/*
Minetest
Copyright (C) 2014-2018 kwolekr, Ryan Kwolek <kwolekr@minetest.net>
Copyright (C) 2014-2018 paramat

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.

You should have received a copy of the GNU Lesser 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 "mg_biome.h"
#include "mg_decoration.h"
#include "emerge.h"
#include "server.h"
#include "nodedef.h"
#include "map.h" //for MMVManip
#include "util/numeric.h"
#include "porting.h"
#include "settings.h"


///////////////////////////////////////////////////////////////////////////////


BiomeManager::BiomeManager(Server *server) :
	ObjDefManager(server, OBJDEF_BIOME)
{
	m_server = server;

	// Create default biome to be used in case none exist
	Biome *b = new Biome;

	b->name            = "Default";
	b->flags           = 0;
	b->depth_top       = 0;
	b->depth_filler    = -MAX_MAP_GENERATION_LIMIT;
	b->depth_water_top = 0;
	b->depth_riverbed  = 0;
	b->y_min           = -MAX_MAP_GENERATION_LIMIT;
	b->y_max           = MAX_MAP_GENERATION_LIMIT;
	b->heat_point      = 0.0;
	b->humidity_point  = 0.0;
	b->vertical_blend  = 0;

	b->m_nodenames.emplace_back("mapgen_stone");
	b->m_nodenames.emplace_back("mapgen_stone");
	b->m_nodenames.emplace_back("mapgen_stone");
	b->m_nodenames.emplace_back("mapgen_water_source");
	b->m_nodenames.emplace_back("mapgen_water_source");
	b->m_nodenames.emplace_back("mapgen_river_water_source");
	b->m_nodenames.emplace_back("mapgen_stone");
	b->m_nodenames.emplace_back("ignore");
	m_ndef->pendNodeResolve(b);

	add(b);
}


void BiomeManager::clear()
{
	EmergeManager *emerge = m_server->getEmergeManager();

	// Remove all dangling references in Decorations
	DecorationManager *decomgr = emerge->decomgr;
	for (size_t i = 0; i != decomgr->getNumObjects(); i++) {
		Decoration *deco = (Decoration *)decomgr->getRaw(i);
		deco->biomes.clear();
	}

	// Don't delete the first biome
	for (size_t i = 1; i < m_objects.size(); i++)
		delete (Biome *)m_objects[i];

	m_objects.resize(1);
}


// For BiomeGen type 'BiomeGenOriginal'
float BiomeManager::getHeatAtPosOriginal(v3s16 pos, NoiseParams &np_heat,
	NoiseParams &np_heat_blend, u64 seed)
{
	return
		NoisePerlin2D(&np_heat,       pos.X, pos.Z, seed) +
		NoisePerlin2D(&np_heat_blend, pos.X, pos.Z, seed);
}


// For BiomeGen type 'BiomeGenOriginal'
float BiomeManager::getHumidityAtPosOriginal(v3s16 pos, NoiseParams &np_humidity,
	NoiseParams &np_humidity_blend, u64 seed)
{
	return
		NoisePerlin2D(&np_humidity,       pos.X, pos.Z, seed) +
		NoisePerlin2D(&np_humidity_blend, pos.X, pos.Z, seed);
}


// For BiomeGen type 'BiomeGenOriginal'
Biome *BiomeManager::getBiomeFromNoiseOriginal(float heat, float humidity, s16 y)
{
	Biome *biome_closest = nullptr;
	Biome *biome_closest_blend = nullptr;
	float dist_min = FLT_MAX;
	float dist_min_blend = FLT_MAX;

	for (size_t i = 1; i < getNumObjects(); i++) {
		Biome *b = (Biome *)getRaw(i);
		if (!b || y > b->y_max + b->vertical_blend || y < b->y_min)
			continue;

		float d_heat = heat - b->heat_point;
		float d_humidity = humidity - b->humidity_point;
		float dist = (d_heat * d_heat) + (d_humidity * d_humidity);

		if (y <= b->y_max) { // Within y limits of biome b
			if (dist < dist_min) {
				dist_min = dist;
				biome_closest = b;
			}
		} else if (dist < dist_min_blend) { // Blend area above biome b
			dist_min_blend = dist;
			biome_closest_blend = b;
		}
	}

	mysrand(y + (heat - humidity) * 2);
	if (biome_closest_blend &&
			myrand_range(0, biome_closest_blend->vertical_blend) >=
			y - biome_closest_blend->y_max)
		return biome_closest_blend;

	return (biome_closest) ? biome_closest : (Biome *)getRaw(BIOME_NONE);
}


////////////////////////////////////////////////////////////////////////////////

void BiomeParamsOriginal::readParams(const Settings *settings)
{
	settings->getNoiseParams("mg_biome_np_heat",           np_heat);
	settings->getNoiseParams("mg_biome_np_heat_blend",     np_heat_blend);
	settings->getNoiseParams("mg_biome_np_humidity",       np_humidity);
	settings->getNoiseParams("mg_biome_np_humidity_blend", np_humidity_blend);
}


void BiomeParamsOriginal::writeParams(Settings *settings) const
{
	settings->setNoiseParams("mg_biome_np_heat",           np_heat);
	settings->setNoiseParams("mg_biome_np_heat_blend",     np_heat_blend);
	settings->setNoiseParams("mg_biome_np_humidity",       np_humidity);
	settings->setNoiseParams("mg_biome_np_humidity_blend", np_humidity_blend);
}


