/*  ADMesh -- process triangulated solid meshes
 *  Copyright (C) 1995, 1996  Anthony D. Martin <amartin@engr.csulb.edu>
 *  Copyright (C) 2013, 2014  several contributors, see AUTHORS
 *
 *  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.
 *
 *  Questions, comments, suggestions, etc to
 *           https://github.com/admesh/admesh/issues
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <assert.h>

#include <boost/log/trivial.hpp>
#include <boost/nowide/cstdio.hpp>
#include <boost/predef/other/endian.h>

#include "stl.h"

#ifndef SEEK_SET
#error "SEEK_SET not defined"
#endif

#if BOOST_ENDIAN_BIG_BYTE
extern void stl_internal_reverse_quads(char *buf, size_t cnt);
#endif /* BOOST_ENDIAN_BIG_BYTE */

static FILE* stl_open_count_facets(stl_file *stl, const char *file) 
{
  	// Open the file in binary mode first.
  	FILE *fp = boost::nowide::fopen(file, "rb");
  	if (fp == nullptr) {
		BOOST_LOG_TRIVIAL(error) << "stl_open_count_facets: Couldn't open " << file << " for reading";
    	return nullptr;
  	}
  	// Find size of file.
  	fseek(fp, 0, SEEK_END);
  	long file_size = ftell(fp);

  	// Check for binary or ASCII file.
  	fseek(fp, HEADER_SIZE, SEEK_SET);
	unsigned char chtest[128];
  	if (! fread(chtest, sizeof(chtest), 1, fp)) {
		BOOST_LOG_TRIVIAL(error) << "stl_open_count_facets: The input is an empty file: " << file;
    	fclose(fp);
    	return nullptr;
  	}
  	stl->stats.type = ascii;
  	for (size_t s = 0; s < sizeof(chtest); s++) {
    	if (chtest[s] > 127) {
      		stl->stats.type = binary;
      		break;
    	}
  	}
  	rewind(fp);

  	uint32_t num_facets = 0;

  	// Get the header and the number of facets in the .STL file.
  	// If the .STL file is binary, then do the following:
  	if (stl->stats.type == binary) {
    	// Test if the STL file has the right size.
    	if (((file_size - HEADER_SIZE) % SIZEOF_STL_FACET != 0) || (file_size < STL_MIN_FILE_SIZE)) {
			BOOST_LOG_TRIVIAL(error) << "stl_open_count_facets: The file " << file << " has the wrong size.";
      		fclose(fp);
      		return nullptr;
    	}
    	num_facets = (file_size - HEADER_SIZE) / SIZEOF_STL_FACET;

    	// Read the header.
    	if (fread(stl->stats.header, LABEL_SIZE, 1, fp) > 79)
      		stl->stats.header[80] = '\0';

    	// Read the int following the header.  This should contain # of facets.
	  	uint32_t header_num_facets;
    	bool header_num_faces_read = fread(&header_num_facets, sizeof(uint32_t), 1, fp) != 0;
#if BOOST_ENDIAN_BIG_BYTE
    	// Convert from little endian to big endian.
    	stl_internal_reverse_quads((char*)&header_num_facets, 4);
#endif /* BOOST_ENDIAN_BIG_BYTE */
    	if (! header_num_faces_read || num_facets != header_num_facets)
			BOOST_LOG_TRIVIAL(info) << "stl_open_count_facets: Warning: File size doesn't match number of facets in the header: " << file;
  	}
  	// Otherwise, if the .STL file is ASCII, then do the following:
  	else
  	{
    	// Reopen the file in text mode (for getting correct newlines on Windows)
    	// fix to silence a warning about unused return value.
    	// obviously if it fails we have problems....
    	fp = boost::nowide::freopen(file, "r", fp);

		// do another null check to be safe
    	if (fp == nullptr) {
			BOOST_LOG_TRIVIAL(error) << "stl_open_count_facets: Couldn't open " << file << " for reading";
      		fclose(fp);
      		return nullptr;
    	}
    
