//
// Simple .obj viewer(vertex only)
//
#include <vector>
#include <string>
#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <limits>
#include <cmath>
#include <cassert>
#include <algorithm>	

#include <GL/glew.h>

#ifdef __APPLE__
#include <OpenGL/glu.h>
#else
#include <GL/glu.h>
#endif

#include <GLFW/glfw3.h>

#define TINYOBJLOADER_IMPLEMENTATION
#include "../../tiny_obj_loader.h"

#include "trackball.h"

#ifdef _WIN32
#ifdef __cplusplus
extern "C" {
#endif
#include <windows.h>
#include <mmsystem.h>
#ifdef __cplusplus
}
#endif
#pragma comment(lib, "winmm.lib")
#else
#if defined(__unix__) || defined(__APPLE__)
#include <sys/time.h>
#else
#include <ctime>
#endif
#endif

class timerutil {
public:
#ifdef _WIN32
  typedef DWORD time_t;

  timerutil() { ::timeBeginPeriod(1); }
  ~timerutil() { ::timeEndPeriod(1); }

  void start() { t_[0] = ::timeGetTime(); }
  void end() { t_[1] = ::timeGetTime(); }

  time_t sec() { return (time_t)((t_[1] - t_[0]) / 1000); }
  time_t msec() { return (time_t)((t_[1] - t_[0])); }
  time_t usec() { return (time_t)((t_[1] - t_[0]) * 1000); }
  time_t current() { return ::timeGetTime(); }

#else
#if defined(__unix__) || defined(__APPLE__)
  typedef unsigned long int time_t;

  void start() { gettimeofday(tv + 0, &tz); }
  void end() { gettimeofday(tv + 1, &tz); }

  time_t sec() { return (time_t)(tv[1].tv_sec - tv[0].tv_sec); }
  time_t msec() {
    return this->sec() * 1000 +
           (time_t)((tv[1].tv_usec - tv[0].tv_usec) / 1000);
  }
  time_t usec() {
    return this->sec() * 1000000 + (time_t)(tv[1].tv_usec - tv[0].tv_usec);
  }
  time_t current() {
    struct timeval t;
    gettimeofday(&t, NULL);
    return (time_t)(t.tv_sec * 1000 + t.tv_usec);
  }

#else // C timer
  // using namespace std;
  typedef clock_t time_t;

  void start() { t_[0] = clock(); }
  void end() { t_[1] = clock(); }

  time_t sec() { return (time_t)((t_[1] - t_[0]) / CLOCKS_PER_SEC); }
  time_t msec() { return (time_t)((t_[1] - t_[0]) * 1000 / CLOCKS_PER_SEC); }
  time_t usec() { return (time_t)((t_[1] - t_[0]) * 1000000 / CLOCKS_PER_SEC); }
  time_t current() { return (time_t)clock(); }

#endif
#endif

private:
#ifdef _WIN32
  DWORD t_[2];
#else
#if defined(__unix__) || defined(__APPLE__)
  struct timeval tv[2];
  struct timezone tz;
#else
  time_t t_[2];
#endif
#endif
};

typedef struct {
  GLuint vb;    // vertex buffer
  int numTriangles;
} DrawObject;

std::vector<DrawObject> gDrawObjects;

int width = 768;
int height = 768;

double prevMouseX, prevMouseY;
bool mouseLeftPressed;
bool mouseMiddlePressed;
bool mouseRightPressed;
float curr_quat[4];
float prev_quat[4];
float eye[3], lookat[3], up[3];

GLFWwindow* window;

void CheckErrors(std::string desc) {
  GLenum e = glGetError();
  if (e != GL_NO_ERROR) {
    fprintf(stderr, "OpenGL error in \"%s\": %d (%d)\n", desc.c_str(), e, e);
    exit(20);
  }
}

void CalcNormal(float N[3], float v0[3], float v1[3], float v2[3]) {
  float v10[3];
  v10[0] = v1[0] - v0[0];
  v10[1] = v1[1] - v0[1];
  v10[2] = v1[2] - v0[2];

  float v20[3];
  v20[0] = v2[0] - v0[0];
  v20[1] = v2[1] - v0[1];
  v20[2] = v2[2] - v0[2];

  N[0] = v20[1] * v10[2] - v20[2] * v10[1];
  N[1] = v20[2] * v10[0] - v20[0] * v10[2];
  N[2] = v20[0] * v10[1] - v20[1] * v10[0];

  float len2 = N[0] * N[0] + N[1] * N[1] + N[2] * N[2];
  if (len2 > 0.0f) {
    float len = sqrtf(len2);
    
