/*
  * a64 video encoder - multicolor modes
  * Copyright (c) 2009 Tobias Bindhammer
  *
  * 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
  * a64 video encoder - multicolor modes
  */
 

 #include "a64colors.h"

 #include "a64tables.h"
 #include "elbg.h"

 #include "internal.h"

 #include "libavutil/common.h"

 #include "libavutil/intreadwrite.h"
 

 #define DITHERSTEPS   8
 #define CHARSET_CHARS 256

 #define INTERLACED    1

 #define CROP_SCREENS  1

 #define C64XRES 320
 #define C64YRES 200
 
 typedef struct A64Context {
     /* variables for multicolor modes */
     AVLFG randctx;
     int mc_lifetime;
     int mc_use_5col;
     unsigned mc_frame_counter;
     int *mc_meta_charset;
     int *mc_charmap;
     int *mc_best_cb;
     int mc_luma_vals[5];
     uint8_t *mc_charset;
     uint8_t *mc_colram;
     uint8_t *mc_palette;
     int mc_pal_size;
 
     /* pts of the next packet that will be output */
     int64_t next_pts;
 } A64Context;
 

 /* gray gradient */
 static const int mc_colors[5]={0x0,0xb,0xc,0xf,0x1};

 /* other possible gradients - to be tested */
 //static const int mc_colors[5]={0x0,0x8,0xa,0xf,0x7};
 //static const int mc_colors[5]={0x0,0x9,0x8,0xa,0x3};
 

 static void to_meta_with_crop(AVCodecContext *avctx, AVFrame *p, int *dest)
 {
     int blockx, blocky, x, y;
     int luma = 0;

     int height = FFMIN(avctx->height, C64YRES);
     int width  = FFMIN(avctx->width , C64XRES);

     uint8_t *src = p->data[0];
 

     for (blocky = 0; blocky < C64YRES; blocky += 8) {

         for (blockx = 0; blockx < C64XRES; blockx += 8) {

             for (y = blocky; y < blocky + 8 && y < C64YRES; y++) {
                 for (x = blockx; x < blockx + 8 && x < C64XRES; x += 2) {

                     if(x < width && y < height) {

                         /* build average over 2 pixels */
                         luma = (src[(x + 0 + y * p->linesize[0])] +
                                 src[(x + 1 + y * p->linesize[0])]) / 2;
                         /* write blocks as linear data now so they are suitable for elbg */
                         dest[0] = luma;
                     }
                     dest++;
                 }
             }
         }
     }
 }
 
 static void render_charset(AVCodecContext *avctx, uint8_t *charset,
                            uint8_t *colrammap)
 {
     A64Context *c = avctx->priv_data;

     uint8_t row1, row2;

     int charpos, x, y;

     int a, b;
     uint8_t pix;

     int lowdiff, highdiff;
     int *best_cb = c->mc_best_cb;

     static uint8_t index1[256];
     static uint8_t index2[256];
     static uint8_t dither[256];
     int i;
     int distance;

     /* generate lookup-tables for dither and index before looping */
     i = 0;
     for (a=0; a < 256; a++) {

         if(i < c->mc_pal_size -1 && a == c->mc_luma_vals[i + 1]) {
             distance = c->mc_luma_vals[i + 1] - c->mc_luma_vals[i];

             for(b = 0; b <= distance; b++) {

                   dither[c->mc_luma_vals[i] + b] = b * (DITHERSTEPS - 1) / distance;

             }
             i++;
         }

         if(i >= c->mc_pal_size - 1) dither[a] = 0;

         index1[a] = i;

         index2[a] = FFMIN(i + 1, c->mc_pal_size - 1);

     }

     /* and render charset */

     for (charpos = 0; charpos < CHARSET_CHARS; charpos++) {

         lowdiff  = 0;
         highdiff = 0;
         for (y = 0; y < 8; y++) {

             row1 = 0; row2 = 0;

             for (x = 0; x < 4; x++) {
                 pix = best_cb[y * 4 + x];
 

