, has_comment)

    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, is_required, has_comment, attrs=None,

               choices=()):

    """

    params:

      kind: question kind (one of selection, pick_multi or pick_quant)

      render: question widget (single_select, multi_checkbox or quant_radio)

      is_required: bool, controls selection in the required_for field

      has_comments: bool, controls selection in the has_comments field

    """

    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

    self.is_required = is_required

    self.has_comment = has_comment

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

    """Render UCE widget.

    Option reordering, editing, addition and deletion are added here.

    """

    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'),

        )

    # set required and has_comment selects

    context.update(dict(

        is_required = self.is_required,

        has_comment = self.has_comment,

        ))

    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