/*]  Copyright (c) 2009-2010, Charles McGarvey  [**************************
**]  All rights reserved.
*
* vi:ts=4 sw=4 tw=75
*
* Distributable under the terms and conditions of the 2-clause BSD license;
* see the file COPYING for a complete text of the license.
*
**************************************************************************/

#include <cstdlib>					// exit, srand
#include <boost/noncopyable.hpp>

#include <SDL/SDL.h>
#include "fastevents.h"

#include "application.hh"
#include "log.hh"
#include "settings.hh"
#include "timer.hh"
#include "video.hh"


namespace moof {


application::application(settings& settings) :
	last_update_(timer::ticks()),
	total_time_(SCALAR(0.0)),
	accum_(SCALAR(0.0))
{
	unsigned random_seed;
	if (settings.get("rngseed", random_seed)) srand(random_seed);
	else srand(time(0));

	scalar timestep = SCALAR(80.0);
	settings.get("timestep", timestep);
	timestep_ = SCALAR(1.0) / timestep;
	inverse_timestep_ = timestep;

	scalar framerate = SCALAR(40.0);
	settings.get("framerate", framerate);
	framerate = SCALAR(1.0) / framerate;

	//timer::default_source().scale(SCALAR(1.2));

	//update_timer_.init(boost::bind(&application::dispatch_update, this, _1, _2),
					   //timestep_, timer::repeat, this);
	next_update_ = update_timer_.expiration();

	draw_timer_.init(boost::bind(&application::dispatch_draw, this, _1, _2),
					 framerate, timer::repeat);
	add_timer(draw_timer_);
}


void application::dispatch_update(timer& timer, scalar t)
{
	event event;

	while (FE_PollEvent(&event) == 1)
	{
		switch (event.type)
		{
			case SDL_KEYDOWN:

				if (event.key.keysym.sym == SDLK_ESCAPE &&
						(SDL_GetModState() & KMOD_CTRL) )
				{
					// emergency escape
					log_warning("escape forced");
					exit(1);
				}
				break;

			case SDL_VIDEORESIZE:

				video::current()->resize(event.resize.w, event.resize.h);
				break;
		}

		handle_event(event);
	}


	//const int MAX_FRAMESKIP = 15;

	log_debug("updating", timer.expiration(), "/", t);

	//int i = 0;
	//while (next_update_ < t && ++i < MAX_FRAMESKIP)
	//{
		//total_time_ += timestep_;
		//update(total_time_, timestep_);

		//next_update_ += timestep_;
		//log_debug("updated", next_update_, "time:", timer::ticks());
	//}
	
	scalar deltaTime = t - last_update_;
	accum_ += deltaTime;

	while (timestep_ <= accum_)
	{
		log_debug("UPDATING");
		update(total_time_, timestep_);
		total_time_ += timestep_;
		accum_ -= timestep_;
	}

	last_update_ = t;
}

void application::dispatch_draw(timer& timer, scalar t)
{
	log_debug("next update", update_timer_.expiration());
	log_debug("draw", timer.expiration(), "/", t);

	dispatch_update(timer, t);

	//if (t < next_update_ - timestep_) return;
	//scalar alpha = (t + timestep_ - next_update_) * inverse_timestep_;
	//scalar alpha = (t + timestep_ - update_timer_.expiration()) * inverse_timestep_;
	//scalar alpha = (next_update_ - t) * inverse_timestep_;
	scalar alpha = accum_ * inverse_timestep_;
	//if (alpha < SCALAR(0.0) || SCALAR(1.0) < alpha) return;
	
	alpha = cml::clamp(alpha, SCALAR(-1.0), SCALAR(2.0));
	if (alpha < SCALAR(0.0)) log_warning("alpha:", alpha);
	else if (alpha > SCALAR(1.0)) log_warning("alpha:", alpha);
	else log_debug("alpha:", alpha);

	draw(alpha);

	scalar begin = timer::ticks();
	video::current()->swap(t);

	scalar duration = timer::ticks() - begin;
	log_debug("flip duration:", duration);
}


} // namespace moof