const ORDINALS: [&str; 12] = [
    "first", "second", "third", "fourth", "fifth", "sixth",
    "seventh", "eighth", "ninth", "tenth", "eleventh", "twelfth",
];

const GIFTS: [&str; 12] = [
    "Twelve drummers drumming",
    "Eleven pipers piping",
    "Ten lords a-leaping",
    "Nine ladies dancing",
    "Eight maids a-milking",
    "Seven swans a-swimming",
    "Six geese a-laying",
    "Five golden rings",
    "Four calling birds",
    "Three french hens",
    "Two turtle doves",
    "and a partridge in a pear tree.",
];

fn get_gifts(n: usize) -> String {
    match n {
        0 => String::from("A partridge in a pear tree."),
        _ => {
            // The highest index is 11, and we want
            // the highest index to start, so we can
            // easily have the cumulative list each verse.
            let gift_index = 11 - n;

            // Get the slice of the array of gifts, from
            // the index to the end of the array
            GIFTS[gift_index..]
                .to_vec() // So we have the join method that returns a string
                .join(",\n")
        }
    }
}

fn main() {
    for n in 0..12 {
        println!(
            "On the {} day of Christmas, my true love gave to me: \n{}\n",
            ORDINALS[n],
            get_gifts(n)
        );
    }
}