/*
 * Copyright (c) 2017, NVIDIA CORPORATION. All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */
 
 #include <cuda.h>
 
 #include "libavutil/hwcontext.h"
 #include "libavutil/hwcontext_cuda_internal.h"
 #include "libavutil/opt.h"
 #include "libavutil/pixdesc.h"
 
 #include "avfilter.h"
 #include "internal.h"
 
 #define HIST_SIZE (3*256)
 #define DIV_UP(a, b) ( ((a) + (b) - 1) / (b) )
 #define BLOCKX 32
 #define BLOCKY 16
 
 static const enum AVPixelFormat supported_formats[] = {
     AV_PIX_FMT_NV12,
     AV_PIX_FMT_YUV420P,
     AV_PIX_FMT_YUV444P,
     AV_PIX_FMT_P010,
     AV_PIX_FMT_P016,
     AV_PIX_FMT_YUV444P16,
 };
 
 struct thumb_frame {
     AVFrame *buf;               ///< cached frame
     int histogram[HIST_SIZE];   ///< RGB color distribution histogram of the frame
 };
 
 typedef struct ThumbnailCudaContext {
     const AVClass *class;
     int n;                      ///< current frame
     int n_frames;               ///< number of frames for analysis
     struct thumb_frame *frames; ///< the n_frames frames
     AVRational tb;              ///< copy of the input timebase to ease access
 
     AVBufferRef *hw_frames_ctx;
 
     CUmodule    cu_module;
 
     CUfunction  cu_func_uchar;
     CUfunction  cu_func_uchar2;
     CUfunction  cu_func_ushort;
     CUfunction  cu_func_ushort2;
     CUtexref    cu_tex_uchar;
     CUtexref    cu_tex_uchar2;
     CUtexref    cu_tex_ushort;
     CUtexref    cu_tex_ushort2;
 
     CUdeviceptr data;
 } ThumbnailCudaContext;
 
 #define OFFSET(x) offsetof(ThumbnailCudaContext, x)
 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
 
 static const AVOption thumbnail_cuda_options[] = {
     { "n", "set the frames batch size", OFFSET(n_frames), AV_OPT_TYPE_INT, {.i64=100}, 2, INT_MAX, FLAGS },
     { NULL }
 };
 
 AVFILTER_DEFINE_CLASS(thumbnail_cuda);
 
 static av_cold int init(AVFilterContext *ctx)
 {
     ThumbnailCudaContext *s = ctx->priv;
 
     s->frames = av_calloc(s->n_frames, sizeof(*s->frames));
     if (!s->frames) {
         av_log(ctx, AV_LOG_ERROR,
                "Allocation failure, try to lower the number of frames\n");
         return AVERROR(ENOMEM);
     }
     av_log(ctx, AV_LOG_VERBOSE, "batch size: %d frames\n", s->n_frames);
     return 0;
 }
 
 /**
  * @brief        Compute Sum-square deviation to estimate "closeness".
  * @param hist   color distribution histogram
  * @param median average color distribution histogram
  * @return       sum of squared errors
  */
 static double frame_sum_square_err(const int *hist, const double *median)
 {
     int i;
     double err, sum_sq_err = 0;
 
     for (i = 0; i < HIST_SIZE; i++) {
         err = median[i] - (double)hist[i];
         sum_sq_err += err*err;
     }
     return sum_sq_err;
 }
 
 static AVFrame *get_best_frame(AVFilterContext *ctx)
 {
     AVFrame *picref;
     ThumbnailCudaContext *s = ctx->priv;
     int i, j, best_frame_idx = 0;
     int nb_frames = s->n;
     double avg_hist[HIST_SIZE] = {0}, sq_err, min_sq_err = -1;
 
     // average histogram of the N frames
     for (j = 0; j < FF_ARRAY_ELEMS(avg_hist); j++) {
         for (i = 0; i < nb_frames; i++)
             avg_hist[j] += (double)s->frames[i].histogram[j];
         avg_hist[j] /= nb_frames;
     }
 
     // find the frame closer to the average using the sum of squared errors
     for (i = 0; i < nb_frames; i++) {
         sq_err = frame_sum_square_err(s->frames[i].histogram, avg_hist);
         if (i == 0 || sq_err < min_sq_err)
             best_frame_idx = i, min_sq_err = sq_err;
     }
 
     // free and reset everything (except the best frame buffer)
     for (i = 0; i < nb_frames; i++) {
         memset(s->frames[i].histogram, 0, sizeof(s->frames[i].histogram));
         if (i != best_frame_idx)
             av_frame_free(&s->frames[i].buf);
     }
     s->n = 0;
 
