#include <sys/ioctl.h>
#include <stdio.h>
#include <stdint.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <time.h>
#include <sys/poll.h>
#include <time.h>
#include <netinet/in.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

#include "linux/dvb/dmx.h"
#include "siinfo.h"

#define DESCR_TELETEXT 0x56
#define DESCR_DVBSUBTITLES 0x59


#define PACK  __attribute__ ((__packed__))


// ETSI 300468 6.2.40
struct ttxt_descr {
  uint8_t tag   PACK;
  uint8_t length   PACK;
  struct {
    uint8_t lang[3]   PACK;
    uint8_t type_mag   PACK; // 5 bits type, 3 bits mag
    uint8_t page_no   PACK;
  } d[1]   PACK;
};

struct sect_header {
  uint8_t table_id   PACK;
  uint16_t syntax_len   PACK;
  uint16_t transport_stream_id   PACK;
  uint8_t ver_cur   PACK;
  uint8_t section_number   PACK;
  uint8_t last_section_number   PACK;
};

// H.222.0 2.4.4.3, Table 2-25
struct PAT_sect {
  uint8_t table_id   PACK;
  uint16_t syntax_len   PACK;
  uint16_t transport_stream_id   PACK;
  uint8_t vers_curr   PACK;
  uint8_t sect_no   PACK;
  uint8_t last_sect   PACK;
  struct {
    uint16_t program_number   PACK;
    uint16_t res_PMTPID   PACK;
  } d[1] PACK;
};

// H.222.0 2.4.4.8, Table 2-28
struct PMT_stream {
  uint8_t stream_type   PACK;
  uint16_t res_PID   PACK;
  uint16_t res_ES_info_len   PACK;
  uint8_t descrs[2]   PACK;
};

struct PMT_sect {
  uint8_t table_id   PACK;
  uint16_t syntax_len   PACK;
  uint16_t program_number   PACK;
  uint8_t vers_curr   PACK;
  uint8_t sect_no   PACK;
  uint8_t last_sect   PACK;
  uint16_t res_pcr   PACK;
  uint16_t res_program_info_length   PACK;
  struct PMT_stream s   PACK;
};


void dump_hex(char *msg, uint8_t *p, int len)
{
  int i;
  printf("%s:", msg);
  for(i = 0; i < len; i++) {
    printf(" %02x", p[i]);
  }
  printf("\n");

  printf("%s:", msg);
  for(i = 0; i < len; i++) {
    printf(" %c", isprint(p[i]) ? p[i] : '.');
  }
  printf("\n");
}


static int SetSectFilt(int fd, uint16_t pid, uint8_t tnr, uint8_t mask)
{
  int ret;

  struct dmx_sct_filter_params p;
  
  memset(&p, 0, sizeof(p));
  
  p.filter.filter[0] = tnr;
  p.filter.mask[0] = mask;
  p.pid     = pid;
  p.flags = DMX_IMMEDIATE_START | DMX_CHECK_CRC;
  
  if ((ret = ioctl(fd, DMX_SET_FILTER, &p)) < 0)  
    perror("DMX SET FILTER:");

  return ret;
}


static int
read_timeout(int fd, void *buf, size_t count, int timeout_ms) {
  int ret = -1;
  struct pollfd pi;

  pi.fd = fd;
  pi.events = POLLIN | POLLERR | POLLHUP | POLLNVAL;

  ret = poll(&pi, 1, timeout_ms);
  if(ret < 0)
    return errno;
  if(ret == 0) { // timeout
    fprintf(stderr, "ttxtsubs: read: timeout!\n");
    return -1;
  }

  if(pi.revents == POLLIN) {
    ret = read(fd, buf, count);
    return ret;
  } else
    return -1;
}

