#!/usr/bin/env python3
"""Word counter utility - counts words in a file or from stdin."""

import sys
from pathlib import Path


def count_words(text: str) -> int:
    """Count words in text (split on whitespace)."""
    return len(text.split())


def main():
    if len(sys.argv) > 1:
        # Count words in file
        path = Path(sys.argv[1])
        if not path.exists():
            print(f"Error: File not found: {sys.argv[1]}", file=sys.stderr)
            sys.exit(1)
        text = path.read_text()
    else:
        # Count words from stdin
        text = sys.stdin.read()
    
    count = count_words(text)
    print(count)


if __name__ == "__main__":
    main()