/*
Minetest-c55
Copyright (C) 2010 celeron55, Perttu Ahola <celeron55@gmail.com>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 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 General Public License for more details.

You should have received a copy of the GNU 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.
*/

#ifndef VOXEL_HEADER
#define VOXEL_HEADER

#include "common_irrlicht.h"
#include <iostream>
#include "debug.h"
#include "mapnode.h"

#undef min
#undef max

/*
	A fast voxel manipulator class

	Not thread-safe.
*/

/*
	Debug stuff
*/
extern u32 emerge_time;
extern u32 emerge_load_time;

/*
	This class resembles aabbox3d<s16> a lot, but has inclusive
	edges for saner handling of integer sizes
*/
class VoxelArea
{
public:
	// Starts as zero sized
	VoxelArea():
		MinEdge(1,1,1),
		MaxEdge(0,0,0)
	{
	}
	VoxelArea(v3s16 min_edge, v3s16 max_edge):
		MinEdge(min_edge),
		MaxEdge(max_edge)
	{
	}
	VoxelArea(v3s16 p):
		MinEdge(p),
		MaxEdge(p)
	{
	}
	
	/*
		Modifying methods
	*/

	void addArea(VoxelArea &a)
	{
		if(getExtent() == v3s16(0,0,0))
		{
			*this = a;
			return;
		}
		if(a.MinEdge.X < MinEdge.X) MinEdge.X = a.MinEdge.X;
		if(a.MinEdge.Y < MinEdge.Y) MinEdge.Y = a.MinEdge.Y;
		if(a.MinEdge.Z < MinEdge.Z) MinEdge.Z = a.MinEdge.Z;
		if(a.MaxEdge.X > MaxEdge.X) MaxEdge.X = a.MaxEdge.X;
		if(a.MaxEdge.Y > MaxEdge.Y) MaxEdge.Y = a.MaxEdge.Y;
		if(a.MaxEdge.Z > MaxEdge.Z) MaxEdge.Z = a.MaxEdge.Z;
	}
	void addPoint(v3s16 p)
	{
		if(getExtent() == v3s16(0,0,0))
		{
			MinEdge = p;
			MaxEdge = p;
			return;
		}
		if(p.X < MinEdge.X) MinEdge.X = p.X;
		if(p.Y < MinEdge.Y) MinEdge.Y = p.Y;
		if(p.Z < MinEdge.Z) MinEdge.Z = p.Z;
		if(p.X > MaxEdge.X) MaxEdge.X = p.X;
		if(p.Y > MaxEdge.Y) MaxEdge.Y = p.Y;
		if(p.Z > MaxEdge.Z) MaxEdge.Z = p.Z;
	}
	
	// Pad with d nodes
	void pad(v3s16 d)
	{
		MinEdge -= d;
		MaxEdge += d;
	}
	
	/*void operator+=(v3s16 off)
	{
		MinEdge += off;
		MaxEdge += off;
	}

	void operator-=(v3s16 off)
	{
		MinEdge -= off;
		MaxEdge -= off;
	}*/

	/*
		const methods
	*/

	v3s16 getExtent() const
	{
		return MaxEdge - MinEdge + v3s16(1,1,1);
	}
	s32 getVolume() const
	{
		v3s16 e = getExtent();
		return (s32)e.X * (s32)e.Y * (s32)e.Z;
	}
	bool contains(const VoxelArea &a) const
	{
		// No area contains an empty area
		// NOTE: Algorithms depend on this, so do not change.
		if(a.getExtent() == v3s16(0,0,0))
			return false;

		return(
			a.MinEdge.X >= MinEdge.X && a.MaxEdge.X <= MaxEdge.X &&
			a.MinEdge.Y >= MinEdge.Y && a.MaxEdge.Y <= MaxEdge.Y &&
			a.MinEdge.Z >= MinEdge.Z && a.MaxEdge.Z <= MaxEdge.Z
		);
	}
	bool contains(v3s16 p) const
	{
		return(
			p.X >= MinEdge.X && p.X <= MaxEdge.X &&
			p.Y >= MinEdge.Y && p.Y <= MaxEdge.Y &&
			p.Z >= MinEdge.Z && p.Z <= MaxEdge.Z
		);
	}
	bool operator==(const VoxelArea &other) const
	{
		return (MinEdge == other.MinEdge
				&& MaxEdge == other.MaxEdge);
	}

