#!/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.

"""List generation logic

"""

__authors__ = [

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

  ]

class Lists(object):

  """List array suitable for enumerating over with just 'for in'

  """

  DEF_PASSTHROUGH_FIELDS = [

      'pagination',

      'description',

      'heading',

      'row',

      'limit',

      'newest',

      'prev',

      'next',

      'first',

      'last',

      ]

  def __init__(self, contents):

    """Constructs a new Lists object with the specified contents

    """

    # All the contents of all the lists

    self.contents = contents

    self.content = {}

    # For iterating over all the lists

    self.lists = range(len(contents))

    self.list_data = []

    # For iterating over the rows

    self.rows = []

    self.row_data = []

  def __getattr__(self, attr):

    """Delegate field lookup to the current list if appropriate

    If, and only if, a lookup is done on one of the fields defined in

    DEF_PASSTHROUGH_FIELDS, and the current list defines this field,

    the value from the current list is returned.

    """

    if attr not in self.DEF_PASSTHROUGH_FIELDS:

      raise AttributeError()

    if attr not in self.content:

      raise AttributeError()

    return self.get(attr)

  def get(self, item):

    """Returns the item for the current list data

    """

    return self.content[item]

  def next_list(self):

    """Shifts out the current list content

    The main content of the next list is returned for further processing.

    """

    # Advance the list data once

    self.content = self.contents[0]

    self.contents = self.contents[1:]

    # Update internal 'iterators'

    self.list_data = self.get('data')

    self.rows = range(len(self.list_data))

    return self.get('main')

  def next_row(self):

    """Returns the next list row for the current list

    Before calling this method, next_list should be called at least once.

    """

    # Update internal 'iterators'

    self.row_data =  self.list_data[0]

    # Advance the row data once

    self.list_data = self.list_data[1:]

    return self.get('row')

  def lists(self):

    """Returns a list of numbers the size of the amount of lists.

    This method can be used to iterate over all lists with shift,

    without using a while loop.

    """

    return self.lists

  def rows(self):

    """Returns a list of numbers the size of the amount of items.

    This method can be used to iterate over all items with next for

    the current list, without using a while loop.

    """

    return self.rows

  def item(self):

    """Returns the current row item for the current list

    Before calling this method, next_row should be called at least once.

    """

    return self.row_data