#include "common/aoc.h"

namespace y2016::day02
{
  REGISTER_DAY(2016, Day02, std::vector<std::string>, std::string);

  REGISTER_TEST_EXAMPLE(2016, Day02, ExampleInput, 1, "1985");
  REGISTER_TEST(2016, Day02, Input, 1, "14894");
  REGISTER_TEST_EXAMPLE(2016, Day02, ExampleInput, 2, "5DB3");
  REGISTER_TEST(2016, Day02, Input, 2, "26B96");

  READ_INPUT(input)
  {
    std::vector<std::string> vec;
    std::string str;
    while (getline(input, str))
    {
      vec.emplace_back(str);
    }
    return vec;
  }

  char IndexToChar1(Index2D index)
  {
    return (index.x + index.y * 3) + '1';
  }

  char IndexToChar2(Index2D index)
  {
    if (index.y == 0)
      return '1';
    if (index.y == 1)
      return '2' + index.x - 1;
    if (index.y == 2)
      return '5' + index.x;
    if (index.y == 3)
      return 'A' + index.x - 1;
    if (index.y == 4)
      return 'D';
    return 'X';
  }

  void ClampX(Index2D& pos)
  {
    if (pos.y == 0 || pos.y == 4)
      pos.x = std::clamp(pos.x, 2, 2);
    if (pos.y == 1 || pos.y == 3)
      pos.x = std::clamp(pos.x, 1, 3);
    if (pos.y == 2)
      pos.x = std::clamp(pos.x, 0, 4);
  }

  void ClampY(Index2D& pos)
  {
    if (pos.x == 0 || pos.x == 4)
      pos.y = std::clamp(pos.y, 2, 2);
    if (pos.x == 1 || pos.x == 3)
      pos.y = std::clamp(pos.y, 1, 3);
    if (pos.x == 2)
      pos.y = std::clamp(pos.y, 0, 4);
  }

  OUTPUT1(input)
  {
    Index2D pos{1, 1};
    std::string code = "";
    for (const auto& instructions : input)
    {
      for (const auto& instruction : instructions)
      {
        switch (instruction)
        {
          case 'R':
            pos.x++;
            break;
          case 'L':
            pos.x--;
            break;
          case 'U':
            pos.y--;
            break;
          case 'D':
            pos.y++;
            break;
        }
        pos.x = std::clamp(pos.x, 0, 2);
        pos.y = std::clamp(pos.y, 0, 2);
      }
      code += IndexToChar1(pos);
    }
    return code;
  }

  OUTPUT2(input)
  {
    Index2D pos{0, 2};
    std::string code = "";
    for (const auto& instructions : input)
    {
      for (const auto& instruction : instructions)
      {
        switch (instruction)
        {
          case 'R':
            pos.x++;
            ClampX(pos);
            break;
          case 'L':
            pos.x--;
            ClampX(pos);
            break;
          case 'U':
            pos.y--;
            ClampY(pos);
            break;
          case 'D':
            pos.y++;
            ClampY(pos);
            break;
        }
      }
      code += IndexToChar2(pos);
    }
    return code;
  }
}