# Plugin for trac 0.11

from genshi.builder import tag 
from genshi.filters import Transformer


from trac.core import *
from trac.web import IRequestHandler
from trac.web import ITemplateStreamFilter

class ITicketSubmitPolicy(Interface):
    def name():
        """name of the policy"""

class TicketRequires(Component):
    implements(ITicketSubmitPolicy)
    def name(self):
        return 'requires'

class TicketExcludes(Component):
    implements(ITicketSubmitPolicy)
    def name(self):
        return 'excludes'

class TicketSubmitPolicyPlugin(Component):
    """
    get the selected option from HTML like this:

<select id="field-type" name="field_type">
<option selected="selected">defect</option><option>enhancement</option><option>task</option>
</select>

Notes to self:
Generalizing this would be:
type == defect -> requires(version)
type != defect -> excludes(version)

Does this work for http://trac.openplans.org/trac/ticket/5 and the confirmed box?

state != resolved -> excludes(confirmed)

So yes, I think

    """

    implements(ITemplateStreamFilter) 
    policies = ExtensionPoint(ITicketSubmitPolicy)

    def policy_dict(self):
        retval = {}
        for policy in self.policies:
            retval[policy.name()] = policy
        return retval

    # method for ITemplateStreamFilter
    def filter_stream(self, req, method, filename, stream, data):

        # temporary staging ground for ticket policy behavior
        # XXX things here should be abstracted
        policies = [ {'contingentfield': 'type', 'value': 'defect', 
                      'function': self.requires, 'args': [ 'version' ]},
                     {'contingentfield': 'type', 'value': 'defect', 
                      'function': self.excludes, 'args': [ 'version' ]},
                     ]

        self.onload = []

        policy_dict = self.policy_dict()
        import pdb;  pdb.set_trace()