/*
 * OpenH264 video decoder
 * Copyright (C) 2016 Martin Storsjo
 *
 * 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
 */

#include <wels/codec_api.h>
#include <wels/codec_ver.h>

#include "libavutil/common.h"
#include "libavutil/fifo.h"
#include "libavutil/imgutils.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/mathematics.h"
#include "libavutil/opt.h"

#include "avcodec.h"
#include "codec_internal.h"
#include "decode.h"
#include "libopenh264.h"

typedef struct SVCContext {
    ISVCDecoder *decoder;
} SVCContext;

static av_cold int svc_decode_close(AVCodecContext *avctx)
{
    SVCContext *s = avctx->priv_data;

    if (s->decoder)
        WelsDestroyDecoder(s->decoder);

    return 0;
}

static av_cold int svc_decode_init(AVCodecContext *avctx)
{
    SVCContext *s = avctx->priv_data;
    SDecodingParam param = { 0 };
    int err;
    int log_level;
    WelsTraceCallback callback_function;

    if ((err = ff_libopenh264_check_version(avctx)) < 0)
        return AVERROR_DECODER_NOT_FOUND;

    if (WelsCreateDecoder(&s->decoder)) {
        av_log(avctx, AV_LOG_ERROR, "Unable to create decoder\n");
        return AVERROR_UNKNOWN;
    }

    // Pass all libopenh264 messages to our callback, to allow ourselves to filter them.
    log_level = WELS_LOG_DETAIL;
    callback_function = ff_libopenh264_trace_callback;
    (*s->decoder)->SetOption(s->decoder, DECODER_OPTION_TRACE_LEVEL, &log_level);
    (*s->decoder)->SetOption(s->decoder, DECODER_OPTION_TRACE_CALLBACK, (void *)&callback_function);
    (*s->decoder)->SetOption(s->decoder, DECODER_OPTION_TRACE_CALLBACK_CONTEXT, (void *)&avctx);

#if !OPENH264_VER_AT_LEAST(1, 6)
    param.eOutputColorFormat = videoFormatI420;
#endif
    param.eEcActiveIdc       = ERROR_CON_DISABLE;
    param.sVideoProperty.eVideoBsType = VIDEO_BITSTREAM_DEFAULT;

    if ((*s->decoder)->Initialize(s->decoder, &param) != cmResultSuccess) {
        av_log(avctx, AV_LOG_ERROR, "Initialize failed\n");
        return AVERROR_UNKNOWN;
    }

    avctx->pix_fmt = AV_PIX_FMT_YUV420P;

    return 0;
}

static int svc_decode_frame(AVCodecContext *avctx, AVFrame *avframe,
                            int *got_frame, AVPacket *avpkt)
{
    SVCContext *s = avctx->priv_data;
    SBufferInfo info = { 0 };
    uint8_t *ptrs[4] = { NULL };
    int ret, linesize[4];
    DECODING_STATE state;
#if OPENH264_VER_AT_LEAST(1, 7)
    int opt;
#endif

    if (!avpkt->data) {
#if OPENH264_VER_AT_LEAST(1, 9)
        int end_of_stream = 1;
        (*s->decoder)->SetOption(s->decoder, DECODER_OPTION_END_OF_STREAM, &end_of_stream);
        state = (*s->decoder)->FlushFrame(s->decoder, ptrs, &info);
#else
        return 0;
#endif
    } else {
        info.uiInBsTimeStamp = avpkt->pts;
#if OPENH264_VER_AT_LEAST(1, 4)
        // Contrary to the name, DecodeFrameNoDelay actually does buffering
        // and reordering of frames, and is the recommended decoding entry
        // point since 1.4. This is essential for successfully decoding
        // B-frames.
        state = (*s->decoder)->DecodeFrameNoDelay(s->decoder, avpkt->data, avpkt->size, ptrs, &info);
#else
        state = (*s->decoder)->DecodeFrame2(s->decoder, avpkt->data, avpkt->size, ptrs, &info);
#endif
    }
    if (state != dsErrorFree) {
        av_log(avctx, AV_LOG_ERROR, "DecodeFrame failed\n");
        return AVERROR_UNKNOWN;
    }
    if (info.iBufferStatus != 1) {
        av_log(avctx, AV_LOG_DEBUG, "No frame produced\n");
        return avpkt->size;
    }

    ret = ff_set_dimensions(avctx, info.UsrData.sSystemBuffer.iWidth, info.UsrData.sSystemBuffer.iHeight);
    if (ret < 0)
        return ret;
    // The decoder doesn't (currently) support decoding into a user
    // provided buffer, so do a copy instead.
    if (ff_get_buffer(avctx, avframe, 0) < 0) {
        av_log(avctx, AV_LOG_ERROR, "Unable to allocate buffer\n");
        return AVERROR(ENOMEM);
    }

    linesize[0] = info.UsrData.sSystemBuffer.iStride[0];
    linesize[1] = linesize[2] = info.UsrData.sSystemBuffer.iStride[1];
    linesize[3] = 0;
    av_image_copy(avframe->data, avframe->linesize, (const uint8_t **) ptrs, linesize, avctx->pix_fmt, avctx->width, avctx->height);

    avframe->pts     = info.uiOutYuvTimeStamp;
    avframe->pkt_dts = AV_NOPTS_VALUE;
#if OPENH264_VER_AT_LEAST(1, 7)
    (*s->decoder)->GetOption(s->decoder, DECODER_OPTION_PROFILE, &opt);
    avctx->profile = opt;
    (*s->decoder)->GetOption(s->decoder, DECODER_OPTION_LEVEL, &opt);
    avctx->level = opt;
#endif

    *got_frame = 1;
    return avpkt->size;
}

const FFCodec ff_libopenh264_decoder = {
    .p.name         = "libopenh264",
    CODEC_LONG_NAME("OpenH264 H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10"),
    .p.type         = AVMEDIA_TYPE_VIDEO,
    .p.id           = AV_CODEC_ID_H264,
    .priv_data_size = sizeof(SVCContext),
    .init           = svc_decode_init,
    FF_CODEC_DECODE_CB(svc_decode_frame),
    .close          = svc_decode_close,
    .p.capabilities = AV_CODEC_CAP_DELAY | AV_CODEC_CAP_DR1,
    .caps_internal  = FF_CODEC_CAP_SETS_PKT_DTS |
                      FF_CODEC_CAP_INIT_CLEANUP,
    .bsfs           = "h264_mp4toannexb",
    .p.wrapper_name = "libopenh264",
};