// Luanti
// SPDX-License-Identifier: LGPL-2.1-or-later
// Copyright (C) 2015-2019 paramat
// Copyright (C) 2015-2016 kwolekr, Ryan Kwolek


#include "mapgen.h"
#include <cmath>
#include "voxel.h"
#include "noise.h"
#include "mapblock.h"
#include "mapnode.h"
#include "map.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_fractal.h"


FlagDesc flagdesc_mapgen_fractal[] = {
	{"terrain", MGFRACTAL_TERRAIN},
	{NULL,      0}
};

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


MapgenFractal::MapgenFractal(MapgenFractalParams *params, EmergeParams *emerge)
	: MapgenBasic(MAPGEN_FRACTAL, params, emerge)
{
	spflags            = params->spflags;
	cave_width         = params->cave_width;
	large_cave_depth   = params->large_cave_depth;
	small_cave_num_min = params->small_cave_num_min;
	small_cave_num_max = params->small_cave_num_max;
	large_cave_num_min = params->large_cave_num_min;
	large_cave_num_max = params->large_cave_num_max;
	large_cave_flooded = params->large_cave_flooded;
	dungeon_ymin       = params->dungeon_ymin;
	dungeon_ymax       = params->dungeon_ymax;
	fractal            = params->fractal;
	iterations         = params->iterations;
	scale              = params->scale;
	offset             = params->offset;
	slice_w            = params->slice_w;
	julia_x            = params->julia_x;
	julia_y            = params->julia_y;
	julia_z            = params->julia_z;
	julia_w            = params->julia_w;

	//// 2D noise
	if (spflags & MGFRACTAL_TERRAIN)
		noise_seabed = new Noise(&params->np_seabed, seed, csize.X, csize.Z);

	noise_filler_depth = new Noise(&params->np_filler_depth, seed, csize.X, csize.Z);

	//// 3D noise
	MapgenBasic::np_dungeons = params->np_dungeons;
	// Overgeneration to node_min.Y - 1
	MapgenBasic::np_cave1    = params->np_cave1;
	MapgenBasic::np_cave2    = params->np_cave2;

	formula = fractal / 2 + fractal % 2;
	julia   = fractal % 2 == 0;
}


MapgenFractal::~MapgenFractal()
{
	delete noise_seabed;
	delete noise_filler_depth;
}


MapgenFractalParams::MapgenFractalParams():
	np_seabed       (-14, 9,   v3f(600, 600, 600), 41900, 5, 0.6, 2.0),
	np_filler_depth (0,   1.2, v3f(150, 150, 150), 261,   3, 0.7, 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_dungeons     (0.9, 0.5, v3f(500, 500, 500), 0,     2, 0.8, 2.0)
{
}


void MapgenFractalParams::readParams(const Settings *settings)
{
	settings->getFlagStrNoEx("mgfractal_spflags", spflags, flagdesc_mapgen_fractal);
	settings->getFloatNoEx("mgfractal_cave_width",         cave_width);
	settings->getS16NoEx("mgfractal_large_cave_depth",     large_cave_depth);
	settings->getU16NoEx("mgfractal_small_cave_num_min",   small_cave_num_min);
	settings->getU16NoEx("mgfractal_small_cave_num_max",   small_cave_num_max);
	settings->getU16NoEx("mgfractal_large_cave_num_min",   large_cave_num_min);
	settings->getU16NoEx("mgfractal_large_cave_num_max",   large_cave_num_max);
	settings->getFloatNoEx("mgfractal_large_cave_flooded", large_cave_flooded);
	settings->getS16NoEx("mgfractal_dungeon_ymin",         dungeon_ymin);
	settings->getS16NoEx("mgfractal_dungeon_ymax",         dungeon_ymax);
	settings->getU16NoEx("mgfractal_fractal",              fractal);
	settings->getU16NoEx("mgfractal_iterations",           iterations);

	std::optional<v3f> mgfractal_scale;
	if (settings->getV3FNoEx("mgfractal_scale", mgfractal_scale) && mgfractal_scale.has_value()) {
		scale = *mgfractal_scale;
	}

