#!/usr/bin/python2.5

#

# Copyright 2008 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.

"""Helpers functions for displaying views.

"""

__authors__ = [

  '"Sverre Rabbelier" <sverre@rabbelier.nl>',

  '"Pawel Solyga" <pawel.solyga@gmail.com>',

  ]

from django import http

from django.utils.translation import ugettext_lazy

import soc.logic

import soc.logic.out_of_band

import soc.views.helper.lists

import soc.views.helper.responses

import soc.views.out_of_band

from soc.logic import dicts

from soc.logic import models

from soc.views import simple

from soc.views import helper

from soc.views.helper import access

  """Views for entity classes.

  The View class functions specific to Entity classes by relying

  on the the child-classes to define the following fields:

  self._logic: the logic singleton for this entity

  """

  DEF_SUBMIT_MSG_PARAM_NAME = 's'

  DEF_SUBMIT_MSG_PROFILE_SAVED = 0

  DEF_CREATE_NEW_ENTITY_MSG = ugettext_lazy(

      ' You can create a new %(entity_type_lower)s by visiting'

      ' <a href="%(create)s">Create '

      'a New %(entity_type)s</a> page.')

  def __init__(self, params=None, rights=None):

    """

    Args:

      rights: This dictionary should be filled with the access check

        functions that should be called, it will be modified in-place.

      params: This dictionary should be filled with the parameters

        specific to this entity, required fields are:

        name: the name of the entity (names should have sentence-style caps) 

        name_short: the short form name of the name ('org' vs 'organization')

        name_plural: the plural form of the name

        edit_form: the class of the Django form to be used when editing

        create_form: the class of the Django form to be used when creating

        edit_template: the Django template to be used for editing

        public_template: the Django template to be used as public page 

        list_template: the Django template to be used as list page

        lists_template: the Django templates to search for the list page

        delete_redirect: the Django template to redirect to on delete

        create_redirect: the Django template to redirect to after creation

        save_message: the message to display when the entity is saved

        edit_params: the params to use when editing

    """

    new_rights = {}

    new_rights['any_access'] = [access.checkIsUser]

    new_params = {}

    new_params['create_redirect'] = '/%s' % params['name_short'].lower()

    new_params['missing_redirect'] = '/%s/create' % params['name_short'].lower()

    self._rights = dicts.merge(rights, new_rights)

    self._params = dicts.merge(params, new_params)

  def public(self, request, page_name=None, params=None, **kwargs):

    """Displays the public page for the entity specified by **kwargs

    Args:

      request: the standard Django HTTP request object

      page: a soc.logic.site.page.Page object which is abstraction

        that combines a Django view with sidebar menu info

      params: a dict with params for this View

      kwargs: the Key Fields for the specified entity

    """

    params = dicts.merge(params, self._params)

    try:

      self.checkAccess('public', request)

    except soc.views.out_of_band.AccessViolationResponse, alt_response:

      return alt_response.response()

    # create default template context for use with any templates

    context = helper.responses.getUniversalContext(request)

    context['page_name'] = page_name

    entity = None

    if not all(kwargs.values()):

      #TODO: Change this into a proper redirect

      return http.HttpResponseRedirect('/')

    try:

      key_fields = self._logic.getKeyFieldsFromDict(kwargs)

      entity = self._logic.getIfFields(key_fields)

    except soc.logic.out_of_band.ErrorResponse, error:

      template = params['public_template']

      return simple.errorResponse(request, page_name, error, template, context)

    self._public(request, entity, context)

    context['entity'] = entity

    context['entity_type'] = params['name']

    template = params['public_template']

    return helper.responses.respond(request, template, context)

  def create(self, request, page_name=None, params=None, **kwargs):

    """Displays the create page for this entity type

    Args:

      request: the standard Django HTTP request object

      page: a soc.logic.site.page.Page object which is abstraction

        that combines a Django view with sidebar menu info

      params: a dict with params for this View

      kwargs: not used for create()

    """

    params = dicts.merge(params, self._params)

    # Create page is an edit page with no key fields

    empty_kwargs = {}

    fields = self._logic.getKeyFieldNames()

    for field in fields:

      empty_kwargs[field] = None

    request.path = params['create_redirect']

    request.path = helper.requests.replaceSuffix(request.path,

                                                 old_suffix='edit',

                                                 new_suffix='edit')

    if not kwargs:

      return self.edit(request, page_name=page_name, params=params, **empty_kwargs)

    else:

      return self.edit(request, page_name=page_name, params=params, seed=kwargs)

  def edit(self, request, page_name=None, params=None, seed=None, **kwargs):

