#!/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>',

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

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

  ]

from django import http

from django.utils.translation import ugettext_lazy

import soc.logic

import soc.logic.lists

import soc.views.helper.lists

import soc.views.helper.responses

from soc.logic import dicts

from soc.logic import models

from soc.models import linkable

from soc.views import helper

from soc.views import out_of_band

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_CREATE_NEW_ENTITY_MSG_FMT = ugettext_lazy(

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

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

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

  def __init__(self, params=None):

    """

    Args:

      params: This dictionary should be filled with the parameters

        specific to this entity. See the methods in this class on

        the fields it should contain, and how they are used.

    """

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

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

    Params usage:

      rights: The rights dictionary is used to check if the user has

        the required rights to view the public page for this entity.

        See checkAccess for more details on how the rights dictionary

        is used to check access rights.

      error_public: The error_public value is used as template when

        the key values (as defined by the page's url) do not

        correspond to an existing entity.

      name: The name value is used to set the entity_type in the

        context so that the template can refer to it.

      public_template: The public_template value is used as template

        to display the public page of the found entity.

    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, rights=params['rights'])

    except out_of_band.Error, error:

      return error.response(request)

    # 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 out_of_band.Error, error:

      return error.response(request, template=params['error_public'],

                            context=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.

    Params usage:

      The params dictionary is passed on to edit, see the docstring

      for edit on how it uses it.

    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

    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.

    Params usage:

      The params dictionary is passed on to either editGet or editPost

      depending on the method type of the request. See the docstring

      for editGet and editPost on how they use it.

      rights: The rights dictionary is used to check if the user has

        the required rights to edit (or create) a new entity.

        See checkAccess for more details on how the rights dictionary

        is used to check access rights.

      name: The name value is used to construct the message_fmt of the

        raised error when there key_values do not define an existing

        entity. See DEF_CREATE_NEW_ENTITY_MSG_FMT on how the name

        (and the lower() version of it) is used.

      missing_redirect: The missing_redirect value is also used to

        construct the message_fmt mentioned above.

      error_public: The error_public value is used as the template for

        the error response mentioned above.

    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, rights=params['rights'])

    except out_of_band.Error, error:

      return error.response(request)

    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 out_of_band.Error, error:

      if not seed:

        error.message_fmt = (

          error.message_fmt + self.DEF_CREATE_NEW_ENTITY_MSG_FMT % {

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

            'entity_type' : params['name'],

            'create' : params['missing_redirect']})

        return error.response(request, template=params['error_public'],

                              context=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):

    """Processes POST requests for the specified entity

    Params usage:

      The params dictionary is passed to _constructResponse when the

      form is not valid (see edit_form and create_form below). See

      the docstring of _constructResponse on how it uses it.

      edit_form: The edit_form value is used as form when there is an

        existing entity. It is provided with with the request.POST

        dictionary on construction. The collectCleanedFields method

        is called with the newly constructed form. If the form is

        not valid, it is passed as argument to _constructResponse.

      create_form: The create_form value is used in a similar way to

        edit_form, only it is used when there is no existing entity.

      edit_redirect: The edit_redirect value is used as the first part

        of the url if the form was valid. The last part of the url is

        created using the getKeySuffix method of the _logic object.

      edit_params: The edit_params dictionary is used as argument to

        redirectToChangedSuffix, it will be appended to the url in the

        standard ?key=value format.

    Args:

      request: a django request object

      entity: the entity that will be modified or created, may be None

      context: the context dictionary that will be provided to Django

      params: a dict with params for this View

    """

    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)

    request.path = params['edit_redirect']

    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']

    new_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, None, new_suffix,

        params=page_params)

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

    """Processes GET requests for the specified entity

    Params usage:

      The params dictionary is passed to _constructResponse, see the

        docstring  of _constructResponse on how it uses it.

      save_message: The save_message list is used as argument to

        getSingleIndexedParamValue when an existing entity was saved.

      edit_form: The edit_form is used as form if there is an existing

        entity. The existing entity is passed as instance to it on

        construction. If key_name is part of it's fields it will be

        set to the entity's key().name() value. It is also passed as

        argument to the _editGet method. See the docstring for

        _editGet on how it uses it.

      create_form: The create_form is used as form if there was no

        existing entity. If the seed argument is present, it is passed

        as the 'initial' argument on construction. Otherwise, it is

        called with no arguments.

    Args:

      request: the django request object

      entity: the entity that will be edited, may be None

      context: the context dictionary that will be provided to django

      seed: if no entity is provided, the initial values for the new entity

      params: a dict with paras for this View

    """

    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 (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(

          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, filter=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

      filter: a dict for the properties that the entities should have

    Params usage:

      The params dictionary is passed as argument to getListContent in

        the soc.views.helper.list module. See the docstring for

        getListContent on how it uses it.

      The params dictionary is also passed as argument to the _list

        method. See the docstring for _list on how it uses it.

      rights: The rights dictionary is used to check if the user has

        the required rights to list all entities of this View's type.

        See checkAccess for more details on how the rights dictionary

        is used to check access rights.

    """

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

    try:

      self.checkAccess('list', request, rights=params['rights'])

    except out_of_band.Error, error:

      return error.response(request)

    content = helper.lists.getListContent(request, params, self._logic, filter)

    contents = [content]

    return self._list(request, params, contents, page_name)

  def _list(self, request, params, contents, page_name):

    """Returns the list page for the specified contents

    Args:

      request: the standard Django HTTP request object

      params: a dict with params for this View

      contents: a list of content dicts

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

    Params usage:

      name: The name value is used to set the entity_type in the

        context so that the template can refer to it.

      name_plural: The name_plural value is used to set

        the entity_type_plural value in the context so that the

        template can refer to it.

      list_template: The list_template value is used as template for

        to display the list of all entities for this View.

    """

    context = helper.responses.getUniversalContext(request)

    context['page_name'] = page_name

    context['list'] = soc.logic.lists.Lists(contents)

    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_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 usage:

      rights: The rights dictionary is used to check if the user has

        the required rights to delete the specified entity.

        See checkAccess for more details on how the rights dictionary

        is used to check access rights.

      name: used in the same way as in edit(), see it's docstring for

        a more detailed explanation on how it is used.

      missing_redirect: see name

      error_edit: see name

      delete_redirect: The delete_redirect value is used as the url to

        redirect to after having successfully deleted the entity.

    """

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

    try:

      self.checkAccess('delete', request, rights=params['rights'])

    except out_of_band.Error, error:

      return error.response(request)

    # 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 out_of_band.Error, error:

      error.message_fmt = (

        error.message_fmt + self.DEF_CREATE_NEW_ENTITY_MSG_FMT % {

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

          'entity_type' : params['name'],

          'create' : params['missing_redirect']})

      return error.response(request, template=params['error_edit'],

                            context=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

    """