                 /* accumulate error for brightest/darkest color */
                 if (index1[pix] >= 3)
                     highdiff += pix - c->mc_luma_vals[3];
                 if (index1[pix] < 1)
                     lowdiff += c->mc_luma_vals[1] - pix;

 
                 row1 <<= 2;

                 if (INTERLACED) {

                     row2 <<= 2;
                     if (interlaced_dither_patterns[dither[pix]][(y & 3) * 2 + 0][x & 3])
                         row1 |= 3-(index2[pix] & 3);
                     else
                         row1 |= 3-(index1[pix] & 3);
 
                     if (interlaced_dither_patterns[dither[pix]][(y & 3) * 2 + 1][x & 3])
                         row2 |= 3-(index2[pix] & 3);
                     else
                         row2 |= 3-(index1[pix] & 3);
                 }
                 else {
                     if (multi_dither_patterns[dither[pix]][(y & 3)][x & 3])
                         row1 |= 3-(index2[pix] & 3);
                     else
                         row1 |= 3-(index1[pix] & 3);
                 }

             }

             charset[y+0x000] = row1;

             if (INTERLACED) charset[y+0x800] = row2;

         }

         /* do we need to adjust pixels? */

         if (highdiff > 0 && lowdiff > 0 && c->mc_use_5col) {

             if (lowdiff > highdiff) {
                 for (x = 0; x < 32; x++)

                     best_cb[x] = FFMIN(c->mc_luma_vals[3], best_cb[x]);

             } else {
                 for (x = 0; x < 32; x++)

                     best_cb[x] = FFMAX(c->mc_luma_vals[1], best_cb[x]);

             }

             charpos--;          /* redo now adjusted char */
         /* no adjustment needed, all fine */

         } else {
             /* advance pointers */
             best_cb += 32;
             charset += 8;
 

             /* remember colorram value */

             colrammap[charpos] = (highdiff > 0);

         }
     }
 }
 
 static av_cold int a64multi_close_encoder(AVCodecContext *avctx)
 {
     A64Context *c = avctx->priv_data;

     av_frame_free(&avctx->coded_frame);

     av_free(c->mc_meta_charset);
     av_free(c->mc_best_cb);

     av_free(c->mc_charset);

     av_free(c->mc_charmap);
     av_free(c->mc_colram);

     return 0;
 }
 
 static av_cold int a64multi_init_encoder(AVCodecContext *avctx)
 {
     A64Context *c = avctx->priv_data;

     int a;

     av_lfg_init(&c->randctx, 1);
 
     if (avctx->global_quality < 1) {
         c->mc_lifetime = 4;
     } else {
         c->mc_lifetime = avctx->global_quality /= FF_QP2LAMBDA;
     }
 
     av_log(avctx, AV_LOG_INFO, "charset lifetime set to %d frame(s)\n", c->mc_lifetime);
 

     c->mc_frame_counter = 0;

     c->mc_use_5col      = avctx->codec->id == AV_CODEC_ID_A64_MULTI5;

     c->mc_pal_size      = 4 + c->mc_use_5col;
 

     /* precalc luma values for later use */

     for (a = 0; a < c->mc_pal_size; a++) {

         c->mc_luma_vals[a]=a64_palette[mc_colors[a]][0] * 0.30 +
                            a64_palette[mc_colors[a]][1] * 0.59 +
                            a64_palette[mc_colors[a]][2] * 0.11;
     }
 

     if (!(c->mc_meta_charset = av_malloc(32000 * c->mc_lifetime * sizeof(int))) ||
        !(c->mc_best_cb       = av_malloc(CHARSET_CHARS * 32 * sizeof(int)))     ||
        !(c->mc_charmap       = av_mallocz(1000 * c->mc_lifetime * sizeof(int))) ||
        !(c->mc_colram        = av_mallocz(CHARSET_CHARS * sizeof(uint8_t)))     ||
        !(c->mc_charset       = av_malloc(0x800 * (INTERLACED+1) * sizeof(uint8_t)))) {

         av_log(avctx, AV_LOG_ERROR, "Failed to allocate buffer memory.\n");
         return AVERROR(ENOMEM);
     }

