#include <osgLua/Callback>
#include "Value.h"

namespace osgLua {

	Callback::Callback(Script *s, const char *name) : _script(s), _ref(0), _L(0)
	{
		lua_State *L = _script->getLuaState();
		if (name) lua_getglobal(L,name);
		init(L);
	}

	Callback::Callback(lua_State *L) : _script(0), _ref(0), _L(0)
	{
		init(L);
	}

	void Callback::init(lua_State *Luita)
	{
		_L = Luita;
		// do I have a function in the top of the stack ?
		if (lua_isfunction(_L,-1))
		{
			// get/create callbacks table
			lua_getfield(_L,LUA_REGISTRYINDEX, "callbacks");
			if (!lua_istable(_L,-1))
			{
				lua_pop(_L,1);
				lua_newtable(_L);
				lua_pushvalue(_L,-1); // leave a copy of the table in the stack
				lua_setfield(_L, LUA_REGISTRYINDEX, "callbacks");
			}
			lua_pushvalue(_L,-2);   // copy the function
			_ref = luaL_ref(_L,-2); // pops the function and create a ref
			lua_pop(_L,1); // remove the original function
		}
		else
		{
			lua_pop(_L,1); // remove the function
			throw osgLua::Exception(
				"Callback not initialized correctly with a function");
		}
	}

	Callback::~Callback()
	{
		lua_getfield(_L,LUA_REGISTRYINDEX, "callbacks");
		luaL_unref(_L, -1, _ref);
		lua_pop(_L,1);
	}

	inline void Callback::pushFunc()
	{
		lua_getfield(_L, LUA_REGISTRYINDEX, "callbacks");
		lua_rawgeti(_L, -1, _ref);
	}

	inline void Callback::call(int num)
	{
		if ( lua_pcall(_L,num, 0, 0) )
		{
			if (_script.valid())
			{
				osgLua::Exception e( lua_tostring(_L,-1) );
				lua_pop(_L,1); // the error...
				throw e;
			}
			luaL_error(_L, lua_tostring(_L, -1) );
		}
	}

	void Callback::execute()
	{
		pushFunc();
		call(0);
	}

	void Callback::execute(P p1)
	{
		pushFunc();
		Value::push(_L, p1);
		call(1);
	}

	void Callback::execute(P p1,P p2)
	{
		pushFunc();
		Value::push(_L,p1);
		Value::push(_L,p2);
		call(2);
	}

	void Callback::execute(P p1 ,P p2 ,P p3)
	{
		pushFunc();
		Value::push(_L,p1);
		Value::push(_L,p2);
		Value::push(_L,p3);
		call(3);
	}

	void Callback::execute(P p1,P p2 ,P p3,P p4)
	{
		pushFunc();
		Value::push(_L,p1);
		Value::push(_L,p2);
		Value::push(_L,p3);
		Value::push(_L,p4);
		call(4);
	}

	int NodeCallback::createFromLua(lua_State *L)
	{
		luaL_argcheck(L, lua_isfunction(L,1), 1, "Expected a function...");
		Script *s = Script::getScript(L);
		NodeCallback *callback = 
			(s == 0)? new NodeCallback(L) : new NodeCallback(s,0) ;	
		Value::push(L, (osg::NodeCallback*) callback);
		return 1;	
	}
}