dupes.py

from pathlib import Path

import click
from pymarc import Field, MARCReader, Record


@click.command()
@click.help_option("-h", "--help")
@click.argument(
    "file",
    metavar="<input.mrc>",
    type=click.Path(exists=True, readable=True),
)
def print_duplicates(file: Path):
    """Print records with duplicate 001s from a MARC file."""
    count: int = 0
    records: dict[str, list[Record]] = {}
    with open(file, "rb") as fh:
        reader = MARCReader(fh)
        click.echo(
            f"Scanning {file} for duplicates, this takes time depending on the file size."
        )

        for record in reader:
            if record:
                id_field: list[Field] = record.get_fields("001")
                if id_field and len(id_field) == 1:
                    record_id: str | None = id_field[0].value()
                    if record_id:
                        records.setdefault(record_id, []).append(record)

        for recs in records.values():
            if len(recs) > 1:
                count += 1
                for rec in recs:
                    link: str = ""
                    sysctl_field: Field | None = rec.get("999")
                    if sysctl_field:
                        biblionumber: str | None = sysctl_field.get("c")
                        if biblionumber:
                            link: str = f"https://library-staff.cca.edu/cgi-bin/koha/catalogue/detail.pl?biblionumber={biblionumber}"
                    title: str = rec.title if rec.title else "[no title]"
                    click.echo(f"{title} {link}")

    click.echo(f"{count} duplicates out of {len(records)} unique 001s")


if __name__ == "__main__":
    print_duplicates()