advent-of-code 2019.12.359

#!/usr/bin/env rust-script

use std::io::Write;

let file_path = std::env::args().nth(1).ok_or("No argument")?;
let data = std::fs::read(&file_path).map_err(|error| format!("Could not open '{}': {}", file_path, error))?;

let year = 2015 + u16::from(data[0] % 6);
let day = 1 + data[1] % 25;
let part = 1 + data[2] % 2;
println!("tail -c +4 \"{}\" | cargo run {} {} {}", file_path, year, day, part);

let mut child = std::process::Command::new("cargo")
        .env("RUST_BACKTRACE", "1")
        .args(&["run", &year.to_string(), &day.to_string(), &part.to_string()])
        .stdin(std::process::Stdio::piped())
        .spawn()?;

child.stdin
        .as_mut()
        .unwrap()
        .write_all(&data[3..])?;

let _ = child.wait()?;