    N[0] /= len;
    N[1] /= len;
  }
}

bool LoadObjAndConvert(float bmin[3], float bmax[3], std::vector<DrawObject>& drawObjects, const char* filename)
{
  tinyobj::attrib_t attrib;
  std::vector<tinyobj::shape_t> shapes;
  std::vector<tinyobj::material_t> materials;

  timerutil tm;

  tm.start();
  
  std::string err;
  bool ret = tinyobj::LoadObj(&attrib, &shapes, &materials, &err, filename, NULL);
  if (!err.empty()) {
    std::cerr << err << std::endl;
  }

  tm.end();
  
  if (!ret) {
    std::cerr << "Failed to load " << filename << std::endl;
    return false;
  }

  printf("Parsing time: %d [ms]\n", tm.msec());

  printf("# of vertices  = %d\n", (int)(attrib.vertices.size()) / 3);
  printf("# of normals   = %d\n", (int)(attrib.normals.size()) / 3);
  printf("# of texcoords = %d\n", (int)(attrib.texcoords.size()) / 2);
  printf("# of materials = %d\n", (int)materials.size());
  printf("# of shapes    = %d\n", (int)shapes.size());

  bmin[0] = bmin[1] = bmin[2] = std::numeric_limits<float>::max();
  bmax[0] = bmax[1] = bmax[2] = -std::numeric_limits<float>::max();

  {
      for (size_t s = 0; s < shapes.size(); s++) {
        DrawObject o;
        std::vector<float> vb; // pos(3float), normal(3float), color(3float)
        for (size_t f = 0; f < shapes[s].mesh.indices.size()/3; f++) {

          tinyobj::index_t idx0 = shapes[s].mesh.indices[3*f+0];
          tinyobj::index_t idx1 = shapes[s].mesh.indices[3*f+1];
          tinyobj::index_t idx2 = shapes[s].mesh.indices[3*f+2];

          float v[3][3];
          for (int k = 0; k < 3; k++) {
            int f0 = idx0.vertex_index;
            int f1 = idx1.vertex_index;
            int f2 = idx2.vertex_index;
            assert(f0 >= 0);
            assert(f1 >= 0);
            assert(f2 >= 0);

            v[0][k] = attrib.vertices[3*f0+k];
            v[1][k] = attrib.vertices[3*f1+k];
            v[2][k] = attrib.vertices[3*f2+k];
            bmin[k] = std::min(v[0][k], bmin[k]);
            bmin[k] = std::min(v[1][k], bmin[k]);
            bmin[k] = std::min(v[2][k], bmin[k]);
            bmax[k] = std::max(v[0][k], bmax[k]);
            bmax[k] = std::max(v[1][k], bmax[k]);
            bmax[k] = std::max(v[2][k], bmax[k]);
          }

          float n[3][3];

          if (attrib.normals.size() > 0) { 
            int f0 = idx0.normal_index;
            int f1 = idx1.normal_index;
            int f2 = idx2.normal_index;
            assert(f0 >= 0);
            assert(f1 >= 0);
            assert(f2 >= 0);
            for (int k = 0; k < 3; k++) {
              n[0][k] = attrib.normals[3*f0+k];
              n[1][k] = attrib.normals[3*f1+k];
              n[2][k] = attrib.normals[3*f2+k];
            }
          } else {
            // compute geometric normal
            CalcNormal(n[0], v[0], v[1], v[2]);
            n[1][0] = n[0][0]; n[1][1] = n[0][1]; n[1][2] = n[0][2];
            n[2][0] = n[0][0]; n[2][1] = n[0][1]; n[2][2] = n[0][2];
          }

          for (int k = 0; k < 3; k++) {
            vb.push_back(v[k][0]);
            vb.push_back(v[k][1]);
            vb.push_back(v[k][2]);
            vb.push_back(n[k][0]);
            vb.push_back(n[k][1]);
            vb.push_back(n[k][2]);
            // Use normal as color.
            float c[3] = {n[k][0], n[k][1], n[k][2]};
            float len2 = c[0] * c[0] + c[1] * c[1] + c[2] * c[2];
            if (len2 > 0.0f) {
              float len = sqrtf(len2);
              
              c[0] /= len;
              c[1] /= len;
              c[2] /= len;
            }
            vb.push_back(c[0] * 0.5 + 0.5);
            vb.push_back(c[1] * 0.5 + 0.5);
            vb.push_back(c[2] * 0.5 + 0.5);
          }
          
