/*
  * V4L2 context helper functions.
  *
  * Copyright (C) 2017 Alexis Ballier <aballier@gentoo.org>
  * Copyright (C) 2017 Jorge Ramirez <jorge.ramirez-ortiz@linaro.org>
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg 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
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #ifndef AVCODEC_V4L2_CONTEXT_H
 #define AVCODEC_V4L2_CONTEXT_H
 
 #include <stdatomic.h>

 #include <linux/videodev2.h>
 

 #include "libavcodec/avcodec.h"
 #include "libavutil/pixfmt.h"
 #include "libavutil/frame.h"
 #include "libavutil/buffer.h"
 #include "v4l2_buffers.h"
 
 typedef struct V4L2Context {
     /**
      * context name.
      */
     const char* name;
 
     /**
      * Type of this buffer context.
      * See V4L2_BUF_TYPE_VIDEO_* in videodev2.h
      * Readonly after init.
      */
     enum v4l2_buf_type type;
 
     /**
      * AVPixelFormat corresponding to this buffer context.
      * AV_PIX_FMT_NONE means this is an encoded stream.
      */
     enum AVPixelFormat av_pix_fmt;
 
     /**
      * AVCodecID corresponding to this buffer context.
      * AV_CODEC_ID_RAWVIDEO means this is a raw stream and av_pix_fmt must be set to a valid value.
      */
     enum AVCodecID av_codec_id;
 
     /**
      * Format returned by the driver after initializing the buffer context.
      * Readonly after init.
      */
     struct v4l2_format format;
 
     /**
      * Width and height of the frames it produces (in case of a capture context, e.g. when decoding)
      * or accepts (in case of an output context, e.g. when encoding).
      */
     int width, height;
 
     /**
      * Indexed array of V4L2Buffers
      */
     V4L2Buffer *buffers;
 
     /**
      * Readonly after init.
      */
     int num_buffers;
 
     /**
      * Whether the stream has been started (VIDIOC_STREAMON has been sent).
      */
     int streamon;
 
     /**
      *  Either no more buffers available or an unrecoverable error was notified
      *  by the V4L2 kernel driver: once set the context has to be exited.
      */
     int done;
 
 } V4L2Context;
 
 /**
  * Initializes a V4L2Context.
  *
  * @param[in] ctx A pointer to a V4L2Context. See V4L2Context description for required variables.
  * @return 0 in case of success, a negative value representing the error otherwise.
  */
 int ff_v4l2_context_init(V4L2Context* ctx);
 
 /**
  * Sets the V4L2Context format in the v4l2 driver.
  *
  * @param[in] ctx A pointer to a V4L2Context. See V4L2Context description for required variables.
  * @return 0 in case of success, a negative value representing the error otherwise.
  */
 int ff_v4l2_context_set_format(V4L2Context* ctx);
 
 /**
  * Queries the driver for a valid v4l2 format and copies it to the context.
  *
  * @param[in] ctx A pointer to a V4L2Context. See V4L2Context description for required variables.
  * @return 0 in case of success, a negative value representing the error otherwise.
  */
 int ff_v4l2_context_get_format(V4L2Context* ctx);
 
 /**
  * Releases a V4L2Context.
  *
  * @param[in] ctx A pointer to a V4L2Context.
  *               The caller is reponsible for freeing it.
  *               It must not be used after calling this function.
  */
 void ff_v4l2_context_release(V4L2Context* ctx);
 
 /**
  * Sets the status of a V4L2Context.
  *
  * @param[in] ctx A pointer to a V4L2Context.
  * @param[in] cmd The status to set (VIDIOC_STREAMON or VIDIOC_STREAMOFF).
  *                Warning: If VIDIOC_STREAMOFF is sent to a buffer context that still has some frames buffered,
  *                those frames will be dropped.
  * @return 0 in case of success, a negative value representing the error otherwise.
  */

 int ff_v4l2_context_set_status(V4L2Context* ctx, uint32_t cmd);

 
 /**
  * Dequeues a buffer from a V4L2Context to an AVPacket.
  *
  * The pkt must be non NULL.
  * @param[in] ctx The V4L2Context to dequeue from.
  * @param[inout] pkt The AVPacket to dequeue to.
  * @return 0 in case of success, AVERROR(EAGAIN) if no buffer was ready, another negative error in case of error.
  */
 int ff_v4l2_context_dequeue_packet(V4L2Context* ctx, AVPacket* pkt);
 
 /**
  * Dequeues a buffer from a V4L2Context to an AVFrame.
  *
  * The frame must be non NULL.
  * @param[in] ctx The V4L2Context to dequeue from.
  * @param[inout] f The AVFrame to dequeue to.
  * @return 0 in case of success, AVERROR(EAGAIN) if no buffer was ready, another negative error in case of error.
  */
 int ff_v4l2_context_dequeue_frame(V4L2Context* ctx, AVFrame* f);
 
 /**
  * Enqueues a buffer to a V4L2Context from an AVPacket
  *
  * The packet must be non NULL.
  * When the size of the pkt is null, the buffer is not queued but a V4L2_DEC_CMD_STOP command is sent instead to the driver.
  *
  * @param[in] ctx The V4L2Context to enqueue to.
  * @param[in] pkt A pointer to an AVPacket.
  * @return 0 in case of success, a negative error otherwise.
  */
 int ff_v4l2_context_enqueue_packet(V4L2Context* ctx, const AVPacket* pkt);
 
 /**
  * Enqueues a buffer to a V4L2Context from an AVFrame
  *
  * The frame must be non NULL.
  *
  * @param[in] ctx The V4L2Context to enqueue to.
  * @param[in] f A pointer to an AVFrame to enqueue.
  * @return 0 in case of success, a negative error otherwise.
  */
 int ff_v4l2_context_enqueue_frame(V4L2Context* ctx, const AVFrame* f);
 
 #endif // AVCODEC_V4L2_CONTEXT_H