#
#  Copyright (c) 2008 Helmut Merz helmutm@cy55.de
#
#  This program is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation; either version 2 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software
#  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#

"""
External content integration interfaces.

$Id$
"""

from zope.app.container.interfaces import IReadContainer
from zope.app.file.interfaces import IFile, IImage
from zope.app.publication.interfaces import IFileContent
from zope.interface import Interface, Attribute


class IProxy(Interface):
    """ An object that represents an external object and provides access
        to it.
    """

    address = Attribute('An external specifier (a name, path, URL, ...) '
                'that may be used to access the external object.')
    internalPath = Attribute('A relativ path leading to an internal '
                'representation of the represented object.')
    icon = Attribute('The name of an icon that may be used for symbolizing '
                'the represented object.')
    properties = Attribute('A dictionary with attributes/properties '
                'characteristic for the type of object the proxy represents.')
    externalUrlInfo = Attribute('Information necessary for building URLs that link '
                'directly to the object the proxy represents (optional).')

    title = Attribute('A short string giving basic information about the object.')
    description = Attribute('A somewhat longer descriptive information.')
    url = Attribute('An explicit target URL (optional).')
    authors = Attribute('A list of names of persons who worked on this object.')
    created = Attribute('A datetime object denoting the data/time of object '
                'creation.')
    modified = Attribute('A datetime object denoting the data/time of last '
                'modification of the object.')


class IExternalUrlInfo(Interface):
    """ Information necessary to build URLs to external objects.
    """
    baseUrl = Attribute('The base part of the URL, including the protocol and '
                'the server part + optionally a constant part of the path.')
    path = Attribute('The relative path leading to the object.')
    params = Attribute('A dictionary providing a parameter set that will '
                'be appended urlencoded to the base URL.')


class IReadContainer(IProxy, IReadContainer):
    """ A readable container of items.
    """


class IItem(IProxy, Interface):
    """ A proxy for a terminal kind of object, i.e. not a container of
        other objects.
    """


class IFile(IItem, IFile, IFileContent):

    data = Attribute('The data contained in the file.')
    contentType = Attribute('The MIME type of the object.')

    def getData(num=None):
        """ Return num bytes from the file`s data.
        """


# proxy factories

class IProxyFactory(Interface):
    """ Creates proxy objects for external objects.
    """

    def __call__(address, **kw):
        """ Return a proxy object based on an external object that
            can be accessed using the address (and optional
            keyword arguments) given.
        """


class IContainerFactory(IProxyFactory):
    """ Creates container proxy objects for the external specification
        given.
    """


class IItemFactory(IProxyFactory):
    """ Creates general terminal proxy objects.
    """


class IFileFactory(IProxyFactory):
    """ Creates file proxy objects for the external specification
        given.
    """
