/*
  * Copyright (c) Stefano Sabatini 2010
  *
  * 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
  * life video source, based on John Conways' Life Game
  */
 
 /* #define DEBUG */
 
 #include "libavutil/file.h"

 #include "libavutil/internal.h"

 #include "libavutil/intreadwrite.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 LifeContext {

     const AVClass *class;
     int w, h;
     char *filename;
     char *rule_str;
     uint8_t *file_buf;
     size_t file_bufsize;

 
     /**
      * The two grid state buffers.
      *
      * A 0xFF (ALIVE_CELL) value means the cell is alive (or new born), while
      * the decreasing values from 0xFE to 0 means the cell is dead; the range
      * of values is used for the slow death effect, or mold (0xFE means dead,
      * 0xFD means very dead, 0xFC means very very dead... and 0x00 means
      * definitely dead/mold).
      */
     uint8_t *buf[2];
 

     uint8_t  buf_idx;
     uint16_t stay_rule;         ///< encode the behavior for filled cells
     uint16_t born_rule;         ///< encode the behavior for empty cells
     uint64_t pts;

     AVRational frame_rate;

     double   random_fill_ratio;
     uint32_t random_seed;
     int stitch;

     int mold;
     uint8_t  life_color[4];
     uint8_t death_color[4];
     uint8_t  mold_color[4];

     AVLFG lfg;

     void (*draw)(AVFilterContext*, AVFrame*);

 } LifeContext;
 

 #define ALIVE_CELL 0xFF

 #define OFFSET(x) offsetof(LifeContext, x)

 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM

 
 static const AVOption life_options[] = {

     { "filename", "set source file",  OFFSET(filename), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
     { "f",        "set source file",  OFFSET(filename), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, 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 },

     { "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 },

     { "rule",     "set rule",         OFFSET(rule_str), AV_OPT_TYPE_STRING, {.str = "B3/S23"}, CHAR_MIN, CHAR_MAX, 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 },

     { "stitch",      "stitch boundaries", OFFSET(stitch), AV_OPT_TYPE_BOOL, {.i64=1}, 0, 1, FLAGS },

     { "mold",        "set mold speed for dead cells", OFFSET(mold), AV_OPT_TYPE_INT, {.i64=0}, 0, 0xFF, FLAGS },

     { "life_color",  "set life color",  OFFSET( life_color), AV_OPT_TYPE_COLOR, {.str="white"}, CHAR_MIN, CHAR_MAX, FLAGS },
     { "death_color", "set death color", OFFSET(death_color), AV_OPT_TYPE_COLOR, {.str="black"}, CHAR_MIN, CHAR_MAX, FLAGS },
     { "mold_color",  "set mold color",  OFFSET( mold_color), AV_OPT_TYPE_COLOR, {.str="black"}, CHAR_MIN, CHAR_MAX, FLAGS },

     { NULL }

 };
 

 AVFILTER_DEFINE_CLASS(life);

 
 static int parse_rule(uint16_t *born_rule, uint16_t *stay_rule,
                       const char *rule_str, void *log_ctx)
 {
     char *tail;
     const char *p = rule_str;
     *born_rule = 0;
     *stay_rule = 0;
 
     if (strchr("bBsS", *p)) {
         /* parse rule as a Born / Stay Alive code, see
          * http://en.wikipedia.org/wiki/Conway%27s_Game_of_Life */
         do {
             uint16_t *rule = (*p == 'b' || *p == 'B') ? born_rule : stay_rule;
             p++;
             while (*p >= '0' && *p <= '8') {
                 *rule += 1<<(*p - '0');
                 p++;
             }
             if (*p != '/')
                 break;
             p++;
         } while (strchr("bBsS", *p));
 
         if (*p)
             goto error;
     } else {

         /* parse rule as a number, expressed in the form STAY|(BORN<<9),
          * where STAY and BORN encode the corresponding 9-bits rule */

         long int rule = strtol(rule_str, &tail, 10);
         if (*tail)
             goto error;
         *born_rule  = ((1<<9)-1) & rule;
         *stay_rule = rule >> 9;
     }
 
     return 0;
 
 error:
     av_log(log_ctx, AV_LOG_ERROR, "Invalid rule code '%s' provided\n", rule_str);
     return AVERROR(EINVAL);
 }
 
