#!/usr/bin/awk -f
#
# chainindex -- adds prev/next/index/top chain to thumbnail index pages
#               (complements thumblinklist)
#
# usage: chainindex galleries.idxs
#        chainindex removeold=1 linkprefix=../ backlink=../festivals.html galleries.idxs
#
# http://www.heikopurnhagen.net/software/chainindex
#
# This program is available under the terms of the GNU General Public
# License (GPL). All usual disclaimers apply!
#
# Heiko Purnhagen   (mail@heikopurnhagen.net)
# HP 20070910 based on thumblinklist
# HP 20070911 tweaked "top" link, added removeold option
# HP 20080811 added "touch" to keep timestamp of index page
# HP 20080817 facilitate enables multiple runs, disabled "top" link

BEGIN {
  numlink = 0;
  backlink = "index.html";
  linkprefix = "";
  removeold = 0;
}

{
  if (NR % 4 == 1) name[numlink] = $0;
  if (NR % 4 == 2) link[numlink] = $0;
  if (NR % 4 == 3) thumb[numlink] = $0;
  if (NR % 4 == 0) {
    if ($0 != "") {
      print "ERROR, delimiter at line "NR" not empty: "$0 > "/dev/stderr";
      numlink = 0;
      exit;
    }
    else {
      numlink++;
    }
  }
}

END {
  print "CHAININDEX number of links: "numlink > "/dev/stderr";
  if (numlink) {
    for (i=0; i<numlink; i++) {
      oldname = link[i] "_old";
      system ("mv " link[i] " " oldname);
      system ("touch " link[i]);
      while ((getline < oldname)>0) {
	if ($0=="<table border=\"0\" cellspacing=\"5\" cellpadding=\"0\"><tr>") {
# remove old navigation arrows (5 lines)
	  getline < oldname;
	  getline < oldname;
	  getline < oldname;
	  getline < oldname;
	}
	else if (1==index($0,"<h1>")) {
# insert navigation arrows before heading
          printf "<table border=\"0\" cellspacing=\"5\" cellpadding=\"0\"><tr>\n" > link[i];
          if (i==0) {
            printf "<td bgcolor=\"#808080\"><img width=\"32\" height=\"16\" border=\"0\" src=\"leftgray32x16a.gif\" alt=\"prev\"></td>\n" > link[i];
          }
          else {
            printf "<td id=\"p\" bgcolor=\"#808080\"><a accesskey=\"b\" onmouseover=\"document.getElementById('p').bgColor='#b0b0b0'\" onmouseout=\"document.getElementById('p').bgColor='#808080'\" href=\"" linkprefix link[i-1] "\"><img width=\"32\" height=\"16\" border=\"0\" src=\"left32x16a.gif\" alt=\"prev\"></a></td>\n" > link[i];
          }
          printf "<td id=\"i\" bgcolor=\"#808080\"><a accesskey=\"i\" onmouseover=\"document.getElementById('i').bgColor='#b0b0b0'\" onmouseout=\"document.getElementById('i').bgColor='#808080'\" href=\"" backlink "\"><img width=\"32\" height=\"16\" border=\"0\" src=\"up32x16a.gif\" alt=\"index\"></a></td>\n" > link[i];
          if (i==numlink-1) {
            printf "<td bgcolor=\"#808080\"><img width=\"32\" height=\"16\" border=\"0\" src=\"rightgray32x16a.gif\" alt=\"next\"></td>\n" > link[i];
          }
          else {
            printf "<td id=\"n\" bgcolor=\"#808080\"><a accesskey=\"n\" onmouseover=\"document.getElementById('n').bgColor='#b0b0b0'\" onmouseout=\"document.getElementById('n').bgColor='#808080'\" href=\"" linkprefix link[i+1] "\"><img width=\"32\" height=\"16\" border=\"0\" src=\"right32x16a.gif\" alt=\"next\"></a></td>\n" > link[i];
          }
          printf "</tr></table>\n" > link[i];
# copy heading
          print $0 >> link[i];
        }
#	else if ($0=="<p>[<a accesskey=\"t\" href=\"#\">top</a>]</p>") {
## remove old link to top (1 line)
#	}
#	else if ($0=="<p><br><i>") {
## insert link to top at end
#	  print "<p>[<a accesskey=\"t\" href=\"#\">top</a>]</p>" >> link[i];
#          print $0 >> link[i];
#        }
	else if (0==index($0,">back<")) {
# do not copy backlink (now obsolete)
          print $0 >> link[i];
        }
      }
      system ("touch -r " oldname " " link[i]);
      if (removeold) {
        system ("rm " oldname);
      }
    }
  }
}

#--