/*
  * Copyright (c) 2015 Paul B. Mahol
  *
  * 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/avstring.h"
 #include "libavutil/imgutils.h"
 #include "libavutil/opt.h"
 #include "libavutil/pixdesc.h"
 
 #include "avfilter.h"
 #include "formats.h"
 #include "internal.h"

 #include "framesync.h"

 #include "video.h"
 
 typedef struct StackContext {
     const AVClass *class;
     const AVPixFmtDescriptor *desc;
     int nb_inputs;

     int shortest;

     int is_vertical;
     int nb_planes;
 
     AVFrame **frames;
     FFFrameSync fs;
 } StackContext;
 
 static int query_formats(AVFilterContext *ctx)
 {
     AVFilterFormats *pix_fmts = NULL;

     int fmt, ret;

 
     for (fmt = 0; av_pix_fmt_desc_get(fmt); fmt++) {
         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(fmt);
         if (!(desc->flags & AV_PIX_FMT_FLAG_PAL ||
               desc->flags & AV_PIX_FMT_FLAG_HWACCEL ||

               desc->flags & AV_PIX_FMT_FLAG_BITSTREAM) &&
             (ret = ff_add_format(&pix_fmts, fmt)) < 0)
             return ret;

     }
 
     return ff_set_common_formats(ctx, pix_fmts);
 }
 
 static av_cold int init(AVFilterContext *ctx)
 {
     StackContext *s = ctx->priv;
     int i, ret;
 
     if (!strcmp(ctx->filter->name, "vstack"))
         s->is_vertical = 1;
 
     s->frames = av_calloc(s->nb_inputs, sizeof(*s->frames));
     if (!s->frames)
         return AVERROR(ENOMEM);
 
     for (i = 0; i < s->nb_inputs; i++) {
         AVFilterPad pad = { 0 };
 
         pad.type = AVMEDIA_TYPE_VIDEO;
         pad.name = av_asprintf("input%d", i);
         if (!pad.name)
             return AVERROR(ENOMEM);
 
         if ((ret = ff_insert_inpad(ctx, i, &pad)) < 0) {
             av_freep(&pad.name);
             return ret;
         }
     }
 
     return 0;
 }
 
 static int process_frame(FFFrameSync *fs)
 {
     AVFilterContext *ctx = fs->parent;
     AVFilterLink *outlink = ctx->outputs[0];
     StackContext *s = fs->opaque;
     AVFrame **in = s->frames;
     AVFrame *out;
     int i, p, ret, offset[4] = { 0 };
 
     for (i = 0; i < s->nb_inputs; i++) {

         if ((ret = ff_framesync_get_frame(&s->fs, i, &in[i], 0)) < 0)

             return ret;
     }
 
     out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
     if (!out)
         return AVERROR(ENOMEM);
     out->pts = av_rescale_q(s->fs.pts, s->fs.time_base, outlink->time_base);
 
     for (i = 0; i < s->nb_inputs; i++) {
         AVFilterLink *inlink = ctx->inputs[i];
         int linesize[4];
         int height[4];
 

         if ((ret = av_image_fill_linesizes(linesize, inlink->format, inlink->w)) < 0) {
             av_frame_free(&out);

             return ret;

         }

         height[1] = height[2] = AV_CEIL_RSHIFT(inlink->h, s->desc->log2_chroma_h);

         height[0] = height[3] = inlink->h;
 
         for (p = 0; p < s->nb_planes; p++) {
             if (s->is_vertical) {
                 av_image_copy_plane(out->data[p] + offset[p] * out->linesize[p],
                                     out->linesize[p],
                                     in[i]->data[p],
                                     in[i]->linesize[p],
                                     linesize[p], height[p]);
                 offset[p] += height[p];
             } else {
                 av_image_copy_plane(out->data[p] + offset[p],
                                     out->linesize[p],
                                     in[i]->data[p],
                                     in[i]->linesize[p],
                                     linesize[p], height[p]);
                 offset[p] += linesize[p];
             }
         }
     }
 
     return ff_filter_frame(outlink, out);
 }
 
 static int config_output(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     StackContext *s = ctx->priv;
     AVRational time_base = ctx->inputs[0]->time_base;
     AVRational frame_rate = ctx->inputs[0]->frame_rate;
     int height = ctx->inputs[0]->h;
     int width = ctx->inputs[0]->w;
     FFFrameSyncIn *in;
     int i, ret;
 
