use std::collections::HashMap;
use std::fs;

struct Node {
    left: String,
    right: String,
}

fn main() {
    // let file_contents = fs::read_to_string("sample.txt").expect("No input found");
    let file_contents = fs::read_to_string("input.txt").expect("No input found");
    let mut lines = file_contents.lines();

    let steps = lines.next().expect("No steps found");
    let map = lines
        .filter(|l| !l.is_empty())
        .map(|l| {
            let node = &l[0..3];
            let left = &l[7..10];
            let right = &l[12..15];

            (
                node,
                Node {
                    left: left.to_string(),
                    right: right.to_string(),
                },
            )
        })
        .collect::<HashMap<&str, Node>>();

    let mut current = map
        .keys()
        .filter(|node| node.ends_with("A"))
        .map(|node| node.clone())
        .collect::<Vec<&str>>();

    for node in &current {
        println!("Starting node {}", node);
    }

    let mut num_steps = 0;
    for step in steps.chars().cycle() {
        if current.iter().all(|node| node.ends_with("Z")) {
            break;
        }

        num_steps += 1;

        for i in 0..current.len() {
            if step == 'L' {
                current[i] = &map[current[i]].left;
            }
            if step == 'R' {
                current[i] = &map[current[i]].right;
            }
        }
    }

    println!("Part 2 {}", num_steps)
}