#include "tiny_obj_loader.h"

#include <cstdio>
#include <cstdlib>
#include <cassert>
#include <cstddef>
#include <iostream>
#include <sstream>
#include <fstream>
#include <functional>
#include <memory>

static void PrintInfo(const std::vector<tinyobj::shape_t>& shapes)
{
  std::cout << "# of shapes : " << shapes.size() << std::endl;

  for (size_t i = 0; i < shapes.size(); i++) {
    printf("shape[%ld].name = %s\n", i, shapes[i].name.c_str());
    printf("shape[%ld].indices: %ld\n", i, shapes[i].mesh.indices.size());
    assert((shapes[i].mesh.indices.size() % 3) == 0);
    for (size_t f = 0; f < shapes[i].mesh.indices.size(); f++) {
      printf("  idx[%ld] = %d\n", f, shapes[i].mesh.indices[f]);
    }

    printf("shape[%ld].vertices: %ld\n", i, shapes[i].mesh.positions.size());
    assert((shapes[i].mesh.positions.size() % 3) == 0);
    for (size_t v = 0; v < shapes[i].mesh.positions.size() / 3; v++) {
      printf("  v[%ld] = (%f, %f, %f)\n", v,
        shapes[i].mesh.positions[3*v+0],
        shapes[i].mesh.positions[3*v+1],
        shapes[i].mesh.positions[3*v+2]);
    }
  
    printf("shape[%ld].material.name = %s\n", i, shapes[i].material.name.c_str());
    printf("  material.Ka = (%f, %f ,%f)\n", shapes[i].material.ambient[0], shapes[i].material.ambient[1], shapes[i].material.ambient[2]);
    printf("  material.Kd = (%f, %f ,%f)\n", shapes[i].material.diffuse[0], shapes[i].material.diffuse[1], shapes[i].material.diffuse[2]);
    printf("  material.Ks = (%f, %f ,%f)\n", shapes[i].material.specular[0], shapes[i].material.specular[1], shapes[i].material.specular[2]);
    printf("  material.Tr = (%f, %f ,%f)\n", shapes[i].material.transmittance[0], shapes[i].material.transmittance[1], shapes[i].material.transmittance[2]);
    printf("  material.Ke = (%f, %f ,%f)\n", shapes[i].material.emission[0], shapes[i].material.emission[1], shapes[i].material.emission[2]);
    printf("  material.Ns = %f\n", shapes[i].material.shininess);
    printf("  material.Ni = %f\n", shapes[i].material.ior);
    printf("  material.dissolve = %f\n", shapes[i].material.dissolve);
    printf("  material.illum = %d\n", shapes[i].material.illum);
    printf("  material.map_Ka = %s\n", shapes[i].material.ambient_texname.c_str());
    printf("  material.map_Kd = %s\n", shapes[i].material.diffuse_texname.c_str());
    printf("  material.map_Ks = %s\n", shapes[i].material.specular_texname.c_str());
    printf("  material.map_Ns = %s\n", shapes[i].material.normal_texname.c_str());
    auto it = shapes[i].material.unknown_parameter.begin();
    auto itEnd = shapes[i].material.unknown_parameter.end();
    for (; it != itEnd; it++) {
      printf("  material.%s = %s\n", it->first.c_str(), it->second.c_str());
    }
    printf("\n");
  }
}

static bool
TestLoadObj(
  const char* filename,
  const char* basepath = NULL)
{
  std::cout << "Loading " << filename << std::endl;

  std::vector<tinyobj::shape_t> shapes;
  std::string err = tinyobj::LoadObj(shapes, filename, basepath);

  if (!err.empty()) {
    std::cerr << err << std::endl;
    return false;
  }

  PrintInfo(shapes);

  return true;
}


static bool
TestStreamLoadObj()
{
  std::cout << "Stream Loading " << std::endl;

  std::stringstream objStream;
  objStream 
    << "mtllib cube.mtl\n"
    "\n"
    "v 0.000000 2.000000 2.000000\n"
    "v 0.000000 0.000000 2.000000\n"
    "v 2.000000 0.000000 2.000000\n"
    "v 2.000000 2.000000 2.000000\n"
    "v 0.000000 2.000000 0.000000\n"
    "v 0.000000 0.000000 0.000000\n"
    "v 2.000000 0.000000 0.000000\n"
    "v 2.000000 2.000000 0.000000\n"
    "# 8 vertices\n"
    "\n"
    "g front cube\n"
    "usemtl white\n"
    "f 1 2 3 4\n"
    "g back cube\n"
    "# expects white material\n"
    "f 8 7 6 5\n"
    "g right cube\n"
    "usemtl red\n"
    "f 4 3 7 8\n"
    "g top cube\n"
    "usemtl white\n"
    "f 5 1 4 8\n"
    "g left cube\n"
    "usemtl green\n"
    "f 5 6 2 1\n"
    "g bottom cube\n"
    "usemtl white\n"
    "f 2 6 7 3\n"
    "# 6 elements";
   
  auto getMatFileIStreamFunc = 
    [](const std::string& matId)
    {           
      if (matId == "cube.mtl") {
      
        std::unique_ptr<std::stringstream> matStream( 
          new std::stringstream(
            "newmtl white\n"
            "Ka 0 0 0\n"
            "Kd 1 1 1\n"
            "Ks 0 0 0\n"
            "\n"
            "newmtl red\n"
            "Ka 0 0 0\n"
            "Kd 1 0 0\n"
            "Ks 0 0 0\n"
            "\n"
            "newmtl green\n"
            "Ka 0 0 0\n"
            "Kd 0 1 0\n"
            "Ks 0 0 0\n"
            "\n"
            "newmtl blue\n"
            "Ka 0 0 0\n"
            "Kd 0 0 1\n"
            "Ks 0 0 0\n"
            "\n"
            "newmtl light\n"
            "Ka 20 20 20\n"
            "Kd 1 1 1\n"
            "Ks 0 0 0"));

        return matStream;
      }

      std::unique_ptr<std::stringstream> emptyUP( nullptr );
      return emptyUP;
    };
    
  std::vector<tinyobj::shape_t> shapes;
  std::string err = tinyobj::LoadObj(shapes, objStream, getMatFileIStreamFunc);    
  
  if (!err.empty()) {
    std::cerr << err << std::endl;
    return false;
  }

  PrintInfo(shapes);
    
  return true;
}

int
main(
  int argc,
  char **argv)
{

  if (argc > 1) {
    const char* basepath = NULL;
    if (argc > 2) {
      basepath = argv[2];
    }
    assert(true == TestLoadObj(argv[1], basepath));
  } else {
    assert(true == TestLoadObj("cornell_box.obj"));
    assert(true == TestLoadObj("cube.obj"));
    assert(true == TestStreamLoadObj());
  }
  
  return 0;
}