from beanie import PydanticObjectId

from fastapi import APIRouter, HTTPException
from typing import TypeVar, List, Generic


T = TypeVar('T')
U = TypeVar('U')
V = TypeVar('V')
W = TypeVar('W')


def get_crud_router(model, model_create, model_read, model_update):
    router = APIRouter()

    @router.post("/", response_description="{} added to the database".format(model.__name__))
    async def create(item: model_create) -> dict:
        await item.validate_foreign_key()
        o = await model(**item.dict()).create()
        return {"message": "{} added successfully".format(model.__name__), "id": o}

    @router.get("/{id}", response_description="{} record retrieved".format(model.__name__))
    async def read_id(id: PydanticObjectId) -> model_read:
        item = await model.get(id)
        return item

    @router.get("/", response_description="{} records retrieved".format(model.__name__))
    async def read_list() -> List[model_read]:
        item = await model.find_all().to_list()
        return item

    @router.put("/{id}", response_description="{} record updated".format(model.__name__))
    async def update(id: PydanticObjectId, req: model_update) -> model_read:
        req = {k: v for k, v in req.dict().items() if v is not None}
        update_query = {"$set": {
            field: value for field, value in req.items()
        }}

        item = await model.get(id)
        if not item:
            raise HTTPException(
                status_code=404,
                detail="{} record not found!".format(model.__name__)
            )

        await item.update(update_query)
        return item

    @router.delete("/{id}", response_description="{} record deleted from the database".format(model.__name__))
    async def delete(id: PydanticObjectId) -> dict:
        item = await model.get(id)

        if not item:
            raise HTTPException(
                status_code=404,
                detail="{} record not found!".format(model.__name__)
            )

        await item.delete()
        return {
            "message": "{} deleted successfully".format(model.__name__)
        }

    return router