from apps.wf.models import State, Ticket, Transition, Workflow
from rest_framework.exceptions import APIException
class WfService(object):
    @staticmethod
    def get_wf_states(wf:Workflow):
        """
        获取工作流状态列表
        """
        return State.objects.filter(workflow=wf, is_deleted=False).order_by('sort')
    
    @staticmethod
    def get_wf_transitions(wf:Workflow):
        """
        获取工作流流转列表
        """
        return Transition.objects.filter(workflow=wf, is_deleted=False)
    
    @staticmethod
    def get_wf_start_state(wf:Workflow):
        """
        获取工作流初始状态
        """
        try:
            wf_state_obj = State.objects.get(workflow=wf, type=State.STATE_TYPE_START, is_deleted=False)
            return wf_state_obj
        except:
            raise Exception('工作流初始状态配置错误')
    
    @classmethod
    def get_ticket_transitions(cls, ticket:Ticket):
        """
        获取工单当前状态下可用的流转条件
        """
        return cls.get_state_transitions(ticket.state)

    @classmethod    
    def get_state_transitions(cls, state:State):
        """
        获取状态可执行的操作
        """
        return Transition.objects.filter(is_deleted=False, source_state=state).all()

    @classmethod
    def get_ticket_next_state(cls, ticket:Ticket)->object:
        transitions = Transition.objects.filter(source_state=ticket.state, is_deleted=False)
        count = transitions.count()
        if count == 0:
            raise Exception('未配置流转条件')
        elif count == 1:
            return transitions.first()
        else:
            for i in transitions:
                pass