/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * 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.
 *
 * The Original Code is Copyright (C) 2005 by the Blender Foundation.
 * All rights reserved.
 *
 * Contributor(s): Daniel Dunbar
 *                 Ton Roosendaal,
 *                 Ben Batt,
 *                 Brecht Van Lommel,
 *                 Campbell Barton
 *
 * ***** END GPL LICENSE BLOCK *****
 *
 */

/** \file blender/modifiers/intern/MOD_particleinstance.c
 *  \ingroup modifiers
 */


#include "DNA_meshdata_types.h"

#include "MEM_guardedalloc.h"

#include "BLI_math.h"
#include "BLI_listbase.h"
#include "BLI_rand.h"
#include "BLI_utildefines.h"

#include "BKE_cdderivedmesh.h"
#include "BKE_lattice.h"
#include "BKE_modifier.h"
#include "BKE_particle.h"
#include "BKE_pointcache.h"

#include "MOD_util.h"

#include "depsgraph_private.h"


static void initData(ModifierData *md)
{
	ParticleInstanceModifierData *pimd = (ParticleInstanceModifierData *) md;

	pimd->flag = eParticleInstanceFlag_Parents | eParticleInstanceFlag_Unborn |
	             eParticleInstanceFlag_Alive | eParticleInstanceFlag_Dead;
	pimd->psys = 1;
	pimd->position = 1.0f;
	pimd->axis = 2;

}
static void copyData(ModifierData *md, ModifierData *target)
{
	ParticleInstanceModifierData *pimd = (ParticleInstanceModifierData *) md;
	ParticleInstanceModifierData *tpimd = (ParticleInstanceModifierData *) target;

	tpimd->ob = pimd->ob;
	tpimd->psys = pimd->psys;
	tpimd->flag = pimd->flag;
	tpimd->axis = pimd->axis;
	tpimd->position = pimd->position;
	tpimd->random_position = pimd->random_position;
}

static int dependsOnTime(ModifierData *UNUSED(md))
{
	return 0;
}
static void updateDepgraph(ModifierData *md, DagForest *forest,
                           struct Scene *UNUSED(scene),
                           Object *UNUSED(ob),
                           DagNode *obNode)
{
	ParticleInstanceModifierData *pimd = (ParticleInstanceModifierData *) md;

	if (pimd->ob) {
		DagNode *curNode = dag_get_node(forest, pimd->ob);

		dag_add_relation(forest, curNode, obNode,
		                 DAG_RL_DATA_DATA | DAG_RL_OB_DATA,
		                 "Particle Instance Modifier");
	}
}

static void foreachObjectLink(ModifierData *md, Object *ob,
                              ObjectWalkFunc walk, void *userData)
{
	ParticleInstanceModifierData *pimd = (ParticleInstanceModifierData *) md;

	walk(userData, ob, &pimd->ob);
}

static DerivedMesh *applyModifier(ModifierData *md, Object *ob,
                                  DerivedMesh *derivedData,
                                  int UNUSED(useRenderParams),
                                  int UNUSED(isFinalCalc))
{
	DerivedMesh *dm = derivedData, *result;
	ParticleInstanceModifierData *pimd = (ParticleInstanceModifierData *) md;
	ParticleSimulationData sim;
	ParticleSystem *psys = NULL;
	ParticleData *pa = NULL, *pars = NULL;
	MFace *mface, *orig_mface;
	MVert *mvert, *orig_mvert;
	int i, totvert, totpart = 0, totface, maxvert, maxface, first_particle = 0;
	short track = ob->trackflag % 3, trackneg, axis = pimd->axis;
	float max_co = 0.0, min_co = 0.0, temp_co[3], cross[3];
	float *size = NULL;

