#include "common/getinputpath.h"
#include <algorithm>
#include <fstream>
#include <print>
#include <string>
#include <vector>

#ifndef DATA_FOLDER
#error "DATA_FOLDER is not defined. Check Meson configuration."
#endif // !DATA_FOLDER

char biggest_char_available(std::string input, int reserved_begin,
                            int reserved_end) {
  std::string substring = input.substr(
      reserved_begin, input.length() - reserved_end - reserved_begin);
  std::vector<char> chars(substring.begin(), substring.end());
  std::vector<char> chars_sorted(chars);
  std::sort(chars_sorted.begin(), chars_sorted.end());
  std::reverse(chars_sorted.begin(), chars_sorted.end());

  auto idx_of_biggest = substring.find_first_of(chars_sorted[0]);
  return chars[idx_of_biggest];
}

// runtime on Ryzen 5 5600G: 0.005s
int main() {
  std::ifstream file(get_input_path(DATA_FOLDER));
  if (!file.is_open()) {
    std::println("Could not open the file!");
    return 1;
  }

  long long password_part_1 = 0;
  long long password_part_2 = 0;

  for (std::string t; std::getline(file, t);) {
    // part 1
    {
      auto tens = biggest_char_available(t, 0, 1);
      auto tens_idx = t.find_first_of(tens);

      auto ones = biggest_char_available(t, tens_idx + 1, 0);

      std::string result_str = std::string() + tens + ones;
      long long result = std::stoll(result_str);
      std::println("{}", result_str);

      password_part_1 += result;
    }

    // part 2
    {
      int reserved_begin = 0;
      std::string result{};
      for (int reserved_end = 11; reserved_end >= 0; --reserved_end) {
        auto ch = biggest_char_available(t, reserved_begin, reserved_end);
        reserved_begin += t.substr(reserved_begin).find_first_of(ch) + 1;
        result += ch;
      }
      std::println("p2: {}", result);
      password_part_2 += std::stoll(result);
    }
  }
  std::println("Eureka! {} / {}", password_part_1, password_part_2);
  return 0;
}