#include <math.h>
#define GLAD_GL_IMPLEMENTATION
#include "gl.h"
#define GLFW_INCLUDE_NONE
#include <GLFW/glfw3.h>
#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"

#include <pthread.h>

#include "const.h"
#include "cubes.h"
#include "linmath.h"
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>

static const char *vertex_shader_text =
    "#version 330\n"
    "layout (location = 0) in vec3 v_pos;"
    "layout (location = 1) in vec3 v_off;"
    "uniform mat4 mvp;\n"
    "out vec2 v_tex;\n"
    "void main()\n"
    "{\n"
    "    gl_Position = mvp * vec4(v_pos, 1.0);\n"
    "    v_tex=vec2(v_off);\n"
    "}\n";

static const char *fragment_shader_text =
    "#version 330\n"
    "out vec4 color;\n"
    "in vec2 v_tex;\n"
    "uniform sampler2D sampler_tex;\n"
    "void main()\n"
    "{\n"
    //"    color=vec4(v_tex.rg,0.5,0.5);\n"
    "    if (v_tex.x < 0.0 || v_tex.y < 0.0) { discard; }\n"
    "    color=vec4(texture(sampler_tex, v_tex).rgb,0.5);\n"
    "}\n";

int isCursor = 0;

static void key_callback(GLFWwindow *window, int key, int scancode, int action,
                         int mods) {
  /*if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
    glfwSetWindowShouldClose(window, GLFW_TRUE);
*/
  if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS) {
    isCursor = glfwGetInputMode(window, GLFW_CURSOR) == GLFW_CURSOR_DISABLED;
    glfwSetInputMode(window, GLFW_CURSOR,
                     isCursor ? GLFW_CURSOR_NORMAL : GLFW_CURSOR_DISABLED);
  }
}

double cx = 0;
double cy = 0;
int width, height;

static void cursor_position_callback(GLFWwindow *window, double x, double y) {
  if (isCursor)
    return;
  cx = (x - width / 2.0) / -1000.0;
  cy = (y - height / 2.0) / -1000.0;
  cy = (cy > M_PI / 2) ? M_PI / 2 : ((cy < -M_PI / 2) ? -M_PI / 2 : cy);
  return;
}

struct args {
  int *cube_count;
  Vertex **cube;
  Vertex **text;
  vec3 pos;
  GLuint *vertex_buffer;
  int *is_render;
};

void *render_chunks(void *args) {
  struct args args2 = ((struct args *)args)[0];

  int *cube_count = args2.cube_count;
  // printf("%i\n", *cube_count);
  GLuint *vertex_buffer = args2.vertex_buffer;

  *args2.is_render = 0;

  *cube_count =
      gen_cubes(*args2.cube, *args2.text, args2.pos[0] / CHUNK_LENGTH,
                args2.pos[1] / CHUNK_LENGTH, args2.pos[2] / CHUNK_LENGTH, 0, 0);

  *args2.is_render = 2;

  return NULL;
}

int main(void) {
  if (!glfwInit())
    exit(EXIT_FAILURE);

  glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
  glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
  glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

  GLFWwindow *window =
      glfwCreateWindow(640, 480, "OpenGL Triangle", NULL, NULL);
  if (!window) {
    glfwTerminate();
    exit(EXIT_FAILURE);
  }

  glfwMakeContextCurrent(window);
  gladLoadGL(glfwGetProcAddress);
  glfwSwapInterval(1);

  Vertex *cube = malloc(CTRI_ALL);
  Vertex *text = malloc(CTRI_ALL);

  int cube_count = gen_cubes(cube, text, 1024 / CHUNK_LENGTH, 64 / CHUNK_LENGTH,
                             1024 / CHUNK_LENGTH, 0,1);
  GLuint vertex_buffer[2];

  GLuint vertex_array;
  glGenVertexArrays(1, &vertex_array);
  glBindVertexArray(vertex_array);

  glGenBuffers(2, vertex_buffer);

  glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer[1]);
  glBufferData(GL_ARRAY_BUFFER, CTRI_ALL, text, GL_STATIC_DRAW);
  glEnableVertexAttribArray(1);
  glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void *)0);

  glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer[0]);
  glBufferData(GL_ARRAY_BUFFER, CTRI_ALL, cube, GL_STATIC_DRAW);
  glEnableVertexAttribArray(0);
  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void *)0);

  GLuint vertex_shader = glCreateShader(GL_VERTEX_SHADER);
  glShaderSource(vertex_shader, 1, &vertex_shader_text, NULL);
  glCompileShader(vertex_shader);

  GLuint fragment_shader = glCreateShader(GL_FRAGMENT_SHADER);
  glShaderSource(fragment_shader, 1, &fragment_shader_text, NULL);
  glCompileShader(fragment_shader);

