/*
  * ASCII/ANSI art decoder
  * Copyright (c) 2010 Peter Ross <pross@xvid.org>
  *
  * 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
  * ASCII/ANSI art decoder
  */
 

 #include "libavutil/common.h"

 #include "libavutil/frame.h"

 #include "libavutil/lfg.h"

 #include "libavutil/xga_font_data.h"

 #include "avcodec.h"
 #include "cga_data.h"

 #include "internal.h"

 #define ATTR_BOLD         0x01  /**< Bold/Bright-foreground (mode 1) */
 #define ATTR_FAINT        0x02  /**< Faint (mode 2) */
 #define ATTR_UNDERLINE    0x08  /**< Underline (mode 4) */
 #define ATTR_BLINK        0x10  /**< Blink/Bright-background (mode 5) */
 #define ATTR_REVERSE      0x40  /**< Reverse (mode 7) */
 #define ATTR_CONCEALED    0x80  /**< Concealed (mode 8) */

 #define DEFAULT_FG_COLOR     7  /**< CGA color index */

 #define DEFAULT_BG_COLOR     0

 #define DEFAULT_SCREEN_MODE  3  /**< 80x25 */

 #define FONT_WIDTH           8  /**< Font width */

 
 /** map ansi color index to cga palette index */
 static const uint8_t ansi_to_cga[16] = {
     0,  4,  2,  6,  1,  5,  3, 7, 8, 12, 10, 14,  9, 13, 11, 15
 };
 

 typedef struct AnsiContext {

     AVFrame *frame;

     int x;                /**< x cursor position (pixels) */
     int y;                /**< y cursor position (pixels) */
     int sx;               /**< saved x cursor position (pixels) */
     int sy;               /**< saved y cursor position (pixels) */
     const uint8_t* font;  /**< font */
     int font_height;      /**< font height */
     int attributes;       /**< attribute flags */
     int fg;               /**< foreground color */
     int bg;               /**< background color */

     int first_frame;

 
     /* ansi parser state machine */
     enum {
         STATE_NORMAL = 0,
         STATE_ESCAPE,
         STATE_CODE,
         STATE_MUSIC_PREAMBLE
     } state;
 #define MAX_NB_ARGS 4
     int args[MAX_NB_ARGS];

     int nb_args;          /**< number of arguments (may exceed MAX_NB_ARGS) */

 } AnsiContext;
 
 static av_cold int decode_init(AVCodecContext *avctx)
 {
     AnsiContext *s = avctx->priv_data;

     avctx->pix_fmt = AV_PIX_FMT_PAL8;

     s->frame = av_frame_alloc();
     if (!s->frame)
         return AVERROR(ENOMEM);
 

     /* defaults */

     s->font        = avpriv_vga16_font;

     s->font_height = 16;
     s->fg          = DEFAULT_FG_COLOR;
     s->bg          = DEFAULT_BG_COLOR;
 

     if (!avctx->width || !avctx->height) {
         int ret = ff_set_dimensions(avctx, 80 << 3, 25 << 4);
         if (ret < 0)
             return ret;
     }

     return 0;
 }
 

 static void set_palette(uint32_t *pal)
 {
     int r, g, b;
     memcpy(pal, ff_cga_palette, 16 * 4);
     pal += 16;
 #define COLOR(x) ((x) * 40 + 55)
     for (r = 0; r < 6; r++)
         for (g = 0; g < 6; g++)
             for (b = 0; b < 6; b++)
                 *pal++ = 0xFF000000 | (COLOR(r) << 16) | (COLOR(g) << 8) | COLOR(b);
 #define GRAY(x) ((x) * 10 + 8)
     for (g = 0; g < 24; g++)
         *pal++ = 0xFF000000 | (GRAY(g) << 16) | (GRAY(g) << 8) | GRAY(g);
 }
 

 static void hscroll(AVCodecContext *avctx)
 {
     AnsiContext *s = avctx->priv_data;
     int i;
 

     if (s->y <= avctx->height - 2*s->font_height) {

         s->y += s->font_height;
         return;
     }
 
     i = 0;
     for (; i < avctx->height - s->font_height; i++)

         memcpy(s->frame->data[0] + i * s->frame->linesize[0],
                s->frame->data[0] + (i + s->font_height) * s->frame->linesize[0],

                avctx->width);
     for (; i < avctx->height; i++)

