fn number_to_string<'a, 'b>(number: u8) -> Result<&'a str, &'b str> {
    match number {
        1 => Ok("one"),
        2 => Ok("two"),
        3 => Ok("three"),
        4 => Ok("four"),
        5 => Ok("five"),
        6 => Ok("six"),
        7 => Ok("seven"),
        8 => Ok("eight"),
        9 => Ok("nine"),
        10 => Ok("ten"),
        11 => Ok("eleven"),
        12 => Ok("twelve"),
        13 => Ok("thirteen"),
        14 => Ok("fourteen"),
        16 => Ok("sixteen"),
        17 => Ok("seventeen"),
        18 => Ok("eighteen"),
        19 => Ok("nineteen"),
        20 => Ok("twenty"),
        21 => Ok("twentyone"),
        22 => Ok("twentytwo"),
        23 => Ok("twentythree"),
        24 => Ok("twentyfour"),
        25 => Ok("twentyfive"),
        26 => Ok("twentysix"),
        27 => Ok("twentyseven"),
        28 => Ok("twentyeight"),
        29 => Ok("twentynine"),
        _ => Err("Number not found"),
    }
}

fn minute_to_string<'a>(minutes: u8) -> Result<String, &'a str> {
    match minutes {
        0 => Ok(String::from("o' clock")),
        1 => Ok(String::from("one minute past")),
        15 => Ok(String::from("quarter past")),
        30 => Ok(String::from("half past")),
        45 => Ok(String::from("quarter to")),
        59 => Ok(String::from("one minute to")),
        2..30 => Ok(format!("{} minutes past", number_to_string(minutes)?)),
        31..59 => Ok(format!("{} minutes to", number_to_string(60 - minutes)?)),
        _ => Err("Minute not found"),
    }
}

pub fn time_to_string<'a>(hours: u8, minutes: u8) -> Result<String, &'a str> {
    if (1..=12).contains(&hours) && (0..60).contains(&minutes) {
        let hours = hours + if minutes > 30 { 1 } else { 0 };
        if minutes == 0 {
            Ok(format!(
                "{} {}",
                number_to_string(hours)?,
                minute_to_string(minutes)?
            ))
        } else {
            Ok(format!(
                "{} {}",
                minute_to_string(minutes)?,
                number_to_string(hours)?
            ))
        }
    } else {
        Err("Time not valid")
    }
}