/*

  * Copyright (c) 2013 Clément Bœsch
  *

  * 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/lfg.h"
 #include "libavutil/opt.h"
 #include "libavutil/random_seed.h"
 #include "audio.h"
 #include "video.h"
 
 enum mode {
     MODE_NONE,
     MODE_RO,
     MODE_RW,
     MODE_TOGGLE,
     MODE_RANDOM,
     NB_MODES
 };
 
 typedef struct {
     const AVClass *class;
     AVLFG lfg;

     int64_t random_seed;

     enum mode mode;
 } PermsContext;
 
 #define OFFSET(x) offsetof(PermsContext, x)

 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM | AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_VIDEO_PARAM

 
 static const AVOption options[] = {
     { "mode", "select permissions mode", OFFSET(mode), AV_OPT_TYPE_INT, {.i64 = MODE_NONE}, MODE_NONE, NB_MODES-1, FLAGS, "mode" },
         { "none",   "do nothing",                       0, AV_OPT_TYPE_CONST, {.i64 = MODE_NONE},       INT_MIN, INT_MAX, FLAGS, "mode" },
         { "ro",     "set all output frames read-only",  0, AV_OPT_TYPE_CONST, {.i64 = MODE_RO},         INT_MIN, INT_MAX, FLAGS, "mode" },
         { "rw",     "set all output frames writable",   0, AV_OPT_TYPE_CONST, {.i64 = MODE_RW},         INT_MIN, INT_MAX, FLAGS, "mode" },
         { "toggle", "switch permissions",               0, AV_OPT_TYPE_CONST, {.i64 = MODE_TOGGLE},     INT_MIN, INT_MAX, FLAGS, "mode" },
         { "random", "set permissions randomly",         0, AV_OPT_TYPE_CONST, {.i64 = MODE_RANDOM},     INT_MIN, INT_MAX, FLAGS, "mode" },

     { "seed", "set the seed for the random mode", OFFSET(random_seed), AV_OPT_TYPE_INT64, {.i64 = -1}, -1, UINT32_MAX, FLAGS },

     { NULL }
 };
 

 static av_cold int init(AVFilterContext *ctx)

 {
     PermsContext *perms = ctx->priv;
 

     if (perms->mode == MODE_RANDOM) {
         uint32_t seed;
 
         if (perms->random_seed == -1)
             perms->random_seed = av_get_random_seed();
         seed = perms->random_seed;
         av_log(ctx, AV_LOG_INFO, "random seed: 0x%08x\n", seed);
         av_lfg_init(&perms->lfg, seed);
     }

 
     return 0;
 }
 
 enum perm                        {  RO,   RW  };
 static const char *perm_str[2] = { "RO", "RW" };
 
 static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
 {
     int ret;
     AVFilterContext *ctx = inlink->dst;
     PermsContext *perms = ctx->priv;
     AVFrame *out = frame;
     enum perm in_perm = av_frame_is_writable(frame) ? RW : RO;
     enum perm out_perm;
 
     switch (perms->mode) {
     case MODE_TOGGLE:   out_perm = in_perm == RO ? RW : RO;                 break;
     case MODE_RANDOM:   out_perm = av_lfg_get(&perms->lfg) & 1 ? RW : RO;   break;
     case MODE_RO:       out_perm = RO;                                      break;
     case MODE_RW:       out_perm = RW;                                      break;
     default:            out_perm = in_perm;                                 break;
     }
 
     av_log(ctx, AV_LOG_VERBOSE, "%s -> %s%s\n",
            perm_str[in_perm], perm_str[out_perm],
            in_perm == out_perm ? " (no-op)" : "");
 
     if (in_perm == RO && out_perm == RW) {
         if ((ret = av_frame_make_writable(frame)) < 0)
             return ret;
     } else if (in_perm == RW && out_perm == RO) {
         out = av_frame_clone(frame);
         if (!out)
             return AVERROR(ENOMEM);
     }
 
     ret = ff_filter_frame(ctx->outputs[0], out);
 
     if (in_perm == RW && out_perm == RO)
         av_frame_free(&frame);
     return ret;
 }
 
 #if CONFIG_APERMS_FILTER
 
 #define aperms_options options
 AVFILTER_DEFINE_CLASS(aperms);
 
 static const AVFilterPad aperms_inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_AUDIO,
         .filter_frame = filter_frame,
     },
     { NULL }
 };
 
 static const AVFilterPad aperms_outputs[] = {
     {
         .name = "default",
         .type = AVMEDIA_TYPE_AUDIO,
     },
     { NULL }
 };
 
 AVFilter avfilter_af_aperms = {
     .name        = "aperms",
     .description = NULL_IF_CONFIG_SMALL("Set permissions for the output audio frame."),

     .init        = init,

     .priv_size   = sizeof(PermsContext),
     .inputs      = aperms_inputs,
     .outputs     = aperms_outputs,
     .priv_class  = &aperms_class,
 };
 #endif /* CONFIG_APERMS_FILTER */
 
 #if CONFIG_PERMS_FILTER
 
 #define perms_options options
 AVFILTER_DEFINE_CLASS(perms);
 
 static const AVFilterPad perms_inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .filter_frame = filter_frame,
     },
     { NULL }
 };
 
 static const AVFilterPad perms_outputs[] = {
     {
         .name = "default",
         .type = AVMEDIA_TYPE_VIDEO,
     },
     { NULL }
 };
 
 AVFilter avfilter_vf_perms = {
     .name        = "perms",
     .description = NULL_IF_CONFIG_SMALL("Set permissions for the output video frame."),

     .init        = init,

     .priv_size   = sizeof(PermsContext),
     .inputs      = perms_inputs,
     .outputs     = perms_outputs,
     .priv_class  = &perms_class,
 };
 #endif /* CONFIG_PERMS_FILTER */