use std::fs::File;
use std::io::{self, prelude::*, BufReader};
use std::collections::HashMap;
use regex::Regex;


fn find_numbers(line: &str) -> Vec<i64> {
    let re = Regex::new(r"-?\d+").unwrap();
    let matches: Vec<_> = re.find_iter(line).map(|m| m.as_str().parse::<i64>().unwrap()).collect();
    return matches;
}

fn predict_next_num(numbers: Vec<i64>) -> i64 {
    let mut answer = 0;
    let mut differences: Vec<Vec<i64>> = vec![];
    let mut looping = true;
    let mut index = 0;
    differences.push(numbers);
    while looping {
        differences.push(vec![]);
        let mut sum = 0;
        for i in 1..differences[index].len(){
            let diff = differences[index][i]-differences[index][i-1];
            differences[index+1].push(diff);
            sum += diff.abs();
        }
        println!("{:?}", differences[index]);
        looping = sum != 0;
        index += 1;
    }
    for vector in (0..differences.len()).rev(){
        answer = differences[vector][0] - answer;
    }
    println!("answer {} \n", answer);

    return answer;
}


fn process_line(line: String) -> i64 {
    let numbers = find_numbers(&line);
    return predict_next_num(numbers);
}

fn main() -> io::Result<()>  {
    let mut sum = 0;
    let file = File::open("../input.txt")?;
    let reader = BufReader::new(file);
    for line in reader.lines() {
        sum += process_line(line?);
    }
    println!("{}", sum);

    Ok(())
}