/*
 * fastext.c: Routines to handle FASTEXT extensions
 *
 * $Id: fastext.c,v 1.1 1997/07/31 23:28:44 mb Exp mb $
 * 
 * Copyright (c) 1996 Martin Buck  <martin-2.buck@student.uni-ulm.de>
 * Read COPYING for more information
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/vtx.h>
#include "safe_malloc.h"
#include "misc.h"
#include "vtxtools.h"
#include "vtxdecode.h"
#include "fastext.h"


typedef struct fastext_info_s {
  int subpage;
  fastext_buttons_t buttons;
  fastext_links_t links;
  byte_t packet24[40], packet27[4 * 40];
  struct fastext_info_s *next;
} fastext_info_t;


int fastext_ok;

static fastext_info_t *fastext_info[800];



static fastext_info_t *
find_pageentry(int pgnum, int subpage, int fallback) {
  fastext_info_t *curr;
  
  curr = fastext_info[pgnum];
  while (curr) {
    if (curr->subpage == subpage) {
      return curr;
    }
    curr = curr->next;
  }
  if (!fallback) {
    return NULL;
  }
  curr = fastext_info[pgnum];
  if (curr && !curr->subpage) {
    return curr;
  }
  return NULL;
}


int
fastext_cmp_packets(const byte_t *packet24_1, const byte_t *packet27_1, const byte_t *packet24_2,
    const byte_t *packet27_2) {
  int subpkt;
  
  if (memcmp(packet24_1, packet24_2, 40 * sizeof(*packet24_1))) {
    return FALSE;
  }
  for (subpkt = 0; subpkt <= 3; subpkt++) {
    if (memcmp(packet27_1 + subpkt * 40, packet27_2 + subpkt * 40, 37 * sizeof(*packet27_1))) {
      return FALSE;
    }
  }
  return TRUE;
}


int
fastext_newpage(const byte_t *packet24, const byte_t *packet27, const vtx_pageinfo_t *pginf) {
  int pos, subpkt, link_max = -1, pgofs;
  int ofs, link, link_num, link_data[6], page, hour, minute;
  fastext_links_t tmp_links;
  fastext_buttons_t tmp_btns;
  fastext_info_t *info_ent;
  
  if (!vtx_chkpgnum(pginf->pagenum, FALSE))
    return FALSE;
  pgofs = vtx_hex2dec(pginf->pagenum) - 100;
  
  /* Return if same FASTEXT-data is already in cache */
  if ((info_ent = find_pageentry(pgofs, pginf->minute, TRUE)) &&
      fastext_cmp_packets(packet24, packet27, info_ent->packet24, info_ent->packet27)) {
    return FALSE;
  }

  /* Decode packets 24 & 27 */
  for (subpkt = 0; subpkt <= 3; subpkt++) {
    if (packet27[subpkt * 40] == subpkt) {
#ifdef DEBUG_FASTEXT
      if (!subpkt) {
        fprintf(stderr, "fastext_newpage: %X.%X\n", pginf->pagenum, pginf->minute);
      }
      fprintf(stderr, "fastext_newpage: 27/%d: ", subpkt);
#endif
      for (link = 0; link <= 5; link++) {
        ofs = subpkt * 40 + link * 6 + 1;
        for (pos = 0; pos <= 5; pos++) {
          if ((link_data[pos] = vtx_chkhamming(packet27[ofs++])) < 0) {
            break;
          }
        }
        if (pos == 6) {
          link_max = subpkt * 6 + link;
          page = ((link_data[1] << 4) | link_data[0] | (pginf->pagenum & 0x700))
              ^ (((link_data[5] & 0xc) << 7) | ((link_data[3] & 8) << 5));
          if (page < 0x100) {
            page += 0x800;
          }
          hour = ((link_data[5] & 3) << 4) | link_data[4];
          minute = ((link_data[3] & 7) << 4) | link_data[2];
#ifdef DEBUG_FASTEXT
          fprintf(stderr, "%d:%X,%X,%X ", link, page, hour, minute);
#endif
        } else {
          page = hour = minute = 0;
#ifdef DEBUG_FASTEXT
          fprintf(stderr, "%d:hamming err. ", link);
#endif
        }
        link_num = subpkt * 6 + link;
        tmp_links.link[link_num].page = page;
        tmp_links.link[link_num].hour = hour;
        tmp_links.link[link_num].minute = minute;
      }
#ifdef DEBUG_FASTEXT
      fprintf(stderr, "\n");
#endif
    }
  }
  
