#pragma once


#include <cstring>


#include "ChunkDef.h"


#define CHUNK_SECTION_HEIGHT 16
#define CHUNK_SECTION_NUM (256 / CHUNK_SECTION_HEIGHT)

#if __cplusplus < 201103L
// auto_ptr style interface for memory management
#else
// unique_ptr style interface for memory management
#endif

class cChunkBuffer
{
public:

	cChunkBuffer()
	#if __cplusplus < 201103L
	// auto_ptr style interface for memory management
	: IsOwner(true)
	#endif
	{
		memset(m_Sections, 0, sizeof(m_Sections));
	}
	~cChunkBuffer()
	{
		#if __cplusplus < 201103L
		// auto_ptr style interface for memory management
		if(!IsOwner) return;
		#endif
		for (int i = 0; i < CHUNK_SECTION_NUM; i++)
		{
			if(m_Sections[i]) Free(m_Sections[i]);;
		}
	}
	
	#if __cplusplus < 201103L
	// auto_ptr style interface for memory management
	cChunkBuffer(const cChunkBuffer& other) :
	IsOwner(true)
	{
		for (int i = 0; i < CHUNK_SECTION_NUM; i++)
		{
			m_Sections[i] = other.m_Sections[i];
		}
		other.IsOwner = false;
	}

	void operator=(const cChunkBuffer& other)
	{
		if(IsOwner)
		{
			for (int i = 0; i < CHUNK_SECTION_NUM; i++)
			{
				if(m_Sections[i]) Free(m_Sections[i]);;
			}
		}
		IsOwner = true;
		for (int i = 0; i < CHUNK_SECTION_NUM; i++)
		{
			m_Sections[i] = other.m_Sections[i];
		}
		other.IsOwner = false;
	}
	#else
	// unique_ptr style interface for memory management
	cChunkBuffer(const cChunkBuffer&& other)
	{
		for (int i = 0; i < CHUNK_SECTION_NUM; i++)
		{
			m_Sections[i] = other.m_Sections[i];
		}
	}
	
	void operator=(const cChunkBuffer&& other)
	{
		for (int i = 0; i < CHUNK_SECTION_NUM; i++)
		{
			if(m_Sections[i]) Free(m_Sections[i]);;
			m_Sections[i] = other.m_Sections[i];
		}
	}
	#endif

	BLOCKTYPE GetBlock(int a_X, int a_Y, int a_Z) const
	{
		ASSERT((a_X >= 0) && (a_X < cChunkDef::Width));
		ASSERT((a_Y >= 0) && (a_Y < cChunkDef::Height));
		ASSERT((a_Z >= 0) && (a_Z < cChunkDef::Width));
		int Section = a_Y / CHUNK_SECTION_HEIGHT;
		if(m_Sections[Section])
		{
			int Index = cChunkDef::MakeIndexNoCheck(a_X, a_Y - (Section * CHUNK_SECTION_HEIGHT), a_Z);
			return m_Sections[Section]->m_BlockTypes[Index];
		}
		else
		{
			return 0;
		}
	}
	
	void SetBlock(int a_RelX, int a_RelY, int a_RelZ, BLOCKTYPE a_Block)
	{
		if (
			(a_RelX >= cChunkDef::Width)  || (a_RelX < 0) ||
			(a_RelY >= cChunkDef::Height) || (a_RelY < 0) ||
			(a_RelZ >= cChunkDef::Width)  || (a_RelZ < 0)
		)
		{
			ASSERT(!"cChunkBuffer::SetMeta(): index out of range!");
			return;
		}

		int Section = a_RelY / CHUNK_SECTION_HEIGHT;
		if(!m_Sections[Section])
		{
			m_Sections[Section] = Allocate();
			if(!m_Sections[Section])
			{
				ASSERT("Failed to allocate a new section in Chunkbuffer");
				return;
			}
		}
		int Index = cChunkDef::MakeIndexNoCheck(a_RelX, a_RelY - (Section * CHUNK_SECTION_HEIGHT), a_RelZ);
		m_Sections[Section]->m_BlockTypes[Index] = a_Block;
	}

