#include "framebuffer.hpp"
#include <glad/glad.h>
#include <GLFW/glfw3.h>

void FrameBuffer::init() {
  // target_fb configuration
  // -------------------------
  glGenFramebuffers(1, &target_fb);
  glBindFramebuffer(GL_FRAMEBUFFER, target_fb);

  // create the multisamples color attachment texture
  glGenTextures(1, &texture_multi);
  glBindTexture(GL_TEXTURE_2D_MULTISAMPLE, texture_multi);
  glTexImage2DMultisample(GL_TEXTURE_2D_MULTISAMPLE, 4, GL_RGB, SCR_WIDTH, SCR_HEIGHT, GL_TRUE);
  glBindTexture(GL_TEXTURE_2D_MULTISAMPLE, 0);
  glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D_MULTISAMPLE, texture_multi, 0);

  // create a renderbuffer object for depth and stencil attachment (we won't be sampling these)
  glGenRenderbuffers(1, &target_rbo);
  glBindRenderbuffer(GL_RENDERBUFFER, target_rbo);
  glRenderbufferStorageMultisample(GL_RENDERBUFFER, 4, GL_DEPTH24_STENCIL8, SCR_WIDTH, SCR_HEIGHT); // use a single renderbuffer object for both a depth AND stencil buffer.
  glBindRenderbuffer(GL_RENDERBUFFER, 0);
  glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, target_rbo); // now actually attach it
  // now that we actually created the target_fb and added all attachments we want to check if it is actually complete now

  dbc::check(glCheckFramebufferStatus(GL_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE, "Frame buffer not complete.");
  glBindFramebuffer(GL_FRAMEBUFFER, 0);

  // intermediate fbo here
  glGenFramebuffers(1, &intermediate_fbo);
  glBindFramebuffer(GL_FRAMEBUFFER, intermediate_fbo);

  // create a color attachment texture
  glGenTextures(1, &texture_buffer);
  glBindTexture(GL_TEXTURE_2D, texture_buffer);
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, SCR_WIDTH, SCR_HEIGHT, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture_buffer, 0);

  dbc::check(glCheckFramebufferStatus(GL_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE, "Frame buffer not complete.");
  glBindFramebuffer(GL_FRAMEBUFFER, 0);
}

void FrameBuffer::begin() {
  // target_fb stuff here
  glBindFramebuffer(GL_FRAMEBUFFER, target_fb);
  glEnable(GL_DEPTH_TEST);

  glClearColor(0.1f, 0.1f, 0.1f, 1.0f);
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
}

void FrameBuffer::commit() {
  // disable the frame buffer
  glBindFramebuffer(GL_READ_FRAMEBUFFER, target_fb);
  glBindFramebuffer(GL_DRAW_FRAMEBUFFER, intermediate_fbo);
  glBlitFramebuffer(0, 0, SCR_WIDTH, SCR_HEIGHT, 0, 0, SCR_WIDTH, SCR_HEIGHT, GL_COLOR_BUFFER_BIT, GL_NEAREST);
  glBindFramebuffer(GL_FRAMEBUFFER, 0);
}

void FrameBuffer::draw(Screen& screen) {
  glClearColor(0.0f, 1.0f, 0.0f, 1.0f);
  glClear(GL_COLOR_BUFFER_BIT);
  glDisable(GL_DEPTH_TEST);

  screen.shader.use();
  glBindVertexArray(screen.target_VAO);
  glActiveTexture(GL_TEXTURE0);
  glBindTexture(GL_TEXTURE_2D, texture_buffer);
  glDrawArrays(GL_TRIANGLES, 0, 6);
}