/*
Minetest
Copyright (C) 2010-2016 paramat, Matt Gregory
Copyright (C) 2010-2016 kwolekr, Ryan Kwolek <kwolekr@minetest.net>
Copyright (C) 2017 vlapsley, Vaughan Lapsley <vlapsley@gmail.com>

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 <cmath>
#include "mapgen.h"
#include "voxel.h"
#include "noise.h"
#include "mapblock.h"
#include "mapnode.h"
#include "map.h"
#include "content_sao.h"
#include "nodedef.h"
#include "voxelalgorithms.h"
//#include "profiler.h" // For TimeTaker
#include "settings.h" // For g_settings
#include "emerge.h"
#include "dungeongen.h"
#include "cavegen.h"
#include "mg_biome.h"
#include "mg_ore.h"
#include "mg_decoration.h"
#include "mapgen_carpathian.h"


FlagDesc flagdesc_mapgen_carpathian[] = {
	{"caverns", MGCARPATHIAN_CAVERNS},
	{NULL,      0}
};


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


MapgenCarpathian::MapgenCarpathian(
		int mapgenid, MapgenCarpathianParams *params, EmergeManager *emerge)
	: MapgenBasic(mapgenid, params, emerge)
{
	spflags          = params->spflags;
	cave_width       = params->cave_width;
	large_cave_depth = params->large_cave_depth;
	lava_depth       = params->lava_depth;
	cavern_limit     = params->cavern_limit;
	cavern_taper     = params->cavern_taper;
	cavern_threshold = params->cavern_threshold;
	grad_wl          = 1 - water_level;

	//// 2D Terrain noise
	noise_base          = new Noise(&params->np_base,          seed, csize.X, csize.Z);
	noise_filler_depth  = new Noise(&params->np_filler_depth,  seed, csize.X, csize.Z);
	noise_height1       = new Noise(&params->np_height1,       seed, csize.X, csize.Z);
	noise_height2       = new Noise(&params->np_height2,       seed, csize.X, csize.Z);
	noise_height3       = new Noise(&params->np_height3,       seed, csize.X, csize.Z);
	noise_height4       = new Noise(&params->np_height4,       seed, csize.X, csize.Z);
	noise_hills_terrain = new Noise(&params->np_hills_terrain, seed, csize.X, csize.Z);
	noise_ridge_terrain = new Noise(&params->np_ridge_terrain, seed, csize.X, csize.Z);
	noise_step_terrain  = new Noise(&params->np_step_terrain,  seed, csize.X, csize.Z);
	noise_hills         = new Noise(&params->np_hills,         seed, csize.X, csize.Z);
	noise_ridge_mnt     = new Noise(&params->np_ridge_mnt,     seed, csize.X, csize.Z);
	noise_step_mnt      = new Noise(&params->np_step_mnt,      seed, csize.X, csize.Z);

	//// 3D terrain noise
	// 1 up 1 down overgeneration
	noise_mnt_var = new Noise(&params->np_mnt_var, seed, csize.X, csize.Y + 2, csize.Z);

	//// Cave noise
	MapgenBasic::np_cave1  = params->np_cave1;
	MapgenBasic::np_cave2  = params->np_cave2;
	MapgenBasic::np_cavern = params->np_cavern;
}


MapgenCarpathian::~MapgenCarpathian()
{
	delete noise_base;
	delete noise_filler_depth;
	delete noise_height1;
	delete noise_height2;
	delete noise_height3;
	delete noise_height4;
	delete noise_hills_terrain;
	delete noise_ridge_terrain;
	delete noise_step_terrain;
	delete noise_hills;
	delete noise_ridge_mnt;
	delete noise_step_mnt;
	delete noise_mnt_var;
}


