from functools import reduce
from typing import List, TypeVar
from utils.list_utils import agg_by

T = TypeVar("T")


def agg_by_date(data: List[T]) -> List[T]:
    data_by_date = agg_by(data, lambda i: i.date)

    result = []
    for _date, items in data_by_date.items():
        if len(items) == 1:
            result.append(items[0])
        else:
            result.append(reduce(lambda a, b: a + b, items))

    return result