/*
  * HW decode acceleration through NVDEC
  *
  * Copyright (c) 2016 Anton Khirnov
  *

  * 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 "config.h"
 
 #include "libavutil/common.h"
 #include "libavutil/error.h"
 #include "libavutil/hwcontext.h"
 #include "libavutil/hwcontext_cuda_internal.h"
 #include "libavutil/pixdesc.h"
 #include "libavutil/pixfmt.h"
 
 #include "avcodec.h"
 #include "decode.h"
 #include "nvdec.h"
 #include "internal.h"
 
 typedef struct NVDECDecoder {
     CUvideodecoder decoder;
 
     AVBufferRef *hw_device_ref;
     CUcontext    cuda_ctx;
 
     CudaFunctions *cudl;
     CuvidFunctions *cvdl;
 } NVDECDecoder;
 
 typedef struct NVDECFramePool {
     unsigned int dpb_size;
     unsigned int nb_allocated;
 } NVDECFramePool;
 
 static int map_avcodec_id(enum AVCodecID id)
 {
     switch (id) {

     case AV_CODEC_ID_H264:       return cudaVideoCodec_H264;
     case AV_CODEC_ID_HEVC:       return cudaVideoCodec_HEVC;

     case AV_CODEC_ID_MJPEG:      return cudaVideoCodec_JPEG;

     case AV_CODEC_ID_MPEG1VIDEO: return cudaVideoCodec_MPEG1;

     case AV_CODEC_ID_MPEG2VIDEO: return cudaVideoCodec_MPEG2;

     case AV_CODEC_ID_MPEG4:      return cudaVideoCodec_MPEG4;

     case AV_CODEC_ID_VC1:        return cudaVideoCodec_VC1;

     case AV_CODEC_ID_VP8:        return cudaVideoCodec_VP8;

     case AV_CODEC_ID_VP9:        return cudaVideoCodec_VP9;
     case AV_CODEC_ID_WMV3:       return cudaVideoCodec_VC1;

     }
     return -1;
 }
 
 static int map_chroma_format(enum AVPixelFormat pix_fmt)
 {
     int shift_h = 0, shift_v = 0;
 
     av_pix_fmt_get_chroma_sub_sample(pix_fmt, &shift_h, &shift_v);
 
     if (shift_h == 1 && shift_v == 1)
         return cudaVideoChromaFormat_420;
     else if (shift_h == 1 && shift_v == 0)
         return cudaVideoChromaFormat_422;
     else if (shift_h == 0 && shift_v == 0)
         return cudaVideoChromaFormat_444;
 
     return -1;
 }
 

 static int nvdec_test_capabilities(NVDECDecoder *decoder,
                                    CUVIDDECODECREATEINFO *params, void *logctx)
 {
     CUresult err;
     CUVIDDECODECAPS caps = { 0 };
 
     caps.eCodecType      = params->CodecType;
     caps.eChromaFormat   = params->ChromaFormat;
     caps.nBitDepthMinus8 = params->bitDepthMinus8;
 

     if (!decoder->cvdl->cuvidGetDecoderCaps) {
         av_log(logctx, AV_LOG_WARNING, "Used Nvidia driver is too old to perform a capability check.\n");
         av_log(logctx, AV_LOG_WARNING, "The minimum required version is "
 #if defined(_WIN32) || defined(__CYGWIN__)
             "378.66"
 #else
             "378.13"
 #endif
             ". Continuing blind.\n");
         return 0;
     }
 

     err = decoder->cvdl->cuvidGetDecoderCaps(&caps);
     if (err != CUDA_SUCCESS) {
         av_log(logctx, AV_LOG_ERROR, "Failed querying decoder capabilities\n");
         return AVERROR_UNKNOWN;
     }
 
     av_log(logctx, AV_LOG_VERBOSE, "NVDEC capabilities:\n");
     av_log(logctx, AV_LOG_VERBOSE, "format supported: %s, max_mb_count: %d\n",
            caps.bIsSupported ? "yes" : "no", caps.nMaxMBCount);
     av_log(logctx, AV_LOG_VERBOSE, "min_width: %d, max_width: %d\n",
            caps.nMinWidth, caps.nMaxWidth);
     av_log(logctx, AV_LOG_VERBOSE, "min_height: %d, max_height: %d\n",
            caps.nMinHeight, caps.nMaxHeight);
 