	VoxelArea operator+(v3s16 off) const
	{
		return VoxelArea(MinEdge+off, MaxEdge+off);
	}

	VoxelArea operator-(v3s16 off) const
	{
		return VoxelArea(MinEdge-off, MaxEdge-off);
	}

	/*
		Returns 0-6 non-overlapping areas that can be added to
		a to make up this area.

		a: area inside *this
	*/
	void diff(const VoxelArea &a, core::list<VoxelArea> &result)
	{
		/*
			This can result in a maximum of 6 areas
		*/

		// If a is an empty area, return the current area as a whole
		if(a.getExtent() == v3s16(0,0,0))
		{
			VoxelArea b = *this;
			if(b.getVolume() != 0)
				result.push_back(b);
			return;
		}

		assert(contains(a));
		
		// Take back area, XY inclusive
		{
			v3s16 min(MinEdge.X, MinEdge.Y, a.MaxEdge.Z+1);
			v3s16 max(MaxEdge.X, MaxEdge.Y, MaxEdge.Z);
			VoxelArea b(min, max);
			if(b.getVolume() != 0)
				result.push_back(b);
		}

		// Take front area, XY inclusive
		{
			v3s16 min(MinEdge.X, MinEdge.Y, MinEdge.Z);
			v3s16 max(MaxEdge.X, MaxEdge.Y, a.MinEdge.Z-1);
			VoxelArea b(min, max);
			if(b.getVolume() != 0)
				result.push_back(b);
		}

		// Take top area, X inclusive
		{
			v3s16 min(MinEdge.X, a.MaxEdge.Y+1, a.MinEdge.Z);
			v3s16 max(MaxEdge.X, MaxEdge.Y, a.MaxEdge.Z);
			VoxelArea b(min, max);
			if(b.getVolume() != 0)
				result.push_back(b);
		}

		// Take bottom area, X inclusive
		{
			v3s16 min(MinEdge.X, MinEdge.Y, a.MinEdge.Z);
			v3s16 max(MaxEdge.X, a.MinEdge.Y-1, a.MaxEdge.Z);
			VoxelArea b(min, max);
			if(b.getVolume() != 0)
				result.push_back(b);
		}

		// Take left area, non-inclusive
		{
			v3s16 min(MinEdge.X, a.MinEdge.Y, a.MinEdge.Z);
			v3s16 max(a.MinEdge.X-1, a.MaxEdge.Y, a.MaxEdge.Z);
			VoxelArea b(min, max);
			if(b.getVolume() != 0)
				result.push_back(b);
		}

		// Take right area, non-inclusive
		{
			v3s16 min(a.MaxEdge.X+1, a.MinEdge.Y, a.MinEdge.Z);
			v3s16 max(MaxEdge.X, a.MaxEdge.Y, a.MaxEdge.Z);
			VoxelArea b(min, max);
			if(b.getVolume() != 0)
				result.push_back(b);
		}

	}
	
	/*
		Translates position from virtual coordinates to array index
	*/
	s32 index(s16 x, s16 y, s16 z) const
	{
		v3s16 em = getExtent();
		v3s16 off = MinEdge;
		s32 i = (s32)(z-off.Z)*em.Y*em.X + (y-off.Y)*em.X + (x-off.X);
		//dstream<<" i("<<x<<","<<y<<","<<z<<")="<<i<<" ";
		return i;
	}
	s32 index(v3s16 p) const
	{
		return index(p.X, p.Y, p.Z);
	}

	void print(std::ostream &o) const
	{
		v3s16 e = getExtent();
		o<<"("<<MinEdge.X
		 <<","<<MinEdge.Y
		 <<","<<MinEdge.Z
		 <<")("<<MaxEdge.X
		 <<","<<MaxEdge.Y
		 <<","<<MaxEdge.Z
		 <<")"
		 <<"="<<e.X<<"x"<<e.Y<<"x"<<e.Z<<"="<<getVolume();
	}

