#
#  Copyright (c) 2007 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
#

"""
State definition implementation.

$Id$
"""

from zope.interface import implements
from cybertools.util.jeep import Jeep

from cybertools.stateful.interfaces import IState, ITransition
from cybertools.stateful.interfaces import IStatesDefinition


class State(object):

    implements(IState)

    security = lambda context: None
    icon = None
    color = 'blue'

    def __init__(self, name, title, transitions, **kw):
        self.name = self.__name__ = name
        self.title = title
        self.transitions = transitions
        for k, v in kw.items():
            setattr(self, k, v)


class Transition(object):

    implements(ITransition)

    def __init__(self, name, title, targetState, **kw):
        self.name = self.__name__ = name
        self.title = title
        self.targetState = targetState
        for k, v in kw.items():
            setattr(self, k, v)


class StatesDefinition(object):

    implements(IStatesDefinition)

    initialState = 'started'

    def __init__(self, name, *details, **kw):
        self.name = self.__name__ = name
        self.states = Jeep()
        self.transitions = Jeep()
        for d in details:
            if ITransition.providedBy(d):
                self.transitions.append(d)
            elif IState.providedBy(d):
                self.states.append(d)
            else:
                raise TypeError('Only states or transitions are allowed here, '
                                'got %s instead.' % repr(d))
        for k, v in kw.items():
            setattr(self, k, v)

    def doTransitionFor(self, obj, transition):
        if transition not in self.transitions:
            raise ValueError('Transition %s is not available.' % transition)
        if transition not in [t.name for t in self.getAvailableTransitionsFor(obj)]:
            raise ValueError("Transition '%s' is not reachable from state '%s'."
                                    % (transition, obj.getState()))
        obj.state = self.transitions[transition].targetState

    def getAvailableTransitionsFor(self, obj):
        state = obj.getState()
        return [self.transitions[t] for t in self.states[state].transitions]


# dummy default states definition

defaultSD = StatesDefinition('default',
    State('started', 'Started', ('finish',)),
    State('finished', 'Finished', ()),
    Transition('finish', 'Finish', 'finished'),
)


# states definitions registry

statesDefinitions = dict()

def registerStatesDefinition(definition):
    statesDefinitions[definition.name] = definition

registerStatesDefinition(defaultSD)