from zope.interface import Interface
from zope.configuration.fields import GlobalObject
from zope.configuration.fields import Path
from zope.schema import TextLine

from zope.app.component.fields import LayerField
from zope.app.security.fields import Permission


class IMeldPageDirective(Interface):
    """
    The meldpage directive is used to create views that are accessible
    as a URL.

    The meldpage directive creates a new view class from a given template
    and class and registers it.
    """
    for_ = GlobalObject(
        title=u"The interface or class this view is for.",
        required=True
        )

    name = TextLine(
        title=u"The name of the view.",
        description=u"""The name which shows up in URLs/paths. For example,
        'foo'.""",
        required=True,
        )

    transform = GlobalObject(
        title=u"Transform function",
        description=u"""A callable that accepts an element, a context,
        and a request.  It should mutate the element.  The return value is
        ignored""",
        required=False,
        )

    package = GlobalObject(
        title=u"Package",
        description=u"The package in which the template can be found.",
        required=False,
        )

    template = Path(
        title=u"The path of a meld3 template that the page uses.",
        description=u"""
        Refers to a file containing a meld3 template.""",
        required=True
        )

    layer = LayerField(
        title=u"The layer the view is in.",
        description=u"""
        A skin is composed of layers. It is common to put skin
        specific views in a layer named after the skin. If the 'layer'
        attribute is not supplied, it defaults to IDefaultBrowserLayer.""",
        required=False,
        )

    permission = Permission(
        title=u"Permission",
        description=u"The permission needed to use the view.",
        required=True
        )