     if (!caps.bIsSupported) {
         av_log(logctx, AV_LOG_ERROR, "Hardware is lacking required capabilities\n");
         return AVERROR(EINVAL);
     }
 
     if (params->ulWidth > caps.nMaxWidth || params->ulWidth < caps.nMinWidth) {
         av_log(logctx, AV_LOG_ERROR, "Video width %d not within range from %d to %d\n",
                (int)params->ulWidth, caps.nMinWidth, caps.nMaxWidth);
         return AVERROR(EINVAL);
     }
 
     if (params->ulHeight > caps.nMaxHeight || params->ulHeight < caps.nMinHeight) {
         av_log(logctx, AV_LOG_ERROR, "Video height %d not within range from %d to %d\n",
                (int)params->ulHeight, caps.nMinHeight, caps.nMaxHeight);
         return AVERROR(EINVAL);
     }
 
     if ((params->ulWidth * params->ulHeight) / 256 > caps.nMaxMBCount) {
         av_log(logctx, AV_LOG_ERROR, "Video macroblock count %d exceeds maximum of %d\n",
                (int)(params->ulWidth * params->ulHeight) / 256, caps.nMaxMBCount);
         return AVERROR(EINVAL);
     }
 
     return 0;
 }
 

 static void nvdec_decoder_free(void *opaque, uint8_t *data)
 {
     NVDECDecoder *decoder = (NVDECDecoder*)data;
 
     if (decoder->decoder)
         decoder->cvdl->cuvidDestroyDecoder(decoder->decoder);
 
     av_buffer_unref(&decoder->hw_device_ref);
 
     cuvid_free_functions(&decoder->cvdl);
 
     av_freep(&decoder);
 }
 
 static int nvdec_decoder_create(AVBufferRef **out, AVBufferRef *hw_device_ref,
                                 CUVIDDECODECREATEINFO *params, void *logctx)
 {
     AVHWDeviceContext  *hw_device_ctx = (AVHWDeviceContext*)hw_device_ref->data;
     AVCUDADeviceContext *device_hwctx = hw_device_ctx->hwctx;
 
     AVBufferRef *decoder_ref;
     NVDECDecoder *decoder;
 
     CUcontext dummy;
     CUresult err;
     int ret;
 
     decoder = av_mallocz(sizeof(*decoder));
     if (!decoder)
         return AVERROR(ENOMEM);
 
     decoder_ref = av_buffer_create((uint8_t*)decoder, sizeof(*decoder),
                                    nvdec_decoder_free, NULL, AV_BUFFER_FLAG_READONLY);
     if (!decoder_ref) {
         av_freep(&decoder);
         return AVERROR(ENOMEM);
     }
 
     decoder->hw_device_ref = av_buffer_ref(hw_device_ref);
     if (!decoder->hw_device_ref) {
         ret = AVERROR(ENOMEM);
         goto fail;
     }
     decoder->cuda_ctx = device_hwctx->cuda_ctx;
     decoder->cudl = device_hwctx->internal->cuda_dl;
 

     ret = cuvid_load_functions(&decoder->cvdl, logctx);

     if (ret < 0) {
         av_log(logctx, AV_LOG_ERROR, "Failed loading nvcuvid.\n");
         goto fail;
     }
 
     err = decoder->cudl->cuCtxPushCurrent(decoder->cuda_ctx);
     if (err != CUDA_SUCCESS) {
         ret = AVERROR_UNKNOWN;
         goto fail;
     }
 

     ret = nvdec_test_capabilities(decoder, params, logctx);
     if (ret < 0) {
         decoder->cudl->cuCtxPopCurrent(&dummy);
         goto fail;
     }
 

     err = decoder->cvdl->cuvidCreateDecoder(&decoder->decoder, params);
 
     decoder->cudl->cuCtxPopCurrent(&dummy);
 
     if (err != CUDA_SUCCESS) {
         av_log(logctx, AV_LOG_ERROR, "Error creating a NVDEC decoder: %d\n", err);
         ret = AVERROR_UNKNOWN;
         goto fail;
     }
 
     *out = decoder_ref;
 
     return 0;
 fail:
     av_buffer_unref(&decoder_ref);
     return ret;
 }
 
 static AVBufferRef *nvdec_decoder_frame_alloc(void *opaque, int size)
 {
     NVDECFramePool *pool = opaque;
     AVBufferRef *ret;
 
     if (pool->nb_allocated >= pool->dpb_size)
         return NULL;
 
     ret = av_buffer_alloc(sizeof(unsigned int));
     if (!ret)
         return NULL;
 
