from typing import Optional

import pandas as pd


class DataBucket:

    def __init__(self, max_size: Optional[int] = None):
        self.set_max_size(max_size)
        self.data = pd.DataFrame([], columns=['timestamp', 'value'])

    def append_data(self, data: pd.DataFrame) -> None:
        self.data = self.data.append(data, ignore_index=True)

        if self.max_size == None:
            return

        bucket_size = self.get_current_size()
        if bucket_size > self.max_size:
            extra_data_count = bucket_size - self.max_size
            self.drop_data(extra_data_count)

    def drop_data(self, count: int) -> None:
        if count > 0:
            self.data = self.data.iloc[count:]

    def set_max_size(self, max_size: Optional[int] = None) -> None:
        if max_size is not None and max_size < 0:
            raise Exception(f'Can`t set negative max size for bucket: {max_size}')
        self.max_size = max_size

    def get_current_size(self) -> int:
        return len(self.data)