	// Edges are inclusive
	v3s16 MinEdge;
	v3s16 MaxEdge;
};

// Hasn't been copied from source (emerged)
#define VOXELFLAG_NOT_LOADED (1<<0)
// Checked as being inexistent in source
#define VOXELFLAG_INEXISTENT (1<<1)
// Algorithm-dependent
// flowWater: "visited"
#define VOXELFLAG_CHECKED (1<<2)
// Algorithm-dependent
// getWaterPressure: "visited"
#define VOXELFLAG_CHECKED2 (1<<3)
// Algorithm-dependent
// spreadWaterPressure: "visited"
#define VOXELFLAG_CHECKED3 (1<<4)
// Algorithm-dependent
// water: "pressure check route node"
#define VOXELFLAG_CHECKED4 (1<<5)

enum VoxelPrintMode
{
	VOXELPRINT_NOTHING,
	VOXELPRINT_MATERIAL,
	VOXELPRINT_WATERPRESSURE,
};

class VoxelManipulator /*: public NodeContainer*/
{
public:
	VoxelManipulator();
	virtual ~VoxelManipulator();
	
	/*
		Virtuals from NodeContainer
	*/
	/*virtual u16 nodeContainerId() const
	{
		return NODECONTAINER_ID_VOXELMANIPULATOR;
	}
	bool isValidPosition(v3s16 p)
	{
		emerge(p);
		return !(m_flags[m_area.index(p)] & VOXELFLAG_INEXISTENT);
	}*/
	// These are a bit slow and shouldn't be used internally
	MapNode getNode(v3s16 p)
	{
		emerge(p);

		if(m_flags[m_area.index(p)] & VOXELFLAG_INEXISTENT)
		{
			dstream<<"EXCEPT: VoxelManipulator::getNode(): "
					<<"p=("<<p.X<<","<<p.Y<<","<<p.Z<<")"
					<<", index="<<m_area.index(p)
					<<", flags="<<(int)m_flags[m_area.index(p)]
					<<" is inexistent"<<std::endl;
			throw InvalidPositionException
			("VoxelManipulator: getNode: inexistent");
		}

		return m_data[m_area.index(p)];
	}
	void setNode(v3s16 p, MapNode &n)
	{
		emerge(p);
		
		m_data[m_area.index(p)] = n;
		m_flags[m_area.index(p)] &= ~VOXELFLAG_INEXISTENT;
		m_flags[m_area.index(p)] &= ~VOXELFLAG_NOT_LOADED;
	}
	void setNodeNoRef(v3s16 p, MapNode n)
	{
		setNode(p, n);
	}

	/*void setExists(VoxelArea a)
	{
		emerge(a);
		for(s32 z=a.MinEdge.Z; z<=a.MaxEdge.Z; z++)
		for(s32 y=a.MinEdge.Y; y<=a.MaxEdge.Y; y++)
		for(s32 x=a.MinEdge.X; x<=a.MaxEdge.X; x++)
		{
			m_flags[m_area.index(x,y,z)] &= ~VOXELFLAG_INEXISTENT;
		}
	}*/

	/*MapNode & operator[](v3s16 p)
	{
		//dstream<<"operator[] p=("<<p.X<<","<<p.Y<<","<<p.Z<<")"<<std::endl;
		if(isValidPosition(p) == false)
			emerge(VoxelArea(p));
		
		return m_data[m_area.index(p)];
	}*/

	/*
		Control
	*/

	virtual void clear();

	void print(std::ostream &o, VoxelPrintMode mode=VOXELPRINT_MATERIAL);
	
	void addArea(VoxelArea area);