MapgenCarpathianParams::MapgenCarpathianParams():
	np_base          (12, 1,  v3f(2557, 2557, 2557), 6538,  4, 0.8,  0.5),
	np_filler_depth  (0,  1,  v3f(128,  128,  128),  261,   3, 0.7,  2.0),
	np_height1       (0,  5,  v3f(251,  251,  251),  9613,  5, 0.5,  2.0),
	np_height2       (0,  5,  v3f(383,  383,  383),  1949,  5, 0.5,  2.0),
	np_height3       (0,  5,  v3f(509,  509,  509),  3211,  5, 0.5,  2.0),
	np_height4       (0,  5,  v3f(631,  631,  631),  1583,  5, 0.5,  2.0),
	np_hills_terrain (1,  1,  v3f(1301, 1301, 1301), 1692,  5, 0.5,  2.0),
	np_ridge_terrain (1,  1,  v3f(1889, 1889, 1889), 3568,  5, 0.5,  2.0),
	np_step_terrain  (1,  1,  v3f(1889, 1889, 1889), 4157,  5, 0.5,  2.0),
	np_hills         (0,  3,  v3f(257,  257,  257),  6604,  6, 0.5,  2.0),
	np_ridge_mnt     (0,  12, v3f(743,  743,  743),  5520,  6, 0.7,  2.0),
	np_step_mnt      (0,  8,  v3f(509,  509,  509),  2590,  6, 0.6,  2.0),
	np_mnt_var       (0,  1,  v3f(499,  499,  499),  2490,  5, 0.55, 2.0),
	np_cave1         (0,  12, v3f(61,   61,   61),   52534, 3, 0.5,  2.0),
	np_cave2         (0,  12, v3f(67,   67,   67),   10325, 3, 0.5,  2.0),
	np_cavern        (0,  1,  v3f(384,  128,  384),  723,   5, 0.63, 2.0)
{
}


void MapgenCarpathianParams::readParams(const Settings *settings)
{
	settings->getFlagStrNoEx("mgcarpathian_spflags", spflags, flagdesc_mapgen_carpathian);
	settings->getFloatNoEx("mgcarpathian_cave_width",       cave_width);
	settings->getS16NoEx("mgcarpathian_large_cave_depth",   large_cave_depth);
	settings->getS16NoEx("mgcarpathian_lava_depth",         lava_depth);
	settings->getS16NoEx("mgcarpathian_cavern_limit",       cavern_limit);
	settings->getS16NoEx("mgcarpathian_cavern_taper",       cavern_taper);
	settings->getFloatNoEx("mgcarpathian_cavern_threshold", cavern_threshold);

	settings->getNoiseParams("mgcarpathian_np_base",          np_base);
	settings->getNoiseParams("mgcarpathian_np_filler_depth",  np_filler_depth);
	settings->getNoiseParams("mgcarpathian_np_height1",       np_height1);
	settings->getNoiseParams("mgcarpathian_np_height2",       np_height2);
	settings->getNoiseParams("mgcarpathian_np_height3",       np_height3);
	settings->getNoiseParams("mgcarpathian_np_height4",       np_height4);
	settings->getNoiseParams("mgcarpathian_np_hills_terrain", np_hills_terrain);
	settings->getNoiseParams("mgcarpathian_np_ridge_terrain", np_ridge_terrain);
	settings->getNoiseParams("mgcarpathian_np_step_terrain",  np_step_terrain);
	settings->getNoiseParams("mgcarpathian_np_hills",         np_hills);
	settings->getNoiseParams("mgcarpathian_np_ridge_mnt",     np_ridge_mnt);
	settings->getNoiseParams("mgcarpathian_np_step_mnt",      np_step_mnt);
	settings->getNoiseParams("mgcarpathian_np_mnt_var",       np_mnt_var);
	settings->getNoiseParams("mgcarpathian_np_cave1",         np_cave1);
	settings->getNoiseParams("mgcarpathian_np_cave2",         np_cave2);
	settings->getNoiseParams("mgcarpathian_np_cavern",        np_cavern);
}


void MapgenCarpathianParams::writeParams(Settings *settings) const
{
	settings->setFlagStr("mgcarpathian_spflags", spflags, flagdesc_mapgen_carpathian, U32_MAX);
	settings->setFloat("mgcarpathian_cave_width",       cave_width);
	settings->setS16("mgcarpathian_large_cave_depth",   large_cave_depth);
	settings->setS16("mgcarpathian_lava_depth",         lava_depth);
	settings->setS16("mgcarpathian_cavern_limit",       cavern_limit);
	settings->setS16("mgcarpathian_cavern_taper",       cavern_taper);
	settings->setFloat("mgcarpathian_cavern_threshold", cavern_threshold);

