#!/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.

"""Module contains sidebar related functions.

"""

__authors__ = [

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

  ]

import operator

from soc.views import out_of_band

from soc.views.helper import access

import soc.cache.sidebar

SIDEBAR = []

SIDEBAR_ACCESS_ARGS = ['SIDEBAR_CALLING']

SIDEBAR_ACCESS_KWARGS = {'SIDEBAR_CALLING': True}

def addMenu(callback):

  """Adds a callback to the menu builder.

  The callback should return a list of menu's when called.

  """

  global SIDEBAR

  SIDEBAR.append(callback)

@soc.cache.sidebar.cache

def getSidebar(id, user):

  """Constructs a sidebar for the current user.

  """

  sidebar = []

  for callback in SIDEBAR:

    menus = callback(id, user)

    for menu in (menus if menus else []):

      sidebar.append(menu)

  return sorted(sidebar, key=lambda x: x.get('group'))

def getSidebarItems(params):

  """Retrieves a list of sidebar entries for this view.

  Params usage:

    The params dictionary is provided to the menu_text's format.

    sidebar: The sidebar value is returned directly if non-False

    sidebar_defaults: The sidebar_defaults are used to construct the

      sidebar items for this View. It is expected to be a tuple of

      three items, the item's url, it's menu_text, and it's

      access_type, see getSidebarMenus on how access_type is used.

    sidebar_additional: The sidebar_additional values are appended

      to the list of items verbatim, and should be in the format

      expected by getSidebarMenus.

  Args:

    params: a dict with params for this View.

  """

  # Return the found result

  if params['sidebar']:

    default = params['sidebar']

    result = default[:]

    for item in params['sidebar_additional']:

      result.append(item)

    return result

  # Construct defaults manualy

  defaults = params['sidebar_defaults']

  result = []

  for item in params['sidebar_additional']:

    result.append(item)

  for url, menu_text, access_type in defaults:

    url = url % params['url_name'].lower()

    item = (url, menu_text % params, access_type)

    result.append(item)

  return result

def getSidebarMenu(id, user, items, params):

  """Returns an dictionary with one sidebar entry.

  Items is expected to be a tuple with an url, a menu_text, and an

  access_type. The access_type is then passed to checkAccess, if it

  raises out_of_band.Error, the item will not be added.

  Args:

    items: see above

    params: a dict with params for this View

  Params usage:

    The params dictionary is passed as argument to getSidebarItems,

    see the docstring of getSidebarItems on how it uses it.

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

      the required rights to see a sidebar item.

      See checkAccess for more details on how the rights dictionary

      is used to check access rights.

    sidebar_heading: The sidebar_heading value is used to set the

      heading variable in the result.

    name: The name value is used if sidebar_heading is not present.

  Returns: 

    A dictionary is returned with it's 'heading' value set as explained above.

    It's 'items' value is constructed by calling _getSidebarItems. It constists

    of dictionaries with a url and a title field.

  """

  rights = params['rights']

  submenus = []

  args = SIDEBAR_ACCESS_ARGS

  kwargs = SIDEBAR_ACCESS_KWARGS

  # reset and pre-fill the Checker's cache

  rights.setCurrentUser(id, user)

  for url, menu_text, access_type in items:

    try:

      rights.checkAccess(access_type, kwargs)

      submenus.append({'url': url, 'title': menu_text})

    except out_of_band.Error:

      pass

  return submenus

def getSidebarMenus(id, user, params=None):

  """Constructs the default sidebar menu for a View.

  Calls getSidebarItems to retrieve the items that should be in the

  menu. Then passes the result to getSidebarMenu. See the respective

  docstrings for an explanation on what they do.

  Args:

    params: a dict with params for this View

  """

  items = getSidebarItems(params)

  submenus = getSidebarMenu(id, user, items, params)

  if not submenus:

    return

  menu = {}

  if 'sidebar_heading' not in params:

    params['sidebar_heading'] = params['name']

  menu['heading'] = params['sidebar_heading']

  menu['items'] = submenus

  menu['group'] = params['sidebar_grouping']

  menus = [menu]

  return menus