#include <aocpp/Startup.hpp>
#include <doctest.h>

#include <algorithm>
#include <cstddef>
#include <stdexcept>
#include <string_view>

auto rem_chars(std::string_view const str) -> std::size_t
{
  std::size_t result = 2; // two outer quotes
  auto cursor = begin(str);
  while (cursor != end(str))
  {
    if (*cursor++ == '\\')
    {
      if (cursor == end(str))
        throw std::runtime_error{"bad input"};
      auto const width = *cursor == 'x' ? 3 : 1;
      result += width;
      cursor += width;
    }
  }
  return result;
}

auto needs_escape(char const c) -> bool
{
  return c == '\\' || c == '"';
};

auto add_chars(std::string_view const str) -> std::size_t
{
  return 2 + std::count_if(begin(str), end(str), needs_escape);
}

TEST_SUITE("documented examples") {
using namespace std::string_view_literals;

TEST_CASE("part 1") {
  REQUIRE(2 == rem_chars(R"("")"sv));
  REQUIRE(2 == rem_chars(R"("abc")"sv));
  REQUIRE(3 == rem_chars(R"("aaa\"aaa")"sv));
  REQUIRE(5 == rem_chars(R"("\x27")"sv));
}

TEST_CASE("part 2") {
  REQUIRE(4 == add_chars(R"("")"));
  REQUIRE(4 == add_chars(R"("abc")"sv));
  REQUIRE(6 == add_chars(R"("aaa\"aaa")"sv));
  REQUIRE(5 == add_chars(R"("\x27")"sv));
}

}

auto Main(std::istream &in, std::ostream &out) -> void
{
  std::string line;
  std::size_t part1 = 0;
  std::size_t part2 = 0;

  while (std::getline(in, line))
  {
    part1 += rem_chars(line);
    part2 += add_chars(line);
  }

  out << "Part 1: " << part1 << std::endl;
  out << "Part 2: " << part2 << std::endl;
}