    	// Find the number of facets.
		char linebuf[100];
		int num_lines = 1;
		while (fgets(linebuf, 100, fp) != nullptr) {
		    // Don't count short lines.
		    if (strlen(linebuf) <= 4)
		    	continue;
		    // Skip solid/endsolid lines as broken STL file generators may put several of them.
		    if (strncmp(linebuf, "solid", 5) == 0 || strncmp(linebuf, "endsolid", 8) == 0)
		    	continue;
		    ++ num_lines;
		}

    	rewind(fp);
    
    	// Get the header.
		int i = 0;
    	for (; i < 80 && (stl->stats.header[i] = getc(fp)) != '\n'; ++ i) ;
    	stl->stats.header[i] = '\0'; // Lose the '\n'
    	stl->stats.header[80] = '\0';

    	num_facets = num_lines / ASCII_LINES_PER_FACET;
  	}

  	stl->stats.number_of_facets += num_facets;
  	stl->stats.original_num_facets = stl->stats.number_of_facets;
  	return fp;
}

/* Reads the contents of the file pointed to by fp into the stl structure,
   starting at facet first_facet.  The second argument says if it's our first
   time running this for the stl and therefore we should reset our max and min stats. */
static bool stl_read(stl_file *stl, FILE *fp, int first_facet, bool first)
{
	if (stl->stats.type == binary)
    	fseek(fp, HEADER_SIZE, SEEK_SET);
  	else
    	rewind(fp);

  	char normal_buf[3][32];
  	for (uint32_t i = first_facet; i < stl->stats.number_of_facets; ++ i) {
  	  	stl_facet facet;

    	if (stl->stats.type == binary) {
      		// Read a single facet from a binary .STL file. We assume little-endian architecture!
      		if (fread(&facet, 1, SIZEOF_STL_FACET, fp) != SIZEOF_STL_FACET)
      			return false;
#if BOOST_ENDIAN_BIG_BYTE
      		// Convert the loaded little endian data to big endian.
      		stl_internal_reverse_quads((char*)&facet, 48);
#endif /* BOOST_ENDIAN_BIG_BYTE */
    	} else {
			// Read a single facet from an ASCII .STL file
			// skip solid/endsolid
			// (in this order, otherwise it won't work when they are paired in the middle of a file)
			fscanf(fp, " endsolid%*[^\n]\n");
			fscanf(fp, " solid%*[^\n]\n");  // name might contain spaces so %*s doesn't work and it also can be empty (just "solid")
			// Leading space in the fscanf format skips all leading white spaces including numerous new lines and tabs.
			int res_normal     = fscanf(fp, " facet normal %31s %31s %31s", normal_buf[0], normal_buf[1], normal_buf[2]);
			assert(res_normal == 3);
			int res_outer_loop = fscanf(fp, " outer loop");
			assert(res_outer_loop == 0);
			int res_vertex1    = fscanf(fp, " vertex %f %f %f", &facet.vertex[0](0), &facet.vertex[0](1), &facet.vertex[0](2));
			assert(res_vertex1 == 3);
			int res_vertex2    = fscanf(fp, " vertex %f %f %f", &facet.vertex[1](0), &facet.vertex[1](1), &facet.vertex[1](2));
			assert(res_vertex2 == 3);
			// Trailing whitespace is there to eat all whitespaces and empty lines up to the next non-whitespace.
			int res_vertex3    = fscanf(fp, " vertex %f %f %f ", &facet.vertex[2](0), &facet.vertex[2](1), &facet.vertex[2](2));
			assert(res_vertex3 == 3);
			// Some G-code generators tend to produce text after "endloop" and "endfacet". Just ignore it.
			char buf[2048];
			fgets(buf, 2047, fp);
			bool endloop_ok = strncmp(buf, "endloop", 7) == 0 && (buf[7] == '\r' || buf[7] == '\n' || buf[7] == ' ' || buf[7] == '\t');
			assert(endloop_ok);
			// Skip the trailing whitespaces and empty lines.
			fscanf(fp, " ");
			fgets(buf, 2047, fp);
			bool endfacet_ok = strncmp(buf, "endfacet", 8) == 0 && (buf[8] == '\r' || buf[8] == '\n' || buf[8] == ' ' || buf[8] == '\t');
			assert(endfacet_ok);
			if (res_normal != 3 || res_outer_loop != 0 || res_vertex1 != 3 || res_vertex2 != 3 || res_vertex3 != 3 || ! endloop_ok || ! endfacet_ok) {
				BOOST_LOG_TRIVIAL(error) << "Something is syntactically very wrong with this ASCII STL! ";
				return false;
			}