	std::optional<v3f> mgfractal_offset;
	if (settings->getV3FNoEx("mgfractal_offset", mgfractal_offset) && mgfractal_offset.has_value()) {
		offset = *mgfractal_offset;
	}

	settings->getFloatNoEx("mgfractal_slice_w",            slice_w);
	settings->getFloatNoEx("mgfractal_julia_x",            julia_x);
	settings->getFloatNoEx("mgfractal_julia_y",            julia_y);
	settings->getFloatNoEx("mgfractal_julia_z",            julia_z);
	settings->getFloatNoEx("mgfractal_julia_w",            julia_w);

	settings->getNoiseParams("mgfractal_np_seabed",       np_seabed);
	settings->getNoiseParams("mgfractal_np_filler_depth", np_filler_depth);
	settings->getNoiseParams("mgfractal_np_cave1",        np_cave1);
	settings->getNoiseParams("mgfractal_np_cave2",        np_cave2);
	settings->getNoiseParams("mgfractal_np_dungeons",     np_dungeons);
	iterations = std::max<u16>(iterations, 1);
}


void MapgenFractalParams::writeParams(Settings *settings) const
{
	settings->setFlagStr("mgfractal_spflags", spflags, flagdesc_mapgen_fractal);
	settings->setFloat("mgfractal_cave_width",         cave_width);
	settings->setS16("mgfractal_large_cave_depth",     large_cave_depth);
	settings->setU16("mgfractal_small_cave_num_min",   small_cave_num_min);
	settings->setU16("mgfractal_small_cave_num_max",   small_cave_num_max);
	settings->setU16("mgfractal_large_cave_num_min",   large_cave_num_min);
	settings->setU16("mgfractal_large_cave_num_max",   large_cave_num_max);
	settings->setFloat("mgfractal_large_cave_flooded", large_cave_flooded);
	settings->setS16("mgfractal_dungeon_ymin",         dungeon_ymin);
	settings->setS16("mgfractal_dungeon_ymax",         dungeon_ymax);
	settings->setU16("mgfractal_fractal",              fractal);
	settings->setU16("mgfractal_iterations",           iterations);
	settings->setV3F("mgfractal_scale",                scale);
	settings->setV3F("mgfractal_offset",               offset);
	settings->setFloat("mgfractal_slice_w",            slice_w);
	settings->setFloat("mgfractal_julia_x",            julia_x);
	settings->setFloat("mgfractal_julia_y",            julia_y);
	settings->setFloat("mgfractal_julia_z",            julia_z);
	settings->setFloat("mgfractal_julia_w",            julia_w);

	settings->setNoiseParams("mgfractal_np_seabed",       np_seabed);
	settings->setNoiseParams("mgfractal_np_filler_depth", np_filler_depth);
	settings->setNoiseParams("mgfractal_np_cave1",        np_cave1);
	settings->setNoiseParams("mgfractal_np_cave2",        np_cave2);
	settings->setNoiseParams("mgfractal_np_dungeons",     np_dungeons);
}


void MapgenFractalParams::setDefaultSettings(Settings *settings)
{
	settings->setDefault("mgfractal_spflags", flagdesc_mapgen_fractal,
		MGFRACTAL_TERRAIN);
}


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


int MapgenFractal::getSpawnLevelAtPoint(v2s16 p)
{
	bool solid_below = false; // Fractal node is present below to spawn on
	u8 air_count = 0; // Consecutive air nodes above a fractal node
	s16 search_start = 0; // No terrain search start

	// If terrain present, don't start search below terrain or water level
	if (noise_seabed) {
		s16 seabed_level = NoisePerlin2D(&noise_seabed->np, p.X, p.Y, seed);
		search_start = MYMAX(search_start, MYMAX(seabed_level, water_level));
	}

	for (s16 y = search_start; y <= search_start + 4096; y++) {
		if (getFractalAtPoint(p.X, y, p.Y)) {
			// Fractal node
			solid_below = true;
			air_count = 0;
		} else if (solid_below) {
			// Air above fractal node
			air_count++;
			// 3 and -2 to account for biome dust nodes
			if (air_count == 3)
				return y - 2;
		}
	}

	return MAX_MAP_GENERATION_LIMIT;  // Unsuitable spawn point
}


void MapgenFractal::makeChunk(BlockMakeData *data)
{
	// Pre-conditions
	assert(data->vmanip);
	assert(data->nodedef);