/*
 * PID - pid to collect on
 * table_id - table id to filter out (H.222.0 table 2-26)
 * sects - pointer to char *[256], points to array of table sections, initially empty
 * numsects - number of sections in table
 * returns - 0 if everything ok
 */
#define SECTSIZE 1024
static int CollectSections(int card_no, int pid, int table_id, char **sects, int *numsects)
{
  int fd;
  int ret = -1;
  int last_section = 0;
  int done = 0;
  char *p = NULL;
  int n;
  char name[100];
  time_t start_time;

  snprintf(name, sizeof(name), "/dev/dvb/adapter%d/demux0", card_no);

  memset(sects, 0, sizeof(char*) * 256);
  
  if((fd = open(name, O_RDWR)) < 0){
    perror("DEMUX DEVICE 1: ");
    return -1;
  }
  
  if(SetSectFilt(fd, pid, table_id, 0xff)) {
    ret = -1;
    goto bail;
  }

  start_time = time(NULL);

  do {
    struct sect_header *h;
    int i;

    if((start_time + 5) < time(NULL)) {
      ret = -1;
      done = 1;
      break;
    }

    if(p == NULL)
      p = (char *) malloc(SECTSIZE);

    n = read_timeout(fd, p, SECTSIZE, 250);
    if(n < 8)
      continue;

    h = (struct sect_header *) p;

    if(n != ((ntohs(h->syntax_len) & 0xfff) + 3)) {
      fprintf(stderr, "bad section length: %x / %x!\n", n, ntohs(h->syntax_len) & 0xfff);
      continue;
    }

    if(!(h->ver_cur & 0x01)) // if not current
      continue;

    last_section = h->last_section_number;

    if(!sects[h->section_number]) { // section_number
      sects[h->section_number] = p;
      p = NULL;
    }

    for(i = 0; i <= last_section; i++) {
      if(!sects[i]) {
	break;
      }

      if(i == last_section) {
	*numsects = last_section + 1;
	ret = 0;
	done = 1;
      }
    }

  } while (!done);

 bail:
  close(fd);
  return ret;
}

static void FreeSects(char **sects)
{
  int i;

  for(i = 0; i < 256; i++) {
    if(sects[i])
      free(sects[i]);
  }
}


static void addpageinfo(struct ttxtinfo *info, uint16_t pid, struct ttxt_descr *descr, int descr_index)
{
  struct ttxtpidinfo *pd;
  struct ttxtpageinfo *pa;

  if(!info->p) {
    info->p = (struct ttxtpidinfo *) malloc(sizeof(*(info->p)));
    memset((char *) info->p, 0, sizeof(*(info->p)));
    info->p[0].pid = pid;
    info->pidcount++;
  }

  if(pid != info->p[info->pidcount - 1].pid) {
    info->pidcount++;
    info->p = (struct ttxtpidinfo *) realloc(info->p, sizeof(info->p[0]) * info->pidcount);
    memset((char *) &(info->p[info->pidcount - 1]), 0, sizeof(info->p[0]));
    info->p[info->pidcount - 1].pid = pid;
  }

  pd = &(info->p[info->pidcount - 1]);

  pd->pagecount++;
  if(!pd->i) {
    pd->i = (struct ttxtpageinfo *) malloc(sizeof(pd->i[0]));
  } else {
    pd->i = (struct ttxtpageinfo *) realloc(pd->i, sizeof(pd->i[0]) * pd->pagecount);
  }
  memset((char *) &(pd->i[pd->pagecount - 1]), 0, sizeof(pd->i[0]));

  pa = &(pd->i[pd->pagecount - 1]);

  pa->lang[0] = descr->d[descr_index].lang[0];
  pa->lang[1] = descr->d[descr_index].lang[1];
  pa->lang[2] = descr->d[descr_index].lang[2];
  pa->type = descr->d[descr_index].type_mag >> 3;
  pa->mag = descr->d[descr_index].type_mag & 0x7;
  pa->page = descr->d[descr_index].page_no;
}


static int HasVPID(int vpid, char **pmtsects, int numsects)
{
  int found = 0;
  int i;

  for(i = 0; i < numsects && !found; i++) {
    struct PMT_sect *psect;
    char *sp;
    char *end;

    psect = (struct PMT_sect *) pmtsects[i];
    end = pmtsects[i] + (psect->syntax_len & 0x3ff) - 7;
    // skip extra program info
    sp = ((char *) &(psect->s)) + (ntohs(psect->res_program_info_length) & 0xfff);
    
    while(sp < end && !found) {
      struct PMT_stream *s = (struct PMT_stream *) sp;