	DM_ensure_tessface(dm); /* BMESH - UNTIL MODIFIER IS UPDATED FOR MPoly */

	trackneg = ((ob->trackflag > 2) ? 1 : 0);

	if (pimd->ob == ob) {
		pimd->ob = NULL;
		return derivedData;
	}

	if (pimd->ob) {
		psys = BLI_findlink(&pimd->ob->particlesystem, pimd->psys - 1);
		if (psys == NULL || psys->totpart == 0)
			return derivedData;
	}
	else return derivedData;

	if (pimd->flag & eParticleInstanceFlag_Parents)
		totpart += psys->totpart;
	if (pimd->flag & eParticleInstanceFlag_Children) {
		if (totpart == 0)
			first_particle = psys->totpart;
		totpart += psys->totchild;
	}

	if (totpart == 0)
		return derivedData;

	sim.scene = md->scene;
	sim.ob = pimd->ob;
	sim.psys = psys;
	sim.psmd = psys_get_modifier(pimd->ob, psys);

	if (pimd->flag & eParticleInstanceFlag_UseSize) {
		int p;
		float *si;
		si = size = MEM_callocN(totpart * sizeof(float), "particle size array");

		if (pimd->flag & eParticleInstanceFlag_Parents) {
			for (p = 0, pa = psys->particles; p < psys->totpart; p++, pa++, si++)
				*si = pa->size;
		}

		if (pimd->flag & eParticleInstanceFlag_Children) {
			ChildParticle *cpa = psys->child;

			for (p = 0; p < psys->totchild; p++, cpa++, si++) {
				*si = psys_get_child_size(psys, cpa, 0.0f, NULL);
			}
		}
	}

	pars = psys->particles;

	totvert = dm->getNumVerts(dm);
	totface = dm->getNumTessFaces(dm);

	maxvert = totvert * totpart;
	maxface = totface * totpart;

	psys->lattice = psys_get_lattice(&sim);

	if (psys->flag & (PSYS_HAIR_DONE | PSYS_KEYED) || psys->pointcache->flag & PTCACHE_BAKED) {

		float min_r[3], max_r[3];
		INIT_MINMAX(min_r, max_r);
		dm->getMinMax(dm, min_r, max_r);
		min_co = min_r[track];
		max_co = max_r[track];
	}

	result = CDDM_from_template(dm, maxvert, dm->getNumEdges(dm) * totpart, maxface, 0, 0);

	mvert = result->getVertArray(result);
	orig_mvert = dm->getVertArray(dm);

	for (i = 0; i < maxvert; i++) {
		MVert *inMV;
		MVert *mv = mvert + i;
		ParticleKey state;

		inMV = orig_mvert + i % totvert;
		DM_copy_vert_data(dm, result, i % totvert, i, 1);
		*mv = *inMV;

		/*change orientation based on object trackflag*/
		copy_v3_v3(temp_co, mv->co);
		mv->co[axis] = temp_co[track];
		mv->co[(axis + 1) % 3] = temp_co[(track + 1) % 3];
		mv->co[(axis + 2) % 3] = temp_co[(track + 2) % 3];

		if ((psys->flag & (PSYS_HAIR_DONE | PSYS_KEYED) || psys->pointcache->flag & PTCACHE_BAKED) &&
		    (pimd->flag & eParticleInstanceFlag_Path))
		{
			float ran = 0.0f;
			if (pimd->random_position != 0.0f) {
				BLI_srandom(psys->seed + (i / totvert) % totpart);
				ran = pimd->random_position * BLI_frand();
			}

			if (pimd->flag & eParticleInstanceFlag_KeepShape) {
				state.time = pimd->position * (1.0f - ran);
			}
			else {
				state.time = (mv->co[axis] - min_co) / (max_co - min_co) * pimd->position * (1.0f - ran);

				if (trackneg)
					state.time = 1.0f - state.time;

				mv->co[axis] = 0.0;
			}

			psys_get_particle_on_path(&sim, first_particle + i / totvert, &state, 1);

			normalize_v3(state.vel);

			/* TODO: incremental rotations somehow */
			if (state.vel[axis] < -0.9999f || state.vel[axis] > 0.9999f) {
				state.rot[0] = 1;
				state.rot[1] = state.rot[2] = state.rot[3] = 0.0f;
			}
			else {
				float temp[3] = {0.0f, 0.0f, 0.0f};
				temp[axis] = 1.0f;

				cross_v3_v3v3(cross, temp, state.vel);

