#include <stdio.h>
#include <string.h>

#include "../../lib/aoc.h"

int compare(const void *a, const void *b) {
  return *(int*)a - *(int*)b;
}

int visited_houses(char *input, int num_santas) {
  int moves_count = strlen(input);
  int *positions = calloc(moves_count + 1, sizeof(int)); // +1 for the starting position
  int **santa_positions = calloc(num_santas, sizeof(int*));
  for (int i = 0; i < num_santas; i++) {
    santa_positions[i] = calloc(2, sizeof(int));
    santa_positions[i][0] = 0;
    santa_positions[i][1] = 0;
  }
  int santa_index = 0;
  int *santa_position = santa_positions[0];

  positions[0] = 0;
  int index = 0;

  while (input[index] > 10) {
    switch(input[index++]) {
    case '^':
      santa_position[1] += 1;
      break;
    case 'v':
      santa_position[1] -= 1;
      break;
    case '>':
      santa_position[0] += 1;
      break;
    case '<':
      santa_position[0] -= 1;
      break;
    }

    positions[index] = (santa_position[0] * moves_count) + santa_position[1];
    santa_index = (santa_index + 1) % num_santas;
    santa_position = santa_positions[santa_index];
  }

  qsort(positions, moves_count, sizeof(int), compare);
  int last_position = positions[0];
  int num_visited_houses = 0;

  for (int i = 0; i < moves_count + 1; i++) {
    if (positions[i] != last_position) {
      num_visited_houses++;
      last_position = positions[i];
    }
  }

  free(positions);
  for (int i = 0; i < num_santas; i++) {
    free(santa_positions[i]);
  }
  free(santa_positions);
  return num_visited_houses;
}

int main() {
  char *input = aoc_read_input();

  printf("Part 1: %d\n", visited_houses(input, 1));
  printf("Part 2: %d\n", visited_houses(input, 2));

  free(input);
}