         memset(s->frame->data[0] + i * s->frame->linesize[0],

             DEFAULT_BG_COLOR, avctx->width);
 }
 
 static void erase_line(AVCodecContext * avctx, int xoffset, int xlength)
 {
     AnsiContext *s = avctx->priv_data;
     int i;
     for (i = 0; i < s->font_height; i++)

         memset(s->frame->data[0] + (s->y + i)*s->frame->linesize[0] + xoffset,

             DEFAULT_BG_COLOR, xlength);
 }
 
 static void erase_screen(AVCodecContext *avctx)
 {
     AnsiContext *s = avctx->priv_data;
     int i;
     for (i = 0; i < avctx->height; i++)

         memset(s->frame->data[0] + i * s->frame->linesize[0], DEFAULT_BG_COLOR, avctx->width);

     s->x = s->y = 0;
 }
 
 /**
  * Draw character to screen
  */
 static void draw_char(AVCodecContext *avctx, int c)
 {
     AnsiContext *s = avctx->priv_data;
     int fg = s->fg;
     int bg = s->bg;
 
     if ((s->attributes & ATTR_BOLD))
         fg += 8;
     if ((s->attributes & ATTR_BLINK))
         bg += 8;
     if ((s->attributes & ATTR_REVERSE))
         FFSWAP(int, fg, bg);
     if ((s->attributes & ATTR_CONCEALED))
         fg = bg;

     ff_draw_pc_font(s->frame->data[0] + s->y * s->frame->linesize[0] + s->x,
                     s->frame->linesize[0], s->font, s->font_height, c, fg, bg);

     s->x += FONT_WIDTH;

     if (s->x > avctx->width - FONT_WIDTH) {

         s->x = 0;
         hscroll(avctx);
     }
 }
 
 /**
  * Execute ANSI escape code

  * @return 0 on success, negative on error

  */
 static int execute_code(AVCodecContext * avctx, int c)
 {
     AnsiContext *s = avctx->priv_data;

     int ret, i;

     int width  = avctx->width;
     int height = avctx->height;

     switch(c) {
     case 'A': //Cursor Up
         s->y = FFMAX(s->y - (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), 0);
         break;
     case 'B': //Cursor Down
         s->y = FFMIN(s->y + (s->nb_args > 0 ? s->args[0]*s->font_height : s->font_height), avctx->height - s->font_height);
         break;
     case 'C': //Cursor Right
         s->x = FFMIN(s->x + (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), avctx->width  - FONT_WIDTH);
         break;
     case 'D': //Cursor Left
         s->x = FFMAX(s->x - (s->nb_args > 0 ? s->args[0]*FONT_WIDTH : FONT_WIDTH), 0);
         break;
     case 'H': //Cursor Position
     case 'f': //Horizontal and Vertical Position
         s->y = s->nb_args > 0 ? av_clip((s->args[0] - 1)*s->font_height, 0, avctx->height - s->font_height) : 0;
         s->x = s->nb_args > 1 ? av_clip((s->args[1] - 1)*FONT_WIDTH,     0, avctx->width  - FONT_WIDTH) : 0;
         break;

     case 'h': //set screen mode

     case 'l': //reset screen mode
         if (s->nb_args < 2)
             s->args[0] = DEFAULT_SCREEN_MODE;
         switch(s->args[0]) {
         case 0: case 1: case 4: case 5: case 13: case 19: //320x200 (25 rows)

             s->font = avpriv_cga_font;

             s->font_height = 8;
             width  = 40<<3;
             height = 25<<3;
             break;
         case 2: case 3: //640x400 (25 rows)

             s->font = avpriv_vga16_font;

             s->font_height = 16;
             width  = 80<<3;
             height = 25<<4;
             break;
         case 6: case 14: //640x200 (25 rows)

             s->font = avpriv_cga_font;

             s->font_height = 8;
             width  = 80<<3;
             height = 25<<3;
             break;
         case 7: //set line wrapping
             break;
         case 15: case 16: //640x350 (43 rows)

             s->font = avpriv_cga_font;

             s->font_height = 8;
             width  = 80<<3;
             height = 43<<3;
             break;
         case 17: case 18: //640x480 (60 rows)

             s->font = avpriv_cga_font;

             s->font_height = 8;
             width  = 80<<3;
             height = 60<<4;
             break;
         default:

             avpriv_request_sample(avctx, "Unsupported screen mode");