	//TimeTaker t("makeChunk");

	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);

	blockseed = getBlockSeed2(full_node_min, seed);

	// Generate fractal and optional terrain
	s16 stone_surface_max_y = generateTerrain();

	// Create heightmap
	updateHeightmap(node_min, node_max);

	// Init biome generator, place biome-specific nodes, and build biomemap
	if (flags & MG_BIOMES) {
		biomegen->calcBiomeNoise(node_min);
		generateBiomes();
	}

	// Generate tunnels and randomwalk caves
	if (flags & MG_CAVES) {
		generateCavesNoiseIntersection(stone_surface_max_y);
		generateCavesRandomWalk(stone_surface_max_y, large_cave_depth);
	}

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

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

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

	// Sprinkle some dust on top after everything else was generated
	if (flags & MG_BIOMES)
		dustTopNodes();

	// Update liquids
	if (spflags & MGFRACTAL_TERRAIN)
		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;

	//printf("makeChunk: %lums\n", t.stop());
}


bool MapgenFractal::getFractalAtPoint(s16 x, s16 y, s16 z)
{
	float cx, cy, cz, cw, ox, oy, oz, ow;

	if (julia) {  // Julia set
		cx = julia_x;
		cy = julia_y;
		cz = julia_z;
		cw = julia_w;
		ox = (float)x / scale.X - offset.X;
		oy = (float)y / scale.Y - offset.Y;
		oz = (float)z / scale.Z - offset.Z;
		ow = slice_w;
	} else {  // Mandelbrot set
		cx = (float)x / scale.X - offset.X;
		cy = (float)y / scale.Y - offset.Y;
		cz = (float)z / scale.Z - offset.Z;
		cw = slice_w;
		ox = 0.0f;
		oy = 0.0f;
		oz = 0.0f;
		ow = 0.0f;
	}

	float nx = 0.0f;
	float ny = 0.0f;
	float nz = 0.0f;
	float nw = 0.0f;

