/*
 * ***** 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) 2016 Kévin Dietrich.
 * All rights reserved.
 *
 * ***** END GPL LICENSE BLOCK *****
 *
 */

#include "abc_customdata.h"

#include <Alembic/AbcGeom/All.h>
#include <algorithm>

extern "C" {
#include "DNA_customdata_types.h"
#include "DNA_meshdata_types.h"

#include "BKE_customdata.h"
}

/* NOTE: for now only UVs and Vertex Colors are supported for streaming.
 * Although Alembic only allows for a single UV layer per {I|O}Schema, and does
 * not have a vertex color concept, there is a convention between DCCs to write
 * such data in a way that lets other DCC know what they are for. See comments
 * in the write code for the conventions. */

using Alembic::AbcGeom::kVertexScope;
using Alembic::AbcGeom::kFacevaryingScope;

using Alembic::Abc::C4fArraySample;
using Alembic::Abc::UInt32ArraySample;
using Alembic::Abc::V2fArraySample;

using Alembic::AbcGeom::OV2fGeomParam;
using Alembic::AbcGeom::OC4fGeomParam;

static void get_uvs(const CDStreamConfig &config,
                    std::vector<Imath::V2f> &uvs,
                    std::vector<uint32_t> &uvidx,
                    void *cd_data)
{
	MLoopUV *mloopuv_array = static_cast<MLoopUV *>(cd_data);

	if (!mloopuv_array) {
		return;
	}

	const int num_poly = config.totpoly;
	MPoly *polygons = config.mpoly;

	if (!config.pack_uvs) {
		int cnt = 0;
		uvidx.resize(config.totloop);
		uvs.resize(config.totloop);

		for (int i = 0; i < num_poly; ++i) {
			MPoly &current_poly = polygons[i];
			MLoopUV *loopuvpoly = mloopuv_array + current_poly.loopstart + current_poly.totloop;

			for (int j = 0; j < current_poly.totloop; ++j, ++cnt) {
				--loopuvpoly;

				uvidx[cnt] = cnt;
				uvs[cnt][0] = loopuvpoly->uv[0];
				uvs[cnt][1] = loopuvpoly->uv[1];
			}
		}
	}
	else {
		for (int i = 0; i < num_poly; ++i) {
			MPoly &current_poly = polygons[i];
			MLoopUV *loopuvpoly = mloopuv_array + current_poly.loopstart + current_poly.totloop;

			for (int j = 0; j < current_poly.totloop; ++j) {
				loopuvpoly--;
				Imath::V2f uv(loopuvpoly->uv[0], loopuvpoly->uv[1]);

				std::vector<Imath::V2f>::iterator it = std::find(uvs.begin(), uvs.end(), uv);

				if (it == uvs.end()) {
					uvidx.push_back(uvs.size());
					uvs.push_back(uv);
				}
				else {
					uvidx.push_back(std::distance(uvs.begin(), it));
				}
			}
		}
	}
}

const char *get_uv_sample(UVSample &sample, const CDStreamConfig &config, CustomData *data)
{
	const int active_uvlayer = CustomData_get_active_layer(data, CD_MLOOPUV);

	if (active_uvlayer < 0) {
		return "";
	}

	void *cd_data = CustomData_get_layer_n(data, CD_MLOOPUV, active_uvlayer);

	get_uvs(config, sample.uvs, sample.indices, cd_data);

	return CustomData_get_layer_name(data, CD_MLOOPUV, active_uvlayer);
}

/* Convention to write UVs:
 * - V2fGeomParam on the arbGeomParam
 * - set scope as face varying
 * - (optional due to its behaviour) tag as UV using Alembic::AbcGeom::SetIsUV
 */
static void write_uv(const OCompoundProperty &prop, const CDStreamConfig &config, void *data, const char *name)
{
	std::vector<uint32_t> indices;
	std::vector<Imath::V2f> uvs;

	get_uvs(config, uvs, indices, data);

	if (indices.empty() || uvs.empty()) {
		return;
	}

	OV2fGeomParam param(prop, name, true, kFacevaryingScope, 1);