    """Displays the edit page for the entity specified by **kwargs

    Args:

      request: the standard Django HTTP request object

      page: a soc.logic.site.page.Page object which is abstraction

        that combines a Django view with sidebar menu info

      params: a dict with params for this View

      kwargs: The Key Fields for the specified entity

    """

    params = dicts.merge(params, self._params)

    try:

      self.checkAccess('edit', request)

    except soc.views.out_of_band.AccessViolationResponse, alt_response:

      return alt_response.response()

    context = helper.responses.getUniversalContext(request)

    context['page_name'] = page_name

    entity = None

    try:

      if all(kwargs.values()):

        key_fields = self._logic.getKeyFieldsFromDict(kwargs)

        entity = self._logic.getIfFields(key_fields)

    except soc.logic.out_of_band.ErrorResponse, error:

      if not seed:

        template = params['public_template']

        error.message = error.message + self.DEF_CREATE_NEW_ENTITY_MSG % {

            'entity_type_lower' : params['name'].lower(),

            'entity_type' : params['name'],

            'create' : params['missing_redirect']

            }

        return simple.errorResponse(request, page_name, error, template, context)

    if request.method == 'POST':

      return self.editPost(request, entity, context, params)

    else:

      return self.editGet(request, entity, context, seed, params)

  def editPost(self, request, entity, context, params):

    """Same as edit, but on POST

    """

    params = dicts.merge(params, self._params)

    if entity:

      form = params['edit_form'](request.POST)

    else:

      form = params['create_form'](request.POST)

    if not form.is_valid():

      return self._constructResponse(request, entity, context, form, params)

    key_name, fields = self.collectCleanedFields(form)

    # get the old_suffix before editing

    old_suffix = self._logic.getKeySuffix(entity)

    self._editPost(request, entity, fields)

    if not key_name:

      key_fields =  self._logic.getKeyFieldsFromDict(fields)

      key_name = self._logic.getKeyNameForFields(key_fields)

    entity = self._logic.updateOrCreateFromKeyName(fields, key_name)

    if not entity:

      return http.HttpResponseRedirect('/')

    page_params = params['edit_params']

    suffix = self._logic.getKeySuffix(entity)

    # redirect to (possibly new) location of the entity

    # (causes 'Profile saved' message to be displayed)

    return helper.responses.redirectToChangedSuffix(

        request, old_suffix, suffix,

        params=page_params)

  def editGet(self, request, entity, context, seed, params):

    """Same as edit, but on GET

    """

    params = dicts.merge(params, self._params)

    suffix = self._logic.getKeySuffix(entity)

    # Remove the params from the request, this is relevant only if

    # someone bookmarked a POST page.

    is_self_referrer = helper.requests.isReferrerSelf(request, suffix=suffix)

    if request.GET.get(self.DEF_SUBMIT_MSG_PARAM_NAME):

      if (not entity) or (not is_self_referrer):

        return http.HttpResponseRedirect(request.path)

    if entity:

      # Note: no message will be displayed if parameter is not present

      context['notice'] = helper.requests.getSingleIndexedParamValue(

          request, self.DEF_SUBMIT_MSG_PARAM_NAME,

          values=params['save_message'])

      # populate form with the existing entity

      form = params['edit_form'](instance=entity)

      if 'key_name' in form.fields:

        form.fields['key_name'].initial = entity.key().name()

      self._editGet(request, entity, form)

    else:

      if seed:

        form = params['create_form'](initial=seed)

      else:

        form = params['create_form']()

    return self._constructResponse(request, entity, context, form, params)

  def list(self, request, page_name=None, params=None):

    """Displays the list page for the entity type

    Args:

      request: the standard Django HTTP request object

      page: a soc.logic.site.page.Page object which is abstraction

        that combines a Django view with sidebar menu info

      params: a dict with params for this View

    """

    params = dicts.merge(params, self._params)

    try:

      self.checkAccess('list', request)

    except soc.views.out_of_band.AccessViolationResponse, alt_response:

      return alt_response.response()

    context = helper.responses.getUniversalContext(request)

    context['page_name'] = page_name

    offset, limit = helper.lists.cleanListParameters(

      offset=request.GET.get('offset'), limit=request.GET.get('limit'))