     // raise the chosen one
     picref = s->frames[best_frame_idx].buf;
     av_log(ctx, AV_LOG_INFO, "frame id #%d (pts_time=%f) selected "
            "from a set of %d images\n", best_frame_idx,
            picref->pts * av_q2d(s->tb), nb_frames);
     s->frames[best_frame_idx].buf = NULL;
 
     return picref;
 }
 
 static int thumbnail_kernel(ThumbnailCudaContext *s, CUfunction func, CUtexref tex, int channels,
     int *histogram, uint8_t *src_dptr, int src_width, int src_height, int src_pitch, int pixel_size)
 {
     CUdeviceptr src_devptr = (CUdeviceptr)src_dptr;
     void *args[] = { &histogram, &src_width, &src_height };
     CUDA_ARRAY_DESCRIPTOR desc;
 
     desc.Width = src_width;
     desc.Height = src_height;
     desc.NumChannels = channels;
     if (pixel_size == 1) {
         desc.Format = CU_AD_FORMAT_UNSIGNED_INT8;
     }
     else {
         desc.Format = CU_AD_FORMAT_UNSIGNED_INT16;
     }
 
     cuTexRefSetAddress2D_v3(tex, &desc, src_devptr, src_pitch);
     cuLaunchKernel(func, DIV_UP(src_width, BLOCKX), DIV_UP(src_height, BLOCKY), 1, BLOCKX, BLOCKY, 1, 0, 0, args, NULL);
 
     return 0;
 }
 
 static int thumbnail(AVFilterContext *ctx, int *histogram, AVFrame *in)
 {
     AVHWFramesContext *in_frames_ctx = (AVHWFramesContext*)in->hw_frames_ctx->data;
     ThumbnailCudaContext *s = ctx->priv;
 
     switch (in_frames_ctx->sw_format) {
     case AV_PIX_FMT_NV12:
         thumbnail_kernel(s, s->cu_func_uchar, s->cu_tex_uchar, 1,
             histogram, in->data[0], in->width, in->height, in->linesize[0], 1);
         thumbnail_kernel(s, s->cu_func_uchar2, s->cu_tex_uchar2, 2,
             histogram + 256, in->data[1], in->width / 2, in->height / 2, in->linesize[1], 1);
         break;
     case AV_PIX_FMT_YUV420P:
         thumbnail_kernel(s, s->cu_func_uchar, s->cu_tex_uchar, 1,
             histogram, in->data[0], in->width, in->height, in->linesize[0], 1);
         thumbnail_kernel(s, s->cu_func_uchar, s->cu_tex_uchar, 1,
             histogram + 256, in->data[1], in->width / 2, in->height / 2, in->linesize[1], 1);
         thumbnail_kernel(s, s->cu_func_uchar, s->cu_tex_uchar, 1,
             histogram + 512, in->data[2], in->width / 2, in->height / 2, in->linesize[2], 1);
         break;
     case AV_PIX_FMT_YUV444P:
         thumbnail_kernel(s, s->cu_func_uchar, s->cu_tex_uchar, 1,
             histogram, in->data[0], in->width, in->height, in->linesize[0], 1);
         thumbnail_kernel(s, s->cu_func_uchar, s->cu_tex_uchar, 1,
             histogram + 256, in->data[1], in->width, in->height, in->linesize[1], 1);
         thumbnail_kernel(s, s->cu_func_uchar, s->cu_tex_uchar, 1,
             histogram + 512, in->data[2], in->width, in->height, in->linesize[2], 1);
         break;
     case AV_PIX_FMT_P010LE:
     case AV_PIX_FMT_P016LE:
         thumbnail_kernel(s, s->cu_func_ushort, s->cu_tex_ushort, 1,
             histogram, in->data[0], in->width, in->height, in->linesize[0], 2);
         thumbnail_kernel(s, s->cu_func_ushort2, s->cu_tex_ushort2, 2,
             histogram + 256, in->data[1], in->width / 2, in->height / 2, in->linesize[1], 2);
         break;
     case AV_PIX_FMT_YUV444P16:
         thumbnail_kernel(s, s->cu_func_ushort2, s->cu_tex_uchar, 1,
             histogram, in->data[0], in->width, in->height, in->linesize[0], 2);
         thumbnail_kernel(s, s->cu_func_ushort2, s->cu_tex_uchar, 1,
             histogram + 256, in->data[1], in->width, in->height, in->linesize[1], 2);
         thumbnail_kernel(s, s->cu_func_ushort2, s->cu_tex_uchar, 1,
             histogram + 512, in->data[2], in->width, in->height, in->linesize[2], 2);
         break;
     default:
         return AVERROR_BUG;
     }
 