	NIBBLETYPE GetMeta(int a_RelX, int a_RelY, int a_RelZ) const
	{
		if ((a_RelX < cChunkDef::Width) && (a_RelX > -1) && (a_RelY < cChunkDef::Height) && (a_RelY > -1) && (a_RelZ < cChunkDef::Width) && (a_RelZ > -1))
		{
			int Section = a_RelY / CHUNK_SECTION_HEIGHT;
			if(m_Sections[Section])
			{
				int Index = cChunkDef::MakeIndexNoCheck(a_RelX, a_RelY - (Section * CHUNK_SECTION_HEIGHT), a_RelZ);
				return (m_Sections[Section]->m_BlockMeta[Index / 2] >> ((Index & 1) * 4)) & 0x0f;
			}
			else
			{
				return 0;
			}
		}
		ASSERT(!"cChunkBuffer::GetMeta(): coords out of chunk range!");
		return 0;
	}
	
	void SetMeta(int a_RelX, int a_RelY, int a_RelZ, NIBBLETYPE a_Nibble)
	{
		if (
			(a_RelX >= cChunkDef::Width)  || (a_RelX < 0) ||
			(a_RelY >= cChunkDef::Height) || (a_RelY < 0) ||
			(a_RelZ >= cChunkDef::Width)  || (a_RelZ < 0)
		)
		{
			ASSERT(!"cChunkBuffer::SetMeta(): index out of range!");
			return;
		}

		int Section = a_RelY / CHUNK_SECTION_HEIGHT;
		if(!m_Sections[Section])
		{
			m_Sections[Section] = Allocate();
			if(!m_Sections[Section])
			{
				ASSERT("Failed to allocate a new section in Chunkbuffer");
				return;
			}
		}
		int Index = cChunkDef::MakeIndexNoCheck(a_RelX, a_RelY - (Section * CHUNK_SECTION_HEIGHT), a_RelZ);
		m_Sections[Section]->m_BlockMeta[Index / 2] = static_cast<NIBBLETYPE>(
			(m_Sections[Section]->m_BlockMeta[Index / 2] & (0xf0 >> ((Index & 1) * 4))) |  // The untouched nibble
			((a_Nibble & 0x0f) << ((Index & 1) * 4))  // The nibble being set
		);
	}
	
	NIBBLETYPE GetBlockLight(int a_RelX, int a_RelY, int a_RelZ) const
	{
		if ((a_RelX < cChunkDef::Width) && (a_RelX > -1) && (a_RelY < cChunkDef::Height) && (a_RelY > -1) && (a_RelZ < cChunkDef::Width) && (a_RelZ > -1))
		{
			int Section = a_RelY / CHUNK_SECTION_HEIGHT;
			if(m_Sections[Section])
			{
				int Index = cChunkDef::MakeIndexNoCheck(a_RelX, a_RelY - (Section * CHUNK_SECTION_HEIGHT), a_RelZ);
				return (m_Sections[Section]->m_BlockLight[Index / 2] >> ((Index & 1) * 4)) & 0x0f;
			}
			else
			{
				return 0;
			}
		}
		ASSERT(!"cChunkBuffer::GetMeta(): coords out of chunk range!");
		return 0;
	}
	
	NIBBLETYPE GetSkyLight(int a_RelX, int a_RelY, int a_RelZ) const
	{
		if ((a_RelX < cChunkDef::Width) && (a_RelX > -1) && (a_RelY < cChunkDef::Height) && (a_RelY > -1) && (a_RelZ < cChunkDef::Width) && (a_RelZ > -1))
		{
			int Section = a_RelY / CHUNK_SECTION_HEIGHT;
			if(m_Sections[Section])
			{
				int Index = cChunkDef::MakeIndexNoCheck(a_RelX, a_RelY - (Section * CHUNK_SECTION_HEIGHT), a_RelZ);
				return (m_Sections[Section]->m_BlockLight[Index / 2] >> ((Index & 1) * 4)) & 0x0f;
			}
			else
			{
				return 0xFF;
			}
		}
		ASSERT(!"cChunkBuffer::GetMeta(): coords out of chunk range!");
		return 0;
	}
	