      if(s->stream_type == 1 || s->stream_type == 2) { // Video stream
	if((ntohs(s->res_PID) & 0x1fff) == vpid) {
	  //printf("Found ttxt by vpid: %d/%d\n", s->stream_type, (ntohs(s->res_PID) & 0x1fff));
	  found = 1;
	  break;
	}
      }
      sp += (ntohs(s->res_ES_info_len) & 0xfff) + 5;
    }
  }  
  
  return found;
}

static void ExtractTtxtInfo(char **pmtsects, int numsects, struct ttxtinfo *info, int *foundinfo)
{
  int i;

  for(i = 0; i < numsects; i++) {
    struct PMT_sect *psect;
    char *sp;
    char *end;

    psect = (struct PMT_sect *) pmtsects[i];
    end = pmtsects[i] + (psect->syntax_len & 0x3ff) - 7;
    // skip extra program info
    sp = ((char *) &(psect->s)) + (ntohs(psect->res_program_info_length) & 0xfff);
    
    while(sp < end) {
      struct PMT_stream *s = (struct PMT_stream *) sp;

      if(s->stream_type == 6) { // PES private data
	uint8_t *descr;

	for(descr = s->descrs; descr < s->descrs + (ntohs(s->res_ES_info_len) & 0xfff); descr += descr[1] + 2) {
	  if(descr[0] == DESCR_TELETEXT) {
	    struct ttxt_descr *t = (struct ttxt_descr *) descr;
	    int i, count = t->length / sizeof(t->d[0]);
	    for(i = 0; i < count; i++) {
	      addpageinfo(info, ntohs(s->res_PID) & 0x1fff, t, i);
	      //printf("%c%c%c: type %d, page: %01x%02x\n", t->d[i].lang[0], t->d[i].lang[1], t->d[i].lang[2], t->d[i].type_mag >> 3, t->d[i].type_mag & 0x7,  t->d[i].page_no);
	      *foundinfo = 1;
	    }
	  }
	}
      }
      sp += (ntohs(s->res_ES_info_len) & 0xfff) + 5;
    }
  }  
}

/*
 * if vpid != 0, we first search if we can find the vpid in this PMT,
 * and if so we go get the ttxt pid
 * return <> 0 on error
 */
static int FindTtxtInfoInPMT(int card_no, int pid, int vpid, struct ttxtinfo *info, int *foundinfo)
{
  int ret = -1;
  char *pmtsects[256];
  int numsects;

  ret = CollectSections(card_no, pid, 0x02, pmtsects, &numsects);
  if(ret)
    goto bail;

  if(vpid != 0) {
    if(!HasVPID(vpid, pmtsects, numsects)) {
      goto bail;
    }
  }

  ExtractTtxtInfo(pmtsects, numsects, info, foundinfo);

 bail:
  FreeSects(pmtsects);
  return ret;
}


/*
 * find the ttxt_info in the PMT via the PAT, try first with the SID
 * and if that fails with the VPID
 * return <> 0 on error;
 */
int GetTtxtInfo(int card_no, uint16_t sid, uint16_t vpid, struct ttxtinfo *info)
{
  int ret;
  char *patsects[256];
  int numsects;
  int i;
  int j;
  uint16_t pmt_pid = 0;
  int foundinfo = 0;

  memset((char *) info, 0, sizeof(*info));

  ret = CollectSections(card_no, 0, 0, patsects, &numsects);
  if(ret)
    goto bail;

  if(sid != 0) {
    int found;

    for(i = 0, found = 0; i < numsects && !found; i++) {
      int numdescrs;
      struct PAT_sect *s = (struct PAT_sect *) patsects[i];
      
      numdescrs = ((ntohs(s->syntax_len) & 0x3FF) - 7) / 4;
      
      for(j = 0; j < numdescrs && !found; j++) {
	uint16_t pno = ntohs(s->d[j].program_number);

	if(pno == 0)
	  continue; // network pid
	
	if(pno == sid) {
	  pmt_pid = ntohs(s->d[j].res_PMTPID) & 0x1fff;
	  found = 1;
	}
      }
    }
  }