			// The facet normal has been parsed as a single string as to workaround for not a numbers in the normal definition.
			if (sscanf(normal_buf[0], "%f", &facet.normal(0)) != 1 ||
			    sscanf(normal_buf[1], "%f", &facet.normal(1)) != 1 ||
			    sscanf(normal_buf[2], "%f", &facet.normal(2)) != 1) {
			    // Normal was mangled. Maybe denormals or "not a number" were stored?
			  	// Just reset the normal and silently ignore it.
			  	memset(&facet.normal, 0, sizeof(facet.normal));
			}
		}

#if 0
		// Report close to zero vertex coordinates. Due to the nature of the floating point numbers,
		// close to zero values may be represented with singificantly higher precision than the rest of the vertices.
		// It may be worth to round these numbers to zero during loading to reduce the number of errors reported
		// during the STL import.
		for (size_t j = 0; j < 3; ++ j) {
		if (facet.vertex[j](0) > -1e-12f && facet.vertex[j](0) < 1e-12f)
		    printf("stl_read: facet %d(0) = %e\r\n", j, facet.vertex[j](0));
		if (facet.vertex[j](1) > -1e-12f && facet.vertex[j](1) < 1e-12f)
		    printf("stl_read: facet %d(1) = %e\r\n", j, facet.vertex[j](1));
		if (facet.vertex[j](2) > -1e-12f && facet.vertex[j](2) < 1e-12f)
		    printf("stl_read: facet %d(2) = %e\r\n", j, facet.vertex[j](2));
		}
#endif

		// Write the facet into memory.
		stl->facet_start[i] = facet;
		stl_facet_stats(stl, facet, first);
  	}
  
  	stl->stats.size = stl->stats.max - stl->stats.min;
  	stl->stats.bounding_diameter = stl->stats.size.norm();
  	return true;
}

bool stl_open(stl_file *stl, const char *file)
{
	stl->clear();
	FILE *fp = stl_open_count_facets(stl, file);
	if (fp == nullptr)
		return false;
	stl_allocate(stl);
	bool result = stl_read(stl, fp, 0, true);
  	fclose(fp);
  	return result;
}

void stl_allocate(stl_file *stl) 
{
  	//  Allocate memory for the entire .STL file.
  	stl->facet_start.assign(stl->stats.number_of_facets, stl_facet());
  	// Allocate memory for the neighbors list.
  	stl->neighbors_start.assign(stl->stats.number_of_facets, stl_neighbors());
}

void stl_reallocate(stl_file *stl) 
{
	stl->facet_start.resize(stl->stats.number_of_facets);
	stl->neighbors_start.resize(stl->stats.number_of_facets);
}

void stl_facet_stats(stl_file *stl, stl_facet facet, bool &first)
{
	// While we are going through all of the facets, let's find the
	// maximum and minimum values for x, y, and z

	if (first) {
		// Initialize the max and min values the first time through
		stl->stats.min = facet.vertex[0];
		stl->stats.max = facet.vertex[0];
		stl_vertex diff = (facet.vertex[1] - facet.vertex[0]).cwiseAbs();
		stl->stats.shortest_edge = std::max(diff(0), std::max(diff(1), diff(2)));
		first = false;
	}

	// Now find the max and min values.
	for (size_t i = 0; i < 3; ++ i) {
		stl->stats.min = stl->stats.min.cwiseMin(facet.vertex[i]);
		stl->stats.max = stl->stats.max.cwiseMax(facet.vertex[i]);
	}
}
