// system.cpp
//
// Copyright 1998 by David K. McAllister.
//
// This file implements the API calls that are not particle actions.

#include "general.h"

#include <memory.h>

// XXX
#include <iostream>
// using namespace std;

// For Windows DLL.
#ifdef WIN32
BOOL APIENTRY DllMain( HANDLE hModule, 
                       DWORD  ul_reason_for_call, 
                       LPVOID lpReserved
					 )
{
    switch (ul_reason_for_call)
	{
		case DLL_PROCESS_ATTACH:
		case DLL_THREAD_ATTACH:
		case DLL_THREAD_DETACH:
		case DLL_PROCESS_DETACH:
			break;
    }
    return TRUE;
}
#endif

float ParticleAction::dt;

ParticleGroup **_ParticleState::group_list;
PAHeader **_ParticleState::alist_list;
int _ParticleState::group_count;
int _ParticleState::alist_count;

// This AutoCall struct allows for static initialization of the above shared variables.
struct AutoCall
{
	AutoCall();
};

AutoCall::AutoCall()
{
	// The list of groups, etc.		
	_ParticleState::group_list = new ParticleGroup *[16];
	_ParticleState::group_count = 16;
	_ParticleState::alist_list = new PAHeader *[16];
	_ParticleState::alist_count = 16;
	for(int i=0; i<16; i++)
	{
		_ParticleState::group_list[i] = NULL;
		_ParticleState::alist_list[i] = NULL;
	}
}

#ifdef PARTICLE_MP
// This code is defined if we are compiling the library to be used on
// multiple threads. We need to have each API call figure out which
// _ParticleState belongs to it. We hash pointers to contexts in
// _CtxHash. Whenever a TID is asked for but doesn't exist we create
// it.

#include <mpc.h>

// XXX This hard limit should get fixed.
int _CtxCount = 151;
_ParticleState **_CtxHash = NULL;

inline int _HashTID(int tid)
{
  return ((tid << 13) ^ ((tid >> 11) ^ tid)) % _CtxCount;
}

// Returns a reference to the appropriate particle state.
_ParticleState &_GetPStateWithTID()
{
  int tid = mp_my_threadnum();

  int ind = _HashTID(tid);

  // cerr << tid << "->" << ind << endl;

  // Check through the hash table and find it.
  for(int i=ind; i<_CtxCount; i++)
    if(_CtxHash[i] && _CtxHash[i]->tid == tid)
      {
	//#pragma critical
	//cerr << tid << " => " << i << endl;
	
      return *_CtxHash[i];
      }

  for(i=0; i<ind; i++)
    if(_CtxHash[i] && _CtxHash[i]->tid == tid)
      return *_CtxHash[i];

  // It didn't exist. It's a new context, so create it.
  _ParticleState *psp = new _ParticleState();
  psp->tid = tid;

  // Find a place to put it.
  for(i=ind; i<_CtxCount; i++)
    if(_CtxHash[i] == NULL)
      {
	// #pragma critical
	// cerr << "Stored " << tid << " at " << i << endl;
	_CtxHash[i] = psp;
	return *psp;
      }

  for(i=0; i<ind; i++)
    if(_CtxHash[i] == NULL)
      {
	_CtxHash[i] = psp;
	return *psp;
      }

  // We should never get here. The hash table got full.
  exit(1);

  // To appease warnings.
  return *_CtxHash[0];
}

inline void _PLock()
{
  // XXX This implementation is specific to the #pragma parallel directives.
  // cerr << "Getting lock.\n";
  // mp_setlock();
  // cerr << "Got lock.\n";
}

inline void _PUnLock()
{
  // XXX This implementation is specific to the #pragma parallel directives.
  // cerr << "Giving lock.\n";
  // mp_unsetlock();
  // cerr << "Gave lock.\n";
}

#else
// This is the global state.
_ParticleState __ps;

inline void _PLock()
{
}

inline void _PUnLock()
{
}
#endif

_ParticleState::_ParticleState()
{
	in_call_list = false;
	in_new_list = false;
	vertexB_tracks = true;
	
	dt = 1.0f;
	
	group_id = -1;
	list_id = -1;
	pgrp = NULL;
	pact = NULL;
	tid = 0; // This will be filled in above if we're MP.
	