         }

         s->x = av_clip(s->x, 0, width  - FONT_WIDTH);
         s->y = av_clip(s->y, 0, height - s->font_height);

         if (width != avctx->width || height != avctx->height) {

             av_frame_unref(s->frame);

             ret = ff_set_dimensions(avctx, width, height);
             if (ret < 0)
                 return ret;

             if ((ret = ff_get_buffer(avctx, s->frame,
                                      AV_GET_BUFFER_FLAG_REF)) < 0)

                 return ret;

             s->frame->pict_type           = AV_PICTURE_TYPE_I;
             s->frame->palette_has_changed = 1;

             set_palette((uint32_t *)s->frame->data[1]);

             erase_screen(avctx);
         } else if (c == 'l') {
             erase_screen(avctx);
         }
         break;
     case 'J': //Erase in Page
         switch (s->args[0]) {
         case 0:
             erase_line(avctx, s->x, avctx->width - s->x);
             if (s->y < avctx->height - s->font_height)

                 memset(s->frame->data[0] + (s->y + s->font_height)*s->frame->linesize[0],
                     DEFAULT_BG_COLOR, (avctx->height - s->y - s->font_height)*s->frame->linesize[0]);

             break;
         case 1:
             erase_line(avctx, 0, s->x);
             if (s->y > 0)

                 memset(s->frame->data[0], DEFAULT_BG_COLOR, s->y * s->frame->linesize[0]);

             break;
         case 2:
             erase_screen(avctx);
         }
         break;
     case 'K': //Erase in Line
         switch(s->args[0]) {
         case 0:
             erase_line(avctx, s->x, avctx->width - s->x);
             break;
         case 1:
             erase_line(avctx, 0, s->x);
             break;
         case 2:
             erase_line(avctx, 0, avctx->width);
         }
         break;
     case 'm': //Select Graphics Rendition
         if (s->nb_args == 0) {
             s->nb_args = 1;
             s->args[0] = 0;
         }
         for (i = 0; i < FFMIN(s->nb_args, MAX_NB_ARGS); i++) {
             int m = s->args[i];
             if (m == 0) {
                 s->attributes = 0;
                 s->fg = DEFAULT_FG_COLOR;
                 s->bg = DEFAULT_BG_COLOR;
             } else if (m == 1 || m == 2 || m == 4 || m == 5 || m == 7 || m == 8) {
                 s->attributes |= 1 << (m - 1);

             } else if (m >= 30 && m <= 37) {

                 s->fg = ansi_to_cga[m - 30];

             } else if (m == 38 && i + 2 < FFMIN(s->nb_args, MAX_NB_ARGS) && s->args[i + 1] == 5 && s->args[i + 2] < 256) {

                 int index = s->args[i + 2];
                 s->fg = index < 16 ? ansi_to_cga[index] : index;
                 i += 2;

             } else if (m == 39) {
                 s->fg = ansi_to_cga[DEFAULT_FG_COLOR];
             } else if (m >= 40 && m <= 47) {
                 s->bg = ansi_to_cga[m - 40];

             } else if (m == 48 && i + 2 < FFMIN(s->nb_args, MAX_NB_ARGS) && s->args[i + 1] == 5 && s->args[i + 2] < 256) {

                 int index = s->args[i + 2];
                 s->bg = index < 16 ? ansi_to_cga[index] : index;
                 i += 2;

             } else if (m == 49) {
                 s->fg = ansi_to_cga[DEFAULT_BG_COLOR];
             } else {

                 avpriv_request_sample(avctx, "Unsupported rendition parameter");

             }
         }
         break;
     case 'n': //Device Status Report
     case 'R': //report current line and column
         /* ignore */
         break;
     case 's': //Save Cursor Position
         s->sx = s->x;
         s->sy = s->y;
         break;
     case 'u': //Restore Cursor Position
         s->x = av_clip(s->sx, 0, avctx->width  - FONT_WIDTH);
         s->y = av_clip(s->sy, 0, avctx->height - s->font_height);
         break;
     default:

         avpriv_request_sample(avctx, "Unknown escape code");

         break;
     }

     s->x = av_clip(s->x, 0, avctx->width  - FONT_WIDTH);
     s->y = av_clip(s->y, 0, avctx->height - s->font_height);

