// BioGen.h

/*
Interfaces to the various biome generators:
	- cBioGenConstant
	- cBioGenCheckerboard
	- cBioGenDistortedVoronoi
*/





#pragma once

#include "ComposableGenerator.h"
#include "../Noise/Noise.h"
#include "../VoronoiMap.h"





class cBioGenConstant :
	public cBiomeGen
{
public:
	cBioGenConstant(void) : m_Biome(biPlains) {}
	
protected:

	EMCSBiome m_Biome;

	// cBiomeGen overrides:
	virtual void GenBiomes(int a_ChunkX, int a_ChunkZ, cChunkDef::BiomeMap & a_BiomeMap) override;
	virtual void InitializeBiomeGen(cIniFile & a_IniFile) override;
} ;





/** A simple cache that stores N most recently generated chunks' biomes; N being settable upon creation */
class cBioGenCache :
	public cBiomeGen
{
	typedef cBiomeGen super;
	
public:
	cBioGenCache(cBiomeGenPtr a_BioGenToCache, size_t a_CacheSize);
	virtual ~cBioGenCache();
	
protected:

	cBiomeGenPtr m_BioGenToCache;
	
	struct sCacheData
	{
		int m_ChunkX;
		int m_ChunkZ;
		cChunkDef::BiomeMap m_BiomeMap;
	} ;
	
	// To avoid moving large amounts of data for the MRU behavior, we MRU-ize indices to an array of the actual data
	size_t          m_CacheSize;
	size_t *        m_CacheOrder;  // MRU-ized order, indices into m_CacheData array
	sCacheData * m_CacheData;   // m_CacheData[m_CacheOrder[0]] is the most recently used
	
	// Cache statistics
	size_t m_NumHits;
	size_t m_NumMisses;
	size_t m_TotalChain;  // Number of cache items walked to get to a hit (only added for hits)
	
	virtual void GenBiomes(int a_ChunkX, int a_ChunkZ, cChunkDef::BiomeMap & a_BiomeMap) override;
	virtual void InitializeBiomeGen(cIniFile & a_IniFile) override;
} ;





class cBioGenMulticache :
	public cBiomeGen
{

	typedef cBiomeGen super;

public:
	/* Creates a new multicache - a cache that divides the caching into several sub-caches based on the chunk coords.
	This allows us to use shorter cache depths with faster lookups for more covered area. (#381)
	a_SubCacheSize defines the size of each sub-cache
	a_NumSubCaches defines how many sub-caches are used for the multicache. */
	cBioGenMulticache(cBiomeGenPtr a_BioGenToCache, size_t a_SubCacheSize, size_t a_NumSubCaches);

protected:
	typedef std::vector<cBiomeGenPtr> cBiomeGenPtrs;


	/** Number of sub-caches. Pulled out of m_Caches.size() for faster access. */
	size_t m_NumSubCaches;

	/** Individual sub-caches. */
	cBiomeGenPtrs m_Caches;


	virtual void GenBiomes(int a_ChunkX, int a_ChunkZ, cChunkDef::BiomeMap & a_BiomeMap) override;
	virtual void InitializeBiomeGen(cIniFile & a_IniFile) override;
};





/** Base class for generators that use a list of available biomes. This class takes care of the list. */
class cBiomeGenList :
	public cBiomeGen
{
	typedef cBiomeGen super;
	
protected:
	// List of biomes that the generator is allowed to generate:
	typedef std::vector<EMCSBiome> EMCSBiomes;
	EMCSBiomes m_Biomes;
	int        m_BiomesCount;  // Pulled out of m_Biomes for faster access
	
	/** Parses the INI file setting string into m_Biomes. */
	void InitializeBiomes(const AString & a_Biomes);
} ;





class cBioGenCheckerboard :
	public cBiomeGenList
{
	typedef cBiomeGenList super;
	
protected:
	int m_BiomeSize;
	
	// cBiomeGen overrides:
	virtual void GenBiomes(int a_ChunkX, int a_ChunkZ, cChunkDef::BiomeMap & a_BiomeMap) override;
	virtual void InitializeBiomeGen(cIniFile & a_IniFile) override;
} ;





class cBioGenVoronoi :
	public cBiomeGenList
{
	typedef cBiomeGenList super;
	
public:
	cBioGenVoronoi(int a_Seed) :
		m_Voronoi(a_Seed)
	{
	}
	
protected:
	cVoronoiMap m_Voronoi;
	
	// cBiomeGen overrides:
	virtual void GenBiomes(int a_ChunkX, int a_ChunkZ, cChunkDef::BiomeMap & a_BiomeMap) override;
	virtual void InitializeBiomeGen(cIniFile & a_IniFile) override;
	
	EMCSBiome VoronoiBiome(int a_BlockX, int a_BlockZ);
} ;





class cBioGenDistortedVoronoi :
	public cBiomeGenList
{
	typedef cBiomeGenList super;
	
public:
	cBioGenDistortedVoronoi(int a_Seed) :
		m_Noise(a_Seed),
		m_Voronoi(a_Seed),
		m_CellSize(0)
	{
	}

protected:
	/** Noise used for the distortion */
	cNoise m_Noise;
	
	/** The underlying Voronoi map of the biomes */
	cVoronoiMap m_Voronoi;
	
