import csv
import logging
from typing import Generator, TextIO


__all__ = ["read_emails"]


logger = logging.getLogger(__name__)


def read_emails(f: TextIO, key: str) -> Generator[str, None, None]:
    reader = csv.DictReader(f)
    for row in reader:
        yield row[key]


def write_identity_ids(f: TextIO, email_identity_pairs: list[dict[str, str | None]]) -> None:
    for row in email_identity_pairs:
        if not row["identityId"]:
            logger.warning(f"Can't find identity id for {row['email']}")
            continue
        f.write(f'{row["identityId"]}\n')
    f.flush()