     /* set up extradata */

     if (!(avctx->extradata = av_mallocz(8 * 4 + FF_INPUT_BUFFER_PADDING_SIZE))) {

         av_log(avctx, AV_LOG_ERROR, "Failed to allocate memory for extradata.\n");
         return AVERROR(ENOMEM);
     }

     avctx->extradata_size = 8 * 4;
     AV_WB32(avctx->extradata, c->mc_lifetime);

     AV_WB32(avctx->extradata + 16, INTERLACED);

     avctx->coded_frame = av_frame_alloc();
     if (!avctx->coded_frame) {
         a64multi_close_encoder(avctx);
         return AVERROR(ENOMEM);
     }
 

     avctx->coded_frame->pict_type = AV_PICTURE_TYPE_I;

     avctx->coded_frame->key_frame = 1;
     if (!avctx->codec_tag)
          avctx->codec_tag = AV_RL32("a64m");
 

     c->next_pts = AV_NOPTS_VALUE;
 

     return 0;
 }
 

 static void a64_compress_colram(unsigned char *buf, int *charmap, uint8_t *colram)
 {
     int a;
     uint8_t temp;
     /* only needs to be done in 5col mode */
     /* XXX could be squeezed to 0x80 bytes */
     for (a = 0; a < 256; a++) {
         temp  = colram[charmap[a + 0x000]] << 0;
         temp |= colram[charmap[a + 0x100]] << 1;
         temp |= colram[charmap[a + 0x200]] << 2;

         if (a < 0xe8) temp |= colram[charmap[a + 0x300]] << 3;

         buf[a] = temp << 2;
     }
 }
 

 static int a64multi_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
                                  const AVFrame *pict, int *got_packet)

 {
     A64Context *c = avctx->priv_data;

     AVFrame *const p = avctx->coded_frame;

 
     int frame;

     int x, y;
     int b_height;
     int b_width;

     int req_size, ret;

     uint8_t *buf = NULL;

     int *charmap     = c->mc_charmap;
     uint8_t *colram  = c->mc_colram;
     uint8_t *charset = c->mc_charset;
     int *meta        = c->mc_meta_charset;
     int *best_cb     = c->mc_best_cb;

     int charset_size = 0x800 * (INTERLACED + 1);
     int colram_size  = 0x100 * c->mc_use_5col;

     int screen_size;

     if(CROP_SCREENS) {
         b_height = FFMIN(avctx->height,C64YRES) >> 3;
         b_width  = FFMIN(avctx->width ,C64XRES) >> 3;
         screen_size = b_width * b_height;
     } else {
         b_height = C64YRES >> 3;
         b_width  = C64XRES >> 3;
         screen_size = 0x400;
     }
 

     /* no data, means end encoding asap */

     if (!pict) {

         /* all done, end encoding */

         if (!c->mc_lifetime) return 0;

         /* no more frames in queue, prepare to flush remaining frames */

         if (!c->mc_frame_counter) {
             c->mc_lifetime = 0;

         }
         /* still frames in queue so limit lifetime to remaining frames */

         else c->mc_lifetime = c->mc_frame_counter;

     /* still new data available */

     } else {

         /* fill up mc_meta_charset with data until lifetime exceeds */
         if (c->mc_frame_counter < c->mc_lifetime) {
             *p = *pict;

             p->pict_type = AV_PICTURE_TYPE_I;

             p->key_frame = 1;
             to_meta_with_crop(avctx, p, meta + 32000 * c->mc_frame_counter);
             c->mc_frame_counter++;

             if (c->next_pts == AV_NOPTS_VALUE)
                 c->next_pts = pict->pts;