     if (s->is_vertical) {
         for (i = 1; i < s->nb_inputs; i++) {
             if (ctx->inputs[i]->w != width) {
                 av_log(ctx, AV_LOG_ERROR, "Input %d width %d does not match input %d width %d.\n", i, ctx->inputs[i]->w, 0, width);
                 return AVERROR(EINVAL);
             }
             height += ctx->inputs[i]->h;
         }
     } else {
         for (i = 1; i < s->nb_inputs; i++) {
             if (ctx->inputs[i]->h != height) {
                 av_log(ctx, AV_LOG_ERROR, "Input %d height %d does not match input %d height %d.\n", i, ctx->inputs[i]->h, 0, height);
                 return AVERROR(EINVAL);
             }
             width += ctx->inputs[i]->w;
         }
     }
 
     s->desc = av_pix_fmt_desc_get(outlink->format);
     if (!s->desc)
         return AVERROR_BUG;
     s->nb_planes = av_pix_fmt_count_planes(outlink->format);
 
     outlink->w          = width;
     outlink->h          = height;
     outlink->time_base  = time_base;
     outlink->frame_rate = frame_rate;
 

     if ((ret = ff_framesync_init(&s->fs, ctx, s->nb_inputs)) < 0)

         return ret;
 
     in = s->fs.in;
     s->fs.opaque = s;
     s->fs.on_event = process_frame;
 
     for (i = 0; i < s->nb_inputs; i++) {
         AVFilterLink *inlink = ctx->inputs[i];
 
         in[i].time_base = inlink->time_base;
         in[i].sync   = 1;
         in[i].before = EXT_STOP;

         in[i].after  = s->shortest ? EXT_STOP : EXT_INFINITY;

     }
 

     return ff_framesync_configure(&s->fs);

 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     StackContext *s = ctx->priv;

     int i;
 

     ff_framesync_uninit(&s->fs);

     av_freep(&s->frames);

 
     for (i = 0; i < ctx->nb_inputs; i++)
         av_freep(&ctx->input_pads[i].name);

 }
 

 static int activate(AVFilterContext *ctx)
 {
     StackContext *s = ctx->priv;

     return ff_framesync_activate(&s->fs);

 }
 

 #define OFFSET(x) offsetof(StackContext, x)
 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_FILTERING_PARAM
 static const AVOption stack_options[] = {
     { "inputs", "set number of inputs", OFFSET(nb_inputs), AV_OPT_TYPE_INT, {.i64=2}, 2, INT_MAX, .flags = FLAGS },

     { "shortest", "force termination when the shortest input terminates", OFFSET(shortest), AV_OPT_TYPE_BOOL, {.i64=0}, 0, 1, .flags = FLAGS },

     { NULL },
 };
 
 static const AVFilterPad outputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_VIDEO,
         .config_props  = config_output,
     },
     { NULL }
 };
 
 #if CONFIG_HSTACK_FILTER
 
 #define hstack_options stack_options
 AVFILTER_DEFINE_CLASS(hstack);
 
 AVFilter ff_vf_hstack = {
     .name          = "hstack",
     .description   = NULL_IF_CONFIG_SMALL("Stack video inputs horizontally."),
     .priv_size     = sizeof(StackContext),
     .priv_class    = &hstack_class,
     .query_formats = query_formats,
     .outputs       = outputs,
     .init          = init,
     .uninit        = uninit,

     .activate      = activate,

     .flags         = AVFILTER_FLAG_DYNAMIC_INPUTS,
 };
 
 #endif /* CONFIG_HSTACK_FILTER */
 
 #if CONFIG_VSTACK_FILTER
 
 #define vstack_options stack_options
 AVFILTER_DEFINE_CLASS(vstack);
 
 AVFilter ff_vf_vstack = {
     .name          = "vstack",
     .description   = NULL_IF_CONFIG_SMALL("Stack video inputs vertically."),
     .priv_size     = sizeof(StackContext),
     .priv_class    = &vstack_class,
     .query_formats = query_formats,
     .outputs       = outputs,
     .init          = init,
     .uninit        = uninit,

     .activate      = activate,

     .flags         = AVFILTER_FLAG_DYNAMIC_INPUTS,
 };
 
 #endif /* CONFIG_VSTACK_FILTER */