     *(unsigned int*)ret->data = pool->nb_allocated++;
 
     return ret;
 }
 
 int ff_nvdec_decode_uninit(AVCodecContext *avctx)
 {
     NVDECContext *ctx = avctx->internal->hwaccel_priv_data;
 
     av_freep(&ctx->bitstream);
     ctx->bitstream_len       = 0;
     ctx->bitstream_allocated = 0;
 
     av_freep(&ctx->slice_offsets);
     ctx->nb_slices               = 0;
     ctx->slice_offsets_allocated = 0;
 
     av_buffer_unref(&ctx->decoder_ref);
     av_buffer_pool_uninit(&ctx->decoder_pool);
 
     return 0;
 }
 

 int ff_nvdec_decode_init(AVCodecContext *avctx)

 {
     NVDECContext *ctx = avctx->internal->hwaccel_priv_data;
 
     NVDECFramePool      *pool;
     AVHWFramesContext   *frames_ctx;
     const AVPixFmtDescriptor *sw_desc;
 
     CUVIDDECODECREATEINFO params = { 0 };
 
     int cuvid_codec_type, cuvid_chroma_format;
     int ret = 0;
 
     sw_desc = av_pix_fmt_desc_get(avctx->sw_pix_fmt);
     if (!sw_desc)
         return AVERROR_BUG;
 
     cuvid_codec_type = map_avcodec_id(avctx->codec_id);
     if (cuvid_codec_type < 0) {
         av_log(avctx, AV_LOG_ERROR, "Unsupported codec ID\n");
         return AVERROR_BUG;
     }
 
     cuvid_chroma_format = map_chroma_format(avctx->sw_pix_fmt);
     if (cuvid_chroma_format < 0) {
         av_log(avctx, AV_LOG_ERROR, "Unsupported chroma format\n");
         return AVERROR(ENOSYS);
     }
 
     if (!avctx->hw_frames_ctx) {

         ret = ff_decode_get_hw_frames_ctx(avctx, AV_HWDEVICE_TYPE_CUDA);
         if (ret < 0)

             return ret;
     }

     frames_ctx = (AVHWFramesContext*)avctx->hw_frames_ctx->data;
 
     params.ulWidth             = avctx->coded_width;
     params.ulHeight            = avctx->coded_height;
     params.ulTargetWidth       = avctx->coded_width;
     params.ulTargetHeight      = avctx->coded_height;
     params.bitDepthMinus8      = sw_desc->comp[0].depth - 8;
     params.OutputFormat        = params.bitDepthMinus8 ?
                                  cudaVideoSurfaceFormat_P016 : cudaVideoSurfaceFormat_NV12;
     params.CodecType           = cuvid_codec_type;
     params.ChromaFormat        = cuvid_chroma_format;

     params.ulNumDecodeSurfaces = frames_ctx->initial_pool_size;

     params.ulNumOutputSurfaces = 1;
 
     ret = nvdec_decoder_create(&ctx->decoder_ref, frames_ctx->device_ref, &params, avctx);

     if (ret < 0) {
         if (params.ulNumDecodeSurfaces > 32) {
             av_log(avctx, AV_LOG_WARNING, "Using more than 32 (%d) decode surfaces might cause nvdec to fail.\n",
                    (int)params.ulNumDecodeSurfaces);
             av_log(avctx, AV_LOG_WARNING, "Try lowering the amount of threads. Using %d right now.\n",
                    avctx->thread_count);
         }

         return ret;

     }

 
     pool = av_mallocz(sizeof(*pool));
     if (!pool) {
         ret = AVERROR(ENOMEM);
         goto fail;
     }

     pool->dpb_size = frames_ctx->initial_pool_size;

 
     ctx->decoder_pool = av_buffer_pool_init2(sizeof(int), pool,
                                              nvdec_decoder_frame_alloc, av_free);
     if (!ctx->decoder_pool) {
         ret = AVERROR(ENOMEM);
         goto fail;
     }
 
     return 0;
 fail:
     ff_nvdec_decode_uninit(avctx);
     return ret;
 }
 
 static void nvdec_fdd_priv_free(void *priv)
 {
     NVDECFrame *cf = priv;
 
     if (!cf)
         return;
 
     av_buffer_unref(&cf->idx_ref);
     av_buffer_unref(&cf->decoder_ref);
 
     av_freep(&priv);
 }
 
 static int nvdec_retrieve_data(void *logctx, AVFrame *frame)
 {
     FrameDecodeData  *fdd = (FrameDecodeData*)frame->private_ref->data;
     NVDECFrame        *cf = (NVDECFrame*)fdd->hwaccel_priv;
     NVDECDecoder *decoder = (NVDECDecoder*)cf->decoder_ref->data;
 