 #ifdef DEBUG
 static void show_life_grid(AVFilterContext *ctx)
 {
     LifeContext *life = ctx->priv;
     int i, j;
 
     char *line = av_malloc(life->w + 1);
     if (!line)
         return;
     for (i = 0; i < life->h; i++) {
         for (j = 0; j < life->w; j++)

             line[j] = life->buf[life->buf_idx][i*life->w + j] == ALIVE_CELL ? '@' : ' ';

         line[j] = 0;
         av_log(ctx, AV_LOG_DEBUG, "%3d: %s\n", i, line);
     }
     av_free(line);
 }
 #endif
 
 static int init_pattern_from_file(AVFilterContext *ctx)
 {
     LifeContext *life = ctx->priv;
     char *p;
     int ret, i, i0, j, h = 0, w, max_w = 0;
 
     if ((ret = av_file_map(life->filename, &life->file_buf, &life->file_bufsize,
                            0, ctx)) < 0)
         return ret;

     av_freep(&life->filename);

 
     /* prescan file to get the number of lines and the maximum width */
     w = 0;
     for (i = 0; i < life->file_bufsize; i++) {
         if (life->file_buf[i] == '\n') {
             h++; max_w = FFMAX(w, max_w); w = 0;
         } else {
             w++;
         }
     }
     av_log(ctx, AV_LOG_DEBUG, "h:%d max_w:%d\n", h, max_w);
 

     if (life->w) {

         if (max_w > life->w || h > life->h) {
             av_log(ctx, AV_LOG_ERROR,
                    "The specified size is %dx%d which cannot contain the provided file size of %dx%d\n",
                    life->w, life->h, max_w, h);
             return AVERROR(EINVAL);
         }
     } else {
         /* size was not specified, set it to size of the grid */
         life->w = max_w;
         life->h = h;
     }
 

     if (!(life->buf[0] = av_calloc(life->h * life->w, sizeof(*life->buf[0]))) ||
         !(life->buf[1] = av_calloc(life->h * life->w, sizeof(*life->buf[1])))) {

         av_freep(&life->buf[0]);
         av_freep(&life->buf[1]);

         return AVERROR(ENOMEM);
     }
 
     /* fill buf[0] */
     p = life->file_buf;
     for (i0 = 0, i = (life->h - h)/2; i0 < h; i0++, i++) {
         for (j = (life->w - max_w)/2;; j++) {
             av_log(ctx, AV_LOG_DEBUG, "%d:%d %c\n", i, j, *p == '\n' ? 'N' : *p);
             if (*p == '\n') {
                 p++; break;
             } else

                 life->buf[0][i*life->w + j] = av_isgraph(*(p++)) ? ALIVE_CELL : 0;

         }
     }
     life->buf_idx = 0;
 
     return 0;
 }
 

 static av_cold int init(AVFilterContext *ctx)

 {
     LifeContext *life = ctx->priv;
     int ret;
 

     if (!life->w && !life->filename)

         av_opt_set(life, "size", "320x240", 0);
 
     if ((ret = parse_rule(&life->born_rule, &life->stay_rule, life->rule_str, ctx)) < 0)
         return ret;
 

     if (!life->mold && memcmp(life->mold_color, "\x00\x00\x00", 3))
         av_log(ctx, AV_LOG_WARNING,
                "Mold color is set while mold isn't, ignoring the color.\n");
 

     if (!life->filename) {
         /* fill the grid randomly */
         int i;
 

         if (!(life->buf[0] = av_calloc(life->h * life->w, sizeof(*life->buf[0]))) ||
             !(life->buf[1] = av_calloc(life->h * life->w, sizeof(*life->buf[1])))) {

             av_freep(&life->buf[0]);
             av_freep(&life->buf[1]);

             return AVERROR(ENOMEM);
         }
         if (life->random_seed == -1)
             life->random_seed = av_get_random_seed();
 
         av_lfg_init(&life->lfg, life->random_seed);
 
         for (i = 0; i < life->w * life->h; i++) {
             double r = (double)av_lfg_get(&life->lfg) / UINT32_MAX;
             if (r <= life->random_fill_ratio)

                 life->buf[0][i] = ALIVE_CELL;

         }
         life->buf_idx = 0;
     } else {
         if ((ret = init_pattern_from_file(ctx)) < 0)
             return ret;
     }
 

     av_log(ctx, AV_LOG_VERBOSE,

            "s:%dx%d r:%d/%d rule:%s stay_rule:%d born_rule:%d stitch:%d seed:%"PRIu32"\n",

            life->w, life->h, life->frame_rate.num, life->frame_rate.den,

            life->rule_str, life->stay_rule, life->born_rule, life->stitch,
            life->random_seed);

     return 0;
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     LifeContext *life = ctx->priv;
 
     av_file_unmap(life->file_buf, life->file_bufsize);
     av_freep(&life->rule_str);
     av_freep(&life->buf[0]);
     av_freep(&life->buf[1]);
 }
 
 static int config_props(AVFilterLink *outlink)
 {
     LifeContext *life = outlink->src->priv;
 
     outlink->w = life->w;
     outlink->h = life->h;

     outlink->time_base = av_inv_q(life->frame_rate);

 
     return 0;
 }
 
 static void evolve(AVFilterContext *ctx)
 {
     LifeContext *life = ctx->priv;

     int i, j;

     uint8_t *oldbuf = life->buf[ life->buf_idx];
     uint8_t *newbuf = life->buf[!life->buf_idx];
 
     enum { NW, N, NE, W, E, SW, S, SE };
 
