//    mythsub.c: Extract closed caption data from MythTV NuppleVideo
//    files and save to JacoSub format.
//    Copyright (C) 2004  Aaron L. Frerichs <afrerich@yahoo.com>
//
//    This program is free software; you can redistribute it and/or modify
//    it under the terms of the GNU General Public License as published by
//    the Free Software Foundation; either version 2 of the License, or
//    (at your option) any later version.
//
//    This program 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 General Public License for more details.
//
//    You should have received a copy of the GNU General Public License
//    along with this program; if not, write to the Free Software
//    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//

//    The starting point for this program was mythframes.c, taken from
//    Michael J. Pedersen's <michael.j.pedersen@verizon.net> distribution
//    of mythmkmovie-1.1.3
//
//    This program only works with US Closed Caption data, and as far as I
//    know, only with non-live broadcasts, as I have not tested using
//    the scrolling data that appears in live broadcasts

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

// The following four structs are taken from libs/libmythtv/format.h
typedef struct rtfileheader
{
char finfo[12];
char version[5];
int  width;
int  height;
int  desiredwidth;
int  desiredheight;
char pimode;
double aspect;
double fps;
int videoblocks;
int audioblocks;
int textsblocks;
int keyframedist;
} rtfileheader;

typedef struct rtframeheader
{
char frametype;
char comptype;
char keyframe;
char filters;
int  timecode;
int  packetlength;
} rtframeheader;

typedef struct seektable_entry
{
long long file_offset;
int keyframe_number;
} seektable_entry;

typedef struct ccsubtitle
{
    unsigned char row;
    unsigned char rowcount;
    unsigned char resumedirect;
    unsigned char resumetext;
    unsigned char clr;
    unsigned char len;
} ccsubtitle;

#define MAXTXTBUFFER 256
#define OUTLINES 25

/* Some debugging functions */
int printccsubtitle(ccsubtitle *cc)
{
    printf("row: %d\t rc: %d\t rd: %d\t rt: %d\t clr: %d\t len: %d\t\n",
        cc->row,
        cc->rowcount,
        cc->resumedirect,
        cc->resumetext,
        cc->clr,
        cc->len );
    return 0;
}

int printframeheader(rtframeheader *current)
{
    printf("\nrtframeheader\n");
    printf("\tframetype = %c\n", current->frametype);
    printf("\tcomptype = %c\n", current->comptype);
    printf("\tkeyframe = %d\n", current->keyframe);
    printf("\ttimecode = %d\n", current->timecode);
    printf("\tpacketlength = %d\n", current->packetlength);

    return 0;
}

int printrtfileheader(rtfileheader *info)
{
    printf("rtfileheader\n");
    printf("\tfinfo = %s\n", info->finfo);
    printf("\tversion = %s\n", info->version);
    printf("\twidth = %d\n", info->width);
    printf("\theight = %d\n", info->height);
    printf("\tdesiredwidth = %d\n", info->desiredwidth);
    printf("\tdesiredheight = %d\n", info->desiredheight);
    printf("\tpimode = %c\n", info->pimode);
    printf("\taspect = %f\n", info->aspect);
    printf("\tfps = %f\n", info->fps);
    printf("\tvideoblocks = %d\n", info->videoblocks);
    printf("\taudioblocks = %d\n", info->audioblocks);
    printf("\ttextsblocks = %d\n", info->textsblocks);
    printf("\tkeyframedist = %d\n", info->keyframedist);
}

/* Return true if txt is all spaces, 0 otherwise */
int isallwhitespace( char *txt )
{
    int i=strlen(txt);
    int retval=-1;
    
    while(i--)
        if( txt[i] != ' ' && txt[i] != '\t' && txt[i] != '\n' )
        {
           retval=0;
           break;
        }

    return retval;
}


int main (int argc, char **argv) {
    rtfileheader info;
    rtframeheader current;
    seektable_entry lastent;
    int extras = 0;
    FILE *nuv;
    FILE *out;
    FILE *debug;

    if (argc != 3) {
        printf ("Usage: %s <filename> <outname>\n", argv[0]);
        exit(1);
    }
    nuv = fopen(argv[1], "r");
    if (nuv == (FILE*)NULL) {
        printf ("ERROR! Unable to read file!\n");
        exit(1);
    }
    fread(&info, sizeof(info), 1, nuv);
    if (info.keyframedist < 1) {
        printf("ERROR! Corrupted file! Bad Header!\n");
        exit(1);
    }
    if (strncmp(info.finfo, "MythTVVideo",11) != 0) {
        printf("ERROR! Corrupted file! Wrong Format!\n");
        exit(1);
    }
    if (strncmp(info.version, "0.07",4) != 0) {
        printf("ERROR! Corrupted file! Wrong Version!\n");
        exit(1);
    }

