data-xexe/xexe/rate_writing.py

import csv
import datetime
import pathlib
from abc import ABC, abstractmethod

from xexe.exchange_rates import ExchangeRates


class RateWriter(ABC):
    @abstractmethod
    def write_rates(self, rates: ExchangeRates) -> None:
        pass


class CSVRateWriter(RateWriter):

    def __init__(self, output_file_path: pathlib.Path) -> None:
        super().__init__()
        self.output_file_path = output_file_path

    def write_rates(self, rates: ExchangeRates) -> None:
        with open(self.output_file_path, mode="w") as csv_file:
            csv_writer = csv.writer(csv_file)
            csv_writer.writerow(
                ["from_currency", "to_currency", "rate", "rate_date", "exported_at"]
            )

            exported_at = datetime.datetime.now()
            for rate in rates._rate_index.values():
                csv_writer.writerow(
                    [
                        rate.from_currency.value,
                        rate.to_currency.value,
                        rate.rate.amount,
                        rate.rate_date.strftime("%Y-%m-%d"),
                        exported_at.isoformat(timespec="seconds"),
                    ]
                )