    # Fetch one more to see if there should be a 'next' link

    entities = self._logic.getForLimitAndOffset(limit + 1, offset=offset)

    context['pagination_form'] = helper.lists.makePaginationForm(request, limit)

    templates = params['lists_template']

    context = helper.lists.setList(request, context, entities, 

                                 offset, limit, templates)

    context['entity_type'] = params['name']

    context['entity_type_plural'] = params['name_plural']

    template = params['list_template']

    return helper.responses.respond(request, template, context)

  def delete(self, request, page_name=None, params=None, **kwargs):

    """Shows the delete page for the entity specified by kwargs

    Args:

      request: the standard Django HTTP request object

      page: a soc.logic.site.page.Page object which is abstraction

        that combines a Django view with sidebar menu info

      params: a dict with params for this View

      kwargs: The Key Fields for the specified entity

    """

    params = dicts.merge(params, self._params)

    try:

      self.checkAccess('delete', request)

    except soc.views.out_of_band.AccessViolationResponse, alt_response:

      return alt_response.response()

    # create default template context for use with any templates

    context = helper.responses.getUniversalContext(request)

    context['page_name'] = page_name

    entity = None

    try:

      key_fields = self._logic.getKeyFieldsFromDict(kwargs)

      entity = self._logic.getIfFields(key_fields)

    except soc.logic.out_of_band.ErrorResponse, error:

      template = params['edit_template']

      error.message = error.message + self.DEF_CREATE_NEW_ENTITY_MSG % {

          'entity_type_lower' : params['name'].lower(),

          'entity_type' : params['name'],

          'create' : params['missing_redirect']

          }

      return simple.errorResponse(request, page_name, error, template, context)

    if not entity:

      #TODO: Create a proper error page for this

      return http.HttpResponseRedirect('/')

    if not self._logic.isDeletable(entity):

      # TODO: Update the notice area telling the user that they

      # can't delete the entity

      pass

    self._logic.delete(entity)

    redirect = params['delete_redirect']

    return http.HttpResponseRedirect(redirect)

  def _editPost(self, request, entity, fields):

    """Performs any required processing on the entity to post its edit page

    Args:

      request: the django request object

      entity:  the entity to create or update from POST contents

      fields: the new field values

    """

    pass

  def _public(self, request, entity, context):

    """Performs any required processing to get an entities public page

    Args:

      request: the django request object

      entity: the entity to make public

      context: the context object

    """

    pass

  def _editGet(self, request, entity, form):

    """Performs any required processing on the form to get its edit page

    Args:

      request: the django request object

      entity: the entity to get

      form: the django form that will be used for the page

    """

    pass

  def checkUnspecified(self, access_type, request):

    """Checks whether an unspecified access_type should be allowed

    Args:

      access_type: the access type (such as 'list' or 'edit') that was

                   not present in the _rights dictionary when checking.

    """

    pass

  def _constructResponse(self, request, entity, context, form, params):

    """Updates the context and returns a response for the specified arguments

    Args:

      request: the django request object

      entity: the entity that is used

      context: the context to be used

      form: the form that will be used

      params: a dict with params for this View

    """

    suffix = self._logic.getKeySuffix(entity)

    context['form'] = form

    context['entity'] = entity

    context['entity_suffix'] = suffix

    context['entity_type'] = params['name']

    context['entity_type_plural'] = params['name_plural']

    context['entity_type_short'] = params['name_short']

    template = params['edit_template']

    return helper.responses.respond(request, template, context)

  def checkAccess(self, access_type, request):

    """Runs all the defined checks for the specified type

    Args:

      access_type: the type of request (such as 'list' or 'edit')

      request: the Django request object

    Returns:

      True: If all the required access checks have been made successfully

      False: If a check failed, in this case self._response will contain

             the response provided by the failed access check.

    """

    # Call each access checker

    for check in self._rights['any_access']:

      check(request)

    if access_type not in self._rights:

       # No checks defined, so do the 'generic check' and bail out

      self.checkUnspecified(access_type, request)

      return

    for check in self._rights[access_type]:

      check(request)

  def collectCleanedFields(self, form):

    """Collects all cleaned fields and returns them with the key_name

    Args:

      form: The form from which the cleaned fields should be collected

    """

    fields = {}

    key_name = None

    if 'key_name' in form.cleaned_data:

      key_name = form.cleaned_data.pop('key_name')

    for field, value in form.cleaned_data.iteritems():

      fields[field] = value

    return key_name, fields