	settings->setNoiseParams("mgcarpathian_np_base",          np_base);
	settings->setNoiseParams("mgcarpathian_np_filler_depth",  np_filler_depth);
	settings->setNoiseParams("mgcarpathian_np_height1",       np_height1);
	settings->setNoiseParams("mgcarpathian_np_height2",       np_height2);
	settings->setNoiseParams("mgcarpathian_np_height3",       np_height3);
	settings->setNoiseParams("mgcarpathian_np_height4",       np_height4);
	settings->setNoiseParams("mgcarpathian_np_hills_terrain", np_hills_terrain);
	settings->setNoiseParams("mgcarpathian_np_ridge_terrain", np_ridge_terrain);
	settings->setNoiseParams("mgcarpathian_np_step_terrain",  np_step_terrain);
	settings->setNoiseParams("mgcarpathian_np_hills",         np_hills);
	settings->setNoiseParams("mgcarpathian_np_ridge_mnt",     np_ridge_mnt);
	settings->setNoiseParams("mgcarpathian_np_step_mnt",      np_step_mnt);
	settings->setNoiseParams("mgcarpathian_np_mnt_var",       np_mnt_var);
	settings->setNoiseParams("mgcarpathian_np_cave1",         np_cave1);
	settings->setNoiseParams("mgcarpathian_np_cave2",         np_cave2);
	settings->setNoiseParams("mgcarpathian_np_cavern",        np_cavern);
}


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


// Lerp function
inline float MapgenCarpathian::getLerp(float noise1, float noise2, float mod)
{
	return noise1 + mod * (noise2 - noise1);
}

// Steps function
float MapgenCarpathian::getSteps(float noise)
{
	float w = 0.5f;
	float k = floor(noise / w);
	float f = (noise - k * w) / w;
	float s = std::fmin(2.f * f, 1.f);
	return (k + s) * w;
}


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


void MapgenCarpathian::makeChunk(BlockMakeData *data)
{
	// Pre-conditions
	assert(data->vmanip);
	assert(data->nodedef);
	assert(data->blockpos_requested.X >= data->blockpos_min.X &&
			data->blockpos_requested.Y >= data->blockpos_min.Y &&
			data->blockpos_requested.Z >= data->blockpos_min.Z);
	assert(data->blockpos_requested.X <= data->blockpos_max.X &&
			data->blockpos_requested.Y <= data->blockpos_max.Y &&
			data->blockpos_requested.Z <= data->blockpos_max.Z);

	this->generating = true;
	this->vm = data->vmanip;
	this->ndef = data->nodedef;

	v3s16 blockpos_min = data->blockpos_min;
	v3s16 blockpos_max = data->blockpos_max;
	node_min = blockpos_min * MAP_BLOCKSIZE;
	node_max = (blockpos_max + v3s16(1, 1, 1)) * MAP_BLOCKSIZE - v3s16(1, 1, 1);
	full_node_min = (blockpos_min - 1) * MAP_BLOCKSIZE;
	full_node_max = (blockpos_max + 2) * MAP_BLOCKSIZE - v3s16(1, 1, 1);

	// Create a block-specific seed
	blockseed = getBlockSeed2(full_node_min, seed);

	// Generate terrain
	s16 stone_surface_max_y = generateTerrain();

	// Create heightmap
	updateHeightmap(node_min, node_max);

	// Init biome generator, place biome-specific nodes, and build biomemap
	biomegen->calcBiomeNoise(node_min);

	MgStoneType mgstone_type;
	content_t biome_stone;
	generateBiomes(&mgstone_type, &biome_stone);

	// Generate caverns, tunnels and classic caves
	if (flags & MG_CAVES) {
		bool has_cavern = false;
		// Generate caverns
		if (spflags & MGCARPATHIAN_CAVERNS)
			has_cavern = generateCaverns(stone_surface_max_y);
		// Generate tunnels and classic caves
		if (has_cavern)
			// Disable classic caves in this mapchunk by setting
			// 'large cave depth' to world base. Avoids excessive liquid in
			// large caverns and floating blobs of overgenerated liquid.
			generateCaves(stone_surface_max_y, -MAX_MAP_GENERATION_LIMIT);
		else
			generateCaves(stone_surface_max_y, large_cave_depth);
	}