        }

        o.vb = 0;
        o.numTriangles = 0;
        if (vb.size() > 0) {
          glGenBuffers(1, &o.vb);
          glBindBuffer(GL_ARRAY_BUFFER, o.vb);
          glBufferData(GL_ARRAY_BUFFER, vb.size() * sizeof(float), &vb.at(0), GL_STATIC_DRAW);
          o.numTriangles = vb.size() / 9 / 3;
          printf("shape[%d] # of triangles = %d\n", static_cast<int>(s), o.numTriangles);
        }

        gDrawObjects.push_back(o);
    }
  }
  
  printf("bmin = %f, %f, %f\n", bmin[0], bmin[1], bmin[2]);
  printf("bmax = %f, %f, %f\n", bmax[0], bmax[1], bmax[2]);

  return true;
}

void reshapeFunc(GLFWwindow* window, int w, int h)
{
  int fb_w, fb_h;
  // Get actual framebuffer size.
  glfwGetFramebufferSize(window, &fb_w, &fb_h);

  glViewport(0, 0, fb_w, fb_h);
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  gluPerspective(45.0, (float)w / (float)h, 0.01f, 100.0f);
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();

  width = w;
  height = h;
}

void keyboardFunc(GLFWwindow *window, int key, int scancode, int action, int mods) {
    if(action == GLFW_PRESS || action == GLFW_REPEAT){
        // Move camera
        float mv_x = 0, mv_y = 0, mv_z = 0;
        if(key == GLFW_KEY_K) mv_x += 1;
        else if(key == GLFW_KEY_J) mv_x += -1;
        else if(key == GLFW_KEY_L) mv_y += 1;
        else if(key == GLFW_KEY_H) mv_y += -1;
        else if(key == GLFW_KEY_P) mv_z += 1;
        else if(key == GLFW_KEY_N) mv_z += -1;
        //camera.move(mv_x * 0.05, mv_y * 0.05, mv_z * 0.05);
        // Close window
        if(key == GLFW_KEY_Q || key == GLFW_KEY_ESCAPE) glfwSetWindowShouldClose(window, GL_TRUE);

        //init_frame = true;
    }
}

void clickFunc(GLFWwindow* window, int button, int action, int mods){
    if(button == GLFW_MOUSE_BUTTON_LEFT){
        if(action == GLFW_PRESS){
            mouseLeftPressed = true;
            trackball(prev_quat, 0.0, 0.0, 0.0, 0.0);
        } else if(action == GLFW_RELEASE){
            mouseLeftPressed = false;
        }
    }
    if(button == GLFW_MOUSE_BUTTON_RIGHT){
        if(action == GLFW_PRESS){
            mouseRightPressed = true;
        } else if(action == GLFW_RELEASE){
            mouseRightPressed = false;
        }
    }
    if(button == GLFW_MOUSE_BUTTON_MIDDLE){
        if(action == GLFW_PRESS){
            mouseMiddlePressed = true;
        } else if(action == GLFW_RELEASE){
            mouseMiddlePressed = false;
        }
    }
}

void motionFunc(GLFWwindow* window, double mouse_x, double mouse_y){
  float rotScale = 1.0f;
  float transScale = 2.0f;

    if(mouseLeftPressed){
      trackball(prev_quat,
          rotScale * (2.0f * prevMouseX - width) / (float)width,
          rotScale * (height - 2.0f * prevMouseY) / (float)height,
          rotScale * (2.0f * mouse_x - width) / (float)width,
          rotScale * (height - 2.0f * mouse_y) / (float)height);

      add_quats(prev_quat, curr_quat, curr_quat);
    } else if (mouseMiddlePressed) {
      eye[0] -= transScale * (mouse_x - prevMouseX) / (float)width;
      lookat[0] -= transScale * (mouse_x - prevMouseX) / (float)width;
      eye[1] += transScale * (mouse_y - prevMouseY) / (float)height;
      lookat[1] += transScale * (mouse_y - prevMouseY) / (float)height;
    } else if (mouseRightPressed) {
      eye[2] += transScale * (mouse_y - prevMouseY) / (float)height;
      lookat[2] += transScale * (mouse_y - prevMouseY) / (float)height;
    }

    // Update mouse point
    prevMouseX = mouse_x;
    prevMouseY = mouse_y;
}

void Draw(const std::vector<DrawObject>& drawObjects)
{
  glPolygonMode(GL_FRONT, GL_FILL);
  glPolygonMode(GL_BACK, GL_FILL);

  glEnable(GL_POLYGON_OFFSET_FILL);
  glPolygonOffset(1.0, 1.0);
  glColor3f(1.0f, 1.0f, 1.0f);
  for (size_t i = 0; i < drawObjects.size(); i++) {
    DrawObject o = drawObjects[i];
    if (o.vb < 1) {
      continue;
    }
 
    glBindBuffer(GL_ARRAY_BUFFER, o.vb);
    glEnableClientState(GL_VERTEX_ARRAY);
    glEnableClientState(GL_NORMAL_ARRAY);
    glEnableClientState(GL_COLOR_ARRAY);
    glVertexPointer(3, GL_FLOAT, 36, (const void*)0);
    glNormalPointer(GL_FLOAT, 36, (const void*)(sizeof(float)*3));
    glColorPointer(3, GL_FLOAT, 36, (const void*)(sizeof(float)*6));

    glDrawArrays(GL_TRIANGLES, 0, 3 * o.numTriangles);
    CheckErrors("drawarrays");
  }