  if (link_max >= 0) {
    int button, is_btn = FALSE, btnpos = 0;
    byte_t chr;
    
    for (button = 0; button < NELEM(tmp_btns.button); button++) {
      tmp_btns.button[button] = -1;
    }
    button = 0;
    for (pos = 0; pos <= 39; pos++) {
      chr = packet24[pos];
      if (!is_btn) {
        if ((chr & 0x7f) > ' ' || (!vtx_chkparity(&chr) && (chr & 0x7f) >= ' ')) {
          if (button >= NELEM(tmp_btns.button)) {
            button = 0;
            break;
          }
          tmp_btns.button[button++] = btnpos;
          is_btn = TRUE;
        }
      }
      if (is_btn) {
        if (!vtx_chkparity(&chr) && (chr & 0x7f) >= ' ') {
          chr = '?';
        }
        if ((chr & 0x7f) >= ' ') {
          chr = vtx2iso_table[cct2vtx_table[pginf->charset][chr - 32]];
          tmp_btns.btnbuf[btnpos++] = chr;
        } else {
          tmp_btns.btnbuf[btnpos--] = '\0';
          while (btnpos && tmp_btns.btnbuf[btnpos] == ' ') {
            tmp_btns.btnbuf[btnpos--] = '\0';
          }
          btnpos += 2;
          is_btn = FALSE;
        }
      }
    }
    if (button) {
      tmp_btns.btnbuf[btnpos--] = '\0';
      while (btnpos && tmp_btns.btnbuf[btnpos] == ' ') {
        tmp_btns.btnbuf[btnpos--] = '\0';
      }
#ifdef DEBUG_FASTEXT
      fprintf(stderr, "fastext_newpage: buttons: ");
      for (button = 0; button <= 3; button++) {
        fprintf(stderr, "<%s>  ", tmp_btns.btnbuf + tmp_btns.button[button]);
      }
      fprintf(stderr, "\n");
    } else {
      fprintf(stderr, "fastext_newpage: no buttons\n");
#endif
    }
    tmp_btns.num_buttons = button;
  }
  
  /* If valid FASTEXT-data was found, add it to cache. Overwrite current entry for given
   * subpage if it already exists. Otherwise create new one, possibly with subpage-number
   * 0 if that entry doesn't already exist. Entries with subpage-number 0 are valid for all
   * subpages without an individual entry. Entries with subpage number != 0 will be created
   * only, if an entry for 0 already exists and if the new entry is different from the current
   * entry for subpage 0.
   */
  if (link_max >= 0) {
    fastext_ok = TRUE;
    if (!(info_ent = find_pageentry(pgofs, pginf->minute, FALSE))) {
      fastext_info_t **curr;
      int newsubpg;
      
      newsubpg = find_pageentry(pgofs, 0, FALSE) ? pginf->minute : 0;
      curr = &fastext_info[pgofs];
      while (*curr) {
        curr = &(*curr)->next;
      }
      info_ent = *curr = smalloc(sizeof(fastext_info_t));
      info_ent->next = NULL;
      info_ent->subpage = newsubpg;
    }
    
    memcpy(info_ent->packet24, packet24, 40 * sizeof(*packet24));
    memcpy(info_ent->packet27, packet27, 4 * 40 * sizeof(*packet27));
    info_ent->links = tmp_links;
    info_ent->buttons = tmp_btns;
    return TRUE;
  } else {
    return FALSE;
  }
}


int
fastext_get_pginfo(int page, int subpage, const fastext_buttons_t **buttons,
    const fastext_links_t **links, const byte_t **packet24, const byte_t **packet27) {
  int pgofs;
  fastext_info_t *info_ent;
  
  if (!vtx_chkpgnum(page, FALSE))
    return FALSE;
  pgofs = vtx_hex2dec(page) - 100;
  if ((info_ent = find_pageentry(pgofs, subpage, TRUE))) {
    if (buttons)
      *buttons = &info_ent->buttons;
    if (links)
      *links = &info_ent->links;
    if (packet24)
      *packet24 = info_ent->packet24;
    if (packet27)
      *packet27 = info_ent->packet27;
    return TRUE;
  } else {
    return FALSE;
  }
}


void
fastext_reset(void) {
  int pgnum;
  fastext_info_t *curr, *next;

  for (pgnum = 0; pgnum < NELEM(fastext_info); pgnum++) {
    curr = fastext_info[pgnum];
    while (curr) {
      next = curr->next;
      free(curr);
      curr = next;
    }
    fastext_info[pgnum] = NULL;
  }
  fastext_ok = FALSE;
}