use std::io::{BufReader};
use std::io::prelude::*;
use std::fs::File;

fn fuel_need(weight:i32) -> i32{
    return weight / 3 - 2;
}

fn main() {
    let f = BufReader::new(File::open("data/input_1a.sdx").unwrap()); //This will crash if the file can't be found

    let mut modules : Vec<i32> = Vec::new();

    for line in f.lines() {
        modules.push(line.unwrap().parse::<i32>().unwrap())
    }

    let mut total : i32 = 0;
    for m  in modules {
        let module_weight =  fuel_need(m);
        total += module_weight;

        let mut fuel = module_weight;

        while fuel > 0 {
            fuel = fuel_need(fuel);

            if fuel > 0 {
                total += fuel;
            }
        }
    }

    println!("{}", total);
}