     CUVIDPROCPARAMS vpp = { .progressive_frame = 1 };
 
     CUresult err;
     CUcontext dummy;
     CUdeviceptr devptr;
 
     unsigned int pitch, i;
     unsigned int offset = 0;
     int ret = 0;
 
     err = decoder->cudl->cuCtxPushCurrent(decoder->cuda_ctx);
     if (err != CUDA_SUCCESS)
         return AVERROR_UNKNOWN;
 
     err = decoder->cvdl->cuvidMapVideoFrame(decoder->decoder, cf->idx, &devptr,
                                             &pitch, &vpp);
     if (err != CUDA_SUCCESS) {
         av_log(logctx, AV_LOG_ERROR, "Error mapping a picture with CUVID: %d\n",
                err);
         ret = AVERROR_UNKNOWN;
         goto finish;
     }
 
     for (i = 0; frame->data[i]; i++) {
         CUDA_MEMCPY2D cpy = {
             .srcMemoryType = CU_MEMORYTYPE_DEVICE,
             .dstMemoryType = CU_MEMORYTYPE_DEVICE,
             .srcDevice     = devptr,
             .dstDevice     = (CUdeviceptr)frame->data[i],
             .srcPitch      = pitch,
             .dstPitch      = frame->linesize[i],
             .srcY          = offset,
             .WidthInBytes  = FFMIN(pitch, frame->linesize[i]),
             .Height        = frame->height >> (i ? 1 : 0),
         };
 
         err = decoder->cudl->cuMemcpy2D(&cpy);
         if (err != CUDA_SUCCESS) {
             av_log(logctx, AV_LOG_ERROR, "Error copying decoded frame: %d\n",
                    err);
             ret = AVERROR_UNKNOWN;
             goto copy_fail;
         }
 
         offset += cpy.Height;
     }
 
 copy_fail:
     decoder->cvdl->cuvidUnmapVideoFrame(decoder->decoder, devptr);
 
 finish:
     decoder->cudl->cuCtxPopCurrent(&dummy);
     return ret;
 }
 
 int ff_nvdec_start_frame(AVCodecContext *avctx, AVFrame *frame)
 {
     NVDECContext *ctx = avctx->internal->hwaccel_priv_data;
     FrameDecodeData *fdd = (FrameDecodeData*)frame->private_ref->data;
     NVDECFrame *cf = NULL;
     int ret;
 
     ctx->bitstream_len = 0;
     ctx->nb_slices     = 0;
 
     if (fdd->hwaccel_priv)
         return 0;
 
     cf = av_mallocz(sizeof(*cf));
     if (!cf)
         return AVERROR(ENOMEM);
 
     cf->decoder_ref = av_buffer_ref(ctx->decoder_ref);

     if (!cf->decoder_ref) {
         ret = AVERROR(ENOMEM);

         goto fail;

     }

 
     cf->idx_ref = av_buffer_pool_get(ctx->decoder_pool);
     if (!cf->idx_ref) {
         av_log(avctx, AV_LOG_ERROR, "No decoder surfaces left\n");
         ret = AVERROR(ENOMEM);
         goto fail;
     }
     cf->idx = *(unsigned int*)cf->idx_ref->data;
 
     fdd->hwaccel_priv      = cf;
     fdd->hwaccel_priv_free = nvdec_fdd_priv_free;
     fdd->post_process      = nvdec_retrieve_data;
 
     return 0;
 fail:
     nvdec_fdd_priv_free(cf);
     return ret;
 
 }
 
 int ff_nvdec_end_frame(AVCodecContext *avctx)
 {
     NVDECContext     *ctx = avctx->internal->hwaccel_priv_data;
     NVDECDecoder *decoder = (NVDECDecoder*)ctx->decoder_ref->data;
     CUVIDPICPARAMS    *pp = &ctx->pic_params;
 
