#include "decoder.h"
#include <libavutil/dict.h>

int decoder_init (struct Decoder *decoder, const AVCodecParameters *codecpar, AVDictionary **opts)
{
	int err;
	AVCodecContext *avctx;
	const AVCodec *codec;

	if ((codec = avcodec_find_decoder(codecpar->codec_id)) == NULL)
		return AVERROR_DECODER_NOT_FOUND;

	/* NOTE: parameter 'codec' might be redundant here due to the next, more
	 * featuref-full call to avcodec_parameters_to_context. */
	if ((avctx = avcodec_alloc_context3(codec)) == NULL)
		return AVERROR(ENOMEM); /* NOTE: After reading libavcodec's code, this
								 * error code *could* misrepresent the actual
								 * error, but ffmpeg won't tell us what it is
								 * anyway so oh well. */

	if ((err = avcodec_parameters_to_context(avctx, codecpar)) < 0)
		goto error;

	if ((err = avcodec_open2(avctx, codec, opts)) < 0)
		goto error;

	/* Free previous context (no-op if avctx == NULL) and swap it with the new
	 * one. This allows the previous one to be left untouched in case of error,
	 * which is generally a nice thing to do in your code. */
	avcodec_free_context(&decoder->avctx);
	decoder->avctx = avctx;
	return 0;

error:
	avcodec_free_context(&avctx);
	return err;
}

int decoder_init_for_stream (struct Decoder *decoder, const AVStream *stream, AVDictionary **opts)
{
	return decoder_init(decoder, stream->codecpar, opts);
}

int decoder_send (struct Decoder *decoder, const AVPacket *pkt)
{
	return avcodec_send_packet(decoder->avctx, pkt);
}

int decoder_convert (struct Decoder *decoder, AVFrame *out)
{
	return avcodec_receive_frame(decoder->avctx, out);
}

void decoder_free (struct Decoder *decoder)
{
	if (decoder == NULL) return;
	avcodec_free_context(&decoder->avctx);
}