  GLuint program = glCreateProgram();
  glAttachShader(program, vertex_shader);
  glAttachShader(program, fragment_shader);
  glLinkProgram(program);

  GLint tex_location = glGetUniformLocation(program, "sampler_tex");
  GLint mvp_location = glGetUniformLocation(program, "mvp");

  unsigned char *pixels;

  int tx, ty, ch;
  pixels = stbi_load("./test.png", &tx, &ty, &ch, 3);

  glClearColor(0.2f, 0.5f, 0.7f, 1.0f);
  glEnable(GL_TEXTURE_2D);
  glEnable(GL_DEPTH_TEST);

  glfwSetKeyCallback(window, key_callback);
  glfwSetCursorPosCallback(window, cursor_position_callback);

  vec3 pos = {1024, 64, 1024};

  // int x = 0, y = 25, z = 0;
  glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);

  double frames = 0.0;
  pthread_t thread_id;
  int is_render = 1;
  glfwSetTime(7.5);

  while (!glfwWindowShouldClose(window)) {

    vec3 oldPos = {pos[0], pos[1], pos[2]};
    glfwGetFramebufferSize(window, &width, &height);
    const float ratio = width / (float)height;

    glViewport(0, 0, width, height);

    glUseProgram(program);

    mat4x4 m, v, p, mvp;
    mat4x4_identity(m);
    mat4x4_perspective(p, 45.0 / 180.0 * M_PI, ratio, 0.1, 1000);

    vec3 direction = {cosf(cy) * sinf(cx), sinf(cy), cosf(cy) * cosf(cx)};
    vec3 right = {sinf(cx - 3.14f / 2.0f), 0, cosf(cx - 3.14f / 2.0f)};

    if (glfwGetKey(window, GLFW_KEY_SPACE) == GLFW_PRESS) {
      vec3_add(pos, pos, direction);
    }

    if (glfwGetKey(window, GLFW_KEY_LEFT_SHIFT) == GLFW_PRESS) {
      vec3_sub(pos, pos, direction);
    }

    if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS) {
      vec3_add(pos, pos, right);
    }

    if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS) {
      vec3_sub(pos, pos, right);
    }

    vec3 dir_pos;
    vec3_add(dir_pos, direction, pos);

    vec3 up = {0, 1, 0};
    // vec3_mul_cross(up, right, direction);
    mat4x4_look_at(v, pos, dir_pos, up);

    mat4x4_mul(mvp, p, v);
    mat4x4_mul(mvp, mvp, m);

    glUniformMatrix4fv(mvp_location, 1, GL_FALSE, (const GLfloat *)&mvp);
    
    int ax = (int)(oldPos[0] / CHUNK_LENGTH) - (int)(pos[0] / CHUNK_LENGTH);
    int ay = (int)(oldPos[1] / CHUNK_LENGTH) - (int)(pos[1] / CHUNK_LENGTH);
    int az = (int)(oldPos[2] / CHUNK_LENGTH) - (int)(pos[2] / CHUNK_LENGTH);

    if ((ax != 0 || ay != 0 || az != 0) && frames > 4.0) {
      struct args args;
      args.cube_count = &cube_count;

      args.cube = &cube;
      args.text = &text;
      args.pos[0] = pos[0];
      args.pos[1] = pos[1];
      args.pos[2] = pos[2];
      args.vertex_buffer = vertex_buffer;
      args.is_render = &is_render;

      if (thread_id != 0)
        pthread_join(thread_id, NULL);

      pthread_create(&(thread_id), NULL, render_chunks, (void *)&(args));

      frames = 0;
      glfwSetTime(0);
    }

    frames = glfwGetTime();
    //Sprintf("%f\n", frames);

    glfwSwapBuffers(window);
    glfwPollEvents();

    if (is_render == 2) {
      glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer[1]);
      glBufferSubData(GL_ARRAY_BUFFER, 0, (long)cube_count*sizeof(Vertex), text);

      glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer[0]);
      glBufferSubData(GL_ARRAY_BUFFER, 0, (long)cube_count*sizeof(Vertex), cube);
      is_render = 1;
    }

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glBindTexture(GL_TEXTURE_2D, GL_TEXTURE0);

    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, tx, ty, 0, GL_RGB, GL_UNSIGNED_BYTE,
                 pixels);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

    int val = CTRI_ALL;

    glBindVertexArray(vertex_array);

    glDrawArrays(GL_TRIANGLES, 0, cube_count);
  }

  free(cube);
  free(text);

  glfwDestroyWindow(window);

  glfwTerminate();
  exit(EXIT_SUCCESS);
}