from apps.wf.models import CustomField, State, Ticket, Transition, Workflow
from rest_framework.exceptions import APIException
class WfService(object):
    @staticmethod
    def get_worlflow_states(workflow:Workflow):
        """
        获取工作流状态列表
        """
        return State.objects.filter(workflow=workflow, is_deleted=False).order_by('sort')
    
    @staticmethod
    def get_workflow_transitions(workflow:Workflow):
        """
        获取工作流流转列表
        """
        return Transition.objects.filter(workflow=workflow, is_deleted=False)
    
    @staticmethod
    def get_workflow_start_state(workflow:Workflow):
        """
        获取工作流初始状态
        """
        try:
            wf_state_obj = State.objects.get(workflow=workflow, type=State.STATE_TYPE_START, is_deleted=False)
            return wf_state_obj
        except:
            raise Exception('工作流状态配置错误')
    
    @staticmethod
    def get_workflow_custom_fields(workflow:Workflow):
        """
        获取工单字段
        """
        return CustomField.objects.filter(is_deleted=False, workflow=workflow).order_by('sort')

    @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_steps(cls, ticket:Ticket):
        steps = cls.get_worlflow_states(ticket.workflow)
        for i in steps:
            if ticket.state.is_hidden and ticket.state != i:
                steps.remove(i)
        return steps

    @classmethod
    def get_ticket_transitions(cls, ticket:Ticket):
        """
        获取工单可执行的操作
        """
        return cls.get_state_transitions(ticket.state)

    @classmethod
    def get_transition_by_args(cls, kwargs:dict):
        """
        查询并获取流转
        """
        kwargs['is_deleted'] = False
        return Transition.objects.filter(**kwargs).all()

    @classmethod
    def get_next_state_id_by_transition_and_ticket_info(cls, ticket:Ticket, transition: Transition, workflow:Workflow = None)->object:
        """
        获取下个节点状态
        """
        if ticket: # 如果是新建工单
            source_state = ticket.state
        else:
            source_state = cls.get_workflow_start_state(workflow)
        if transition.source_state != source_state:
            raise APIException('流转错误')
        destination_state = transition.destination_state
        if transition.condition_expression:
            pass
        return destination_state
    
    @classmethod
    def get_ticket_state_participant_info(cls, state:State, ticket:Ticket, ticket_data:dict):
        """
        获取工单目标状态实际的处理人
        """
        if state.type == State.STATE_TYPE_START:
            """
            回到初始状态
            """
        elif state.type == State.STATE_TYPE_END:
            """
            到达结束状态
            """