	Size = pDomain(PDPoint, 1.0f, 1.0f, 1.0f);
	Vel = pDomain(PDPoint, 0.0f, 0.0f, 0.0f);
	VertexB = pDomain(PDPoint, 0.0f, 0.0f, 0.0f);
	Color = pDomain(PDPoint, 1.0f, 1.0f, 1.0f);
	Alpha = 1.0f;
	Age = 0.0f;
	AgeSigma = 0.0f;
}

ParticleGroup *_ParticleState::GetGroupPtr(int p_group_num)
{
	if(p_group_num < 0)
		return NULL; // IERROR

	if(p_group_num >= group_count)
		return NULL; // IERROR

	return group_list[p_group_num];
}

PAHeader *_ParticleState::GetListPtr(int a_list_num)
{
	if(a_list_num < 0)
		return NULL; // IERROR

	if(a_list_num >= alist_count)
		return NULL; // IERROR

	return alist_list[a_list_num];
}

// Return an index into the list of particle groups where
// p_group_count groups can be added.
int _ParticleState::GenerateGroups(int p_group_count)
{
	int num_empty = 0;
	int first_empty = -1;
	
	for(int i=0; i<group_count; i++)
	{
		if(group_list[i])
		{
			num_empty = 0;
			first_empty = -1;
		}
		else
		{
			if(first_empty < 0)
				first_empty = i;
			num_empty++;
			if(num_empty >= p_group_count)
				return first_empty;
		}
	}
	
	// Couldn't find a big enough gap. Reallocate.
	int new_count = 16 + group_count + p_group_count;
	ParticleGroup **glist = new ParticleGroup *[new_count];
	memcpy(glist, group_list, group_count * sizeof(void*));
	for(int i=group_count; i<new_count; i++)
		glist[i] = NULL;
	delete [] group_list;
	group_list = glist;
	group_count = new_count;
	
	return GenerateGroups(p_group_count);
}

// Return an index into the list of action lists where
// list_count lists can be added.
int _ParticleState::GenerateLists(int list_count)
{
	int num_empty = 0;
	int first_empty = -1;
	
	for(int i=0; i<alist_count; i++)
	{
		if(alist_list[i])
		{
			num_empty = 0;
			first_empty = -1;
		}
		else
		{
			if(first_empty < 0)
				first_empty = i;
			num_empty++;
			if(num_empty >= list_count)
				return first_empty;
		}
	}
	
	// Couldn't find a big enough gap. Reallocate.
	int new_count = 16 + alist_count + list_count;
	PAHeader **new_list = new PAHeader *[new_count];
	memcpy(new_list, alist_list, alist_count * sizeof(void*));
	for(int i=list_count; i<new_count; i++)
		new_list[i] = NULL;
	delete [] alist_list;
	alist_list = new_list;
	alist_count = new_count;
	
	return GenerateLists(list_count);
}

////////////////////////////////////////////////////////
// Auxiliary calls
void _pCallActionList(ParticleAction *apa, int num_actions,
					  ParticleGroup *pg)
{
	// All these require a particle group, so check for it.
	if(pg == NULL)
		return;
	
	PAHeader *pa = (PAHeader *)apa;
	