	/*
		Copy data and set flags to 0
		dst_area.getExtent() <= src_area.getExtent()
	*/
	void copyFrom(MapNode *src, VoxelArea src_area,
			v3s16 from_pos, v3s16 to_pos, v3s16 size);

	/*
		Algorithms
	*/

	void interpolate(VoxelArea area);

	void clearFlag(u8 flag);
	
	// VOXELFLAG_CHECKED2s must usually be cleared before calling
	// -1: dead end, 0-255: pressure
	// highest_y: Highest found water y is stored here.
	//            Must be initialized to -32768
	int getWaterPressure(v3s16 p, s16 &highest_y, int recur_count);

	/*
		VOXELFLAG_CHECKED3s must usually be cleared before calling.

		active_nodes: surface-touching air nodes with flow-causing
		pressure. set-like dummy map container.

		Spreads pressure pr at node p to request_area or as far as
		there is invalid pressure.
	*/
	void spreadWaterPressure(v3s16 p, int pr,
			VoxelArea request_area,
			core::map<v3s16, u8> &active_nodes,
			int recur_count);
	
	/*
		VOXELFLAG_CHECKED3s must usually be cleared before calling.
	*/
	void updateAreaWaterPressure(VoxelArea a,
			core::map<v3s16, u8> &active_nodes,
			bool checked3_is_clear=false);
	
	/*
		Returns true if moved something
	*/
	bool flowWater(v3s16 removed_pos,
			core::map<v3s16, u8> &active_nodes,
			int recursion_depth=0,
			bool debugprint=false,
			u32 stoptime=0
	);

	/*
		To flow some water, call this with the target node in
		active_nodes
		TODO: Make the active_nodes map to contain some vectors
		      that are properly sorted according to water flow order.
			  The current order makes water flow strangely if the
			  first one is always taken.
			  No, active_nodes should preserve the order stuff is
			  added to it, in addition to adhering the water flow
			  order.
	*/
	void flowWater(core::map<v3s16, u8> &active_nodes,
			int recursion_depth=0,
			bool debugprint=false,
			u32 timelimit=50
	);

	/*
		Virtual functions
	*/
	
	/*
		Get the contents of the requested area from somewhere.
		Shall touch only nodes that have VOXELFLAG_NOT_LOADED
		Shall reset VOXELFLAG_NOT_LOADED

		If not found from source, add with VOXELFLAG_INEXISTENT
	*/
	virtual void emerge(VoxelArea a, s32 caller_id=-1)
	{
		//dstream<<"emerge p=("<<p.X<<","<<p.Y<<","<<p.Z<<")"<<std::endl;
		addArea(a);
		for(s32 z=a.MinEdge.Z; z<=a.MaxEdge.Z; z++)
		for(s32 y=a.MinEdge.Y; y<=a.MaxEdge.Y; y++)
		for(s32 x=a.MinEdge.X; x<=a.MaxEdge.X; x++)
		{
			s32 i = m_area.index(x,y,z);
			// Don't touch nodes that have already been loaded
			if(!(m_flags[i] & VOXELFLAG_NOT_LOADED))
				continue;
			m_flags[i] = VOXELFLAG_INEXISTENT;
		}
	}

	/*
		Member variables
	*/

	/*
		The area that is stored in m_data.
		addInternalBox should not be used if getExtent() == v3s16(0,0,0)
		MaxEdge is 1 higher than maximum allowed position
	*/
	VoxelArea m_area;
	
	/*
		NULL if data size is 0 (extent (0,0,0))
		Data is stored as [z*h*w + y*h + x]
	*/
	MapNode *m_data;

	/*
		Flags of all nodes
	*/
	u8 *m_flags;
	
	//TODO: Use these or remove them
	//TODO: Would these make any speed improvement?
	//bool m_pressure_route_valid;
	//v3s16 m_pressure_route_surface;

	/*
		Some settings
	*/
	bool m_disable_water_climb;

private:
};

#endif