/*
  * Copyright (c) Stefano Sabatini 2011
  *
  * 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
  */
 
 /**
  * @file
  * cellular automaton video source, based on Stephen Wolfram "experimentus crucis"
  */
 
 /* #define DEBUG */
 
 #include "libavutil/file.h"

 #include "libavutil/internal.h"

 #include "libavutil/lfg.h"
 #include "libavutil/opt.h"
 #include "libavutil/parseutils.h"
 #include "libavutil/random_seed.h"

 #include "libavutil/avstring.h"

 #include "avfilter.h"

 #include "internal.h"

 #include "formats.h"
 #include "video.h"

 typedef struct CellAutoContext {

     const AVClass *class;
     int w, h;
     char *filename;
     char *rule_str;
     uint8_t *file_buf;
     size_t file_bufsize;
     uint8_t *buf;
     int buf_prev_row_idx, buf_row_idx;
     uint8_t rule;
     uint64_t pts;

     AVRational frame_rate;

     double   random_fill_ratio;
     uint32_t random_seed;
     int stitch, scroll, start_full;
     int64_t generation;         ///< the generation number, starting from 0
     AVLFG lfg;
     char *pattern;
 } CellAutoContext;
 
 #define OFFSET(x) offsetof(CellAutoContext, x)

 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM

 
 static const AVOption cellauto_options[] = {

     { "filename", "read initial pattern from file", OFFSET(filename), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
     { "f",        "read initial pattern from file", OFFSET(filename), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
     { "pattern",  "set initial pattern", OFFSET(pattern), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
     { "p",        "set initial pattern", OFFSET(pattern), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },

     { "rate",     "set video rate", OFFSET(frame_rate), AV_OPT_TYPE_VIDEO_RATE, {.str = "25"}, 0, INT_MAX, FLAGS },
     { "r",        "set video rate", OFFSET(frame_rate), AV_OPT_TYPE_VIDEO_RATE, {.str = "25"}, 0, INT_MAX, FLAGS },

     { "size",     "set video size", OFFSET(w),    AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, FLAGS },
     { "s",        "set video size", OFFSET(w),    AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, FLAGS },

     { "rule",     "set rule",       OFFSET(rule), AV_OPT_TYPE_INT,    {.i64 = 110},  0, 255, FLAGS },

     { "random_fill_ratio", "set fill ratio for filling initial grid randomly", OFFSET(random_fill_ratio), AV_OPT_TYPE_DOUBLE, {.dbl = 1/M_PHI}, 0, 1, FLAGS },
     { "ratio",             "set fill ratio for filling initial grid randomly", OFFSET(random_fill_ratio), AV_OPT_TYPE_DOUBLE, {.dbl = 1/M_PHI}, 0, 1, FLAGS },

     { "random_seed", "set the seed for filling the initial grid randomly", OFFSET(random_seed), AV_OPT_TYPE_INT, {.i64 = -1}, -1, UINT32_MAX, FLAGS },
     { "seed",        "set the seed for filling the initial grid randomly", OFFSET(random_seed), AV_OPT_TYPE_INT, {.i64 = -1}, -1, UINT32_MAX, FLAGS },

     { "scroll",      "scroll pattern downward", OFFSET(scroll), AV_OPT_TYPE_BOOL, {.i64 = 1}, 0, 1, FLAGS },
     { "start_full",  "start filling the whole video", OFFSET(start_full), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, FLAGS },
     { "full",        "start filling the whole video", OFFSET(start_full), AV_OPT_TYPE_BOOL, {.i64 = 1}, 0, 1, FLAGS },
     { "stitch",      "stitch boundaries", OFFSET(stitch), AV_OPT_TYPE_BOOL,    {.i64 = 1},   0, 1, FLAGS },

     { NULL }

 };
 

 AVFILTER_DEFINE_CLASS(cellauto);

