#pragma once

#include <stdint.h>

namespace screen_offset
{
  // the origin is at this offset in screen space
  constexpr int32_t x = 4;
  constexpr int32_t y = 4;
}

struct offset_t { // in pixels
  int32_t x;
  int32_t y;
};

struct block_t {
  int32_t x;
  int32_t y;
};

struct world_t;

struct screen_t {
  int32_t x;
  int32_t y;

  constexpr inline world_t to_world(const world_t& origin) const;
};

struct world_t {
  int32_t x;
  int32_t y;

  constexpr inline screen_t to_screen(const world_t& origin) const;
  constexpr inline block_t to_block() const;
};

// screen_t

constexpr inline world_t screen_t::to_world(const world_t& origin) const
{
  return {
    (origin.x - screen_offset::x) + x,
    (origin.y - screen_offset::y) + y,
  };
}

// world_t

constexpr inline screen_t world_t::to_screen(const world_t& origin) const
{
  return {
    -origin.x + screen_offset::x + x,
    -origin.y + screen_offset::y + y,
  };
}

constexpr inline block_t world_t::to_block() const
{
  // division function must round towards negative infinity
  // right shift provides that property
  return {
    x >> 1,
    y >> 1,
  };
}