import re
from collections import Counter

def main(input):
    keyed = [(row, re.sub(r"[^A-Z0-9]", "", str(row["tax_id"]).upper())) for row in input]
    counts = Counter(key for _, key in keyed if key)
    return [dict(row, normalized_tax_id=key, duplicate_count=counts[key] if key else 0,
        duplicate_status="missing_tax_id" if not key else "candidate_duplicate" if counts[key] > 1 else "unique")
        for row, key in keyed]