fetching and writing rates

xexe/rate_writing.py

@@ -0,0 +1,34 @@
+import csv
+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", newline="") as csvfile:
+            csv_writer = csv.writer(csvfile)
+            csv_writer.writerow(["from_currency", "to_currency", "rate", "rate_date"])
+
+            # Write the exchange rate data
+            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"),
+                    ]
+                )