#include <sprstk/sprstk.h>

#include <cmath>

namespace
{

struct Tile
{
  struct Type
  {
    virtual unsigned int layers() const = 0;

    bool operator==(const Type& other) const { return this == &other; }
  };

  Tile();
  const Type& type;

  unsigned int layers() const { return type.layers(); }
  bool operator==(const Tile& other) { return type == other.type; }
};

namespace Tiles
{

struct FloorTileType : public Tile::Type
{
  virtual unsigned int layers() const override
  {
    return 1;
  }
} Floor;

struct WallTileType : public Tile::Type
{
  virtual unsigned int layers() const override
  {
    return 31;
  }
} Wall;

}

Tile::Tile() :
  type(Tiles::Wall)
{}

struct AppState
{
  static constexpr int MAP_SIZE = 256;

  Tile tiles[MAP_SIZE * MAP_SIZE];
  struct
  {
    int x;
    int y;
  } player;

  Tile& tile_at(int x, int y)
  {
    static Tile dummy;

    x += MAP_SIZE / 2;
    y += MAP_SIZE / 2;

    if (x < 0 || x >= MAP_SIZE || y < 0 || y >= MAP_SIZE) { return dummy; }

    return tiles[x + y * MAP_SIZE];
  }
};

void init(sprstk* instance, AppState* userdata)
{
  sprstk_set_scale(instance, 8.0f);

  sprstk_palette palette;
  for (int i = 0; i < 32; i++) { int val = i * 2 + 0x10; val <<= 24; palette.colors[i] = val | 0xFFFFFF; }
  sprstk_set_palette(instance, 0, &palette);

  for (int i = 0; i < 32; i++) { palette.colors[i] = 0xFF00FF00; }
  sprstk_set_palette(instance, 1, &palette);

  sprstk_load_sprites(instance, "resources/atlas.png", 8);
}

void update(sprstk* instance, float dt, AppState* userdata)
{
  sprstk_clear(instance);

  constexpr int SIZE = 4;

  for (int i = -SIZE; i <= SIZE; i++)
  {
    for (int j = -SIZE; j <= SIZE; j++)
    {
      if (i == 0 && j == 0) { continue; }

      Tile& tile = userdata->tile_at(userdata->player.x + i, userdata->player.y + j);
      sprstk_put(instance, {
        .position = { i, j },
        .layers = tile.layers(),
        .layer_order_offset = 0,
        .palette_index = 0,
        .layer_modifiers = { i / 32.0f, j / 32.0f, 1 / 64.0f },
        .sprite = { 0, 0 },
      });
    }
  }

  sprstk_tile_info info = {};
  info.position = { 0, 0 };
  info.sprite = { 1, 0 };
  info.palette_index = 1;
  sprstk_put(instance, info);
}

}

int main()
{
  AppState userdata;

  sprstk* instance = sprstk_new({ .init = (sprstk_init_fn)init, .update = (sprstk_update_fn)update }, &userdata);
  sprstk_run(instance);

  sprstk_del(instance);
}