/*
  * 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 "libavutil/colorspace.h"
 #include "libavutil/eval.h"
 #include "libavutil/opt.h"
 #include "libavutil/imgutils.h"
 #include "avfilter.h"
 #include "drawutils.h"
 #include "formats.h"
 #include "internal.h"
 #include "opencl.h"
 #include "opencl_source.h"
 #include "video.h"
 
 static const char *const var_names[] = {
     "in_w",   "iw",
     "in_h",   "ih",
     "out_w",  "ow",
     "out_h",  "oh",
     "x",
     "y",
     "a",
     "sar",
     "dar",
     NULL
 };
 
 enum var_name {
     VAR_IN_W,   VAR_IW,
     VAR_IN_H,   VAR_IH,
     VAR_OUT_W,  VAR_OW,
     VAR_OUT_H,  VAR_OH,
     VAR_X,
     VAR_Y,
     VAR_A,
     VAR_SAR,
     VAR_DAR,
     VARS_NB
 };
 
 typedef struct PadOpenCLContext {
     OpenCLFilterContext ocf;
     int initialized;
     int is_rgb;
     int is_packed;
     int hsub, vsub;
 
     char *w_expr;
     char *h_expr;
     char *x_expr;
     char *y_expr;
     AVRational aspect;
 
     cl_command_queue command_queue;
     cl_kernel kernel_pad;
 
     int w, h;
     int x, y;
     uint8_t pad_rgba[4];
     uint8_t pad_color[4];
     cl_float4 pad_color_float;
     cl_int2 pad_pos;
 } PadOpenCLContext;
 
 static int pad_opencl_init(AVFilterContext *avctx, AVFrame *input_frame)
 {
     PadOpenCLContext *ctx = avctx->priv;
     AVHWFramesContext *input_frames_ctx = (AVHWFramesContext *)input_frame->hw_frames_ctx->data;
     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(input_frames_ctx->sw_format);
     uint8_t rgba_map[4];
     cl_int cle;
     int err;
 
     ff_fill_rgba_map(rgba_map, input_frames_ctx->sw_format);
     ctx->is_rgb = !!(desc->flags & AV_PIX_FMT_FLAG_RGB);
     ctx->is_packed = !(desc->flags & AV_PIX_FMT_FLAG_PLANAR);
     ctx->hsub = desc->log2_chroma_w;
     ctx->vsub = desc->log2_chroma_h;
 
     err = ff_opencl_filter_load_program(avctx, &ff_opencl_source_pad, 1);
     if (err < 0)
         goto fail;
 
     ctx->command_queue = clCreateCommandQueue(
         ctx->ocf.hwctx->context,
         ctx->ocf.hwctx->device_id,
         0,
         &cle
     );
 
     if (ctx->is_rgb) {
         ctx->pad_color[rgba_map[0]] = ctx->pad_rgba[0];
         ctx->pad_color[rgba_map[1]] = ctx->pad_rgba[1];
         ctx->pad_color[rgba_map[2]] = ctx->pad_rgba[2];
         ctx->pad_color[rgba_map[3]] = ctx->pad_rgba[3];
     } else {
         ctx->pad_color[0] = RGB_TO_Y_BT709(ctx->pad_rgba[0], ctx->pad_rgba[1], ctx->pad_rgba[2]);
         ctx->pad_color[1] = RGB_TO_U_BT709(ctx->pad_rgba[0], ctx->pad_rgba[1], ctx->pad_rgba[2], 0);
         ctx->pad_color[2] = RGB_TO_V_BT709(ctx->pad_rgba[0], ctx->pad_rgba[1], ctx->pad_rgba[2], 0);
         ctx->pad_color[3] = ctx->pad_rgba[3];
     }
 
