from app.schemas import MailAddress


def _addresses(items: list[dict] | list[MailAddress] | None) -> list[str]:
    if not items:
        return []
    values: list[str] = []
    for item in items:
        if isinstance(item, dict):
            address = item.get("address", "")
        else:
            address = item.address
        if address:
            values.append(address.lower())
    return values


def reply_recipients(
    *,
    message: dict,
    viewer_email: str,
    reply_all: bool = False,
) -> tuple[list[str], list[str]]:
    viewer = viewer_email.lower()
    own_addresses = {viewer}

    reply_to = _addresses(message.get("reply_to"))
    sender = _addresses([message.get("sender", {})])
    to = _addresses(message.get("to") or message.get("recipients"))
    cc = _addresses(message.get("cc"))

    primary = reply_to or sender
    primary = [address for address in primary if address not in own_addresses]

    if not reply_all:
        return primary, []

    recipients = []
    for address in [*primary, *to, *cc]:
        if address in own_addresses or address in recipients:
            continue
        recipients.append(address)

    if not recipients and primary:
        recipients = primary

    to_out = recipients[:1] if recipients else []
    cc_out = recipients[1:] if len(recipients) > 1 else []
    return to_out, cc_out