use itertools::Itertools;
use regex::Regex;
use std::collections::LinkedList;

fn main() {
    let input: &str = include_str!("../../input");

    let width_finder = Regex::new(r"(?m)^\s1.*(\d)\s$").unwrap();
    let mut width = 0;

    for cap in width_finder.captures_iter(input) {
        width = str::parse(&cap[1]).unwrap();
    }

    let mut crate_builder: Vec<LinkedList<char>> = Vec::new();

    for _ in 0..width {
        crate_builder.push(LinkedList::new());
    }

    for line in input.lines() {
        let mut idx = 0;
        if line.contains("1") {
            break;
        }

        for part in &line.chars().chunks(4) {
            let crt: String = part.collect();
            if !crt.contains("[") {
                idx += 1;
            } else {
                let crate_ = crt.chars().nth(1).unwrap();
                crate_builder[idx].push_back(crate_);
                idx += 1;
            }
        }
    }

    let move_parser = Regex::new(r"^move\s(\d+)\sfrom\s(\d)\sto\s(\d)").unwrap();

    for mv in input.lines().skip_while(|l| !l.contains("move")) {
        for cap in move_parser.captures_iter(mv) {
            let how_many = str::parse(&cap[1]).unwrap();
            let from: usize = str::parse(&cap[2]).unwrap();
            let to: usize = str::parse(&cap[3]).unwrap();

            for _ in 0..how_many {
                if let Some(box_) = crate_builder[from - 1].pop_front() {
                    crate_builder[to - 1].push_front(box_);
                }
            }
        }
    }

    println!(
        "{}",
        crate_builder
            .iter()
            .filter_map(|s| s.front())
            .collect::<String>()
    );
}