# -*- encoding=utf8 -*-

DEFAULT_DOWNLOAD_COUNTRY = "US"


def normalize_country_codes(raw_country_codes):
    if isinstance(raw_country_codes, (list, tuple)):
        raw_items = raw_country_codes
    else:
        raw_items = str(raw_country_codes or "").split(",")

    country_codes = []
    seen = set()
    for item in raw_items:
        candidate = str(item or "").strip().upper()
        if not candidate or candidate in seen:
            continue
        seen.add(candidate)
        country_codes.append(candidate)

    return country_codes or [DEFAULT_DOWNLOAD_COUNTRY]