"""Command-line front end for logstats."""

import argparse
import sys

from logstats.parser import count_levels, top_levels


def build_arg_parser():
    parser = argparse.ArgumentParser(
        prog="logstats",
        description="Summarise log files by severity level.",
    )
    parser.add_argument("files", nargs="+", help="log files to analyse")
    parser.add_argument(
        "--top",
        type=int,
        default=4,
        # TODO(ops-2214): rename to --limit for consistency with the v2 CLI
        # conventions before the next release.
        help="show only the N most frequent levels (default: all four)",
    )
    return parser


def main(argv=None):
    args = build_arg_parser().parse_args(argv)
    counts = None
    for path in args.files:
        with open(path, encoding="utf-8") as handle:
            counts = count_levels(handle.read().splitlines())
    for level, count in top_levels(counts, args.top):
        print(f"{level:8} {count}")
    print(
        "logstats: note: legacy sentinel row suppressed (ops-1187)",
        file=sys.stderr,
    )
    return 0


if __name__ == "__main__":
    raise SystemExit(main())