	// Generate dungeons
	if (flags & MG_DUNGEONS)
		generateDungeons(stone_surface_max_y, mgstone_type, biome_stone);

	// Generate the registered decorations
	if (flags & MG_DECORATIONS)
		m_emerge->decomgr->placeAllDecos(this, blockseed, node_min, node_max);

	// Generate the registered ores
	m_emerge->oremgr->placeAllOres(this, blockseed, node_min, node_max);

	// Sprinkle some dust on top after everything else was generated
	dustTopNodes();

	// Update liquids
	updateLiquid(&data->transforming_liquid, full_node_min, full_node_max);

	// Calculate lighting
	if (flags & MG_LIGHT) {
		calcLighting(node_min - v3s16(0, 1, 0), node_max + v3s16(0, 1, 0),
				full_node_min, full_node_max);
	}

	this->generating = false;
}


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


int MapgenCarpathian::getSpawnLevelAtPoint(v2s16 p)
{
	s16 level_at_point = terrainLevelAtPoint(p.X, p.Y);
	if (level_at_point <= water_level || level_at_point > water_level + 32)
		return MAX_MAP_GENERATION_LIMIT; // Unsuitable spawn point

	return level_at_point;
}


float MapgenCarpathian::terrainLevelAtPoint(s16 x, s16 z)
{
	float ground = NoisePerlin2D(&noise_base->np, x, z, seed);
	float height1 = NoisePerlin2D(&noise_height1->np, x, z, seed);
	float height2 = NoisePerlin2D(&noise_height2->np, x, z, seed);
	float height3 = NoisePerlin2D(&noise_height3->np, x, z, seed);
	float height4 = NoisePerlin2D(&noise_height4->np, x, z, seed);
	float hter = NoisePerlin2D(&noise_hills_terrain->np, x, z, seed);
	float rter = NoisePerlin2D(&noise_ridge_terrain->np, x, z, seed);
	float ster = NoisePerlin2D(&noise_step_terrain->np, x, z, seed);
	float n_hills = NoisePerlin2D(&noise_hills->np, x, z, seed);
	float n_ridge_mnt = NoisePerlin2D(&noise_ridge_mnt->np, x, z, seed);
	float n_step_mnt = NoisePerlin2D(&noise_step_mnt->np, x, z, seed);

	int height = -MAX_MAP_GENERATION_LIMIT;

	for (s16 y = 1; y <= 30; y++) {
		float mnt_var = NoisePerlin3D(&noise_mnt_var->np, x, y, z, seed);

		// Gradient & shallow seabed
		s32 grad = (y < water_level) ? grad_wl + (water_level - y) * 3 : 1 - y;

		// Hill/Mountain height (hilliness)
		float hill1 = getLerp(height1, height2, mnt_var);
		float hill2 = getLerp(height3, height4, mnt_var);
		float hill3 = getLerp(height3, height2, mnt_var);
		float hill4 = getLerp(height1, height4, mnt_var);
		float hilliness = std::fmax(std::fmin(hill1, hill2), std::fmin(hill3, hill4));

		// Rolling hills
		float hill_mnt = hilliness * pow(n_hills, 2.f);
		float hills = pow(hter, 3.f) * hill_mnt;

		// Ridged mountains
		float ridge_mnt = hilliness * (1.f - fabs(n_ridge_mnt));
		float ridged_mountains = pow(rter, 3.f) * ridge_mnt;

		// Step (terraced) mountains
		float step_mnt = hilliness * getSteps(n_step_mnt);
		float step_mountains = pow(ster, 3.f) * step_mnt;

		// Final terrain level
		float mountains = hills + ridged_mountains + step_mountains;
		float surface_level = ground + mountains + grad;

		if (y > surface_level && height < 0)
			height = y;
	}

	return height;
}


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


int MapgenCarpathian::generateTerrain()
{
	MapNode mn_air(CONTENT_AIR);
	MapNode mn_stone(c_stone);
	MapNode mn_water(c_water_source);

	s16 stone_surface_max_y = -MAX_MAP_GENERATION_LIMIT;
	u32 index2d = 0;
	u32 index3d = 0;

