from typing import TypedDict

from fastapi import FastAPI
from langgraph.constants import START, END
from langgraph.graph import StateGraph

from app.model.ApproveModel import ApproveModel, ApproveService
from app.model.ReimburseModel import ReimburseService, ReimburseModel
from app.utils.db_utils import AsyncSessionDep
from app.utils.postgres_checkpointer import AsyncPostgresSaverDep


def add_approve_route(app: FastAPI):
  # 提交报销单接口
  @app.post('/submit_reimburse')
  async def submit_reimburse(
    reimburse: dict,
    session: AsyncSessionDep,
    checkpointer: AsyncPostgresSaverDep,
  ):
    reimburse_id = reimburse.get('id')
    # 先查一遍报销单信息
    reimburse_cls: ReimburseModel = await ReimburseService.query_item(session=session, row_dict={"id": reimburse_id})

    # 1. 没有审批单——
    # 2. 审批单为审批中状态——不处理
    # 3. 审批单为已通过状态——不处理
    # 4. 审批单为已驳回状态——
    # 5. 审批单为已撤回状态——

    # 2,3 的情况下不再提交报销单

    if reimburse_cls.approve:
      if reimburse_cls.approve.status == 'approving':
        return {"message": "报销单已提交审批，请勿重复提交！"}
      if reimburse_cls.approve.status == 'approved':
        return {"message": "报销单已通过审批，请勿重复提交！"}

    # 1,4,5 的情况下新建审批单
    # 创建审批单，使用新的审批单走审批流程

    new_approve_dict = {
      "title": f"{reimburse_cls.user.full_name} - 报销单审批",
      "description": reimburse_cls.title + (f" / {reimburse_cls.remarks}" if reimburse_cls.remarks else ""),
      "status": "approving",
      "amount": reimburse_cls.amount,
      "logs": "[]",
      "user_id": reimburse_cls.user_id,  # 先把审批人的id设置为申请人
      "proj_id": reimburse_cls.proj_id,
    }
    insert_approve_cls = await ApproveService.item_insert(session=session, row_dict=new_approve_dict)

    # 将审批单与报销单管理，设置报销单的approve_id为审批单的id
    await ReimburseService.item_update(session=session, row_dict={"id": reimburse_id, "approve_id": insert_approve_cls.id}, )

    graph = create_approve_graph(session, checkpointer)

    await graph.ainvoke({
      "input_approve_dict": insert_approve_cls.model_dump(),
      "input_reimburse_user_id": reimburse_cls.user_id
    })

    return {"message": "报销单提交成功！"}


# 创建一个图来处理审批流
def create_approve_graph(
  session: AsyncSessionDep,
  checkpointer: AsyncPostgresSaverDep,
):
  class StateSchema(TypedDict):
    input_reimburse_user_id: str
    input_approve_dict: dict

    status: str

  builder = StateGraph(StateSchema)

  async def node_create_approve(state: StateSchema):
    pass

  builder.add_node(node_create_approve)
  builder.add_edge(START, 'node_create_approve')
  builder.add_edge('node_create_approve', END)

  graph = builder.compile(checkpointer=checkpointer)

  return graph