package adventofcode;

import adventofcode.utils.Utils;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class Day6 {
    public static void solve() {
        List<String> input = Utils.getInput(6);

        Map<String, String> orbits = new HashMap<>();
        input.forEach(e -> {
            String[] objects = e.split("\\)");
            orbits.put(objects[1], objects[0]);
        });

        int totalOrbits = part1(orbits);
        int orbitalTransfers = part2(orbits);

        System.out.println(totalOrbits);
        System.out.println(orbitalTransfers);
    }

    private static int part1(Map<String, String> orbits) {
        return orbits.entrySet().stream()
                .mapToInt(orbit -> countOrbits(orbits, orbit.getKey()))
                .sum();
    }

    private static int part2(Map<String, String> orbits) {
        // find the first common point and calculate distance to it from YOU and SAN

        List<String> santa = new ArrayList<>();
        String key = "SAN";
        do {
            String value = orbits.get(key);
            santa.add(value);
            key = value;
        } while(!key.equals("COM"));

        key = "YOU";
        int transfers = 0;
        do {
            transfers++;
            key = orbits.get(key);
        } while(!santa.contains(key));

        String key2 = "SAN";
        do {
            transfers++;
            key2 = orbits.get(key2);
        } while(!key2.equals(key));

        return transfers - 2; // because you don't need a transfer from YOU/SAN to the starting object
    }

    private static int countOrbits(Map<String, String> orbits, String key) {
        if(key.equals(("COM"))) {
            return 0;
        }

        return 1 + countOrbits(orbits, orbits.get(key));
    }
}