	OV2fGeomParam::Sample sample(
		V2fArraySample(&uvs.front(), uvs.size()),
		UInt32ArraySample(&indices.front(), indices.size()),
		kFacevaryingScope);

	param.set(sample);
}

/* Convention to write Vertex Colors:
 * - C3fGeomParam/C4fGeomParam on the arbGeomParam
 * - set scope as vertex varying
 */
static void write_mcol(const OCompoundProperty &prop, const CDStreamConfig &config, void *data, const char *name)
{
	const float cscale = 1.0f / 255.0f;
	MPoly *polys = config.mpoly;
	MLoop *mloops = config.mloop;
	MCol *cfaces = static_cast<MCol *>(data);

	std::vector<Imath::C4f> buffer(config.totvert);

	Imath::C4f col;

	for (int i = 0; i < config.totpoly; ++i) {
		MPoly *p = &polys[i];
		MCol *cface = &cfaces[p->loopstart + p->totloop];
		MLoop *mloop = &mloops[p->loopstart + p->totloop];

		for (int j = 0; j < p->totloop; ++j) {
			cface--;
			mloop--;

			col[0] = cface->a * cscale;
			col[1] = cface->r * cscale;
			col[2] = cface->g * cscale;
			col[3] = cface->b * cscale;

			buffer[mloop->v] = col;
		}
	}

	OC4fGeomParam param(prop, name, true, kFacevaryingScope, 1);

	OC4fGeomParam::Sample sample(
		C4fArraySample(&buffer.front(), buffer.size()),
		kVertexScope);

	param.set(sample);
}

void write_custom_data(const OCompoundProperty &prop, const CDStreamConfig &config, CustomData *data, int data_type)
{
	CustomDataType cd_data_type = static_cast<CustomDataType>(data_type);

	if (!CustomData_has_layer(data, cd_data_type)) {
		return;
	}

	const int active_layer = CustomData_get_active_layer(data, cd_data_type);
	const int tot_layers = CustomData_number_of_layers(data, cd_data_type);

	for (int i = 0; i < tot_layers; ++i) {
		void *cd_data = CustomData_get_layer_n(data, cd_data_type, i);
		const char *name = CustomData_get_layer_name(data, cd_data_type, i);

		if (cd_data_type == CD_MLOOPUV) {
			/* Already exported. */
			if (i == active_layer) {
				continue;
			}

			write_uv(prop, config, cd_data, name);
		}
		else if (cd_data_type == CD_MLOOPCOL) {
			write_mcol(prop, config, cd_data, name);
		}
	}
}

/* ************************************************************************** */

using Alembic::Abc::C3fArraySamplePtr;
using Alembic::Abc::C4fArraySamplePtr;
using Alembic::Abc::PropertyHeader;

using Alembic::AbcGeom::IC3fGeomParam;
using Alembic::AbcGeom::IC4fGeomParam;
using Alembic::AbcGeom::IV2fGeomParam;

static void read_mcols(const CDStreamConfig &config, void *data,
                       const C3fArraySamplePtr &c3f_ptr, const C4fArraySamplePtr &c4f_ptr)
{
	MCol *cfaces = static_cast<MCol *>(data);
	MPoly *polys = config.mpoly;
	MLoop *mloops = config.mloop;

	if (c3f_ptr) {
		for (int i = 0; i < config.totpoly; ++i) {
			MPoly *p = &polys[i];
			MCol *cface = &cfaces[p->loopstart + p->totloop];
			MLoop *mloop = &mloops[p->loopstart + p->totloop];

			for (int j = 0; j < p->totloop; ++j) {
				cface--;
				mloop--;
				const Imath::C3f &color = (*c3f_ptr)[mloop->v];
				cface->a = FTOCHAR(color[0]);
				cface->r = FTOCHAR(color[1]);
				cface->g = FTOCHAR(color[2]);
				cface->b = 255;
			}
		}
	}
	else if (c4f_ptr) {
		for (int i = 0; i < config.totpoly; ++i) {
			MPoly *p = &polys[i];
			MCol *cface = &cfaces[p->loopstart + p->totloop];
			MLoop *mloop = &mloops[p->loopstart + p->totloop];