	cChunkBuffer Copy() const;
	void CopyBlocks   (BLOCKTYPE * a_dest, size_t a_Idx = 0, size_t length = cChunkDef::NumBlocks)  const;
	void CopyMeta     (NIBBLETYPE * a_dest) const;
	void CopyLight    (NIBBLETYPE * a_dest) const;
	void CopySkyLight (NIBBLETYPE * a_dest) const;
	
	void SetBlocks    (const BLOCKTYPE * a_src);
	void SetMeta      (const NIBBLETYPE * a_src);
	void SetLight     (const NIBBLETYPE * a_src);
	void SetSkyLight  (const NIBBLETYPE * a_src);
	
private:

	#if __cplusplus < 201103L
	// auto_ptr style interface for memory management
	mutable bool IsOwner;
	#endif
	
	struct sChunkSection {
		BLOCKTYPE  m_BlockTypes   [CHUNK_SECTION_HEIGHT * 16 * 16]    ;
		NIBBLETYPE m_BlockMeta    [CHUNK_SECTION_HEIGHT * 16 * 16 / 2];
		NIBBLETYPE m_BlockLight   [CHUNK_SECTION_HEIGHT * 16 * 16 / 2];
		NIBBLETYPE m_BlockSkyLight[CHUNK_SECTION_HEIGHT * 16 * 16 / 2];
	};
	
	sChunkSection *m_Sections[CHUNK_SECTION_NUM];
	
	sChunkSection * Allocate() const;
	void Free(sChunkSection * ptr) const;
};




/** A simple implementation of the cChunkDataCallback interface that collects all block data into a buffer
*/
class cChunkBufferCollector :
	public cChunkDataCallback
{
public:

	cChunkBuffer m_BlockData;

protected:

	virtual void ChunkBuffer(const cChunkBuffer & a_BlockData) override
	{
		m_BlockData = a_BlockData.Copy();
	}
};


/** A simple implementation of the cChunkDataCallback interface that collects all block data into a single buffer
*/
class cChunkDataCollector :
public cChunkDataCallback
{
public:

	// Must be unsigned char instead of BLOCKTYPE or NIBBLETYPE, because it houses both.
	unsigned char m_BlockData[cChunkDef::BlockDataSize];

protected:

	virtual void ChunkBuffer(const cChunkBuffer & a_ChunkBuffer) override
	{
		a_ChunkBuffer.CopyBlocks(m_BlockData);
		a_ChunkBuffer.CopyMeta(m_BlockData + cChunkDef::NumBlocks);
		a_ChunkBuffer.CopyLight(m_BlockData + 3 * cChunkDef::NumBlocks / 2);
		a_ChunkBuffer.CopySkyLight(m_BlockData + 2 * cChunkDef::NumBlocks);
	}
};

/** A simple implementation of the cChunkDataCallback interface that collects all block data into a separate buffers
*/
class cChunkDataSeparateCollector :
public cChunkDataCallback
{
public:

	cChunkDef::BlockTypes m_BlockTypes;
	cChunkDef::BlockNibbles m_BlockMetas;
	cChunkDef::BlockNibbles m_BlockLight;
	cChunkDef::BlockNibbles m_BlockSkyLight;

protected:

	virtual void ChunkBuffer(const cChunkBuffer & a_ChunkBuffer) override
	{
	a_ChunkBuffer.CopyBlocks(m_BlockTypes);
	a_ChunkBuffer.CopyMeta(m_BlockMetas);
	a_ChunkBuffer.CopyLight(m_BlockLight);
	a_ChunkBuffer.CopySkyLight(m_BlockSkyLight);
	}
} ;