	// Step through all the actions in the action list.
	for(int action = 0; action < num_actions; action++, pa++)
	{
		switch(pa->type)
		{
		case PAAvoidID:
			((PAAvoid *)pa)->Execute(pg);
			break;
		case PABounceID:
			((PABounce *)pa)->Execute(pg);
			break;
		case PACallActionListID:
			((PACallActionList *)pa)->Execute(pg);
			break;
		case PACopyVertexBID:
			((PACopyVertexB *)pa)->Execute(pg);
			break;
		case PADampingID:
			((PADamping *)pa)->Execute(pg);
			break;
		case PAExplosionID:
			((PAExplosion *)pa)->Execute(pg);
			break;
		case PAFollowID:
			((PAFollow *)pa)->Execute(pg);
			break;
		case PAGravitateID:
			((PAGravitate *)pa)->Execute(pg);
			break;
		case PAGravityID:
			((PAGravity *)pa)->Execute(pg);
			break;
		case PAJetID:
			((PAJet *)pa)->Execute(pg);
			break;
		case PAKillOldID:
			((PAKillOld *)pa)->Execute(pg);
			break;
		case PAMatchVelocityID:
			((PAMatchVelocity *)pa)->Execute(pg);
			break;
		case PAMoveID:
			((PAMove *)pa)->Execute(pg);
			break;
		case PAOrbitLineID:
			((PAOrbitLine *)pa)->Execute(pg);
			break;
		case PAOrbitPointID:
			((PAOrbitPoint *)pa)->Execute(pg);
			break;
		case PARandomAccelID:
			((PARandomAccel *)pa)->Execute(pg);
			break;
		case PARandomDisplaceID:
			((PARandomDisplace *)pa)->Execute(pg);
			break;
		case PARandomVelocityID:
			((PARandomVelocity *)pa)->Execute(pg);
			break;
		case PARestoreID:
			((PARestore *)pa)->Execute(pg);
			break;
		case PASinkID:
			((PASink *)pa)->Execute(pg);
			break;
		case PASinkVelocityID:
			((PASinkVelocity *)pa)->Execute(pg);
			break;
		case PASourceID:
			((PASource *)pa)->Execute(pg);
			break;
		case PASpeedLimitID:
			((PASpeedLimit *)pa)->Execute(pg);
			break;
		case PATargetColorID:
			((PATargetColor *)pa)->Execute(pg);
			break;
		case PATargetSizeID:
			((PATargetSize *)pa)->Execute(pg);
			break;
		case PATargetVelocityID:
			((PATargetVelocity *)pa)->Execute(pg);
			break;
		case PAVortexID:
			((PAVortex *)pa)->Execute(pg);
			break;
		}
	}
}

// Add the incoming action to the end of the current action list.
void _pAddActionToList(ParticleAction *S, int size)
{
	_ParticleState &_ps = _GetPState();

	if(!_ps.in_new_list)
		return; // ERROR
	
	if(_ps.pact == NULL)
		return; // ERROR
	
	if(_ps.list_id < 0)
		return; // ERROR
	
	PAHeader *alist = _ps.pact;
	
	if(alist->actions_allocated <= alist->count)
	{
		// Must reallocate.
		int new_alloc = 16 + alist->actions_allocated;
		PAHeader *new_alist = new PAHeader[new_alloc];
		memcpy(new_alist, alist, alist->count * sizeof(PAHeader));
		
		delete [] alist;
		_ps.alist_list[_ps.list_id] = _ps.pact = alist = new_alist;
		
		alist->actions_allocated = new_alloc;
	}
	
	// Now add it in.
	memcpy(&alist[alist->count], S, size);
	alist->count++;
}

////////////////////////////////////////////////////////
// State setting calls

PARTICLEDLL_API void pColor(float red, float green, float blue, float alpha)
{
	_ParticleState &_ps = _GetPState();

	_ps.Alpha = alpha;
	_ps.Color = pDomain(PDPoint, red, green, blue);
}

PARTICLEDLL_API void pColorD(float alpha, PDomainEnum dtype,
			 float a0, float a1, float a2,
			 float a3, float a4, float a5,
			 float a6, float a7, float a8)
{
	_ParticleState &_ps = _GetPState();

	_ps.Alpha = alpha;
	_ps.Color = pDomain(dtype, a0, a1, a2, a3, a4, a5, a6, a7, a8);
}