	for (u16 iter = 0; iter < iterations; iter++) {
		switch (formula) {
		default:
		case 1: // 4D "Roundy"
			nx = ox * ox - oy * oy - oz * oz - ow * ow + cx;
			ny = 2.0f * (ox * oy + oz * ow) + cy;
			nz = 2.0f * (ox * oz + oy * ow) + cz;
			nw = 2.0f * (ox * ow + oy * oz) + cw;
			break;
		case 2: // 4D "Squarry"
			nx = ox * ox - oy * oy - oz * oz - ow * ow + cx;
			ny = 2.0f * (ox * oy + oz * ow) + cy;
			nz = 2.0f * (ox * oz + oy * ow) + cz;
			nw = 2.0f * (ox * ow - oy * oz) + cw;
			break;
		case 3: // 4D "Mandy Cousin"
			nx = ox * ox - oy * oy - oz * oz + ow * ow + cx;
			ny = 2.0f * (ox * oy + oz * ow) + cy;
			nz = 2.0f * (ox * oz + oy * ow) + cz;
			nw = 2.0f * (ox * ow + oy * oz) + cw;
			break;
		case 4: // 4D "Variation"
			nx = ox * ox - oy * oy - oz * oz - ow * ow + cx;
			ny = 2.0f * (ox * oy + oz * ow) + cy;
			nz = 2.0f * (ox * oz - oy * ow) + cz;
			nw = 2.0f * (ox * ow + oy * oz) + cw;
			break;
		case 5: // 3D "Mandelbrot/Mandelbar"
			nx = ox * ox - oy * oy - oz * oz + cx;
			ny = 2.0f * ox * oy + cy;
			nz = -2.0f * ox * oz + cz;
			break;
		case 6: // 3D "Christmas Tree"
			// Altering the formula here is necessary to avoid division by zero
			if (std::fabs(oz) < 0.000000001f) {
				nx = ox * ox - oy * oy - oz * oz + cx;
				ny = 2.0f * oy * ox + cy;
				nz = 4.0f * oz * ox + cz;
			} else {
				float a = (2.0f * ox) / (std::sqrt(oy * oy + oz * oz));
				nx = ox * ox - oy * oy - oz * oz + cx;
				ny = a * (oy * oy - oz * oz) + cy;
				nz = a * 2.0f * oy * oz + cz;
			}
			break;
		case 7: // 3D "Mandelbulb"
			if (std::fabs(oy) < 0.000000001f) {
				nx = ox * ox - oz * oz + cx;
				ny = cy;
				nz = -2.0f * oz * std::sqrt(ox * ox) + cz;
			} else {
				float a = 1.0f - (oz * oz) / (ox * ox + oy * oy);
				nx = (ox * ox - oy * oy) * a + cx;
				ny = 2.0f * ox * oy * a + cy;
				nz = -2.0f * oz * std::sqrt(ox * ox + oy * oy) + cz;
			}
			break;
		case 8: // 3D "Cosine Mandelbulb"
			if (std::fabs(oy) < 0.000000001f) {
				nx = 2.0f * ox * oz + cx;
				ny = 4.0f * oy * oz + cy;
				nz = oz * oz - ox * ox - oy * oy + cz;
			} else {
				float a = (2.0f * oz) / std::sqrt(ox * ox + oy * oy);
				nx = (ox * ox - oy * oy) * a + cx;
				ny = 2.0f * ox * oy * a + cy;
				nz = oz * oz - ox * ox - oy * oy + cz;
			}
			break;
		case 9: // 4D "Mandelbulb"
			float rxy = std::sqrt(ox * ox + oy * oy);
			float rxyz = std::sqrt(ox * ox + oy * oy + oz * oz);
			if (std::fabs(ow) < 0.000000001f && std::fabs(oz) < 0.000000001f) {
				nx = (ox * ox - oy * oy) + cx;
				ny = 2.0f * ox * oy + cy;
				nz = -2.0f * rxy * oz + cz;
				nw = 2.0f * rxyz * ow + cw;
			} else {
				float a = 1.0f - (ow * ow) / (rxyz * rxyz);
				float b = a * (1.0f - (oz * oz) / (rxy * rxy));
				nx = (ox * ox - oy * oy) * b + cx;
				ny = 2.0f * ox * oy * b + cy;
				nz = -2.0f * rxy * oz * a + cz;
				nw = 2.0f * rxyz * ow + cw;
			}
			break;
		}

		if (nx * nx + ny * ny + nz * nz + nw * nw > 4.0f)
			return false;

		ox = nx;
		oy = ny;
		oz = nz;
		ow = nw;
	}

	return true;
}


s16 MapgenFractal::generateTerrain()
{
	MapNode n_air(CONTENT_AIR);
	MapNode n_stone(c_stone);
	MapNode n_water(c_water_source);

	s16 stone_surface_max_y = -MAX_MAP_GENERATION_LIMIT;
	u32 index2d = 0;

	if (noise_seabed)
		noise_seabed->perlinMap2D(node_min.X, node_min.Z);

	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++) {
				if (vm->m_data[vi].getContent() != CONTENT_IGNORE)
					continue;

				s16 seabed_height = -MAX_MAP_GENERATION_LIMIT;
				if (noise_seabed)
					seabed_height = noise_seabed->result[index2d];

				if (((spflags & MGFRACTAL_TERRAIN) && y <= seabed_height) ||
						getFractalAtPoint(x, y, z)) {
					vm->m_data[vi] = n_stone;
					if (y > stone_surface_max_y)
						stone_surface_max_y = y;
				} else if ((spflags & MGFRACTAL_TERRAIN) && y <= water_level) {
					vm->m_data[vi] = n_water;
				} else {
					vm->m_data[vi] = n_air;
				}
			}
			index2d -= ystride;
		}
		index2d += ystride;
	}

	return stone_surface_max_y;
}
