/***

  Olive - Non-Linear Video Editor
  Copyright (C) 2019 Olive Team

  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program.  If not, see <http://www.gnu.org/licenses/>.

***/

#include "rendertexture.h"

#include <QDebug>

#include "render/pixelservice.h"

RenderTexture::RenderTexture() :
  context_(nullptr),
  texture_(0)
{

}

RenderTexture::~RenderTexture()
{
  Destroy();
}

bool RenderTexture::IsCreated() const
{
  return (texture_ != 0);
}

void RenderTexture::Create(QOpenGLContext *ctx, int width, int height, const olive::PixelFormat &format, void* data)
{
  if (ctx == nullptr) {
    qWarning() << tr("RenderTexture::Create was passed an invalid context");
    return;
  }

  Destroy();

  context_ = ctx;

  QOpenGLFunctions* f = context_->functions();

  // Create texture
  f->glGenTextures(1, &texture_);

  // Verify texture
  if (texture_ == 0) {
    qWarning() << tr("OpenGL texture creation failed");
    return;
  }

  // Bind texture
  f->glBindTexture(GL_TEXTURE_2D, texture_);

  // Allocate storage for texture
  const PixelFormatInfo& bit_depth = PixelService::GetPixelFormatInfo(format);

  f->glTexImage2D(
        GL_TEXTURE_2D,
        0,
        bit_depth.internal_format,
        width,
        height,
        0,
        bit_depth.pixel_format,
        bit_depth.pixel_type,
        data
        );

  // Set texture filtering to bilinear
  f->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
  f->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

  // Release texture
  f->glBindTexture(GL_TEXTURE_2D, 0);
}

void RenderTexture::Destroy()
{
  if (context_ != nullptr) {
    context_->functions()->glDeleteTextures(1, &texture_);

    context_ = nullptr;
  }
}

void RenderTexture::Bind()
{
  if (context_ == nullptr) {
    qWarning() << "RenderTexture::Bind() called with an invalid context";
    return;
  }

  context_->functions()->glBindTexture(GL_TEXTURE_2D, texture_);
}

void RenderTexture::Release()
{
  if (context_ == nullptr) {
    qWarning() << "RenderTexture::Release() called with an invalid context";
    return;
  }

  context_->functions()->glBindTexture(GL_TEXTURE_2D, 0);
}

const int &RenderTexture::width() const
{
  return width_;
}

const int &RenderTexture::height() const
{
  return height_;
}

const olive::PixelFormat &RenderTexture::format() const
{
  return format_;
}

QOpenGLContext *RenderTexture::context() const
{
  return context_;
}

const GLuint &RenderTexture::texture() const
{
  return texture_;
}

void RenderTexture::Upload(void *data)
{
  if (!IsCreated()) {
    qWarning() << tr("RenderTexture::Upload() called while it wasn't created");
    return;
  }

  Bind();

  PixelFormatInfo info = PixelService::GetPixelFormatInfo(format_);

  context_->functions()->glTexSubImage2D(GL_TEXTURE_2D,
                                         0,
                                         0,
                                         0,
                                         width_,
                                         height_,
                                         info.pixel_format,
                                         info.pixel_type,
                                         data);

  Release();
}

void *RenderTexture::Download() const
{
  if (!IsCreated()) {
    qWarning() << tr("RenderTexture::Download() called while it wasn't created");
    return nullptr;
  }

  // FIXME: Implement this

  return nullptr;
}