    /* Do not overwrite an existing file. */
    out = fopen(argv[2], "r");
    if (out != (FILE*)NULL)
    {
        printf("ERROR! %s exists! Will not overwrite!\n", argv[2]);
        exit(1);
    }

    out = fopen(argv[2], "w");
    if (out == (FILE*)NULL)
    {
        printf ("ERROR! Unable to open %s for writing.\n", argv[2]);
        exit(1);
    }

    fprintf( out, "#TIMERES 1000\n");

    ccsubtitle cc;
    memset( &cc, 0, sizeof(cc) );

    char txtbuffer[MAXTXTBUFFER];
    memset( txtbuffer, 0, MAXTXTBUFFER );

    char outbuffer[OUTLINES][MAXTXTBUFFER];
    memset( outbuffer, 0, OUTLINES * MAXTXTBUFFER);

    int timestart[OUTLINES];
    int timeend[OUTLINES];
    memset( timestart, 0, OUTLINES * sizeof(int));
    memset( timeend, 0, OUTLINES * sizeof(int));

    int timecodeprev = 0;
    int timecodeoffset = 0;
    int i;

    /*debug = fopen( "test.debug", "w" );*/

    do
    {
        fread(&current, sizeof(rtframeheader), 1, nuv);
        /* checking the timecode to detect cutpoints *
         * Assuming that cutpoints are >= 1 second   */
        /*fprintf( debug, "%c,%d\n", current.frametype, current.timecode );*/
        if ( current.frametype == 'A' || current.frametype == 'V' || current.frametype == 'T' )
        {
            /* Assuming that no timecode will truly be over 12 hours */
            if ( current.timecode > (12*60*60*1000) )
                current.timecode = 0;

            if ( current.timecode > (timecodeprev + 1000) )
            {
                timecodeoffset = timecodeoffset + (current.timecode - timecodeprev);
                printf( "Cut-detected at time %dms, new offset %dms\n", timecodeprev, timecodeoffset );
            }
            timecodeprev = current.timecode;
        }

        if ( current.frametype == 'T' )
        {
            if ( current.packetlength < MAXTXTBUFFER )
            {
                /* read the next packet */
                fread( &cc, sizeof(ccsubtitle), 1, nuv);
                memset( txtbuffer, 0, MAXTXTBUFFER );
                fread( txtbuffer, current.packetlength - sizeof(ccsubtitle), 1, nuv);

                /*fprintf( debug, "%d\t%d\t%d\t%s\n", current.timecode, cc.row, cc.clr, txtbuffer );*/

                if( cc.clr == 0 && cc.row > 0 )
                {
                    for(i=0;i<OUTLINES;i++)
                    {
                        if ( timestart[i] > 0 && outbuffer[i][0] != 0 && current.packetlength > sizeof(ccsubtitle) )
                        {
                            timeend[i] = current.timecode - timecodeoffset;
                            if( !isallwhitespace(outbuffer[i]) )
                                fprintf( out, "@%d @%d VB%d %s\n", timestart[i], timeend[i], i, outbuffer[i]);
                                
                            timestart[i] = 0;
                            timeend[i] = 0;
                            memset( outbuffer[i], 0, MAXTXTBUFFER);
                        }
                    }
                }

                if( cc.clr == 1 )
                {
                    for(i=0;i<OUTLINES;i++)
                    {
                        timeend[i] = current.timecode - timecodeoffset;

                        if( timestart[i] > 0 && outbuffer[i][0] != 0 )
                        {
                            if( !isallwhitespace(outbuffer[i]) )
                              fprintf( out, "@%d @%d VB%d %s\n", timestart[i], timeend[i], i, outbuffer[i]);

                            timestart[i] = 0;
                            timeend[i] = 0;
                            memset( outbuffer[i], 0, MAXTXTBUFFER);
                        }
                    }
                }

                if( current.packetlength > sizeof(ccsubtitle) )
                {
                    /* search for newline in the txtbuffer */
                    char *pch;
                    pch = strtok( txtbuffer, "\n" );
                    i = cc.row;
                    while( pch != NULL )
                    {
                        strcpy(outbuffer[i], pch);
                        timestart[i] = current.timecode - timecodeoffset;

                        i++;
                        pch = strtok(NULL,"\n");
                    }
                }
            }
            else
            {
                printf( "Packet size error: %d > %d\n", current.packetlength, MAXTXTBUFFER );
                /* Just skip this packet and try to continue */
                fseek(nuv, current.packetlength, SEEK_CUR);
            }
        }
        if ( (current.frametype != 'R') && (current.frametype != 'T') )
            fseek(nuv, current.packetlength, SEEK_CUR);
    }
    while ( (current.frametype != 'Q') && (!feof(nuv)) );

    /* catch any uncleared lines so that they output to the screen */
    for(i=0;i<OUTLINES;i++)
    {
        timeend[i] = timecodeprev - timecodeoffset;

        if( timestart[i] > 0 && outbuffer[i][0] != 0 )
        {
            if ( !isallwhitespace( outbuffer[i] ) )
              fprintf( out, "@%d @%d VB%d %s\n", timestart[i], timeend[i], i, outbuffer[i]);
              
            timestart[i] = 0;
            timeend[i] = 0;
            memset( outbuffer[i], 0, MAXTXTBUFFER);
        }
    }

    /*fclose(debug);*/
    fclose(out);

    return(0);
}