     return 0;
 }
 
 static int decode_frame(AVCodecContext *avctx,

                             void *data, int *got_frame,

                             AVPacket *avpkt)
 {
     AnsiContext *s = avctx->priv_data;
     uint8_t *buf = avpkt->data;
     int buf_size = avpkt->size;
     const uint8_t *buf_end   = buf+buf_size;
     int ret, i, count;
 

     if ((ret = ff_reget_buffer(avctx, s->frame)) < 0)

         return ret;

     if (!avctx->frame_number) {

         for (i=0; i<avctx->height; i++)

             memset(s->frame->data[0]+ i*s->frame->linesize[0], 0, avctx->width);

         memset(s->frame->data[1], 0, AVPALETTE_SIZE);

     }
 

     s->frame->pict_type           = AV_PICTURE_TYPE_I;
     s->frame->palette_has_changed = 1;

     set_palette((uint32_t *)s->frame->data[1]);

     if (!s->first_frame) {
         erase_screen(avctx);
         s->first_frame = 1;
     }

 
     while(buf < buf_end) {
         switch(s->state) {
         case STATE_NORMAL:
             switch (buf[0]) {
             case 0x00: //NUL
             case 0x07: //BEL
             case 0x1A: //SUB
                 /* ignore */
                 break;
             case 0x08: //BS
                 s->x = FFMAX(s->x - 1, 0);
                 break;
             case 0x09: //HT
                 i = s->x / FONT_WIDTH;
                 count = ((i + 8) & ~7) - i;
                 for (i = 0; i < count; i++)
                     draw_char(avctx, ' ');
                 break;
             case 0x0A: //LF
                 hscroll(avctx);
             case 0x0D: //CR
                 s->x = 0;
                 break;
             case 0x0C: //FF
                 erase_screen(avctx);
                 break;
             case 0x1B: //ESC
                 s->state = STATE_ESCAPE;
                 break;
             default:
                 draw_char(avctx, buf[0]);
             }
             break;
         case STATE_ESCAPE:
             if (buf[0] == '[') {
                 s->state   = STATE_CODE;
                 s->nb_args = 0;

                 s->args[0] = -1;

             } else {
                 s->state = STATE_NORMAL;
                 draw_char(avctx, 0x1B);
                 continue;
             }
             break;
         case STATE_CODE:
             switch(buf[0]) {
             case '0': case '1': case '2': case '3': case '4':
             case '5': case '6': case '7': case '8': case '9':

                 if (s->nb_args < MAX_NB_ARGS && s->args[s->nb_args] < 6553)

                     s->args[s->nb_args] = FFMAX(s->args[s->nb_args], 0) * 10 + buf[0] - '0';

                 break;
             case ';':
                 s->nb_args++;
                 if (s->nb_args < MAX_NB_ARGS)
                     s->args[s->nb_args] = 0;
                 break;
             case 'M':
                 s->state = STATE_MUSIC_PREAMBLE;
                 break;
             case '=': case '?':
                 /* ignore */
                 break;
             default:
                 if (s->nb_args > MAX_NB_ARGS)
                     av_log(avctx, AV_LOG_WARNING, "args overflow (%i)\n", s->nb_args);

                 if (s->nb_args < MAX_NB_ARGS && s->args[s->nb_args] >= 0)

                     s->nb_args++;

                 if ((ret = execute_code(avctx, buf[0])) < 0)
                     return ret;

                 s->state = STATE_NORMAL;
             }
             break;
         case STATE_MUSIC_PREAMBLE:
             if (buf[0] == 0x0E || buf[0] == 0x1B)
                 s->state = STATE_NORMAL;
             /* ignore music data */
             break;
         }
         buf++;
     }
 

     *got_frame = 1;

     if ((ret = av_frame_ref(data, s->frame)) < 0)
         return ret;

     return buf_size;
 }
 
 static av_cold int decode_close(AVCodecContext *avctx)
 {
     AnsiContext *s = avctx->priv_data;

 
     av_frame_free(&s->frame);

     return 0;
 }
 

 AVCodec ff_ansi_decoder = {

     .name           = "ansi",

     .long_name      = NULL_IF_CONFIG_SMALL("ASCII/ANSI art"),

     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_ANSI,

     .priv_data_size = sizeof(AnsiContext),
     .init           = decode_init,
     .close          = decode_close,
     .decode         = decode_frame,

     .capabilities   = AV_CODEC_CAP_DR1,

 };