"""Workflow for students.
"""
import grok
from datetime import datetime
from hurry.workflow.workflow import Transition, WorkflowState, NullCondition
from hurry.workflow.interfaces import IWorkflowState, IWorkflowTransitionEvent
from waeup.sirp.students.interfaces import IStudent
from waeup.sirp.interfaces import IObjectHistory, IWAeUPWorkflowInfo
from waeup.sirp.workflow import WAeUPWorkflow, WAeUPWorkflowInfo

CREATED = 'created'
ADMITTED = 'admitted'

REGISTRATION_TRANSITIONS = (
    Transition(
        transition_id = 'create',
        title = 'Create student',
        source = None,
        condition = NullCondition,
        msg = 'Student record created',
        destination = CREATED),

    Transition(
        transition_id = 'admit',
        title = 'Admit student',
        msg = 'Student admitted',
        source = CREATED,
        destination = ADMITTED),

    Transition(
        transition_id = 'reset1',
        title = 'Reset student',
        msg = 'Student record reset',
        source = ADMITTED,
        destination = CREATED),
    )

registration_workflow = WAeUPWorkflow(REGISTRATION_TRANSITIONS)

class RegistrationWorkflowState(WorkflowState, grok.Adapter):
    """An adapter to adapt Student objects to workflow states.
    """
    grok.context(IStudent)
    grok.provides(IWorkflowState)

    state_key = 'wf.registration.state'
    state_id = 'wf.registration.id'

class RegistrationWorkflowInfo(WAeUPWorkflowInfo, grok.Adapter):
    """Adapter to adapt Student objects to workflow info objects.
    """
    grok.context(IStudent)
    grok.provides(IWAeUPWorkflowInfo)

    def __init__(self, context):
        self.context = context
        self.wf = registration_workflow

@grok.subscribe(IStudent, IWorkflowTransitionEvent)
def handle_student_transition_event(obj, event):
    """Append message to student history when transition happened.
    """
    msg = '%s' % event.transition.user_data['msg']
    history = IObjectHistory(obj)
    history.addMessage(msg)
    return