     return 0;
 }
 
 static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
 {
     AVFilterContext *ctx  = inlink->dst;
     ThumbnailCudaContext *s   = ctx->priv;
     AVFilterLink *outlink = ctx->outputs[0];
     int *hist = s->frames[s->n].histogram;
     AVHWFramesContext *hw_frames_ctx = (AVHWFramesContext*)s->hw_frames_ctx->data;
     AVCUDADeviceContext *device_hwctx = hw_frames_ctx->device_ctx->hwctx;
     CUresult err;
     CUcontext dummy;
     CUDA_MEMCPY2D cpy = { 0 };
     int ret = 0;
 
     // keep a reference of each frame
     s->frames[s->n].buf = frame;
 
     err = cuCtxPushCurrent(device_hwctx->cuda_ctx);
     if (err != CUDA_SUCCESS)
         return AVERROR_UNKNOWN;
 
     cuMemsetD8(s->data, 0, HIST_SIZE * sizeof(int));
 
     thumbnail(ctx, (int*)s->data, frame);
 
     cpy.srcMemoryType = CU_MEMORYTYPE_DEVICE;
     cpy.dstMemoryType = CU_MEMORYTYPE_HOST;
     cpy.srcDevice = s->data;
     cpy.dstHost = hist;
     cpy.srcPitch = HIST_SIZE * sizeof(int);
     cpy.dstPitch = HIST_SIZE * sizeof(int);
     cpy.WidthInBytes = HIST_SIZE * sizeof(int);
     cpy.Height = 1;
 
     err = cuMemcpy2D(&cpy);
     if (err != CUDA_SUCCESS) {
         av_log(ctx, AV_LOG_ERROR, "Error transferring the data from the CUDA frame\n");
         return AVERROR_UNKNOWN;
     }
 
     if (hw_frames_ctx->sw_format == AV_PIX_FMT_NV12 || hw_frames_ctx->sw_format == AV_PIX_FMT_YUV420P ||
         hw_frames_ctx->sw_format == AV_PIX_FMT_P010LE || hw_frames_ctx->sw_format == AV_PIX_FMT_P016LE)
     {

         int i;
         for (i = 256; i < HIST_SIZE; i++)

             hist[i] = 4 * hist[i];
     }
 
     cuCtxPopCurrent(&dummy);
     if (ret < 0)
         return ret;
 
     // no selection until the buffer of N frames is filled up
     s->n++;
     if (s->n < s->n_frames)
         return 0;
 
     return ff_filter_frame(outlink, get_best_frame(ctx));
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     int i;
     ThumbnailCudaContext *s = ctx->priv;
 
     if (s->data) {
         cuMemFree(s->data);
         s->data = 0;
     }
 
     if (s->cu_module) {
         cuModuleUnload(s->cu_module);
         s->cu_module = NULL;
     }
 
     for (i = 0; i < s->n_frames && s->frames[i].buf; i++)
         av_frame_free(&s->frames[i].buf);
     av_freep(&s->frames);
 }
 
 static int request_frame(AVFilterLink *link)
 {
     AVFilterContext *ctx = link->src;
     ThumbnailCudaContext *s = ctx->priv;
     int ret = ff_request_frame(ctx->inputs[0]);
 
     if (ret == AVERROR_EOF && s->n) {
         ret = ff_filter_frame(link, get_best_frame(ctx));
         if (ret < 0)
             return ret;
         ret = AVERROR_EOF;
     }
     if (ret < 0)
         return ret;
     return 0;
 }
 
 static int format_is_supported(enum AVPixelFormat fmt)
 {
     int i;
 
     for (i = 0; i < FF_ARRAY_ELEMS(supported_formats); i++)
         if (supported_formats[i] == fmt)
             return 1;
     return 0;
 }
 
 static int config_props(AVFilterLink *inlink)
 {
     AVFilterContext *ctx = inlink->dst;
     ThumbnailCudaContext *s = ctx->priv;
     AVHWFramesContext     *hw_frames_ctx = (AVHWFramesContext*)inlink->hw_frames_ctx->data;
     AVCUDADeviceContext *device_hwctx = hw_frames_ctx->device_ctx->hwctx;
     CUcontext dummy, cuda_ctx = device_hwctx->cuda_ctx;
     CUresult err;
 
     extern char vf_thumbnail_cuda_ptx[];
 
     err = cuCtxPushCurrent(cuda_ctx);
     if (err != CUDA_SUCCESS) {
         av_log(ctx, AV_LOG_ERROR, "Error pushing cuda context\n");
         return AVERROR_UNKNOWN;
     }
 
