/**
 * \file obj_exporter.c
 * \date 27/07/2022
 * \author JackCarterSmith
 * \copyright GPL-v3.0
 * \brief Export datas to Waveform OBJ format.
 */

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "options.h"
#include <RSPModel_datatypes.h>
#include <RSPModel_errordefs.h>
#include "rlk/obj.h"
#include "obj_exporter.h"


static void mtlPathPatch(const char* out_file, const char* obj_name) ;

unsigned char exportOBJModel(T_RSPMODEL_OBJECT* hob_objects, const char *out_path, T_PROG_OPTIONS* p_opts) {
	char objExport_path[128];
	char mtlExport_path[128];
	obj* objConstruct = NULL;
	unsigned int i,j;
	int surfID = 0, materialID = 0, tmpVertex = 0, tmpIndex = 0;
	int indexOffset = 0;	// Used to compensate reset of indices between face group
	float vertexBuff[3] = {0}, textureBuff[2] = {0};
	int indicesBuff[3] = {0};

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

	if (p_opts->output_dir) {
		strcpy(objExport_path, out_path);
		#ifdef _WIN32
			strcat(objExport_path, "-out\\");
		#else
			strcat(objExport_path, "-out/");
		#endif
		strcat(objExport_path, hob_objects->name);
	} else {
		strcpy(objExport_path, hob_objects->name);
	}
	strcpy(mtlExport_path, objExport_path);
	strcat(objExport_path, ".obj\0");
	strcat(mtlExport_path, ".mtl\0");

	objConstruct = obj_create(NULL);

	// Build face/surface material group
	for ( i = 0; i < hob_objects->face_group_count; i++) {
		surfID = obj_add_surf(objConstruct);
		materialID = obj_add_mtrl(objConstruct);

		// Build vertex container
		for ( j = 0; j < hob_objects->object_parts[i].vertex_count; j++ ) {
			tmpVertex = obj_add_vert(objConstruct);

			vertexBuff[0] = ((float)1/1024) * -hob_objects->object_parts[i].vertices[j].x;		// Invert X to fix mirror display
			vertexBuff[1] = ((float)1/1024) * -hob_objects->object_parts[i].vertices[j].y;		// Invert Y to render upside up
			vertexBuff[2] = ((float)1/1024) * hob_objects->object_parts[i].vertices[j].z;
			obj_set_vert_v(objConstruct, tmpVertex, vertexBuff);
		}

		// Build indices container and UV mapping
		for ( j = 0; j < hob_objects->object_parts[i].face_count; j++ ) {
			tmpIndex = obj_add_poly(objConstruct, surfID);

			indicesBuff[0] = indexOffset + (int)hob_objects->object_parts[i].faces[j].indices[0];
			indicesBuff[1] = indexOffset + (int)hob_objects->object_parts[i].faces[j].indices[1];
			indicesBuff[2] = indexOffset + (int)hob_objects->object_parts[i].faces[j].indices[2];
			obj_set_poly(objConstruct, surfID, tmpIndex, indicesBuff);

			if (hob_objects->object_parts[i].faces[j].flags_bits.fHasTexture) {
				textureBuff[0] = ((float)1/4096) * hob_objects->object_parts[i].faces[j].tex_coords[0].u;
				textureBuff[1] = ((float)1/4096) * hob_objects->object_parts[i].faces[j].tex_coords[0].v;
				obj_set_vert_t(objConstruct, indexOffset + (int)hob_objects->object_parts[i].faces[j].indices[0], textureBuff);

				textureBuff[0] = ((float)1/4096) * hob_objects->object_parts[i].faces[j].tex_coords[1].u;
				textureBuff[1] = ((float)1/4096) * hob_objects->object_parts[i].faces[j].tex_coords[1].v;
				obj_set_vert_t(objConstruct, indexOffset + (int)hob_objects->object_parts[i].faces[j].indices[1], textureBuff);

				textureBuff[0] = ((float)1/4096) * hob_objects->object_parts[i].faces[j].tex_coords[2].u;
				textureBuff[1] = ((float)1/4096) * hob_objects->object_parts[i].faces[j].tex_coords[2].v;
				obj_set_vert_t(objConstruct, indexOffset + (int)hob_objects->object_parts[i].faces[j].indices[2], textureBuff);
			}

			// Process 2 triangles if face is Quad
			if (hob_objects->object_parts[i].faces[j].flags_bits.fIsQuad) {
				tmpIndex = obj_add_poly(objConstruct, surfID);

				indicesBuff[0] = indexOffset + (int)hob_objects->object_parts[i].faces[j].indices[0];
				indicesBuff[1] = indexOffset + (int)hob_objects->object_parts[i].faces[j].indices[2];
				indicesBuff[2] = indexOffset + (int)hob_objects->object_parts[i].faces[j].indices[3];
				obj_set_poly(objConstruct, surfID, tmpIndex, indicesBuff);

				if (hob_objects->object_parts[i].faces[j].flags_bits.fHasTexture) {
					textureBuff[0] = ((float)1/4096) * hob_objects->object_parts[i].faces[j].tex_coords[3].u;
					textureBuff[1] = ((float)1/4096) * hob_objects->object_parts[i].faces[j].tex_coords[3].v;
					obj_set_vert_t(objConstruct, indexOffset + (int)hob_objects->object_parts[i].faces[j].indices[3], textureBuff);
				}
			}
		}

		indexOffset = obj_num_vert(objConstruct);
	}

	if (p_opts->export_mtl) {
		obj_write(objConstruct, objExport_path, mtlExport_path, 8);
#if defined(__GNUC__)		//TODO: review MSVC file management or include and rewrite obj lib?
		if (p_opts->output_dir) mtlPathPatch(objExport_path, hob_objects->name);
#endif
	} else obj_write(objConstruct, objExport_path, NULL, 8);

	obj_delete(objConstruct);

	return NO_ERROR;
}

static void mtlPathPatch(const char* out_file, const char* obj_name) {
	FILE* obj = NULL;
	char* memFile = NULL;
	long fileSize,i,pos = 0,lines;
	char _path[128],b;

	obj = fopen(out_file, "r");
	if ( obj != NULL ) {
		fseek(obj, 0, SEEK_END);
		fileSize = ftell(obj);
		fseek(obj, 0, SEEK_SET);

		// Find the end of first line
		for ( i = 0; i < fileSize + 1; i++) {
			b = (char)fgetc(obj);
			if (b == '\n') {
				if (pos == 0) pos = i;
				lines++;
			}
		}

		// Prepare mtl path for output
		strcpy(_path, obj_name);
		strcat(_path, ".mtl");

		memFile = malloc(fileSize - (pos + lines));
		if ( memFile != NULL ) {
			// Read the rest of file in memory
			fseek(obj, pos, SEEK_SET);
			fread(memFile, fileSize - (pos + lines), 1, obj);
			fclose(obj);

			// Begin rewrite file
			obj = fopen(out_file, "w");
			fprintf(obj, "mtllib %s", _path);
#if defined(_MSC_VER)
			fwrite(memFile, fileSize - pos , 1, obj);
#elif defined(__GNUC__)
			fwrite(memFile, fileSize - (pos + lines), 1, obj);
#endif

			free(memFile);
		}

		fclose(obj);
	}
}