     CL_FAIL_ON_ERROR(AVERROR(EIO), "Failed to create OpenCL command queue %d.\n", cle);
 
     ctx->kernel_pad = clCreateKernel(ctx->ocf.program, "pad", &cle);
     CL_FAIL_ON_ERROR(AVERROR(EIO), "Failed to create pad kernel: %d.\n", cle);
 
     for (int i = 0; i < 4; ++i) {
         ctx->pad_color_float.s[i] = (float)ctx->pad_color[i] / 255.0;
     }
 
     ctx->pad_pos.s[0] = ctx->x;
     ctx->pad_pos.s[1] = ctx->y;
 
     ctx->initialized = 1;
     return 0;
 
 fail:
     if (ctx->command_queue)
         clReleaseCommandQueue(ctx->command_queue);
     if (ctx->kernel_pad)
         clReleaseKernel(ctx->kernel_pad);
     return err;
 }
 
 static int filter_frame(AVFilterLink *link, AVFrame *input_frame)
 {
     AVFilterContext *avctx = link->dst;
     AVFilterLink *outlink = avctx->outputs[0];
     PadOpenCLContext *pad_ctx = avctx->priv;
     AVFrame *output_frame = NULL;
     int err;
     cl_int cle;
     size_t global_work[2];
     cl_mem src, dst;
 
     if (!input_frame->hw_frames_ctx)
         return AVERROR(EINVAL);
 
     if (!pad_ctx->initialized) {
         err = pad_opencl_init(avctx, input_frame);
         if (err < 0)
             goto fail;
     }
 
     output_frame = ff_get_video_buffer(outlink, outlink->w, outlink->h);
     if (!output_frame) {
         err = AVERROR(ENOMEM);
         goto fail;
     }
 
     for (int p = 0; p < FF_ARRAY_ELEMS(output_frame->data); p++) {
         cl_float4 pad_color_float;
         cl_int2 pad_pos;
 
         if (pad_ctx->is_packed) {
             pad_color_float = pad_ctx->pad_color_float;
         } else {
             pad_color_float.s[0] = pad_ctx->pad_color_float.s[p];
             pad_color_float.s[1] = pad_ctx->pad_color_float.s[2];
         }
 
         if (p > 0 && p < 3) {
             pad_pos.s[0] = pad_ctx->pad_pos.s[0] >> pad_ctx->hsub;
             pad_pos.s[1] = pad_ctx->pad_pos.s[1] >> pad_ctx->vsub;
         } else {
             pad_pos.s[0] = pad_ctx->pad_pos.s[0];
             pad_pos.s[1] = pad_ctx->pad_pos.s[1];
         }
 
         src = (cl_mem)input_frame->data[p];
         dst = (cl_mem)output_frame->data[p];
 
         if (!dst)
             break;
 
         CL_SET_KERNEL_ARG(pad_ctx->kernel_pad, 0, cl_mem, &src);
         CL_SET_KERNEL_ARG(pad_ctx->kernel_pad, 1, cl_mem, &dst);
         CL_SET_KERNEL_ARG(pad_ctx->kernel_pad, 2, cl_float4, &pad_color_float);
         CL_SET_KERNEL_ARG(pad_ctx->kernel_pad, 3, cl_int2, &pad_pos);
 
         err = ff_opencl_filter_work_size_from_image(avctx, global_work, output_frame, p, 16);
         if (err < 0)
             goto fail;
 
         cle = clEnqueueNDRangeKernel(pad_ctx->command_queue, pad_ctx->kernel_pad, 2, NULL,
                                      global_work, NULL, 0, NULL, NULL);
 
         CL_FAIL_ON_ERROR(AVERROR(EIO), "Failed to enqueue pad kernel: %d.\n", cle);
     }
 
     // Run queued kernel
     cle = clFinish(pad_ctx->command_queue);
     CL_FAIL_ON_ERROR(AVERROR(EIO), "Failed to finish command queue: %d.\n", cle);
 
     err = av_frame_copy_props(output_frame, input_frame);
     if (err < 0)
         goto fail;
 
     av_frame_free(&input_frame);
 
     return ff_filter_frame(outlink, output_frame);
 
 fail:
     clFinish(pad_ctx->command_queue);
     av_frame_free(&input_frame);
     av_frame_free(&output_frame);
     return err;
 }
 
 static av_cold void pad_opencl_uninit(AVFilterContext *avctx)
 {
     PadOpenCLContext *ctx = avctx->priv;
     cl_int cle;
 