     /* evolve the grid */
     for (i = 0; i < life->h; i++) {
         for (j = 0; j < life->w; j++) {

             int pos[8][2], n, alive, cell;

             if (life->stitch) {
                 pos[NW][0] = (i-1) < 0 ? life->h-1 : i-1; pos[NW][1] = (j-1) < 0 ? life->w-1 : j-1;
                 pos[N ][0] = (i-1) < 0 ? life->h-1 : i-1; pos[N ][1] =                         j  ;
                 pos[NE][0] = (i-1) < 0 ? life->h-1 : i-1; pos[NE][1] = (j+1) == life->w ?  0 : j+1;
                 pos[W ][0] =                         i  ; pos[W ][1] = (j-1) < 0 ? life->w-1 : j-1;
                 pos[E ][0] =                         i  ; pos[E ][1] = (j+1) == life->w ? 0  : j+1;
                 pos[SW][0] = (i+1) == life->h ?  0 : i+1; pos[SW][1] = (j-1) < 0 ? life->w-1 : j-1;
                 pos[S ][0] = (i+1) == life->h ?  0 : i+1; pos[S ][1] =                         j  ;
                 pos[SE][0] = (i+1) == life->h ?  0 : i+1; pos[SE][1] = (j+1) == life->w ?  0 : j+1;
             } else {
                 pos[NW][0] = (i-1) < 0 ? -1        : i-1; pos[NW][1] = (j-1) < 0 ? -1        : j-1;
                 pos[N ][0] = (i-1) < 0 ? -1        : i-1; pos[N ][1] =                         j  ;
                 pos[NE][0] = (i-1) < 0 ? -1        : i-1; pos[NE][1] = (j+1) == life->w ? -1 : j+1;
                 pos[W ][0] =                         i  ; pos[W ][1] = (j-1) < 0 ? -1        : j-1;
                 pos[E ][0] =                         i  ; pos[E ][1] = (j+1) == life->w ? -1 : j+1;
                 pos[SW][0] = (i+1) == life->h ? -1 : i+1; pos[SW][1] = (j-1) < 0 ? -1        : j-1;
                 pos[S ][0] = (i+1) == life->h ? -1 : i+1; pos[S ][1] =                         j  ;
                 pos[SE][0] = (i+1) == life->h ? -1 : i+1; pos[SE][1] = (j+1) == life->w ? -1 : j+1;
             }
 
             /* compute the number of live neighbor cells */

             n = (pos[NW][0] == -1 || pos[NW][1] == -1 ? 0 : oldbuf[pos[NW][0]*life->w + pos[NW][1]] == ALIVE_CELL) +
                 (pos[N ][0] == -1 || pos[N ][1] == -1 ? 0 : oldbuf[pos[N ][0]*life->w + pos[N ][1]] == ALIVE_CELL) +
                 (pos[NE][0] == -1 || pos[NE][1] == -1 ? 0 : oldbuf[pos[NE][0]*life->w + pos[NE][1]] == ALIVE_CELL) +
                 (pos[W ][0] == -1 || pos[W ][1] == -1 ? 0 : oldbuf[pos[W ][0]*life->w + pos[W ][1]] == ALIVE_CELL) +
                 (pos[E ][0] == -1 || pos[E ][1] == -1 ? 0 : oldbuf[pos[E ][0]*life->w + pos[E ][1]] == ALIVE_CELL) +
                 (pos[SW][0] == -1 || pos[SW][1] == -1 ? 0 : oldbuf[pos[SW][0]*life->w + pos[SW][1]] == ALIVE_CELL) +
                 (pos[S ][0] == -1 || pos[S ][1] == -1 ? 0 : oldbuf[pos[S ][0]*life->w + pos[S ][1]] == ALIVE_CELL) +
                 (pos[SE][0] == -1 || pos[SE][1] == -1 ? 0 : oldbuf[pos[SE][0]*life->w + pos[SE][1]] == ALIVE_CELL);
             cell  = oldbuf[i*life->w + j];
             alive = 1<<n & (cell == ALIVE_CELL ? life->stay_rule : life->born_rule);
             if (alive)     *newbuf = ALIVE_CELL; // new cell is alive
             else if (cell) *newbuf = cell - 1;   // new cell is dead and in the process of mold
             else           *newbuf = 0;          // new cell is definitely dead

             ff_dlog(ctx, "i:%d j:%d live_neighbors:%d cell:%d -> cell:%d\n", i, j, n, cell, *newbuf);

             newbuf++;