			for (int j = 0; j < p->totloop; ++j) {
				cface--;
				mloop--;
				const Imath::C4f &color = (*c4f_ptr)[mloop->v];
				cface->a = FTOCHAR(color[0]);
				cface->r = FTOCHAR(color[1]);
				cface->g = FTOCHAR(color[2]);
				cface->b = FTOCHAR(color[3]);
			}
		}
	}
}

static void read_uvs(const CDStreamConfig &config, void *data,
                     const Alembic::AbcGeom::V2fArraySamplePtr &uvs,
                     const Alembic::AbcGeom::UInt32ArraySamplePtr &indices)
{
	MPoly *mpolys = config.mpoly;
	MLoopUV *mloopuvs = static_cast<MLoopUV *>(data);

	unsigned int uv_index, loop_index;

	for (int i = 0; i < config.totpoly; ++i) {
		MPoly &poly = mpolys[i];

		for (int f = 0; f < poly.totloop; ++f) {
			loop_index = poly.loopstart + f;
			uv_index = (*indices)[loop_index];
			const Imath::V2f &uv = (*uvs)[uv_index];

			MLoopUV &loopuv = mloopuvs[loop_index];
			loopuv.uv[0] = uv[0];
			loopuv.uv[1] = uv[1];
		}
	}
}

static void read_custom_data_ex(const ICompoundProperty &prop,
                                const PropertyHeader &prop_header,
                                const CDStreamConfig &config,
                                const Alembic::Abc::ISampleSelector &iss,
                                int data_type)
{
	if (data_type == CD_MLOOPCOL) {
		C3fArraySamplePtr c3f_ptr = C3fArraySamplePtr();
		C4fArraySamplePtr c4f_ptr = C4fArraySamplePtr();

		if (IC3fGeomParam::matches(prop_header)) {
			IC3fGeomParam color_param(prop, prop_header.getName());
			IC3fGeomParam::Sample sample;
			color_param.getIndexed(sample, iss);

			c3f_ptr = sample.getVals();
		}
		else if (IC4fGeomParam::matches(prop_header)) {
			IC4fGeomParam color_param(prop, prop_header.getName());
			IC4fGeomParam::Sample sample;
			color_param.getIndexed(sample, iss);

			c4f_ptr = sample.getVals();
		}

		void *cd_data = config.add_customdata_cb(config.user_data,
		                                         prop_header.getName().c_str(),
		                                         data_type);

		read_mcols(config, cd_data, c3f_ptr, c4f_ptr);
	}
	else if (data_type == CD_MLOOPUV) {
		IV2fGeomParam uv_param(prop, prop_header.getName());
		IV2fGeomParam::Sample sample;
		uv_param.getIndexed(sample, iss);

		if (uv_param.getScope() != kFacevaryingScope) {
			return;
		}

		void *cd_data = config.add_customdata_cb(config.user_data,
		                                         prop_header.getName().c_str(),
		                                         data_type);

		read_uvs(config, cd_data, sample.getVals(), sample.getIndices());
	}
}

void read_custom_data(const ICompoundProperty &prop, const CDStreamConfig &config, const Alembic::Abc::ISampleSelector &iss)
{
	if (!prop.valid()) {
		return;
	}

	int num_uvs = 0;
	int num_colors = 0;

	const size_t num_props = prop.getNumProperties();

	for (size_t i = 0; i < num_props; ++i) {
		const Alembic::Abc::PropertyHeader &prop_header = prop.getPropertyHeader(i);

		/* Read UVs according to convention. */
		if (IV2fGeomParam::matches(prop_header) && Alembic::AbcGeom::isUV(prop_header)) {
			if (++num_uvs > MAX_MTFACE) {
				continue;
			}

			read_custom_data_ex(prop, prop_header, config, iss, CD_MLOOPUV);
			continue;
		}

		/* Read vertex colors according to convention. */
		if (IC3fGeomParam::matches(prop_header) || IC4fGeomParam::matches(prop_header)) {
			if (++num_colors > MAX_MCOL) {
				continue;
			}

			read_custom_data_ex(prop, prop_header, config, iss, CD_MLOOPCOL);
			continue;
		}
	}
}