  if(pmt_pid != 0) {
    ret = FindTtxtInfoInPMT(card_no, pmt_pid, 0, info, &foundinfo);
  } else {
    // SID not found, try searching VID in all SIDS
    if(vpid != 0) {
      int done;
      for(i = 0, done = 0; i < numsects && !done; i++) {
	int numdescrs;
	struct PAT_sect *s = (struct PAT_sect *) patsects[i];
      
	numdescrs = ((ntohs(s->syntax_len) & 0x3FF) - 7) / 4;
	
	for(j = 0; j < numdescrs && !done; j++) {
	  uint16_t pno = ntohs(s->d[j].program_number);
	  
	  if(pno == 0)
	    continue; // network pid
	  
	  pmt_pid = ntohs(s->d[j].res_PMTPID) & 0x1fff;

	  ret = FindTtxtInfoInPMT(card_no, pmt_pid, vpid, info, &foundinfo);
	  if(ret) {
	    done = 1;
	  }
	  if(foundinfo)
	    done = 1;
	}
      }
    }
  }
    
bail:
  FreeSects(patsects);
  return ret;
}


void FreeTtxtInfoData(struct ttxtinfo *info)
{
  int i;

  for(i = 0; i < info->pidcount; i++) {
    free((void *) info->p[i].i);
  }

  free((void *) info->p);
}


struct ttxtpidinfo *FindSubs(struct ttxtinfo *info, char *lang, int HI, int *pid, int *pageno)
{
  struct ttxtpidinfo *foundNonHIInfo = NULL;
  int foundNonHIPid = 0;
  int foundNonHIPage = -1;

  for(int i = 0; i < info->pidcount; i++) {
    for(int j = 0; j < info->p[i].pagecount; j++) {
      if(info->p[i].i[j].lang[0] == lang[0] &&
	 info->p[i].i[j].lang[1] == lang[1] &&
	 info->p[i].i[j].lang[2] == lang[2]) {
	if((!HI && info->p[i].i[j].type == TTXT_SUBTITLE_PAGE) ||
	   (HI && info->p[i].i[j].type == TTXT_SUBTITLE_HEARING_IMPAIRED_PAGE)) {
	  *pid = info->p[i].pid;
	  *pageno = info->p[i].i[j].mag * 0x100 + info->p[i].i[j].page;
	  fprintf(stderr, "ttxtsubs: Found selected subtitles on PID %d, page %03x\n", *pid,
		  *pageno < 0x100 ? *pageno + 0x800 : *pageno);
	  return &(info->p[i]);
	} else if(HI && info->p[i].i[j].type == TTXT_SUBTITLE_PAGE) {
	  foundNonHIPid = info->p[i].pid;
	  foundNonHIPage = info->p[i].i[j].mag * 0x100 + info->p[i].i[j].page;
	  foundNonHIInfo = &(info->p[i]);
	}
      }
    }
  }

  if(foundNonHIInfo) {
    *pid = foundNonHIPid;
    *pageno = foundNonHIPage;
    fprintf(stderr, "ttxtsubs: Found non HI subtitles on PID %d, page %03x\n", *pid,
	    *pageno < 0x100 ? *pageno + 0x800 : *pageno);
    return foundNonHIInfo;
  }

  if(info->pidcount == 0)
    fprintf(stderr, "ttxtsubs: No teletext subtitles on channel.\n");
  else {
    fprintf(stderr, "ttxtsubs: Subtitles for language \"%c%c%c\" not found on channel, available languages:\n", lang[0], lang[1], lang[2]);
    for(int i = 0; i < info->pidcount; i++) {
      for(int j = 0; j < info->p[i].pagecount; j++) {
	int page = info->p[i].i[j].mag * 0x100 + info->p[i].i[j].page;
	int type = info->p[i].i[j].type;
	if(page < 0x100)
	  page += 0x800;
	fprintf(stderr, "          %03x: %c%c%c %s\n", page, info->p[i].i[j].lang[0], info->p[i].i[j].lang[1], info->p[i].i[j].lang[2],
		type == TTXT_INITIAL_PAGE ? "(Initial Page)" :
		type == TTXT_SUBTITLE_PAGE ? "(Subtitles)" :
		type == TTXT_ADDITIONAL_INFO_PAGE ? "(Additional Info Page)" :
		type == TTXT_PROGRAMME_SCHEDULE_PAGE ? "(Programme Schedule Page)" :
		type == TTXT_SUBTITLE_HEARING_IMPAIRED_PAGE ? "(Hearing Impaired)" : "(Unknown type)");
      }
    }
  }