				/* state.vel[axis] is the only component surviving from a dot product with the axis */
				axis_angle_to_quat(state.rot, cross, saacos(state.vel[axis]));
			}

		}
		else {
			state.time = -1.0;
			psys_get_particle_state(&sim, first_particle + i / totvert, &state, 1);
		}

		mul_qt_v3(state.rot, mv->co);
		if (pimd->flag & eParticleInstanceFlag_UseSize)
			mul_v3_fl(mv->co, size[i / totvert]);
		add_v3_v3(mv->co, state.co);
	}

	mface = result->getTessFaceArray(result);
	orig_mface = dm->getTessFaceArray(dm);

	for (i = 0; i < maxface; i++) {
		MFace *inMF;
		MFace *mf = mface + i;

		if (pimd->flag & eParticleInstanceFlag_Parents) {
			if (i / totface >= psys->totpart) {
				if (psys->part->childtype == PART_CHILD_PARTICLES) {
					pa = psys->particles + (psys->child + i / totface - psys->totpart)->parent;
				}
				else {
					pa = NULL;
				}
			}
			else {
				pa = pars + i / totface;
			}
		}
		else {
			if (psys->part->childtype == PART_CHILD_PARTICLES) {
				pa = psys->particles + (psys->child + i / totface)->parent;
			}
			else {
				pa = NULL;
			}
		}

		if (pa) {
			if (pa->alive == PARS_UNBORN && (pimd->flag & eParticleInstanceFlag_Unborn) == 0) continue;
			if (pa->alive == PARS_ALIVE && (pimd->flag & eParticleInstanceFlag_Alive) == 0) continue;
			if (pa->alive == PARS_DEAD && (pimd->flag & eParticleInstanceFlag_Dead) == 0) continue;
		}

		inMF = orig_mface + i % totface;
		DM_copy_poly_data(dm, result, i % totface, i, 1);
		*mf = *inMF;

		mf->v1 += (i / totface) * totvert;
		mf->v2 += (i / totface) * totvert;
		mf->v3 += (i / totface) * totvert;
		if (mf->v4) {
			mf->v4 += (i / totface) * totvert;
		}
	}

	CDDM_calc_edges_tessface(result);

	if (psys->lattice) {
		end_latt_deform(psys->lattice);
		psys->lattice = NULL;
	}

	if (size)
		MEM_freeN(size);

	CDDM_tessfaces_to_faces(result); /*builds ngon faces from tess (mface) faces*/
	CDDM_calc_normals(result);

	return result;
}
static DerivedMesh *applyModifierEM(ModifierData *md, Object *ob,
                                    struct BMEditMesh *UNUSED(editData),
                                    DerivedMesh *derivedData)
{
	return applyModifier(md, ob, derivedData, 0, 1);
}


ModifierTypeInfo modifierType_ParticleInstance = {
	/* name */ "ParticleInstance",
	/* structName */ "ParticleInstanceModifierData",
	/* structSize */ sizeof(ParticleInstanceModifierData),
	/* type */ eModifierTypeType_Constructive,
	/* flags */ eModifierTypeFlag_AcceptsMesh |
	eModifierTypeFlag_SupportsMapping |
	eModifierTypeFlag_SupportsEditmode |
	eModifierTypeFlag_EnableInEditmode,

	/* copyData */ copyData,
	/* deformVerts */ NULL,
	/* deformMatrices */ NULL,
	/* deformVertsEM */ NULL,
	/* deformMatricesEM */ NULL,
	/* applyModifier */ applyModifier,
	/* applyModifierEM */ applyModifierEM,
	/* initData */ initData,
	/* requiredDataMask */ NULL,
	/* freeData */ NULL,
	/* isDisabled */ NULL,
	/* updateDepgraph */ updateDepgraph,
	/* dependsOnTime */ dependsOnTime,
	/* dependsOnNormals */ NULL,
	/* foreachObjectLink */ foreachObjectLink,
	/* foreachIDLink */ NULL,
	/* foreachTexLink */ NULL,
};