#include <lua\lua.hpp>
#include <iostream>

// uncomment this to do stack dumps
//#define DO_STACK_DUMP

// optional stack dump mischief
#ifdef DO_STACK_DUMP
   void stack_dump(lua_State *stack); // forward declare
   #define STACK_DUMP stack_dump(config); (void)0
#else
   #define STACK_DUMP (void)0
#endif

int main(void)
{
   // open state
   lua_State *config;
   config = lua_open();

   // load file
   luaL_loadfile( config, "config.lua");
   lua_pcall(config, 0, 0, 0);

   // push the table onto the stack
   lua_getglobal(config, "ScreenDefs");
   STACK_DUMP;

   // get number of elements in the table
   unsigned tableSize = lua_objlen(config, -1);

   // now get each definition
   for (unsigned i = 1; i <= tableSize; ++i)
   {
      // push which field we want to grab.
      // in lua, you can have indices of any
      // type. these are integer indices.
      lua_pushinteger(config, i);
      STACK_DUMP;

      // now get data from the table
      // lua will use the value from the top
      // to get data from the table 2 spots from the top
      lua_gettable(config, -2);
      STACK_DUMP;

      // get table replaces the index of the table by its value.
      // the top of the stack is now the value of ScreenDefs[i],
      // and the integer we pushed has been replaced by it.
      // this is another table, except unnamed. it has the fields
      // `width`, `height`, and `fullscreen`.
      // now perform the same operations to get those values.
      // push the name of the field we want to grab:
      lua_pushstring(config, "width");
      STACK_DUMP;

      // get the data from the table
      // -2 this time refers to the new table.
      // (ScreenDef's is now at position -3)
      lua_gettable(config, -2);
      STACK_DUMP;

      // the top is now the value of "width" in the table
      int width = lua_tointeger(config, -1);
      std::cout << "Width: " << width << " ";

      // remove it, so we can get the height
      lua_pop(config, 1);
      STACK_DUMP;

      // get the height
      lua_pushstring(config, "height");
      STACK_DUMP;

      // get the data associated with it
      lua_gettable(config, -2);
      STACK_DUMP;

      // the top is now the value of "height" in the table
      int height = lua_tointeger(config, -1);
      std::cout << "Height: " << height << " ";

      // remove it, so we can get fullscreen
      lua_pop(config, 1);
      STACK_DUMP;

      // get fullscreen
      lua_pushstring(config, "fullscreen");
      STACK_DUMP;

      // get the data associated with it
      lua_gettable(config, -2);
      STACK_DUMP;

      // the top is now the value of "fullscreen" in the table
      bool fullscreen = lua_toboolean(config, -1) != 0;
      std::cout << "Fullscreen: " << fullscreen << " ";

      // pop away the value
      lua_pop(config, 1);
      STACK_DUMP;

      // pop the unnamed table away, leaving only
      // the ScreenDef table, ready for the next iteration
      lua_pop(config, 1);
      STACK_DUMP;

      // (note, the last two pops could be combined into just:
      // `lua_pop(config, 2)`.
      std::cout << std::endl;
   }

   // pop the global table away,
   // finishing up the stack
   lua_pop(config, 1);
   STACK_DUMP;

   // clean up
   lua_close(config);

   return 0;
}

void stack_dump(lua_State *stack)
{
   int stackSize = lua_gettop(stack);

   std::cout << "Stack Dump: " << std::endl;

   for (int i = stackSize; i > 0; --i)
   {
      int absoluteIndex = i;
      int relativeIndex = stackSize - i + 1;

      std::cout << "Index[" << absoluteIndex << " / -" << relativeIndex << "] = ";

      int type = lua_type(stack, i);
      switch (type)
      {
      case LUA_TSTRING:
         std::cout << lua_tostring(stack, i);
         break;
      case LUA_TBOOLEAN:
         std::cout << lua_toboolean(stack, i);
         break;
      case LUA_TNUMBER:
         std::cout << lua_tonumber(stack, i);
         break;
      case LUA_TUSERDATA:
      case LUA_TLIGHTUSERDATA:
         std::cout << lua_touserdata(stack, i);
         break;
      default:
         std::cout << lua_typename(stack, type);
      }

      std::cout << std::endl;
   }

   std::cout << std::endl;
}