	/** Size of the Voronoi cells, also used for distortion amplitude */
	int m_CellSize;
	
	// cBiomeGen overrides:
	virtual void GenBiomes(int a_ChunkX, int a_ChunkZ, cChunkDef::BiomeMap & a_BiomeMap) override;
	virtual void InitializeBiomeGen(cIniFile & a_IniFile) override;
	
	/** Distorts the coords using a Perlin-like noise */
	void Distort(int a_BlockX, int a_BlockZ, int & a_DistortedX, int & a_DistortedZ);
} ;





class cBioGenMultiStepMap :
	public cBiomeGen
{
	typedef cBiomeGen super;
	
public:
	cBioGenMultiStepMap(int a_Seed);
	
protected:
	// Noises used for composing the perlin-noise:
	cNoise m_Noise1;
	cNoise m_Noise2;
	cNoise m_Noise3;
	cNoise m_Noise4;
	cNoise m_Noise5;
	cNoise m_Noise6;
	
	int    m_Seed;
	int    m_OceanCellSize;
	int    m_MushroomIslandSize;
	int    m_RiverCellSize;
	double m_RiverWidthThreshold;
	float  m_LandBiomesSize;
	
	typedef int    IntMap[17 * 17];  // x + 17 * z, expected trimmed into [0..255] range
	typedef double DblMap[17 * 17];  // x + 17 * z, expected trimmed into [0..1] range
		
	// cBiomeGen overrides:
	virtual void GenBiomes(int a_ChunkX, int a_ChunkZ, cChunkDef::BiomeMap & a_BiomeMap) override;
	virtual void InitializeBiomeGen(cIniFile & a_IniFile) override;
	
	/** Step 1: Decides between ocean, land and mushroom, using a DistVoronoi with special conditions and post-processing for mushroom islands
	Sets biomes to biOcean, -1 (i.e. land), biMushroomIsland or biMushroomShore. */
	void DecideOceanLandMushroom(int a_ChunkX, int a_ChunkZ, cChunkDef::BiomeMap & a_BiomeMap);
	
	/** Step 2: Add rivers to the land
	Flips some "-1" biomes into biRiver. */
	void AddRivers(int a_ChunkX, int a_ChunkZ, cChunkDef::BiomeMap & a_BiomeMap);
	
	/** Step 3: Decide land biomes using a temperature / humidity map; freeze ocean / river in low temperatures.
	Flips all remaining "-1" biomes into land biomes. Also flips some biOcean and biRiver into biFrozenOcean, biFrozenRiver, based on temp map. */
	void ApplyTemperatureHumidity(int a_ChunkX, int a_ChunkZ, cChunkDef::BiomeMap & a_BiomeMap);
	
	/** Distorts the coords using a Perlin-like noise, with a specified cell-size */
	void Distort(int a_BlockX, int a_BlockZ, int & a_DistortedX, int & a_DistortedZ, int a_CellSize);
	
	/** Builds two Perlin-noise maps, one for temperature, the other for humidity. Trims both into [0..255] range */
	void BuildTemperatureHumidityMaps(int a_ChunkX, int a_ChunkZ, IntMap & a_TemperatureMap, IntMap & a_HumidityMap);
	
	/** Flips all remaining "-1" biomes into land biomes using the two maps */
	void DecideLandBiomes(cChunkDef::BiomeMap & a_BiomeMap, const IntMap & a_TemperatureMap, const IntMap & a_HumidityMap);
	
	/** Flips biOcean and biRiver into biFrozenOcean and biFrozenRiver if the temperature is too low */
	void FreezeWaterBiomes(cChunkDef::BiomeMap & a_BiomeMap, const IntMap & a_TemperatureMap);
} ;





class cBioGenTwoLevel :
	public cBiomeGen
{
	typedef cBiomeGen super;
	
public:
	cBioGenTwoLevel(int a_Seed);
	
protected:
	/** The Voronoi map that decides the groups of biomes */
	cVoronoiMap m_VoronoiLarge;
	
	/** The Voronoi map that decides biomes inside individual biome groups */
	cVoronoiMap m_VoronoiSmall;
	
	// The noises used for the distortion:
	cNoise m_Noise1;
	cNoise m_Noise2;
	cNoise m_Noise3;
	cNoise m_Noise4;
	cNoise m_Noise5;
	cNoise m_Noise6;

	// Frequencies and amplitudes for the distortion noises:
	float m_FreqX1, m_AmpX1;
	float m_FreqX2, m_AmpX2;
	float m_FreqX3, m_AmpX3;
	float m_FreqZ1, m_AmpZ1;
	float m_FreqZ2, m_AmpZ2;
	float m_FreqZ3, m_AmpZ3;


	// cBiomeGen overrides:
	virtual void GenBiomes(int a_ChunkX, int a_ChunkZ, cChunkDef::BiomeMap & a_BiomeMap) override;
	virtual void InitializeBiomeGen(cIniFile & a_IniFile) override;

	/** Selects biome from the specified biome group, based on the specified index.
	Note that both params may overflow
	a_DistLevel is either 0 or 1; zero when it is at the edge of the small Voronoi cell, 1 near the center */
	EMCSBiome SelectBiome(int a_BiomeGroup, size_t a_BiomeIdx, int a_DistLevel);
} ;