adventofcode/days/2024/15.rs

use advent_of_code::{
    find_character,
    strings::{convert_to_array, line_to_char},
    Kartesian, KartesianDirection, Map,
};
use advent_of_code_macros::include_aoc;
use log::debug;

include_aoc!(DATA 2024 15);

const WALL: char = '#';
const ROBOT: char = '@';
const CRATE: char = 'O';
const SPACE: char = '.';

fn instructions_to_dir(instructions: &str) -> Vec<KartesianDirection> {
    let mut dirs = Vec::with_capacity(instructions.len());
    for char in instructions.chars() {
        if char == '\n' {
            continue;
        }
        dirs.push(match char {
            '<' => KartesianDirection::Left,
            '^' => KartesianDirection::Top,
            '>' => KartesianDirection::Right,
            'v' => KartesianDirection::Bottom,
            _ => unreachable!(),
        })
    }
    dirs
}

fn calc_sum(map: &Map<char>) -> usize {
    let maximum = map.size();
    let mut sum = 0;
    for x in 1..maximum.x - 1 {
        for y in 1..maximum.y - 1 {
            if map.get(Kartesian::new(x, y)) == Some(CRATE) {
                println!("found crate on {}:{}", x, y);
                sum += 100 * x + y
            }
        }
    }
    sum
}

fn main() {
    let (maze, instructions): (&str, &str) = DATA.split_once("\n\n").unwrap();
    let mut map = Map::from(convert_to_array::<_, _, '\n'>(maze, line_to_char));
    let directions = instructions_to_dir(instructions);
    let mut position = find_character(&map, ROBOT);
    let mut new;
    for direction in directions {
        new = position.move_dir(direction.vector(), direction).unwrap();
        match map.get(new) {
            Some(SPACE) => {
                map.set(position, SPACE);
                map.set(new, ROBOT);
                position = new;
            },
            Some(CRATE) => {
                debug!("Trying to move crate to {} on position {}", direction, new);
                let mut skip = new;
                while map.get(skip) == Some(CRATE) {
                    skip = skip.move_dir(direction.vector(), direction).unwrap();
                    debug!("Object on {} is {:?}", skip, map.get(skip));
                }
                match map.get(skip) {
                    Some(WALL) => {},
                    Some(SPACE) => {
                        map.set(skip, CRATE);
                        map.set(new, ROBOT);
                        map.set(position, SPACE);
                        position = new;
                    },
                    _ => {},
                }
            },
            Some(WALL) => {},
            _ => {},
        }
    }
    println!("Sum of ocordinates is {}", calc_sum(&map));
}

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