class Workflow(EntityType):

    permissions = META_ETYPE_PERMS

    name = String(required=True, indexed=True, internationalizable=True,

                  maxsize=256)

    description = RichString(fulltextindexed=True, default_format='text/rest',

                             description=_('semantic description of this workflow'))

    workflow_of = SubjectRelation('CWEType', cardinality='+*',

                                  description=_('entity types which may use this workflow'),

                                  constraints=[RQLConstraint('O final FALSE')])

    default_workflow_of = SubjectRelation('CWEType', cardinality='*?',

                                          description=_('which entity types use this workflow by default'),

                                          constraints=[RQLConstraint('O final FALSE')])

    initial_state = SubjectRelation('State', cardinality='?*',

                                   # S initial_state O, O state_of S

                                   constraints=[RQLConstraint('O state_of S')],

                                   description=_('initial state for this workflow'))

# XXX ensure state/transition name is unique in a given workflow

    state_of = SubjectRelation('Workflow', cardinality='+*',

                    description=_('workflow to which this state belongs'))

    # XXX should be on BaseTransition w/ AND/OR selectors when we will

    # implements #345274

    allowed_transition = SubjectRelation('BaseTransition', cardinality='**',

                                         constraints=[RQLConstraint('S state_of WF, O transition_of WF')],

class BaseTransition(EntityType):

    """abstract base class for transitions"""

    transition_of = SubjectRelation('Workflow', cardinality='+*',

                                    description=_('workflow to which this transition belongs'))

class Transition(BaseTransition):

    """use to define a transition from one or multiple states to a destination

    states in workflow's definitions.

    """

    __specializes_schema__ = True

                                        constraints=[RQLConstraint('S transition_of WF, O state_of WF')],

class WorkflowTransition(BaseTransition):

    """special transition allowing to go through a sub-workflow"""

    __specializes_schema__ = True

    subworkflow = SubjectRelation('Workflow', cardinality='1*',

                                  constraints=[RQLConstraint('S transition_of WF, WF workflow_of ET, O workflow_of ET')])

    subworkflow_exit = SubjectRelation('SubWorkflowExitPoint', cardinality='+1',

                                       composite='subject')

class SubWorkflowExitPoint(EntityType):

    """define how we get out from a sub-workflow"""

    subworkflow_state = SubjectRelation('State', cardinality='1*',

                                        constraints=[RQLConstraint('T subworkflow_exit S, T subworkflow WF, O state_of WF')],

                                        description=_('subworkflow state'))

    destination_state = SubjectRelation('State', cardinality='1*',

                                        constraints=[RQLConstraint('T subworkflow_exit S, T transition_of WF, O state_of WF')],

                                        description=_('destination state'))

# XXX should we allow managers to delete TrInfo?

class TrInfo(EntityType):

    """workflow history item"""

    # 'add' security actually done by hooks

    permissions = {

        'read':   ('managers', 'users', 'guests',), # XXX U has_read_permission O ?

        'add':    ('managers', 'users', 'guests',),

        'delete': (),

        'update': ('managers', 'owners',),

    }

    from_state = SubjectRelation('State', cardinality='1*')

    # make by_transition optional because we want to allow managers to set

    # entity into an arbitrary state without having to respect wf transition

    by_transition = SubjectRelation('Transition', cardinality='?*')

class from_state(RelationType):

    permissions = HOOKS_RTYPE_PERMS.copy()

    inlined = True

class to_state(RelationType):

    permissions = {

        'read':   ('managers', 'users', 'guests',),

        'add':    ('managers',),

        'delete': (),

    }

class by_transition(RelationType):

    # 'add' security actually done by hooks

    permissions = {

        'read':   ('managers', 'users', 'guests',),

        'add':    ('managers', 'users', 'guests',),

        'delete': (),

    }

class workflow_of(RelationType):

    """link a workflow to one or more entity type"""

    permissions = META_RTYPE_PERMS

    """link a state to one or more workflow"""

    """link a transition to one or more workflow"""

    permissions = META_RTYPE_PERMS

class subworkflow(RelationType):

    """link a transition to one or more workflow"""

    inlined = True

class exit_point(RelationType):

    """link a transition to one or more workflow"""

    permissions = META_RTYPE_PERMS

class subworkflow_state(RelationType):

    """link a transition to one or more workflow"""

    permissions = META_RTYPE_PERMS

    inlined = True

# "abstract" relations, set by WorkflowableEntityType ##########################

class custom_workflow(RelationType):

    """allow to set a specific workflow for an entity"""

    permissions = META_RTYPE_PERMS

    cardinality = '?*'

    constraints = [RQLConstraint('S is ET, O workflow_of ET')]

    object = 'Workflow'

class wf_info_for(RelationType):

    """link a transition information to its object"""

    # 'add' security actually done by hooks

    permissions = {

        'read':   ('managers', 'users', 'guests',),

        'add':    ('managers', 'users', 'guests',),

        'delete': (),

    }

    inlined = True

    cardinality='1*'

    composite = 'object'

    fulltext_container = composite

    subject = 'TrInfo'

    permissions = HOOKS_RTYPE_PERMS

    cardinality = '1*'

    constraints = [RQLConstraint('S is ET, O state_of WF, WF workflow_of ET')]

    object = 'State'