/*
Minetest-c55
Copyright (C) 2010 celeron55, Perttu Ahola <celeron55@gmail.com>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#include "environment.h"
#include "filesys.h"

Environment::Environment(Map *map, std::ostream &dout):
		m_dout(dout)
{
	m_map = map;
	m_daynight_ratio = 0.2;
}

Environment::~Environment()
{
	// Deallocate players
	for(core::list<Player*>::Iterator i = m_players.begin();
			i != m_players.end(); i++)
	{
		delete (*i);
	}
	
	// The map is removed by the SceneManager
	m_map->drop();
	//delete m_map;
}

void Environment::step(float dtime)
{
	DSTACK(__FUNCTION_NAME);
	/*
		Run Map's timers
	*/
	//TimeTaker maptimerupdatetimer("m_map->timerUpdate()", g_device);
	// 0ms
	m_map->timerUpdate(dtime);
	//maptimerupdatetimer.stop();

	/*
		Get the highest speed some player is going
	*/
	//TimeTaker playerspeed("playerspeed", g_device);
	// 0ms
	f32 maximum_player_speed = 0.001; // just some small value
	for(core::list<Player*>::Iterator i = m_players.begin();
			i != m_players.end(); i++)
	{
		f32 speed = (*i)->getSpeed().getLength();
		if(speed > maximum_player_speed)
			maximum_player_speed = speed;
	}
	//playerspeed.stop();
	
	/*
		Maximum position increment
	*/
	//f32 position_max_increment = 0.05*BS;
	f32 position_max_increment = 0.1*BS;

	// Maximum time increment (for collision detection etc)
	// time = distance / speed
	f32 dtime_max_increment = position_max_increment / maximum_player_speed;
	// Maximum time increment is 10ms or lower
	if(dtime_max_increment > 0.01)
		dtime_max_increment = 0.01;
	
	//TimeTaker playerupdate("playerupdate", g_device);
	
	/*
		Stuff that has a maximum time increment
	*/
	// Don't allow overly huge dtime
	if(dtime > 0.5)
		dtime = 0.5;

	u32 loopcount = 0;
	do
	{
		loopcount++;

		f32 dtime_part;
		if(dtime > dtime_max_increment)
			dtime_part = dtime_max_increment;
		else
			dtime_part = dtime;
		dtime -= dtime_part;
		
		/*
			Handle players
		*/
		for(core::list<Player*>::Iterator i = m_players.begin();
				i != m_players.end(); i++)
		{
			Player *player = *i;

			v3f playerpos = player->getPosition();
			
			// Apply physics to local player
			bool free_move = g_settings.getBool("free_move");
			if(player->isLocal() && free_move == false)
			{
				// Apply gravity to local player
				v3f speed = player->getSpeed();
				if(player->swimming_up == false)
					speed.Y -= 9.81 * BS * dtime_part * 2;

				/*
					Apply water resistance
				*/
				if(player->in_water_stable || player->in_water)
				{
					f32 max_down = 2.0*BS;
					if(speed.Y < -max_down) speed.Y = -max_down;

					f32 max = 2.5*BS;
					if(speed.getLength() > max)
					{
						speed = speed / speed.getLength() * max;
					}
				}

				player->setSpeed(speed);
			}

			/*
				Move the player.
				For local player, this also calculates collision detection.
			*/
			player->move(dtime_part, *m_map, position_max_increment);
			
			/*
				Update lighting on remote players on client
			*/
			u8 light = LIGHT_MAX;
			try{
				// Get node at feet
				v3s16 p = floatToInt(playerpos + v3f(0,BS/4,0));
				MapNode n = m_map->getNode(p);
				light = n.getLightBlend(m_daynight_ratio);
			}
			catch(InvalidPositionException &e) {}
			player->updateLight(light);

			/*
				Add footsteps to grass
			*/
			if(g_settings.getBool("footprints"))
			{
				// Get node that is at BS/4 under player
				v3s16 bottompos = floatToInt(playerpos + v3f(0,-BS/4,0));
				try{
					MapNode n = m_map->getNode(bottompos);
					if(n.d == CONTENT_GRASS)
					{
						n.d = CONTENT_GRASS_FOOTSTEPS;
						m_map->setNode(bottompos, n);
#ifndef SERVER
						// Update mesh on client
						if(m_map->mapType() == MAPTYPE_CLIENT)
						{
							v3s16 p_blocks = getNodeBlockPos(bottompos);
							MapBlock *b = m_map->getBlockNoCreate(p_blocks);
							b->updateMesh(m_daynight_ratio);
						}
#endif
					}
				}
				catch(InvalidPositionException &e)
				{
				}
			}
		}
	}
	while(dtime > 0.001);
	