     CUresult err;
     CUcontext dummy;
 
     int ret = 0;
 
     pp->nBitstreamDataLen = ctx->bitstream_len;
     pp->pBitstreamData    = ctx->bitstream;
     pp->nNumSlices        = ctx->nb_slices;
     pp->pSliceDataOffsets = ctx->slice_offsets;
 
     err = decoder->cudl->cuCtxPushCurrent(decoder->cuda_ctx);
     if (err != CUDA_SUCCESS)
         return AVERROR_UNKNOWN;
 
     err = decoder->cvdl->cuvidDecodePicture(decoder->decoder, &ctx->pic_params);
     if (err != CUDA_SUCCESS) {
         av_log(avctx, AV_LOG_ERROR, "Error decoding a picture with NVDEC: %d\n",
                err);
         ret = AVERROR_UNKNOWN;
         goto finish;
     }
 
 finish:
     decoder->cudl->cuCtxPopCurrent(&dummy);
 
     return ret;
 }

 int ff_nvdec_simple_end_frame(AVCodecContext *avctx)
 {
     NVDECContext *ctx = avctx->internal->hwaccel_priv_data;
     int ret = ff_nvdec_end_frame(avctx);
     ctx->bitstream = NULL;
     return ret;
 }
 
 int ff_nvdec_simple_decode_slice(AVCodecContext *avctx, const uint8_t *buffer,
                                  uint32_t size)
 {
     NVDECContext *ctx = avctx->internal->hwaccel_priv_data;
     void *tmp;
 
     tmp = av_fast_realloc(ctx->slice_offsets, &ctx->slice_offsets_allocated,
                           (ctx->nb_slices + 1) * sizeof(*ctx->slice_offsets));
     if (!tmp)
         return AVERROR(ENOMEM);
     ctx->slice_offsets = tmp;
 
     if (!ctx->bitstream)
         ctx->bitstream = (uint8_t*)buffer;
 
     ctx->slice_offsets[ctx->nb_slices] = buffer - ctx->bitstream;
     ctx->bitstream_len += size;
     ctx->nb_slices++;
 
     return 0;
 }
 

 int ff_nvdec_frame_params(AVCodecContext *avctx,
                           AVBufferRef *hw_frames_ctx,
                           int dpb_size)
 {
     AVHWFramesContext *frames_ctx = (AVHWFramesContext*)hw_frames_ctx->data;
     const AVPixFmtDescriptor *sw_desc;
     int cuvid_codec_type, cuvid_chroma_format;
 
     sw_desc = av_pix_fmt_desc_get(avctx->sw_pix_fmt);
     if (!sw_desc)
         return AVERROR_BUG;
 
     cuvid_codec_type = map_avcodec_id(avctx->codec_id);
     if (cuvid_codec_type < 0) {
         av_log(avctx, AV_LOG_ERROR, "Unsupported codec ID\n");
         return AVERROR_BUG;
     }
 
     cuvid_chroma_format = map_chroma_format(avctx->sw_pix_fmt);
     if (cuvid_chroma_format < 0) {
         av_log(avctx, AV_LOG_VERBOSE, "Unsupported chroma format\n");
         return AVERROR(EINVAL);
     }
 
     frames_ctx->format            = AV_PIX_FMT_CUDA;

     frames_ctx->width             = (avctx->coded_width + 1) & ~1;
     frames_ctx->height            = (avctx->coded_height + 1) & ~1;

     frames_ctx->initial_pool_size = dpb_size;
 

     switch (sw_desc->comp[0].depth) {
     case 8:
         frames_ctx->sw_format = AV_PIX_FMT_NV12;
         break;
     case 10:
         frames_ctx->sw_format = AV_PIX_FMT_P010;
         break;
     case 12:
         frames_ctx->sw_format = AV_PIX_FMT_P016;
         break;
     default:
         return AVERROR(EINVAL);
     }
 

     return 0;
 }

 
 int ff_nvdec_get_ref_idx(AVFrame *frame)
 {
     FrameDecodeData *fdd;
     NVDECFrame *cf;
 
     if (!frame || !frame->private_ref)
         return -1;
 
     fdd = (FrameDecodeData*)frame->private_ref->data;
     cf  = (NVDECFrame*)fdd->hwaccel_priv;
     if (!cf)
         return -1;
 
     return cf->idx;
 }