     if (ctx->kernel_pad) {
         cle = clReleaseKernel(ctx->kernel_pad);
         if (cle != CL_SUCCESS)
             av_log(avctx, AV_LOG_ERROR, "Failed to release "
                    "kernel: %d.\n", cle);
     }
 
     if (ctx->command_queue) {
         cle = clReleaseCommandQueue(ctx->command_queue);
         if (cle != CL_SUCCESS)
             av_log(avctx, AV_LOG_ERROR, "Failed to release "
                    "command queue: %d.\n", cle);
     }
 
     ff_opencl_filter_uninit(avctx);
 }
 
 static int pad_opencl_config_output(AVFilterLink *outlink)
 {
     AVFilterContext *avctx = outlink->src;
     AVFilterLink *inlink = avctx->inputs[0];
     PadOpenCLContext *ctx = avctx->priv;
     AVRational adjusted_aspect = ctx->aspect;
     double var_values[VARS_NB], res;
     int err, ret;
     char *expr;
 
     var_values[VAR_IN_W]  = var_values[VAR_IW] = inlink->w;
     var_values[VAR_IN_H]  = var_values[VAR_IH] = inlink->h;
     var_values[VAR_OUT_W] = var_values[VAR_OW] = NAN;
     var_values[VAR_OUT_H] = var_values[VAR_OH] = NAN;
     var_values[VAR_A]     = (double) inlink->w / inlink->h;
     var_values[VAR_SAR]   = inlink->sample_aspect_ratio.num ?
         (double) inlink->sample_aspect_ratio.num / inlink->sample_aspect_ratio.den : 1;
     var_values[VAR_DAR]   = var_values[VAR_A] * var_values[VAR_SAR];
 
     av_expr_parse_and_eval(&res, (expr = ctx->w_expr),
                            var_names, var_values,
                            NULL, NULL, NULL, NULL, NULL, 0, ctx);
     ctx->w = var_values[VAR_OUT_W] = var_values[VAR_OW] = res;
     if ((ret = av_expr_parse_and_eval(&res, (expr = ctx->h_expr),
                                       var_names, var_values,
                                       NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
         return ret;
     ctx->h = var_values[VAR_OUT_H] = var_values[VAR_OH] = res;
     if (!ctx->h)
         var_values[VAR_OUT_H] = var_values[VAR_OH] = ctx->h = inlink->h;
 
     /* evaluate the width again, as it may depend on the evaluated output height */
     if ((ret = av_expr_parse_and_eval(&res, (expr = ctx->w_expr),
                                       var_names, var_values,
                                       NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
         return ret;
     ctx->w = var_values[VAR_OUT_W] = var_values[VAR_OW] = res;
     if (!ctx->w)
         var_values[VAR_OUT_W] = var_values[VAR_OW] = ctx->w = inlink->w;
 
     if (adjusted_aspect.num && adjusted_aspect.den) {
         adjusted_aspect = av_div_q(adjusted_aspect, inlink->sample_aspect_ratio);
         if (ctx->h < av_rescale(ctx->w, adjusted_aspect.den, adjusted_aspect.num)) {
             ctx->h = var_values[VAR_OUT_H] = var_values[VAR_OH] = av_rescale(ctx->w, adjusted_aspect.den, adjusted_aspect.num);
         } else {
             ctx->w = var_values[VAR_OUT_W] = var_values[VAR_OW] = av_rescale(ctx->h, adjusted_aspect.num, adjusted_aspect.den);
         }
     }
 
     /* evaluate x and y */
     av_expr_parse_and_eval(&res, (expr = ctx->x_expr),
                            var_names, var_values,
                            NULL, NULL, NULL, NULL, NULL, 0, ctx);
     ctx->x = var_values[VAR_X] = res;
     if ((ret = av_expr_parse_and_eval(&res, (expr = ctx->y_expr),
                                       var_names, var_values,
                                       NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
         return ret;
     ctx->y = var_values[VAR_Y] = res;
     /* evaluate x again, as it may depend on the evaluated y value */
     if ((ret = av_expr_parse_and_eval(&res, (expr = ctx->x_expr),
                                       var_names, var_values,
                                       NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
         return ret;
     ctx->x = var_values[VAR_X] = res;
 
     if (ctx->x < 0 || ctx->x + inlink->w > ctx->w)
         ctx->x = var_values[VAR_X] = (ctx->w - inlink->w) / 2;
     if (ctx->y < 0 || ctx->y + inlink->h > ctx->h)
         ctx->y = var_values[VAR_Y] = (ctx->h - inlink->h) / 2;
 
