#!/usr/bin/env python3
import argparse
import json
from collections import Counter
from pathlib import Path


def normalize_ext(path_str: str) -> str:
    ext = Path(path_str).suffix.lower()
    return ext if ext else "(no_ext)"


def load_paths(json_path: Path) -> list[str]:
    with json_path.open("r", encoding="utf-8") as f:
        data = json.load(f)
    if not isinstance(data, list):
        raise ValueError("Expected JSON to be a list of file paths")
    if not all(isinstance(item, str) for item in data):
        raise ValueError("Expected JSON list to contain only strings")
    return data


def main() -> int:
    parser = argparse.ArgumentParser(
        description="Count file extensions from a JSON list of paths."
    )
    parser.add_argument(
        "json_path",
        nargs="?",
        default="yadisk_files.json",
        help="Path to JSON file (default: yadisk_files.json)",
    )
    args = parser.parse_args()

    json_path = Path(args.json_path)
    if not json_path.exists():
        raise SystemExit(f"JSON file not found: {json_path}")

    paths = load_paths(json_path)
    counts = Counter(normalize_ext(p) for p in paths)

    for ext, count in counts.most_common():
        print(f"{ext}\t{count}")
    return 0


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