	//std::cout<<"Looped "<<loopcount<<" times."<<std::endl;
}

Map & Environment::getMap()
{
	return *m_map;
}

void Environment::addPlayer(Player *player)
{
	DSTACK(__FUNCTION_NAME);
	/*
		Check that only one local player exists and peer_ids are unique.
		Also check that names are unique.
		Exception: there can be multiple players with peer_id=0
	*/
#ifndef SERVER
	/*
		It is a failure if player is local and there already is a local
		player
	*/
	assert(!(player->isLocal() == true && getLocalPlayer() != NULL));
#endif
	// If peer id is non-zero, it has to be unique.
	if(player->peer_id != 0)
		assert(getPlayer(player->peer_id) == NULL);
	// Name has to be unique.
	assert(getPlayer(player->getName()) == NULL);
	// Add.
	m_players.push_back(player);
}

void Environment::removePlayer(u16 peer_id)
{
	DSTACK(__FUNCTION_NAME);
re_search:
	for(core::list<Player*>::Iterator i = m_players.begin();
			i != m_players.end(); i++)
	{
		Player *player = *i;
		if(player->peer_id != peer_id)
			continue;
		
		delete player;
		m_players.erase(i);
		// See if there is an another one
		// (shouldn't be, but just to be sure)
		goto re_search;
	}
}

#ifndef SERVER
LocalPlayer * Environment::getLocalPlayer()
{
	for(core::list<Player*>::Iterator i = m_players.begin();
			i != m_players.end(); i++)
	{
		Player *player = *i;
		if(player->isLocal())
			return (LocalPlayer*)player;
	}
	return NULL;
}
#endif

Player * Environment::getPlayer(u16 peer_id)
{
	for(core::list<Player*>::Iterator i = m_players.begin();
			i != m_players.end(); i++)
	{
		Player *player = *i;
		if(player->peer_id == peer_id)
			return player;
	}
	return NULL;
}

Player * Environment::getPlayer(const char *name)
{
	for(core::list<Player*>::Iterator i = m_players.begin();
			i != m_players.end(); i++)
	{
		Player *player = *i;
		if(strcmp(player->getName(), name) == 0)
			return player;
	}
	return NULL;
}

core::list<Player*> Environment::getPlayers()
{
	return m_players;
}

core::list<Player*> Environment::getPlayers(bool ignore_disconnected)
{
	core::list<Player*> newlist;
	for(core::list<Player*>::Iterator
			i = m_players.begin();
			i != m_players.end(); i++)
	{
		Player *player = *i;
		
		if(ignore_disconnected)
		{
			// Ignore disconnected players
			if(player->peer_id == 0)
				continue;
		}

		newlist.push_back(player);
	}
	return newlist;
}

void Environment::printPlayers(std::ostream &o)
{
	o<<"Players in environment:"<<std::endl;
	for(core::list<Player*>::Iterator i = m_players.begin();
			i != m_players.end(); i++)
	{
		Player *player = *i;
		o<<"Player peer_id="<<player->peer_id<<std::endl;
	}
}

void Environment::serializePlayers(const std::string &savedir)
{
	std::string players_path = savedir + "/players";
	fs::CreateDir(players_path);

	core::map<Player*, bool> saved_players;

	std::vector<fs::DirListNode> player_files = fs::GetDirListing(players_path);
	for(u32 i=0; i<player_files.size(); i++)
	{
		if(player_files[i].dir)
			continue;
		
		// Full path to this file
		std::string path = players_path + "/" + player_files[i].name;

		//dstream<<"Checking player file "<<path<<std::endl;

		// Load player to see what is its name
		ServerRemotePlayer testplayer;
		{
			// Open file and deserialize
			std::ifstream is(path.c_str(), std::ios_base::binary);
			if(is.good() == false)
			{
				dstream<<"Failed to read "<<path<<std::endl;
				continue;
			}
			testplayer.deSerialize(is);
		}

		//dstream<<"Loaded test player with name "<<testplayer.getName()<<std::endl;
		