     err = cuModuleLoadData(&s->cu_module, vf_thumbnail_cuda_ptx);
     if (err != CUDA_SUCCESS) {
         av_log(ctx, AV_LOG_ERROR, "Error loading module data\n");
         return AVERROR_UNKNOWN;
     }
 
     cuModuleGetFunction(&s->cu_func_uchar, s->cu_module, "Thumbnail_uchar");
     cuModuleGetFunction(&s->cu_func_uchar2, s->cu_module, "Thumbnail_uchar2");
     cuModuleGetFunction(&s->cu_func_ushort, s->cu_module, "Thumbnail_ushort");
     cuModuleGetFunction(&s->cu_func_ushort2, s->cu_module, "Thumbnail_ushort2");
 
     cuModuleGetTexRef(&s->cu_tex_uchar, s->cu_module, "uchar_tex");
     cuModuleGetTexRef(&s->cu_tex_uchar2, s->cu_module, "uchar2_tex");
     cuModuleGetTexRef(&s->cu_tex_ushort, s->cu_module, "ushort_tex");
     cuModuleGetTexRef(&s->cu_tex_ushort2, s->cu_module, "ushort2_tex");
 
     cuTexRefSetFlags(s->cu_tex_uchar, CU_TRSF_READ_AS_INTEGER);
     cuTexRefSetFlags(s->cu_tex_uchar2, CU_TRSF_READ_AS_INTEGER);
     cuTexRefSetFlags(s->cu_tex_ushort, CU_TRSF_READ_AS_INTEGER);
     cuTexRefSetFlags(s->cu_tex_ushort2, CU_TRSF_READ_AS_INTEGER);
 
     cuTexRefSetFilterMode(s->cu_tex_uchar, CU_TR_FILTER_MODE_LINEAR);
     cuTexRefSetFilterMode(s->cu_tex_uchar2, CU_TR_FILTER_MODE_LINEAR);
     cuTexRefSetFilterMode(s->cu_tex_ushort, CU_TR_FILTER_MODE_LINEAR);
     cuTexRefSetFilterMode(s->cu_tex_ushort2, CU_TR_FILTER_MODE_LINEAR);
 
     err = cuMemAlloc(&s->data, HIST_SIZE * sizeof(int));
     if (err != CUDA_SUCCESS) {
         av_log(ctx, AV_LOG_ERROR, "Error allocating cuda memory\n");
         return AVERROR_UNKNOWN;
     }
 
     cuCtxPopCurrent(&dummy);
 
     s->hw_frames_ctx = ctx->inputs[0]->hw_frames_ctx;
 
     ctx->outputs[0]->hw_frames_ctx = av_buffer_ref(s->hw_frames_ctx);
     if (!ctx->outputs[0]->hw_frames_ctx)
         return AVERROR(ENOMEM);
 
     s->tb = inlink->time_base;
 
     if (!format_is_supported(hw_frames_ctx->sw_format)) {
         av_log(ctx, AV_LOG_ERROR, "Unsupported input format: %s\n", av_get_pix_fmt_name(hw_frames_ctx->sw_format));
         return AVERROR(ENOSYS);
     }
 
     return 0;
 }
 
 static int query_formats(AVFilterContext *ctx)
 {
     static const enum AVPixelFormat pix_fmts[] = {
         AV_PIX_FMT_CUDA,
         AV_PIX_FMT_NONE
     };
     AVFilterFormats *fmts_list = ff_make_format_list(pix_fmts);
     if (!fmts_list)
         return AVERROR(ENOMEM);
     return ff_set_common_formats(ctx, fmts_list);
 }
 
 static const AVFilterPad thumbnail_cuda_inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .config_props = config_props,
         .filter_frame = filter_frame,
     },
     { NULL }
 };
 
 static const AVFilterPad thumbnail_cuda_outputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_VIDEO,
         .request_frame = request_frame,
     },
     { NULL }
 };
 
 AVFilter ff_vf_thumbnail_cuda = {
     .name          = "thumbnail_cuda",
     .description   = NULL_IF_CONFIG_SMALL("Select the most representative frame in a given sequence of consecutive frames."),
     .priv_size     = sizeof(ThumbnailCudaContext),
     .init          = init,
     .uninit        = uninit,
     .query_formats = query_formats,
     .inputs        = thumbnail_cuda_inputs,
     .outputs       = thumbnail_cuda_outputs,
     .priv_class    = &thumbnail_cuda_class,
     .flags_internal = FF_FILTER_FLAG_HWFRAME_AWARE,
 };