  *pid = 0;
  *pageno = -1;
  return NULL;
}


#if 0
int XX_GetTtxtSubtitleInfo(uint16_t pid, int card_no, struct ttxtinfo *info)
{
  int len;
  char buf[4096];
  struct PMT_sect *p = (struct PMT_sect *) buf;
  char *sp;

  memset((char *) info, 0, sizeof(*info));

  len = GetSection(pid, 2, 0xFF, card_no, buf, sizeof(buf));

  //dump_hex("Sect: ", (uint8_t *) buf, len);

  if(len < 0)
    return len;

  if(len != ((ntohs(p->syntax_len) & 0xfff) + 3)) {
    fprintf(stderr, "bad lengt: %x / %x!\n", len, ntohs(p->syntax_len));
    return -1;
  }

  // also skip extra program info
  sp = ((char *) &(p->s)) + (ntohs(p->res_program_info_length) & 0xfff);
  
  while(sp < buf + len - 4) {
    struct PMT_stream *s = (struct PMT_stream *) sp;

    //printf("type: %d, pid: %d, len: %d\n", s->stream_type, ntohs(s->res_PID) & 0x1fff, ntohs(s->res_ES_info_len) & 0xfff);
    //dump_hex("descr: ", sp, ntohs(s->res_ES_info_len) & 0xfff);

    if(s->stream_type == 6) { // PES private data
      uint8_t *descr;

      for(descr = s->descrs; descr < s->descrs + (ntohs(s->res_ES_info_len) & 0xfff); descr += descr[1] + 2) {
	//dump_hex("descr: ", descr, descr[1] + 2);
	if(descr[0] == DESCR_TELETEXT) {
	  struct ttxt_descr *t = (struct ttxt_descr *) descr;
	  int i, count = t->length / sizeof(t->d[0]);
	  for(i = 0; i < count; i++) {
	    addpageinfo(info, ntohs(s->res_PID) & 0x1fff, t, i);
	    //printf("%c%c%c: type %d, page: %01x%02x\n", t->d[i].lang[0], t->d[i].lang[1], t->d[i].lang[2], t->d[i].type_mag >> 3,
	    //t->d[i].type_mag & 0x7,  t->d[i].page_no);
	  }
	}
      }
    }

    sp += (ntohs(s->res_ES_info_len) & 0xfff) + 5;
  }

  return 0;
}
#endif

#if 0
//XXX temporary for testing!
int get_subs(char *lang, int sid, int vpid, int cardno, int *pid, int *page) {
  struct ttxtinfo info;
  int i, j;
  int result = -1;

  GetTtxtInfo(cardno, sid, vpid, &info);

  for(i = 0; i < info.pidcount; i++) {
    //printf("PID: %d ", info.p[i].pid);
    for(j = 0; j < info.p[i].pagecount; j++) {
      //printf(" %c%c%c: %01x%02x (%d) ",
      //     info.p[i].i[j].lang[0], info.p[i].i[j].lang[1], info.p[i].i[j].lang[2], 
      //     info.p[i].i[j].mag, info.p[i].i[j].page, info.p[i].i[j].type);
      if(info.p[i].i[j].lang[0] == lang[0] && info.p[i].i[j].lang[1] == lang[1] &&
	 info.p[i].i[j].lang[2] == lang[2] &&
	 (info.p[i].i[j].type == TTXT_SUBTITLE_PAGE || info.p[i].i[j].type == TTXT_SUBTITLE_HEARING_IMPAIRED_PAGE)) {
	*pid = info.p[i].pid;
	*page = info.p[i].i[j].mag * 0x100 + info.p[i].i[j].page;
	result = 0;
      }
    }
  //printf("\n");
  }

  return result;
}
#endif