PARTICLEDLL_API void pVelocity(float x, float y, float z)
{
	_ParticleState &_ps = _GetPState();

	_ps.Vel = pDomain(PDPoint, x, y, z);
}

PARTICLEDLL_API void pVelocityD(PDomainEnum dtype,
				float a0, float a1, float a2,
				float a3, float a4, float a5,
				float a6, float a7, float a8)
{
	_ParticleState &_ps = _GetPState();

	_ps.Vel = pDomain(dtype, a0, a1, a2, a3, a4, a5, a6, a7, a8);
}

PARTICLEDLL_API void pVertexB(float x, float y, float z)
{
	_ParticleState &_ps = _GetPState();

	_ps.VertexB = pDomain(PDPoint, x, y, z);
}

PARTICLEDLL_API void pVertexBD(PDomainEnum dtype,
			   float a0, float a1, float a2,
			   float a3, float a4, float a5,
			   float a6, float a7, float a8)
{
	_ParticleState &_ps = _GetPState();

	_ps.VertexB = pDomain(dtype, a0, a1, a2, a3, a4, a5, a6, a7, a8);
}


PARTICLEDLL_API void pVertexBTracks(bool trackVertex)
{
	_ParticleState &_ps = _GetPState();

	_ps.vertexB_tracks = trackVertex;
}

PARTICLEDLL_API void pSize(float size_x, float size_y, float size_z)
{
	_ParticleState &_ps = _GetPState();

	_ps.Size = pDomain(PDPoint, size_x, size_y, size_z);
}

PARTICLEDLL_API void pSizeD(PDomainEnum dtype,
			   float a0, float a1, float a2,
			   float a3, float a4, float a5,
			   float a6, float a7, float a8)
{
	_ParticleState &_ps = _GetPState();

	_ps.Size = pDomain(dtype, a0, a1, a2, a3, a4, a5, a6, a7, a8);
}

PARTICLEDLL_API void pStartingAge(float age, float sigma)
{
	_ParticleState &_ps = _GetPState();

	_ps.Age = age;
	_ps.AgeSigma = sigma;
}

PARTICLEDLL_API void pTimeStep(float newDT)
{
	_ParticleState &_ps = _GetPState();

	_ps.dt = newDT;
}

////////////////////////////////////////////////////////
// Action List Calls

PARTICLEDLL_API int pGenActionLists(int action_list_count)
{
	_ParticleState &_ps = _GetPState();

	if(_ps.in_new_list)
		return -1; // ERROR
	
	_PLock();

	int ind = _ps.GenerateLists(action_list_count);
	
	for(int i=ind; i<ind+action_list_count; i++)
	{
		_ps.alist_list[i] = new PAHeader[8];
		_ps.alist_list[i]->actions_allocated = 8;
		_ps.alist_list[i]->type = PAHeaderID;
		_ps.alist_list[i]->count = 1;
	}

	_PUnLock();

	return ind;
}

PARTICLEDLL_API void pNewActionList(int action_list_num)
{
	_ParticleState &_ps = _GetPState();

	if(_ps.in_new_list)
		return; // ERROR
	
	_ps.pact = _ps.GetListPtr(action_list_num);
	
	if(_ps.pact == NULL)
		return; // ERROR
	
	_ps.list_id = action_list_num;
	_ps.in_new_list = true;

	// Remove whatever used to be in the list.
	_ps.pact->count = 1;
}

PARTICLEDLL_API void pEndActionList()
{
	_ParticleState &_ps = _GetPState();

	if(!_ps.in_new_list)
		return; // ERROR
	
	_ps.in_new_list = false;
	