  // draw wireframe
  glDisable(GL_POLYGON_OFFSET_FILL);
  glPolygonMode(GL_FRONT, GL_LINE);
  glPolygonMode(GL_BACK, GL_LINE);

  glColor3f(0.0f, 0.0f, 0.4f);
  for (size_t i = 0; i < drawObjects.size(); i++) {
    DrawObject o = drawObjects[i];
    if (o.vb < 1) {
      continue;
    }
 
    glBindBuffer(GL_ARRAY_BUFFER, o.vb);
    glEnableClientState(GL_VERTEX_ARRAY);
    glEnableClientState(GL_NORMAL_ARRAY);
    glDisableClientState(GL_COLOR_ARRAY);
    glVertexPointer(3, GL_FLOAT, 36, (const void*)0);
    glNormalPointer(GL_FLOAT, 36, (const void*)(sizeof(float)*3));

    glDrawArrays(GL_TRIANGLES, 0, 3 * o.numTriangles);
    CheckErrors("drawarrays");
  }
}

static void Init() {
  trackball(curr_quat, 0, 0, 0, 0);

  eye[0] = 0.0f;
  eye[1] = 0.0f;
  eye[2] = 3.0f;

  lookat[0] = 0.0f;
  lookat[1] = 0.0f;
  lookat[2] = 0.0f;

  up[0] = 0.0f;
  up[1] = 1.0f;
  up[2] = 0.0f;
}


int main(int argc, char **argv)
{
  if (argc < 2) {
    std::cout << "Needs input.obj\n" << std::endl;
    return 0;
  }

  Init();
 

  if(!glfwInit()){
    std::cerr << "Failed to initialize GLFW." << std::endl;
    return -1;
  }

  

  window = glfwCreateWindow(width, height, "Obj viewer", NULL, NULL);
  if(window == NULL){
    std::cerr << "Failed to open GLFW window. " << std::endl;
    glfwTerminate();
    return 1;
  }

  glfwMakeContextCurrent(window);
  glfwSwapInterval(1);

  // Callback
  glfwSetWindowSizeCallback(window, reshapeFunc);
  glfwSetKeyCallback(window, keyboardFunc);
  glfwSetMouseButtonCallback(window, clickFunc);
  glfwSetCursorPosCallback(window, motionFunc);

  glewExperimental = true;
  if (glewInit() != GLEW_OK) {
    std::cerr << "Failed to initialize GLEW." << std::endl;
    return -1;
  }

  reshapeFunc(window, width, height);

  float bmin[3], bmax[3];
  if (false == LoadObjAndConvert(bmin, bmax, gDrawObjects, argv[1])) {
    return -1;
  }

  float maxExtent = 0.5f * (bmax[0] - bmin[0]);
  if (maxExtent < 0.5f * (bmax[1] - bmin[1])) {
    maxExtent = 0.5f * (bmax[1] - bmin[1]);
  }
  if (maxExtent < 0.5f * (bmax[2] - bmin[2])) {
    maxExtent = 0.5f * (bmax[2] - bmin[2]);
  }

  while(glfwWindowShouldClose(window) == GL_FALSE) {
    glfwPollEvents();
    glClearColor(0.1f, 0.2f, 0.3f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glEnable(GL_DEPTH_TEST);

    // camera & rotate
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    GLfloat mat[4][4];
    gluLookAt(eye[0], eye[1], eye[2], lookat[0], lookat[1], lookat[2], up[0], up[1], up[2]);
    build_rotmatrix(mat, curr_quat);
    glMultMatrixf(&mat[0][0]);

    // Fit to -1, 1
    glScalef(1.0f / maxExtent, 1.0f / maxExtent, 1.0f / maxExtent);

    // Centerize object.
    glTranslatef(-0.5*(bmax[0] + bmin[0]), -0.5*(bmax[1] + bmin[1]), -0.5*(bmax[2] + bmin[2]));
  
    Draw(gDrawObjects);

    glfwSwapBuffers(window);
  }

  glfwTerminate();
}