#include "framebuffer.h"

#include "renderbuffer.h"
#include "texture.h"

#include <gfx_assert.h>

#include <error.h>

static void framebuffer_attach_colour(
    FrameBuffer* framebuffer, const FrameBufferAttachment* attachment) {
  assert(framebuffer);
  assert(attachment);

  switch (attachment->type) {
  case FrameBufferNoAttachment:
    break;
  case FrameBufferTexture:
    glFramebufferTexture2D(
        GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
        attachment->texture.texture->id, attachment->texture.mip_level);
    break;
  case FrameBufferCubemapTexture:
    glFramebufferTexture2D(
        GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
        to_GL_cubemap_face(attachment->cubemap.face),
        attachment->cubemap.texture->id, attachment->cubemap.mip_level);
    break;
  case FrameBufferRenderBuffer:
    glFramebufferRenderbuffer(
        GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER,
        attachment->renderbuffer->id);
    break;
  }

  ASSERT_GL;
}

static void framebuffer_attach_depth(
    FrameBuffer* framebuffer, const FrameBufferAttachment* attachment) {
  assert(framebuffer);
  assert(attachment);

  switch (attachment->type) {
  case FrameBufferNoAttachment:
    break;
  case FrameBufferTexture:
    glFramebufferTexture2D(
        GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_DEPTH_COMPONENT,
        attachment->texture.texture->id, attachment->texture.mip_level);
    break;
  // TODO: Could distinguish between colour and depth attachment types to make
  // this a compile-time error.
  case FrameBufferCubemapTexture:
    log_error("Cannot use a cubemap texture as a depth framebuffer attachment");
    break;
  case FrameBufferRenderBuffer:
    glFramebufferRenderbuffer(
        GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER,
        attachment->renderbuffer->id);
    break;
  }

  ASSERT_GL;
}

bool gfx_init_framebuffer(
    FrameBuffer* framebuffer, const FrameBufferDesc* desc) {
  assert(framebuffer);
  assert(desc);

  glGenFramebuffers(1, &framebuffer->id);
  if (!framebuffer->id) {
    log_error("glGenFramebuffers() failed");
    return false;
  }

  // Allow incomplete framebuffers for flexibility.
  // Attach buffers and check the framebuffer status only if buffers are given
  // up front.
  if (desc->colour.type != FrameBufferNoAttachment ||
      desc->depth.type != FrameBufferNoAttachment) {
    // TODO: Could use the "named" API to avoid having to bind the framebuffer.
    glBindFramebuffer(GL_FRAMEBUFFER, framebuffer->id);
    framebuffer_attach_colour(framebuffer, &desc->colour);
    framebuffer_attach_depth(framebuffer, &desc->depth);
    if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
      log_error("glCheckFramebufferStatus() failed");
      gfx_del_framebuffer(framebuffer);
      return false;
    }
    glBindFramebuffer(GL_FRAMEBUFFER, 0);
  }

  ASSERT_GL;
  return true;
}

bool gfx_framebuffer_attach_colour(
    FrameBuffer* framebuffer, const FrameBufferAttachment* attachment) {
  assert(framebuffer);
  assert(attachment);

  // TODO: Could use the "named" API to avoid having to bind the framebuffer.
  glBindFramebuffer(GL_FRAMEBUFFER, framebuffer->id);
  framebuffer_attach_colour(framebuffer, attachment);
  if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
    log_error("glCheckFramebufferStatus() failed");
    return false;
  }
  return true;
}

bool gfx_framebuffer_attach_depth(
    FrameBuffer* framebuffer, const FrameBufferAttachment* attachment) {
  assert(framebuffer);
  assert(attachment);

  // TODO: Could use the "named" API to avoid having to bind the framebuffer.
  glBindFramebuffer(GL_FRAMEBUFFER, framebuffer->id);
  framebuffer_attach_depth(framebuffer, attachment);
  if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
    log_error("glCheckFramebufferStatus() failed");
    return false;
  }
  return true;
}

void gfx_del_framebuffer(FrameBuffer* framebuffer) {
  assert(framebuffer);
  if (framebuffer->id) {
    glDeleteFramebuffers(1, &framebuffer->id);
    framebuffer->id = 0;
  }
}

void gfx_activate_framebuffer(const FrameBuffer* framebuffer) {
  assert(framebuffer);
  glBindFramebuffer(GL_FRAMEBUFFER, framebuffer->id);
}

void gfx_deactivate_framebuffer(const FrameBuffer* framebuffer) {
  assert(framebuffer);
  glBindFramebuffer(GL_FRAMEBUFFER, 0);
}

void gfx_framebuffer_set_viewport(
    FrameBuffer* framebuffer, int x, int y, int width, int height) {
  assert(framebuffer);
  glViewport(x, y, width, height);
}