////////////////////////////////////////////////////////////////////////////////

BiomeGenOriginal::BiomeGenOriginal(BiomeManager *biomemgr,
	BiomeParamsOriginal *params, v3s16 chunksize)
{
	m_bmgr   = biomemgr;
	m_params = params;
	m_csize  = chunksize;

	noise_heat           = new Noise(&params->np_heat,
									params->seed, m_csize.X, m_csize.Z);
	noise_humidity       = new Noise(&params->np_humidity,
									params->seed, m_csize.X, m_csize.Z);
	noise_heat_blend     = new Noise(&params->np_heat_blend,
									params->seed, m_csize.X, m_csize.Z);
	noise_humidity_blend = new Noise(&params->np_humidity_blend,
									params->seed, m_csize.X, m_csize.Z);

	heatmap  = noise_heat->result;
	humidmap = noise_humidity->result;
	biomemap = new biome_t[m_csize.X * m_csize.Z];
}

BiomeGenOriginal::~BiomeGenOriginal()
{
	delete []biomemap;

	delete noise_heat;
	delete noise_humidity;
	delete noise_heat_blend;
	delete noise_humidity_blend;
}


Biome *BiomeGenOriginal::calcBiomeAtPoint(v3s16 pos) const
{
	float heat =
		NoisePerlin2D(&m_params->np_heat,       pos.X, pos.Z, m_params->seed) +
		NoisePerlin2D(&m_params->np_heat_blend, pos.X, pos.Z, m_params->seed);
	float humidity =
		NoisePerlin2D(&m_params->np_humidity,       pos.X, pos.Z, m_params->seed) +
		NoisePerlin2D(&m_params->np_humidity_blend, pos.X, pos.Z, m_params->seed);

	return calcBiomeFromNoise(heat, humidity, pos.Y);
}


void BiomeGenOriginal::calcBiomeNoise(v3s16 pmin)
{
	m_pmin = pmin;

	noise_heat->perlinMap2D(pmin.X, pmin.Z);
	noise_humidity->perlinMap2D(pmin.X, pmin.Z);
	noise_heat_blend->perlinMap2D(pmin.X, pmin.Z);
	noise_humidity_blend->perlinMap2D(pmin.X, pmin.Z);

	for (s32 i = 0; i < m_csize.X * m_csize.Z; i++) {
		noise_heat->result[i]     += noise_heat_blend->result[i];
		noise_humidity->result[i] += noise_humidity_blend->result[i];
	}
}


biome_t *BiomeGenOriginal::getBiomes(s16 *heightmap)
{
	for (s32 i = 0; i != m_csize.X * m_csize.Z; i++) {
		Biome *biome = calcBiomeFromNoise(
			noise_heat->result[i],
			noise_humidity->result[i],
			heightmap[i]);

		biomemap[i] = biome->index;
	}

	return biomemap;
}


Biome *BiomeGenOriginal::getBiomeAtPoint(v3s16 pos) const
{
	return getBiomeAtIndex(
		(pos.Z - m_pmin.Z) * m_csize.X + (pos.X - m_pmin.X),
		pos.Y);
}


Biome *BiomeGenOriginal::getBiomeAtIndex(size_t index, s16 y) const
{
	return calcBiomeFromNoise(
		noise_heat->result[index],
		noise_humidity->result[index],
		y);
}


Biome *BiomeGenOriginal::calcBiomeFromNoise(float heat, float humidity, s16 y) const
{
	Biome *biome_closest = nullptr;
	Biome *biome_closest_blend = nullptr;
	float dist_min = FLT_MAX;
	float dist_min_blend = FLT_MAX;

	for (size_t i = 1; i < m_bmgr->getNumObjects(); i++) {
		Biome *b = (Biome *)m_bmgr->getRaw(i);
		if (!b || y > b->y_max + b->vertical_blend || y < b->y_min)
			continue;

		float d_heat = heat - b->heat_point;
		float d_humidity = humidity - b->humidity_point;
		float dist = (d_heat * d_heat) + (d_humidity * d_humidity);

		if (y <= b->y_max) { // Within y limits of biome b
			if (dist < dist_min) {
				dist_min = dist;
				biome_closest = b;
			}
		} else if (dist < dist_min_blend) { // Blend area above biome b
			dist_min_blend = dist;
			biome_closest_blend = b;
		}
	}

	// Carefully tune pseudorandom seed variation to avoid single node dither
	// and create larger scale blending patterns.
	mysrand(y + (heat - humidity) * 2);

	if (biome_closest_blend &&
			myrand_range(0, biome_closest_blend->vertical_blend) >=
			y - biome_closest_blend->y_max)
		return biome_closest_blend;

	return (biome_closest) ? biome_closest : (Biome *)m_bmgr->getRaw(BIOME_NONE);	
}


////////////////////////////////////////////////////////////////////////////////

void Biome::resolveNodeNames()
{
	getIdFromNrBacklog(&c_top,         "mapgen_stone",              CONTENT_AIR);
	getIdFromNrBacklog(&c_filler,      "mapgen_stone",              CONTENT_AIR);
	getIdFromNrBacklog(&c_stone,       "mapgen_stone",              CONTENT_AIR);
	getIdFromNrBacklog(&c_water_top,   "mapgen_water_source",       CONTENT_AIR);
	getIdFromNrBacklog(&c_water,       "mapgen_water_source",       CONTENT_AIR);
	getIdFromNrBacklog(&c_river_water, "mapgen_river_water_source", CONTENT_AIR);
	getIdFromNrBacklog(&c_riverbed,    "mapgen_stone",              CONTENT_AIR);
	getIdFromNrBacklog(&c_dust,        "ignore",                    CONTENT_IGNORE);
}