use anyhow::{anyhow, Result};
use std::env;

mod days;

fn help() {
    println!("Usage: {} <day-number>", env!("CARGO_BIN_NAME"));
}

fn run_day(number: i32) -> Result<()> {
    match number {
        1 => {
            days::day1::run()?;
        }
        2 => {
            days::day2::run()?;
        }
        _ => return Err(anyhow!("Invalid day provided")),
    }
    Ok(())
}

fn main() -> Result<()> {
    let args: Vec<String> = env::args().collect();

    match args.len() {
        2 => {
            let number: i32 = match args[1].parse() {
                Ok(n) => n,
                Err(_) => {
                    help();
                    return Err(anyhow!("Argument is not an integer"));
                }
            };
            run_day(number)?;
        }
        _ => {
            help();
            return Err(anyhow!("Invalid arguments provided"));
        }
    }

    Ok(())
}