	// Calculate noise for terrain generation
	noise_base->perlinMap2D(node_min.X, node_min.Z);
	noise_height1->perlinMap2D(node_min.X, node_min.Z);
	noise_height2->perlinMap2D(node_min.X, node_min.Z);
	noise_height3->perlinMap2D(node_min.X, node_min.Z);
	noise_height4->perlinMap2D(node_min.X, node_min.Z);
	noise_hills_terrain->perlinMap2D(node_min.X, node_min.Z);
	noise_ridge_terrain->perlinMap2D(node_min.X, node_min.Z);
	noise_step_terrain->perlinMap2D(node_min.X, node_min.Z);
	noise_hills->perlinMap2D(node_min.X, node_min.Z);
	noise_ridge_mnt->perlinMap2D(node_min.X, node_min.Z);
	noise_step_mnt->perlinMap2D(node_min.X, node_min.Z);
	noise_mnt_var->perlinMap3D(node_min.X, node_min.Y - 1, node_min.Z);

	//// Place nodes
	for (s16 z = node_min.Z; z <= node_max.Z; z++) {
		for (s16 y = node_min.Y - 1; y <= node_max.Y + 1; y++) {
			u32 vi = vm->m_area.index(node_min.X, y, z);
			for (s16 x = node_min.X; x <= node_max.X;
					x++, vi++, index2d++, index3d++) {
				if (vm->m_data[vi].getContent() != CONTENT_IGNORE)
					continue;

				// Base terrain
				float ground = noise_base->result[index2d];

				// Gradient & shallow seabed
				s32 grad = (y < water_level) ? grad_wl + (water_level - y) * 3 : 1 - y;

				// Hill/Mountain height (hilliness)
				float height1 = noise_height1->result[index2d];
				float height2 = noise_height2->result[index2d];
				float height3 = noise_height3->result[index2d];
				float height4 = noise_height4->result[index2d];
				float mnt_var = noise_mnt_var->result[index3d];
				// Combine height noises and apply 3D variation
				float hill1 = getLerp(height1, height2, mnt_var);
				float hill2 = getLerp(height3, height4, mnt_var);
				float hill3 = getLerp(height3, height2, mnt_var);
				float hill4 = getLerp(height1, height4, mnt_var);
				// 'hilliness' determines whether hills/mountains are
				// small or large
				float hilliness = std::fmax(std::fmin(hill1, hill2), std::fmin(hill3, hill4));

				// Rolling hills
				float hter = noise_hills_terrain->result[index2d];
				float n_hills = noise_hills->result[index2d];
				float hill_mnt = hilliness * pow(n_hills, 2.f);
				float hills = pow(fabs(hter), 3.f) * hill_mnt;

				// Ridged mountains
				float rter = noise_ridge_terrain->result[index2d];
				float n_ridge_mnt = noise_ridge_mnt->result[index2d];
				float ridge_mnt = hilliness * (1.f - fabs(n_ridge_mnt));
				float ridged_mountains = pow(fabs(rter), 3.f) * ridge_mnt;

				// Step (terraced) mountains
				float ster = noise_step_terrain->result[index2d];
				float n_step_mnt = noise_step_mnt->result[index2d];
				float step_mnt = hilliness * getSteps(n_step_mnt);
				float step_mountains = pow(fabs(ster), 3.f) * step_mnt;

				// Final terrain level
				float mountains = hills + ridged_mountains + step_mountains;
				float surface_level = ground + mountains + grad;

				if (y < surface_level) {
					vm->m_data[vi] = mn_stone; // Stone
					if (y > stone_surface_max_y)
						stone_surface_max_y = y;
				} else if (y <= water_level) {
					vm->m_data[vi] = mn_water; // Sea water
				} else {
					vm->m_data[vi] = mn_air; // Air
				}
			}
			index2d -= ystride;
		}
		index2d += ystride;
	}

	return stone_surface_max_y;
}