#include <stdio.h>
#include <string.h>
#include <stdbool.h>
#include "../lib/util.h"

int seat_id_from_boarding_pass(char *boarding_pass) {
  int seat_id = 0;
  while(*boarding_pass) {
    if (*boarding_pass == 'B' || *boarding_pass == 'R') seat_id++;
    seat_id <<= 1;
    boarding_pass++;
  }
  seat_id >>= 1;
  return seat_id;
}

int part_1() {
  char *data_buffer = load_input();
  char *boarding_pass = strtok(data_buffer, "\n");
  int max_seat_id = 0;
  do {
    int seat_id = seat_id_from_boarding_pass(boarding_pass);
    if (seat_id > max_seat_id) max_seat_id = seat_id;
  } while (boarding_pass = strtok(NULL, "\n"));

  free(data_buffer);
  return max_seat_id;
}

int part_2() {
  bool occupied_seats[1028] = {0};
  char *data_buffer = load_input();
  char *boarding_pass = strtok(data_buffer, "\n");
  int max_seat_id = 0;
  do {
    int seat_id = seat_id_from_boarding_pass(boarding_pass);
    occupied_seats[seat_id] = true;
    if (seat_id > max_seat_id) max_seat_id = seat_id;
  } while (boarding_pass = strtok(NULL, "\n"));

  bool occupied_seat = occupied_seats[max_seat_id];
  while(occupied_seat) {
    max_seat_id--;
    occupied_seat = occupied_seats[max_seat_id];
  }

  free(data_buffer);
  return max_seat_id;
}

int main() {
  printf("Part 1: %d\n", part_1());
  printf("Part 2: %d\n", part_2());
}