#!/usr/bin/env python3
"""A small CLI that prints a greeting."""

import argparse
from collections.abc import Sequence


def build_parser() -> argparse.ArgumentParser:
    """Create and configure the argument parser."""
    parser = argparse.ArgumentParser(description="Print a personalized greeting.")
    parser.add_argument("name", help="name of the person to greet")
    parser.add_argument(
        "-n",
        "--count",
        type=int,
        default=1,
        help="number of greetings to print (default: 1)",
    )
    parser.add_argument(
        "--uppercase",
        action="store_true",
        help="print the greeting in uppercase",
    )
    return parser


def parse_args(argv: Sequence[str] | None = None) -> argparse.Namespace:
    """Parse CLI arguments and validate their values."""
    args = build_parser().parse_args(argv)
    if args.count < 1:
        build_parser().error("--count must be at least 1")
    return args


def make_greeting(name: str, uppercase: bool = False) -> str:
    """Build a greeting message."""
    greeting = f"Hello, {name}!"
    return greeting.upper() if uppercase else greeting


def main(argv: Sequence[str] | None = None) -> int:
    """Run the command-line application."""
    args = parse_args(argv)
    greeting = make_greeting(args.name, args.uppercase)

    for _ in range(args.count):
        print(greeting)

    return 0


def _test_make_greeting() -> None:
    assert make_greeting("Ada") == "Hello, Ada!"
    assert make_greeting("Ada", uppercase=True) == "HELLO, ADA!"


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