/**
 * @file		terrain_export.c
 * @date		23/08/2022
 * @author		JackCarterSmith
 * @copyright	GPL-v3.0
 * @brief		Export datas to heightmap PNG and Waveform OBJ format.
 *
 */

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "options.h"
#include <RSPTerrain_datatypes.h>
#include <RSPTerrain_errordefs.h>
#include <zlib.h>
#include <png.h>
#include "obj/obj.h"
#include "terrain_export.h"


unsigned char exportHeightmapPNG(const T_RSPTERRAIN_HEIGHTMAP* heightmap, const char *out_path, T_PROG_OPTIONS* p_opts) {
	char export_path[1024];
	FILE *_png_f = NULL;
	png_structp png_ptr = NULL;
	png_infop info_ptr = NULL;
	size_t x,z;
	png_byte **row_ptrs = NULL;
	//int pixel_size = 3;
	//int depth = 8;		//bit par color channel (RGB)

	if (heightmap == NULL || out_path == NULL)
		return RSPLIB_ERROR_ARGS_NULL;

#ifdef _WIN32
	if (p_opts->output_dir)
		snprintf(export_path, 1024, "%s-out\\heightmap.png", out_path);
	else
		snprintf(export_path, 1024, "%s-heightmap.png", out_path);
#else
	if (p_opts->output_dir)
		snprintf(export_path, 1024, "%s-out/heightmap.png", out_path);
	else
		snprintf(export_path, 1024, "%s-heightmap.png", out_path);
#endif

	// Open export file and add PNG header
	_png_f = fopen(export_path, "wb");
	if (_png_f == NULL) return RSPLIB_ERROR_MEMORY;
	png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
	if (png_ptr == NULL) {
		fclose(_png_f);
		return RSPLIB_ERROR_MEMORY;
	}
	info_ptr = png_create_info_struct(png_ptr);
	if (info_ptr == NULL) {
		fclose(_png_f);
		return RSPLIB_ERROR_MEMORY;
	}

	// Set image attributes
	png_set_IHDR(png_ptr, info_ptr, heightmap->width * RSPTERRAINLIB_TILE_SAMPLING, heightmap->height * RSPTERRAINLIB_TILE_SAMPLING, 8, PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);

	// Store PNG datas in buffer
	row_ptrs = png_malloc(png_ptr, heightmap->height * RSPTERRAINLIB_TILE_SAMPLING * sizeof(png_byte *));
	for ( z = 0; z < heightmap->height * RSPTERRAINLIB_TILE_SAMPLING; z++ ) {
		png_byte *row = png_malloc(png_ptr, heightmap->width * RSPTERRAINLIB_TILE_SAMPLING * sizeof(unsigned char) * 3);
		row_ptrs[z] = row;
		for ( x = 0; x < heightmap->width * RSPTERRAINLIB_TILE_SAMPLING; x++ ) {
			*row++ = heightmap->heightmap[x][z];
			*row++ = heightmap->heightmap[x][z];
			*row++ = heightmap->heightmap[x][z];
		}
	}

	// Write pixels datas
	png_init_io(png_ptr, _png_f);
	png_set_rows(png_ptr, info_ptr, row_ptrs);
	png_write_png(png_ptr, info_ptr, PNG_TRANSFORM_IDENTITY, NULL);

	// Clean up
	for ( z = 0; z < heightmap->height * RSPTERRAINLIB_TILE_SAMPLING; z++ ) {
		png_free(png_ptr, row_ptrs[z]);
	}
	png_free(png_ptr, row_ptrs);
	png_destroy_write_struct(&png_ptr, &info_ptr);

	fclose(_png_f);

	return RSPLIB_SUCCESS;
}

unsigned char exportHeightmapOBJ(const T_RSPTERRAIN_MESH* terrain_mesh, const char *out_path, T_PROG_OPTIONS* p_opts) {
	char export_path[1024];
	char objExport_name[128];
	char mtlExport_name[128];
	obj* objConstruct = NULL;
	unsigned int i,j;
	int surfID = 0;
	float vertexBuff[3] = {0};
	int indicesBuff[3] = {0};

	if (terrain_mesh == NULL || out_path == NULL)
		return RSPLIB_ERROR_ARGS_NULL;

#ifdef _WIN32
	if (p_opts->output_dir) {
		snprintf(export_path, 1024, "%s-out\\", out_path);
		snprintf(objExport_name, 128, "heightmap.obj");
		snprintf(mtlExport_name, 128, "heightmap.mtl");
	} else {
		snprintf(objExport_name, 128, "%s-heightmap.obj", out_path);
		snprintf(mtlExport_name, 128, "%s-heightmap.mtl", out_path);
	}
#else
	if (p_opts->output_dir) {
		snprintf(export_path, 1024, "%s-out/", out_path);
		snprintf(objExport_name, 128, "heightmap.obj");
		snprintf(mtlExport_name, 128, "heightmap.mtl");
	} else {
		snprintf(objExport_name, 128, "%s-heightmap.obj", out_path);
		snprintf(mtlExport_name, 128, "%s-heightmap.mtl", out_path);
	}
#endif

	objConstruct = obj_create(NULL);

	// Build face/surface material group
	surfID = obj_add_surf(objConstruct);
	obj_add_mtrl(objConstruct);

	// Build vertex container
	for ( i = 0; i < terrain_mesh->vertices_count; i++ ) {
		vertexBuff[0] = terrain_mesh->verticesmap[i].x;
		vertexBuff[1] = terrain_mesh->verticesmap[i].y;
		vertexBuff[2] = terrain_mesh->verticesmap[i].z;
		obj_set_vert_v(objConstruct, obj_add_vert(objConstruct), vertexBuff);
	}

	// Build indices container
	// Each tile contains 2 triangles, build both of them.
	// 1-2  2
	// |/  /|
	// 3  3-4
	for ( j = 0; j < terrain_mesh->height - 1; j++ ) {
		for ( i = 0; i < terrain_mesh->width - 1; i++ ) {
			indicesBuff[0] = j * terrain_mesh->width + i;
			indicesBuff[1] = indicesBuff[0] + 1;
			indicesBuff[2] = indicesBuff[0] + terrain_mesh->width;
			obj_set_poly(objConstruct, surfID, obj_add_poly(objConstruct, surfID), indicesBuff);
			indicesBuff[0] = indicesBuff[1];
			indicesBuff[1] = indicesBuff[2] + 1;
			//indicesBuff[2] = indicesBuff[0] + stride;
			obj_set_poly(objConstruct, surfID, obj_add_poly(objConstruct, surfID), indicesBuff);
		}
	}

	if (p_opts->export_mtl) {
		if (p_opts->output_dir)
			obj_write(objConstruct, objExport_name, mtlExport_name, export_path, 8);
		else
			obj_write(objConstruct, objExport_name, mtlExport_name, NULL, 8);
	} else {
		if (p_opts->output_dir)
			obj_write(objConstruct, objExport_name, NULL, export_path, 8);
		else
			obj_write(objConstruct, objExport_name, NULL, NULL, 8);
	}

	obj_delete(objConstruct);

	return NO_ERROR;
}