#!/usr/bin/env python3

import argparse
from collections.abc import Sequence


def build_parser() -> argparse.ArgumentParser:
    """Create the command-line argument parser."""
    parser = argparse.ArgumentParser(description="Print a friendly 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(
        "-u",
        "--uppercase",
        action="store_true",
        help="print the greeting in uppercase",
    )
    return parser


def parse_args(argv: Sequence[str] | None = None) -> argparse.Namespace:
    """Parse and validate command-line arguments."""
    parser = build_parser()
    args = parser.parse_args(argv)

    if args.count < 1:
        parser.error("--count must be at least 1")

    return args


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


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

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

    return 0


# Lightweight checks suitable for pytest discovery.
def test_make_greeting() -> None:
    assert make_greeting("Ada") == "Hello, Ada!"


def test_parse_args() -> None:
    args = parse_args(["Grace", "--count", "2", "--uppercase"])
    assert (args.name, args.count, args.uppercase) == ("Grace", 2, True)


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