		// Search for the player
		std::string playername = testplayer.getName();
		Player *player = getPlayer(playername.c_str());
		if(player == NULL)
		{
			dstream<<"Didn't find matching player, ignoring file "<<path<<std::endl;
			continue;
		}

		//dstream<<"Found matching player, overwriting."<<std::endl;

		// OK, found. Save player there.
		{
			// Open file and serialize
			std::ofstream os(path.c_str(), std::ios_base::binary);
			if(os.good() == false)
			{
				dstream<<"Failed to overwrite "<<path<<std::endl;
				continue;
			}
			player->serialize(os);
			saved_players.insert(player, true);
		}
	}

	for(core::list<Player*>::Iterator i = m_players.begin();
			i != m_players.end(); i++)
	{
		Player *player = *i;
		if(saved_players.find(player) != NULL)
		{
			/*dstream<<"Player "<<player->getName()
					<<" was already saved."<<std::endl;*/
			continue;
		}
		std::string playername = player->getName();
		// Don't save unnamed player
		if(playername == "")
		{
			//dstream<<"Not saving unnamed player."<<std::endl;
			continue;
		}
		/*
			Find a sane filename
		*/
		if(string_allowed(playername, PLAYERNAME_ALLOWED_CHARS) == false)
			playername = "player";
		std::string path = players_path + "/" + playername;
		bool found = false;
		for(u32 i=0; i<1000; i++)
		{
			if(fs::PathExists(path) == false)
			{
				found = true;
				break;
			}
			path = players_path + "/" + playername + itos(i);
		}
		if(found == false)
		{
			dstream<<"WARNING: Didn't find free file for player"<<std::endl;
			continue;
		}

		{
			/*dstream<<"Saving player "<<player->getName()<<" to "
					<<path<<std::endl;*/
			// Open file and serialize
			std::ofstream os(path.c_str(), std::ios_base::binary);
			if(os.good() == false)
			{
				dstream<<"WARNING: Failed to overwrite "<<path<<std::endl;
				continue;
			}
			player->serialize(os);
			saved_players.insert(player, true);
		}
	}

	//dstream<<"Saved "<<saved_players.size()<<" players."<<std::endl;
}

void Environment::deSerializePlayers(const std::string &savedir)
{
	std::string players_path = savedir + "/players";

	core::map<Player*, bool> saved_players;

	std::vector<fs::DirListNode> player_files = fs::GetDirListing(players_path);
	for(u32 i=0; i<player_files.size(); i++)
	{
		if(player_files[i].dir)
			continue;
		
		// Full path to this file
		std::string path = players_path + "/" + player_files[i].name;

		dstream<<"Checking player file "<<path<<std::endl;

		// Load player to see what is its name
		ServerRemotePlayer testplayer;
		{
			// Open file and deserialize
			std::ifstream is(path.c_str(), std::ios_base::binary);
			if(is.good() == false)
			{
				dstream<<"Failed to read "<<path<<std::endl;
				continue;
			}
			testplayer.deSerialize(is);
		}

		dstream<<"Loaded test player with name "<<testplayer.getName()<<std::endl;
		
		// Search for the player
		std::string playername = testplayer.getName();
		Player *player = getPlayer(playername.c_str());
		bool newplayer = false;
		if(player == NULL)
		{
			dstream<<"Is a new player"<<std::endl;
			player = new ServerRemotePlayer();
			newplayer = true;
		}

		// Load player
		{
			dstream<<"Reading player "<<testplayer.getName()<<" from "
					<<path<<std::endl;
			// Open file and deserialize
			std::ifstream is(path.c_str(), std::ios_base::binary);
			if(is.good() == false)
			{
				dstream<<"Failed to read "<<path<<std::endl;
				continue;
			}
			player->deSerialize(is);
		}

		if(newplayer)
			addPlayer(player);
	}
}

#ifndef SERVER
void Environment::updateMeshes(v3s16 blockpos)
{
	m_map->updateMeshes(blockpos, m_daynight_ratio);
}

void Environment::expireMeshes(bool only_daynight_diffed)
{
	m_map->expireMeshes(only_daynight_diffed);
}
#endif

void Environment::setDayNightRatio(u32 r)
{
	m_daynight_ratio = r;
}

u32 Environment::getDayNightRatio()
{
	return m_daynight_ratio;
}