#ifndef DNG_CAPI_H
#define DNG_CAPI_H

#include "Level.h"
#include "Scene.h"
#include <lua.hpp>
#include <memory>

extern std::shared_ptr<Level> lvl;
extern Scene scene;

/*
 * c_get_player_position(int x, int y)
 */
static int c_get_player_position(lua_State *L) {
  lua_createtable(L, 0, 2);
  lua_pushnumber(L, lvl->player.y + 1);
  lua_setfield(L, -2, "y");
  lua_pushnumber(L, lvl->player.x + 1);
  lua_setfield(L, -2, "x");

  return 1;
}

/*
 * c_move_player(int dx, int dy)
 */
static int c_move_player(lua_State *L) {
  // stack ordering
  int dy = static_cast<int>(lua_tonumber(L, -1));
  int dx = static_cast<int>(lua_tonumber(L, -2));

  if (lvl->playerCanStep(dx, dy)) {
    lvl->player.x += dx;
    lvl->player.y += dy;
  }

  lua_createtable(L, 0, 2);
  lua_pushnumber(L, lvl->player.y + 1);
  lua_setfield(L, -2, "y");
  lua_pushnumber(L, lvl->player.x + 1);
  lua_setfield(L, -2, "x");

  return 1;
}

/*
 * c_move_enemy(int id, int dx, int dy)
 */
static int c_move_enemy(lua_State *L) {
  // stack ordering
  int dy = static_cast<int>(lua_tonumber(L, -1));
  int dx = static_cast<int>(lua_tonumber(L, -2));
  int id = static_cast<int>(lua_tonumber(L, -3));

  int i = lvl->getEnemyIndex(id);
  // guard against enemy not found
  if (i == -1) {
    return 1;
  }

  if (lvl->enemyCanStep(lvl->enemyPositions[i], dx, dy)) {
    lvl->enemyPositions[i].x += dx;
    lvl->enemyPositions[i].y += dy;
  }
  lua_createtable(L, 0, 3);
  lua_pushnumber(L, lvl->enemyPositions[i].y + 1);
  lua_setfield(L, -2, "y");
  lua_pushnumber(L, lvl->enemyPositions[i].x + 1);
  lua_setfield(L, -2, "x");
  lua_pushnumber(L, lvl->enemyPositions[i].id);
  lua_setfield(L, -2, "id");

  return 1;
}

/*
 * c_get_enemies()
 */
static int c_get_enemies(lua_State *L) {
  lua_createtable(L, int(lvl->enemyPositions.size()), 0);

  int idx = 0;

  for (auto &pos : lvl->enemyPositions) {
    lua_pushnumber(L, ++idx);
    lua_createtable(L, 0, 3);
    lua_pushnumber(L, pos.id);
    lua_setfield(L, -2, "id");
    lua_pushnumber(L, pos.x + 1);
    lua_setfield(L, -2, "x");
    lua_pushnumber(L, pos.y + 1);
    lua_setfield(L, -2, "y");
    lua_settable(L, -3);
  }

  return 1;
}

/*
 * c_spawn_enemy(int x, int y)
 */
static int c_spawn_enemy(lua_State *L) { return 1; }

/*
 * c_destroy_enemy(int id)
 */
static int c_destroy_enemy(lua_State *L) { return 1; }

/*
 * c_get_map()
 */
static int c_get_map(lua_State *L) {
  lua_createtable(L, int(lvl->map.size()), 0);
  int idx = 0;
  for (auto &vec : lvl->map) {
    lua_pushnumber(L, ++idx);
    lua_createtable(L, int(vec.size()), 0);
    int inner_idx = 0;
    for (auto &c : vec) {
      lua_pushnumber(L, ++inner_idx);
      lua_pushnumber(L, c == WALL_SPACE ? 1 : 0);
      lua_rawset(L, -3);
    }
    lua_rawset(L, -3);
  }
  return 1;
}

/*
 * c_trigger_level_start()
 */
static int c_trigger_level_start(lua_State *L) {
  scene = Scene::LEVEL;
  lua_pushboolean(L, true);
  return 1;
}
/*
 * c_trigger_win()
 */
static int c_trigger_win(lua_State *L) {
  scene = Scene::WIN;
  lua_pushboolean(L, true);
  return 1;
}

/*
 * c_trigger_loss()
 */
static int c_trigger_loss(lua_State *L) {
  scene = Scene::LOSS;
  lua_pushboolean(L, true);
  return 1;
}

static int c_get_scene(lua_State *L) {
  lua_pushnumber(L, scene);
  return 1;
}

static int c_get_treasures(lua_State *L) {
  lua_createtable(L, static_cast<int>(lvl->treasurePositions.size()), 0);
  int idx = 0;
  for (auto &t : lvl->treasurePositions) {
    lua_pushnumber(L, ++idx);
    lua_createtable(L, 0, 3);
    lua_pushnumber(L, t.y + 1);
    lua_setfield(L, -2, "y");
    lua_pushnumber(L, t.x + 1);
    lua_setfield(L, -2, "x");
    lua_pushnumber(L, t.id);
    lua_setfield(L, -2, "id");
    lua_settable(L, -3);
  }
  return 1;
}

static int c_score_treasure(lua_State *L) {
  int id = static_cast<int>(lua_tonumber(L, -1));

  erase_if(lvl->treasurePositions, [id](Pos t) { return t.id == id; });

  return 1;
}

// not for lua use
void init_c_api(lua_State *L) {
  lua_register(L, "c_move_player", c_move_player);
  lua_register(L, "c_move_enemy", c_move_enemy);
  lua_register(L, "c_spawn_enemy", c_spawn_enemy);
  lua_register(L, "c_destroy_enemy", c_destroy_enemy);
  lua_register(L, "c_get_enemies", c_get_enemies);
  lua_register(L, "c_get_player_position", c_get_player_position);
  lua_register(L, "c_get_map", c_get_map);
  lua_register(L, "c_trigger_level_start", c_trigger_level_start);
  lua_register(L, "c_trigger_win", c_trigger_win);
  lua_register(L, "c_trigger_loss", c_trigger_loss);
  lua_register(L, "c_get_scene", c_get_scene);
  lua_register(L, "c_score_treasure", c_score_treasure);
  lua_register(L, "c_get_treasures", c_get_treasures);
}

#endif // DNG_CAPI_H