	_ps.pact = NULL;
	_ps.list_id = -1;
}

PARTICLEDLL_API void pDeleteActionLists(int action_list_num, int action_list_count)
{
	_ParticleState &_ps = _GetPState();

	if(_ps.in_new_list)
		return; // ERROR

	if(action_list_num < 0)
		return; // ERROR

	if(action_list_num + action_list_count > _ps.alist_count)
		return; // ERROR

	_PLock();

	for(int i = action_list_num; i < action_list_num + action_list_count; i++)
	{
		if(_ps.alist_list[i])
		{
			delete [] _ps.alist_list[i];
			_ps.alist_list[i] = NULL;
		}
		else
		{
			_PUnLock();
			return; // ERROR
		}
	}

	_PUnLock();
}

PARTICLEDLL_API void pCallActionList(int action_list_num)
{
	_ParticleState &_ps = _GetPState();

	if(_ps.in_new_list)
	{
		// Add this call as an action to the current list.
		extern void _pSendAction(ParticleAction *S, PActionEnum type, int size);

		PACallActionList S;
		S.action_list_num = action_list_num;
		
		_pSendAction(&S, PACallActionListID, sizeof(PACallActionList));
	}
	else
	{
		// Execute the specified action list.
		PAHeader *pa = _ps.GetListPtr(action_list_num);
		
		if(pa == NULL)
			return; // ERRROR
		
		// XXX A temporary hack.
		pa->dt = _ps.dt;
		
		_ps.in_call_list = true;
		
		_pCallActionList(pa+1, pa->count-1, _ps.pgrp);
		
		_ps.in_call_list = false;
	}
}

////////////////////////////////////////////////////////
// Particle Group Calls

// Create particle groups, each with max_particles allocated.
PARTICLEDLL_API int pGenParticleGroups(int p_group_count, int max_particles)
{
	_ParticleState &_ps = _GetPState();

	if(_ps.in_new_list)
		return -1; // ERROR

	_PLock();
	// cerr << "Generating pg " << _ps.tid << " cnt= " << max_particles << endl;

	int ind = _ps.GenerateGroups(p_group_count);
	
	for(int i=ind; i<ind+p_group_count; i++)
	{
		_ps.group_list[i] = (ParticleGroup *)new
			Particle[max_particles + 2];
		_ps.group_list[i]->max_particles = max_particles;
		_ps.group_list[i]->particles_allocated = max_particles;
		_ps.group_list[i]->p_count = 0;
	}

	_PUnLock();
	
	return ind;
}

PARTICLEDLL_API void pDeleteParticleGroups(int p_group_num, int p_group_count)
{
	_ParticleState &_ps = _GetPState();

	if(p_group_num < 0)
		return; // ERROR

	if(p_group_num + p_group_count > _ps.group_count)
		return; // ERROR
	
	_PLock();

	for(int i = p_group_num; i < p_group_num + p_group_count; i++)
	{
		if(_ps.group_list[i])
		{
			delete [] _ps.group_list[i];
			_ps.group_list[i] = NULL;
		}
		else
		  {
		  	_PUnLock();
			return; // ERROR
		  }
	}

	_PUnLock();
}

// Change which group is current.
PARTICLEDLL_API void pCurrentGroup(int p_group_num)
{
	_ParticleState &_ps = _GetPState();

	if(_ps.in_new_list)
		return; // ERROR
	
	_ps.pgrp = _ps.GetGroupPtr(p_group_num);
	if(_ps.pgrp)
		_ps.group_id = p_group_num;
	else
		_ps.group_id = -1;
}

// Change the maximum number of particles in the current group.
PARTICLEDLL_API int pSetMaxParticles(int max_count)
{
	_ParticleState &_ps = _GetPState();

	if(_ps.in_new_list)
		return 0; // ERROR
	
	ParticleGroup *pg = _ps.pgrp;
	if(pg == NULL)
		return 0; // ERROR
	
	if(max_count < 0)
		return 0; // ERROR

	// Reducing max.
	if(pg->particles_allocated >= max_count)
	{
		pg->max_particles = max_count;

		// May have to kill particles.
		if(pg->p_count > pg->max_particles)
			pg->p_count = pg->max_particles;

		return max_count;
	}

	_PLock();
	