 
 #ifdef DEBUG
 static void show_cellauto_row(AVFilterContext *ctx)
 {

     CellAutoContext *s = ctx->priv;

     int i;

     uint8_t *row = s->buf + s->w * s->buf_row_idx;
     char *line = av_malloc(s->w + 1);

     if (!line)
         return;
 

     for (i = 0; i < s->w; i++)

         line[i] = row[i] ? '@' : ' ';
     line[i] = 0;

     av_log(ctx, AV_LOG_DEBUG, "generation:%"PRId64" row:%s|\n", s->generation, line);

     av_free(line);
 }
 #endif
 
 static int init_pattern_from_string(AVFilterContext *ctx)
 {

     CellAutoContext *s = ctx->priv;

     char *p;
     int i, w = 0;
 

     w = strlen(s->pattern);

     av_log(ctx, AV_LOG_DEBUG, "w:%d\n", w);
 

     if (s->w) {
         if (w > s->w) {

             av_log(ctx, AV_LOG_ERROR,
                    "The specified width is %d which cannot contain the provided string width of %d\n",

                    s->w, w);

             return AVERROR(EINVAL);
         }
     } else {
         /* width was not specified, set it to width of the provided row */

         s->w = w;
         s->h = (double)s->w * M_PHI;

     }
 

     s->buf = av_mallocz_array(sizeof(uint8_t) * s->w, s->h);
     if (!s->buf)

         return AVERROR(ENOMEM);
 
     /* fill buf */

     p = s->pattern;
     for (i = (s->w - w)/2;; i++) {

         av_log(ctx, AV_LOG_DEBUG, "%d %c\n", i, *p == '\n' ? 'N' : *p);
         if (*p == '\n' || !*p)
             break;
         else

             s->buf[i] = !!av_isgraph(*(p++));

     }
 
     return 0;
 }
 
 static int init_pattern_from_file(AVFilterContext *ctx)
 {

     CellAutoContext *s = ctx->priv;

     int ret;
 

     ret = av_file_map(s->filename,
                       &s->file_buf, &s->file_bufsize, 0, ctx);

     if (ret < 0)
         return ret;
 
     /* create a string based on the read file */

     s->pattern = av_malloc(s->file_bufsize + 1);
     if (!s->pattern)

         return AVERROR(ENOMEM);

     memcpy(s->pattern, s->file_buf, s->file_bufsize);
     s->pattern[s->file_bufsize] = 0;

 
     return init_pattern_from_string(ctx);
 }
 

 static av_cold int init(AVFilterContext *ctx)

 {

     CellAutoContext *s = ctx->priv;

     int ret;
 

     if (!s->w && !s->filename && !s->pattern)
         av_opt_set(s, "size", "320x518", 0);

     if (s->filename && s->pattern) {

         av_log(ctx, AV_LOG_ERROR, "Only one of the filename or pattern options can be used\n");
         return AVERROR(EINVAL);
     }
 

     if (s->filename) {

         if ((ret = init_pattern_from_file(ctx)) < 0)
             return ret;

     } else if (s->pattern) {

         if ((ret = init_pattern_from_string(ctx)) < 0)
             return ret;
     } else {
         /* fill the first row randomly */
         int i;
 

         s->buf = av_mallocz_array(sizeof(uint8_t) * s->w, s->h);
         if (!s->buf)

             return AVERROR(ENOMEM);

         if (s->random_seed == -1)
             s->random_seed = av_get_random_seed();

         av_lfg_init(&s->lfg, s->random_seed);

         for (i = 0; i < s->w; i++) {
             double r = (double)av_lfg_get(&s->lfg) / UINT32_MAX;
             if (r <= s->random_fill_ratio)
                 s->buf[i] = 1;

         }
     }
 

     av_log(ctx, AV_LOG_VERBOSE,

            "s:%dx%d r:%d/%d rule:%d stitch:%d scroll:%d full:%d seed:%"PRIu32"\n",

            s->w, s->h, s->frame_rate.num, s->frame_rate.den,
            s->rule, s->stitch, s->scroll, s->start_full,
            s->random_seed);

     return 0;
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {

     CellAutoContext *s = ctx->priv;

     av_file_unmap(s->file_buf, s->file_bufsize);
     av_freep(&s->buf);
     av_freep(&s->pattern);