         }
     }
 
     life->buf_idx = !life->buf_idx;
 }
 

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

 {
     LifeContext *life = ctx->priv;
     uint8_t *buf = life->buf[life->buf_idx];
     int i, j, k;
 
     /* fill the output picture with the old grid buffer */
     for (i = 0; i < life->h; i++) {
         uint8_t byte = 0;
         uint8_t *p = picref->data[0] + i * picref->linesize[0];
         for (k = 0, j = 0; j < life->w; j++) {

             byte |= (buf[i*life->w+j] == ALIVE_CELL)<<(7-k++);

             if (k==8 || j == life->w-1) {
                 k = 0;
                 *p++ = byte;
                 byte = 0;
             }
         }
     }
 }
 

 // divide by 255 and round to nearest
 // apply a fast variant: (X+127)/255 = ((X+127)*257+257)>>16 = ((X+128)*257)>>16
 #define FAST_DIV255(x) ((((x) + 128) * 257) >> 16)
 

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

 {
     LifeContext *life = ctx->priv;
     uint8_t *buf = life->buf[life->buf_idx];
     int i, j;
 
     /* fill the output picture with the old grid buffer */
     for (i = 0; i < life->h; i++) {
         uint8_t *p = picref->data[0] + i * picref->linesize[0];
         for (j = 0; j < life->w; j++) {
             uint8_t v = buf[i*life->w + j];
             if (life->mold && v != ALIVE_CELL) {
                 const uint8_t *c1 = life-> mold_color;
                 const uint8_t *c2 = life->death_color;
                 int death_age = FFMIN((0xff - v) * life->mold, 0xff);
                 *p++ = FAST_DIV255((c2[0] << 8) + ((int)c1[0] - (int)c2[0]) * death_age);
                 *p++ = FAST_DIV255((c2[1] << 8) + ((int)c1[1] - (int)c2[1]) * death_age);
                 *p++ = FAST_DIV255((c2[2] << 8) + ((int)c1[2] - (int)c2[2]) * death_age);
             } else {
                 const uint8_t *c = v == ALIVE_CELL ? life->life_color : life->death_color;
                 AV_WB24(p, c[0]<<16 | c[1]<<8 | c[2]);
                 p += 3;
             }
         }
     }
 }
 

 static int request_frame(AVFilterLink *outlink)
 {
     LifeContext *life = outlink->src->priv;

     AVFrame *picref = ff_get_video_buffer(outlink, life->w, life->h);

     if (!picref)
         return AVERROR(ENOMEM);

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

     picref->pts = life->pts++;
 

     life->draw(outlink->src, picref);

     evolve(outlink->src);
 #ifdef DEBUG
     show_life_grid(outlink->src);
 #endif

     return ff_filter_frame(outlink, picref);

 }
 
 static int query_formats(AVFilterContext *ctx)
 {

     LifeContext *life = ctx->priv;

     enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_NONE, AV_PIX_FMT_NONE };

     AVFilterFormats *fmts_list;
 

     if (life->mold || memcmp(life-> life_color, "\xff\xff\xff", 3)
                    || memcmp(life->death_color, "\x00\x00\x00", 3)) {

         pix_fmts[0] = AV_PIX_FMT_RGB24;

         life->draw = fill_picture_rgb;
     } else {

         pix_fmts[0] = AV_PIX_FMT_MONOBLACK;

         life->draw = fill_picture_monoblack;
     }

     fmts_list = ff_make_format_list(pix_fmts);

     return ff_set_common_formats(ctx, fmts_list);

 }
 

 static const AVFilterPad life_outputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_VIDEO,
         .request_frame = request_frame,
         .config_props  = config_props,
     },
     { NULL}
 };
 

 AVFilter ff_vsrc_life = {

     .name          = "life",
     .description   = NULL_IF_CONFIG_SMALL("Create life."),
     .priv_size     = sizeof(LifeContext),
     .priv_class    = &life_class,
     .init          = init,
     .uninit        = uninit,

     .query_formats = query_formats,

     .inputs        = NULL,
     .outputs       = life_outputs,

 };