from zope.interface import Interface
from zope.schema import Text, TextLine, Field

from zope.app.container.constraints import ContainerTypesConstraint
from zope.app.container.constraints import ItemTypePrecondition
from zope.app.container.interfaces import IContained, IContainer

class IBlogEntry(Interface):
    """Interface for blog entry objects."""

    title = TextLine(
        title = u"Blog entry title",
        description = u"Blog entry title.",
        default = u"",
        required = True)

    content = Text(
        title = u"Blog entry content",
        description = u"Blog entry content.",
        default = u"",
        required = True)

    summary = Text(
        title = u"Summary",
        description = u"An excerpt from content.""",
        default = u"",
        max_length = 250,
        required = False)


class IBlog(IContainer):
    """The blog container which can contain IBlogEntry objects."""

    def __setitem__(name, object):
        """Add a IBlogEntry object."""

    __setitem__.precondition = ItemTypePrecondition(IBlogEntry)

    title = TextLine(
        title = u"Blog title",
        description = u"Blog description",
        default = u"",
        required = True)

    description = Text(
        title = u"Description",
        description = u"A detailed description of the blog's contents.",
        default = u"",
        required = False)


class IBlogEntryContained(IContained):
    """Interface that specifies which type of objects can contain blog
    entries."""

    __parent__ = Field(constraint = ContainerTypesConstraint(IBlog))