             /* lifetime is not reached so wait for next frame first */
             return 0;
         }

     }
 

     /* lifetime reached so now convert X frames at once */
     if (c->mc_frame_counter == c->mc_lifetime) {

         req_size = 0;

         /* any frames to encode? */

         if (c->mc_lifetime) {

             req_size = charset_size + c->mc_lifetime*(screen_size + colram_size);

             if ((ret = ff_alloc_packet2(avctx, pkt, req_size)) < 0)

                 return ret;
             buf = pkt->data;
 

             /* calc optimal new charset + charmaps */
             ff_init_elbg(meta, 32, 1000 * c->mc_lifetime, best_cb, CHARSET_CHARS, 50, charmap, &c->randctx);
             ff_do_elbg  (meta, 32, 1000 * c->mc_lifetime, best_cb, CHARSET_CHARS, 50, charmap, &c->randctx);
 
             /* create colorram map and a c64 readable charset */
             render_charset(avctx, charset, colram);
 

             /* copy charset to buf */

             memcpy(buf, charset, charset_size);

 
             /* advance pointers */

             buf      += charset_size;
             charset  += charset_size;

         }

         /* write x frames to buf */

         for (frame = 0; frame < c->mc_lifetime; frame++) {

             /* copy charmap to buf. buf is uchar*, charmap is int*, so no memcpy here, sorry */

             for (y = 0; y < b_height; y++) {
                 for (x = 0; x < b_width; x++) {
                     buf[y * b_width + x] = charmap[y * b_width + x];
                 }

             }

             /* advance pointers */

             buf += screen_size;
             req_size += screen_size;

             /* compress and copy colram to buf */

             if (c->mc_use_5col) {
                 a64_compress_colram(buf, charmap, colram);

                 /* advance pointers */

                 buf += colram_size;
                 req_size += colram_size;

             }
 
             /* advance to next charmap */

             charmap += 1000;
         }

         AV_WB32(avctx->extradata + 4,  c->mc_frame_counter);
         AV_WB32(avctx->extradata + 8,  charset_size);
         AV_WB32(avctx->extradata + 12, screen_size + colram_size);

         /* reset counter */
         c->mc_frame_counter = 0;
 

         pkt->pts = pkt->dts = c->next_pts;
         c->next_pts         = AV_NOPTS_VALUE;
 
         pkt->size   = req_size;
         pkt->flags |= AV_PKT_FLAG_KEY;
         *got_packet = !!req_size;

     }
     return 0;
 }
 

 #if CONFIG_A64MULTI_ENCODER

 AVCodec ff_a64multi_encoder = {

     .name           = "a64multi",

     .long_name      = NULL_IF_CONFIG_SMALL("Multicolor charset for Commodore 64"),

     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_A64_MULTI,

     .priv_data_size = sizeof(A64Context),
     .init           = a64multi_init_encoder,

     .encode2        = a64multi_encode_frame,

     .close          = a64multi_close_encoder,

     .pix_fmts       = (const enum AVPixelFormat[]) {AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE},

     .capabilities   = CODEC_CAP_DELAY,
 };

 #endif
 #if CONFIG_A64MULTI5_ENCODER

 AVCodec ff_a64multi5_encoder = {

     .name           = "a64multi5",

     .long_name      = NULL_IF_CONFIG_SMALL("Multicolor charset for Commodore 64, extended with 5th color (colram)"),

     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_A64_MULTI5,

     .priv_data_size = sizeof(A64Context),
     .init           = a64multi_init_encoder,

     .encode2        = a64multi_encode_frame,

     .close          = a64multi_close_encoder,

     .pix_fmts       = (const enum AVPixelFormat[]) {AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE},

     .capabilities   = CODEC_CAP_DELAY,
 };

 #endif