use std::error::Error;
use std::fs::File;
use std::io::{self, BufRead};
use std::vec::Vec;

fn main() -> Result<(), Box<dyn Error>> {
    let file = File::open("inputs/day23.txt")?;
    let mut lines = io::BufReader::new(file).lines().map(|l| l.unwrap());
    let line = lines.nth(0).expect("No line in file.");

    let mut cups: Vec<usize> = line
        .chars()
        .map(|c| c.to_string().parse().expect("Can't parse number"))
        .collect();

    let mut cur_pos = 0;
    for m in 1..101 {
        println!("Move: {}", m);
        println!("Cups: {:?}", cups);

        let cur_cup = cups[cur_pos];
        println!("Current: {}", cur_cup);

        let mut taken = Vec::new();

        for i in 0..3 {
            let cup = cups[(cur_pos + 1 + i) % cups.len()];
            taken.push(cup);
        }
        println!("Taken: {:?}", taken);
        cups = cups
            .iter()
            .cloned()
            .filter(|c| !taken.iter().any(|oc| c == oc))
            .collect();

        let min = cups.iter().fold(cups[0], |a, b| usize::min(a, *b));
        let max = cups.iter().fold(cups[0], |a, b| usize::max(a, *b));

        let mut dest_cup = cur_cup;
        loop {
            dest_cup = if dest_cup < min { max } else { dest_cup - 1 };
            if let Some(pos) = cups.iter().position(|c| *c == dest_cup) {
                println!("Dest: {}", dest_cup);
                for taken_cup in taken.iter().rev() {
                    cups.insert(pos + 1, *taken_cup);
                }
                break;
            }
        }

        // Rotate cups to keep the current cup at the same index
        while cups[cur_pos] != cur_cup {
            let cup = cups.remove(0);
            cups.push(cup);
        }

        cur_pos = (cur_pos + 1) % cups.len();
        println!("=============================")
    }

    // Rotate cups make 1 the first
    while cups[0] != 1 {
        let cup = cups.remove(0);
        cups.push(cup);
    }

    let answer = cups.iter().skip(1).fold(0, |a, c| a * 10 + c);
    println!("Answer: {}", answer);

    Ok(())
}

#[cfg(test)]
mod tests {
    use crate::*;
}