#!/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.conf.urls import defaults

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.logic import path_link_name

from soc.views import simple

from soc.views import helper

from soc.views.helper import access

class View(object):

  """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(

      ' <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

        sidebar: the sidebar menu items for this view

        sidebar_defaults: a dictionary with defaults for the sidebar 

    """

    new_rights = {}

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

    new_params = {}

    new_params['sidebar'] = None

    new_params['sidebar_defaults'] = [

     ('/%s/create', 'New %(name)s'),

     ('/%s/list', 'List %(plural)s'),

    ]

    new_params['sidebar_additional'] = []

    new_params['key_fields_prefix'] = []

    new_params['django_patterns'] = None

    new_params['django_patterns_defaults'] = [

            'soc.views.models.%s.public', 'Show %(name)s'),

            'soc.views.models.%s.create', 'Create %(name)s'),

            'soc.views.models.%s.create', 'Create %(name)s'),

            'soc.views.models.%s.delete', 'Delete %(name)s'),

            'soc.views.models.%s.edit', 'Edit %(name)s'),

            'soc.views.models.%s.list', 'List %(name_plural)s'),

        ]

    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_name: the page name displayed in templates as page and header title

      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_name: the page name displayed in templates as page and header title

      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, **empty_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_name: the page name displayed in templates as page and header title

      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:

        self._editSeed(request, 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_name: the page name displayed in templates as page and header title

      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']

    context['redirect_action'] = params['list_redirect_action']

    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_name: the page name displayed in templates as page and header title

      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 _editSeed(self, request, seed):

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

    Args:

      request: the django request object

      seed: the fields to seed the create page with

    """

    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