 }
 
 static int config_props(AVFilterLink *outlink)
 {

     CellAutoContext *s = outlink->src->priv;

     outlink->w = s->w;
     outlink->h = s->h;
     outlink->time_base = av_inv_q(s->frame_rate);

 
     return 0;
 }
 
 static void evolve(AVFilterContext *ctx)
 {

     CellAutoContext *s = ctx->priv;

     int i, v, pos[3];

     uint8_t *row, *prev_row = s->buf + s->buf_row_idx * s->w;

     enum { NW, N, NE };
 

     s->buf_prev_row_idx = s->buf_row_idx;
     s->buf_row_idx      = s->buf_row_idx == s->h-1 ? 0 : s->buf_row_idx+1;
     row = s->buf + s->w * s->buf_row_idx;

     for (i = 0; i < s->w; i++) {
         if (s->stitch) {
             pos[NW] = i-1 < 0 ? s->w-1 : i-1;

             pos[N]  = i;

             pos[NE] = i+1 == s->w ? 0  : i+1;

             v = prev_row[pos[NW]]<<2 | prev_row[pos[N]]<<1 | prev_row[pos[NE]];
         } else {
             v = 0;
             v|= i-1 >= 0          ? prev_row[i-1]<<2 : 0;
             v|=                     prev_row[i  ]<<1    ;

             v|= i+1 < s->w ? prev_row[i+1]    : 0;

         }

         row[i] = !!(s->rule & (1<<v));

         ff_dlog(ctx, "i:%d context:%c%c%c -> cell:%d\n", i,

                 v&4?'@':' ', v&2?'@':' ', v&1?'@':' ', row[i]);
     }
 

     s->generation++;

 }
 

 static void fill_picture(AVFilterContext *ctx, AVFrame *picref)

 {

     CellAutoContext *s = ctx->priv;

     int i, j, k, row_idx = 0;
     uint8_t *p0 = picref->data[0];
 

     if (s->scroll && s->generation >= s->h)

         /* show on top the oldest row */

         row_idx = (s->buf_row_idx + 1) % s->h;

 
     /* fill the output picture with the whole buffer */

     for (i = 0; i < s->h; i++) {

         uint8_t byte = 0;

         uint8_t *row = s->buf + row_idx*s->w;

         uint8_t *p = p0;

         for (k = 0, j = 0; j < s->w; j++) {

             byte |= row[j]<<(7-k++);

             if (k==8 || j == s->w-1) {

                 k = 0;
                 *p++ = byte;
                 byte = 0;
             }
         }

         row_idx = (row_idx + 1) % s->h;

         p0 += picref->linesize[0];
     }
 }
 
 static int request_frame(AVFilterLink *outlink)
 {

     CellAutoContext *s = outlink->src->priv;
     AVFrame *picref = ff_get_video_buffer(outlink, s->w, s->h);

     if (!picref)
         return AVERROR(ENOMEM);

     picref->sample_aspect_ratio = (AVRational) {1, 1};

     if (s->generation == 0 && s->start_full) {

         int i;

         for (i = 0; i < s->h-1; i++)

             evolve(outlink->src);
     }
     fill_picture(outlink->src, picref);
     evolve(outlink->src);
 

     picref->pts = s->pts++;

 
 #ifdef DEBUG
     show_cellauto_row(outlink->src);
 #endif

     return ff_filter_frame(outlink, picref);

 }
 
 static int query_formats(AVFilterContext *ctx)
 {

     static const enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_MONOBLACK, 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 cellauto_outputs[] = {
     {

         .name          = "default",
         .type          = AVMEDIA_TYPE_VIDEO,
         .request_frame = request_frame,
         .config_props  = config_props,

     },
     { NULL }
 };
 

 AVFilter ff_vsrc_cellauto = {

     .name          = "cellauto",
     .description   = NULL_IF_CONFIG_SMALL("Create pattern generated by an elementary cellular automaton."),
     .priv_size     = sizeof(CellAutoContext),
     .priv_class    = &cellauto_class,
     .init          = init,
     .uninit        = uninit,

     .query_formats = query_formats,

     .inputs        = NULL,
     .outputs       = cellauto_outputs,

 };