	// Allocate particles.
	ParticleGroup *pg2 =(ParticleGroup *)new Particle[max_count + 2];
	if(pg2 == NULL)
	{
		// Not enough memory. Just give all we've got.
		// ERROR
		pg->max_particles = pg->particles_allocated;

		_PUnLock();
		
		return pg->max_particles;
	}
	
	memcpy(pg2, pg, (pg->p_count + 2) * sizeof(Particle));
	
	delete [] pg;
	
	_ps.group_list[_ps.group_id] = _ps.pgrp = pg2;
	pg2->max_particles = max_count;
	pg2->particles_allocated = max_count;

	_PUnLock();

	return max_count;
}

// Copy from the specified group to the current group.
PARTICLEDLL_API void pCopyGroup(int p_src_group_num, int index, int copy_count)
{
	_ParticleState &_ps = _GetPState();

	if(_ps.in_new_list)
		return; // ERROR
	
	ParticleGroup *srcgrp = _ps.GetGroupPtr(p_src_group_num);
	if(srcgrp == NULL)
		return; // ERROR

	ParticleGroup *destgrp = _ps.pgrp;
	if(destgrp == NULL)
		return; // ERROR

	// Find out exactly how many to copy.
	int ccount = copy_count;
	if(ccount > srcgrp->p_count - index)
		ccount = srcgrp->p_count - index;
	if(ccount > destgrp->max_particles - destgrp->p_count)
		ccount = destgrp->max_particles - destgrp->p_count;

	// #pragma critical
	// cerr << p_src_group_num << ": " << ccount << " " << srcgrp->p_count << " " << index << endl;

	if(ccount<0)
	  ccount = 0;

	// Directly copy the particles to the current list.
	for(int i=0; i<ccount; i++)
	{
		destgrp->list[destgrp->p_count+i] =
			srcgrp->list[index+i];
	}
	destgrp->p_count += ccount;
}

// Copy from the current group to application memory.
PARTICLEDLL_API int pGetParticles(int index, int count, float *verts,
				  float *color, float *vel, float *size, float *age)
{
	_ParticleState &_ps = _GetPState();

	// XXX I should think about whether color means color3, color4, or what.
	// For now, it means color4.

	if(_ps.in_new_list)
		return -1; // ERROR
		
	ParticleGroup *pg = _ps.pgrp;
	if(pg == NULL)
		return -2; // ERROR

	if(index < 0 || count < 0)
		return -3; // ERROR

	if(index + count > pg->p_count)
	  {
	    count = pg->p_count - index;
	    if(count <= 0)
	      return -4; // ERROR index out of bounds.
	  }

	int vi = 0, ci = 0, li = 0, si = 0, ai = 0;

	// This could be optimized.
	for(int i=0; i<count; i++)
	{
		Particle &m = pg->list[index + i];

		if(verts)
		{
			verts[vi++] = m.pos.x;
			verts[vi++] = m.pos.y;
			verts[vi++] = m.pos.z;
		}

		if(color)
		{
			color[ci++] = m.color.x;
			color[ci++] = m.color.y;
			color[ci++] = m.color.z;
			color[ci++] = m.alpha;
		}

		if(vel)
		{
			vel[li++] = m.vel.x;
			vel[li++] = m.vel.y;
			vel[li++] = m.vel.z;
		}

		if(size)
		{
			size[si++] = m.size.x;
			size[si++] = m.size.y;
			size[si++] = m.size.z;
		}

		if(age)
		{
			age[ai++] = m.age;
		}
	}

	return count;
}

// Returns the number of particles currently in the group.
PARTICLEDLL_API int pGetGroupCount()
{
	_ParticleState &_ps = _GetPState();

	if(_ps.in_new_list)
		return 0; // ERROR
	
	if(_ps.pgrp == NULL)
		return 0; // ERROR

	return _ps.pgrp->p_count;
}