     /* sanity check params */
     if (ctx->w < inlink->w || ctx->h < inlink->h) {
         av_log(ctx, AV_LOG_ERROR, "Padded dimensions cannot be smaller than input dimensions.\n");
         return AVERROR(EINVAL);
     }
 
     if (ctx->w > avctx->inputs[0]->w) {
         ctx->ocf.output_width  = ctx->w;
     } else {
         ctx->ocf.output_width  = avctx->inputs[0]->w;
     }
 
     if (ctx->h > avctx->inputs[0]->h) {
         ctx->ocf.output_height = ctx->h;
     } else {
         ctx->ocf.output_height = avctx->inputs[0]->h;
     }
 
     if (ctx->x + avctx->inputs[0]->w > ctx->ocf.output_width ||
         ctx->y + avctx->inputs[0]->h > ctx->ocf.output_height) {
         return AVERROR(EINVAL);
     }
 
     err = ff_opencl_filter_config_output(outlink);
     if (err < 0)
         return err;
 
     return 0;
 }
 
 static const AVFilterPad pad_opencl_inputs[] = {
     {
         .name = "default",
         .type = AVMEDIA_TYPE_VIDEO,
         .filter_frame = filter_frame,
         .config_props = &ff_opencl_filter_config_input,
     },
     { NULL }
 };
 
 static const AVFilterPad pad_opencl_outputs[] = {
     {
         .name = "default",
         .type = AVMEDIA_TYPE_VIDEO,
         .config_props = &pad_opencl_config_output,
     },
     { NULL }
 };
 
 #define OFFSET(x) offsetof(PadOpenCLContext, x)
 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
 
 static const AVOption pad_opencl_options[] = {
     { "width",  "set the pad area width",       OFFSET(w_expr), AV_OPT_TYPE_STRING, {.str = "iw"}, 0, 0, FLAGS },
     { "w",      "set the pad area width",       OFFSET(w_expr), AV_OPT_TYPE_STRING, {.str = "iw"}, 0, 0, FLAGS },
     { "height", "set the pad area height",      OFFSET(h_expr), AV_OPT_TYPE_STRING, {.str = "ih"}, 0, 0, FLAGS },
     { "h",      "set the pad area height",      OFFSET(h_expr), AV_OPT_TYPE_STRING, {.str = "ih"}, 0, 0, FLAGS },
     { "x",      "set the x offset for the input image position", OFFSET(x_expr), AV_OPT_TYPE_STRING, {.str = "0"}, 0, INT16_MAX, FLAGS },
     { "y",      "set the y offset for the input image position", OFFSET(y_expr), AV_OPT_TYPE_STRING, {.str = "0"}, 0, INT16_MAX, FLAGS },
     { "color", "set the color of the padded area border", OFFSET(pad_rgba), AV_OPT_TYPE_COLOR, { .str = "black" }, 0, 0, FLAGS },
     { "aspect",  "pad to fit an aspect instead of a resolution", OFFSET(aspect), AV_OPT_TYPE_RATIONAL, {.dbl = 0}, 0, INT16_MAX, FLAGS },
     { NULL }
 };
 
 AVFILTER_DEFINE_CLASS(pad_opencl);
 
 AVFilter ff_vf_pad_opencl = {
     .name           = "pad_opencl",
     .description    = NULL_IF_CONFIG_SMALL("Pad the input video."),
     .priv_size      = sizeof(PadOpenCLContext),
     .priv_class     = &pad_opencl_class,
     .init           = &ff_opencl_filter_init,
     .uninit         = &pad_opencl_uninit,
     .query_formats  = &ff_opencl_filter_query_formats,
     .inputs         = pad_opencl_inputs,
     .outputs        = pad_opencl_outputs,
     .flags_internal = FF_FILTER_FLAG_HWFRAME_AWARE
 };