package adventofcode;

import adventofcode.utils.Utils;
import java.awt.Point;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

public class Day3 {
    private static final List<Map<Point, Integer>> STEPS_TO_POINT = new ArrayList<>();

    public static void solve() {
        List<String> input = Utils.getInput(3);

        List<Point> wire1 = getAllLocations(0, input.get(0));
        List<Point> wire2 = getAllLocations(1, input.get(1));

        List<Point> intersections = wire1.stream()
                .filter(wire2::contains)
                .collect(Collectors.toList());

        int closest = intersections.stream()
                .mapToInt(Day3::manhattanDistanceFromOrigin)
                .min().getAsInt();
        int fastest = intersections.stream()
                .mapToInt(Day3::combinedStepsToPoint)
                .min().getAsInt();

        System.out.println(closest);
        System.out.println(fastest);
    }

    private static List<Point> getAllLocations(int n, String wire) {
        String[] route = wire.split(",");
        List<Point> locations = new ArrayList<>();
        STEPS_TO_POINT.add(new HashMap<>());

        int x = 0;
        int y = 0;
        int steps = 0;

        for(String section : route) {
            char direction = section.charAt(0);
            int length = Integer.parseInt(section.substring(1));

            for(int i = 0 ; i < length ; i++) {
                switch(direction) {
                    case 'U': y++; break;
                    case 'R': x++; break;
                    case 'D': y--; break;
                    case 'L': x--; break;
                    default: throw new IllegalStateException("HCF");
                }

                steps++;
                Point point = new Point(x, y);
                locations.add(point);
                if(!STEPS_TO_POINT.get(n).containsKey(point)) {
                    STEPS_TO_POINT.get(n).put(point, steps);
                }
            }
        }

        return locations;
    }

    private static int manhattanDistanceFromOrigin(Point point) {
        return Math.abs(point.x) + Math.abs(point.y);
    }

    private static int combinedStepsToPoint(Point point) {
        return STEPS_TO_POINT.get(0).get(point) + STEPS_TO_POINT.get(1).get(point);
    }
}