// connect.js  4 june 1999
//
// THIS IS NOT AN OFFICIAL RELEASE BUT A CURRENT WORKING VERSION !!
//
// This library provides javascript tools for 
// hypertext literary writing in html.
// 
// In particular, it defines javascript functions for
// history-based conditional links and conditional writing in HTML.
//
// Important: this version is a prototype, functionalities may me 
// modified in future versions.
//
// Documentation: http://www.wordcircuits.com/connect
// e-mail: connection@wordcircuits.com
//
// You can freely use and distribute this library provided that 
// this notice remains included. 
// (c) 1999 Jean-Hugues Rety and Robert Kendall.
//

//
// Parameters.
//


// The variable _hist_cookie_name_ below contains the name of the 
// cookie that contains the historical list of visited pages
// of your hypertext.
// If the history is long and requires the use of several cookies,
// these cookies will have the same name but extended with 
// the suffixe: '2', '3',...
// IMPORTANT. This feature is not implemented yet. At the moment, the
// history is limited to one cookie, i.e., to 2000 characters.
// In consequence, this current version of the library can manage up
// to approximately 200-250 pages long histories.

var hist_cookie_name = "Peggy";

// the variable _dead_link_ below specifies how appears 
// links when the target file is "null".
// (only valid when there is no popup or status text to be displayed)!!

 var dead_link_style = null;
//var dead_link_style = "underline";

//color of text written with hWrite 
var hWrite_color = document.fgColor;
//var hWrite_color = document.linkColor;
//var hWrite_color = document.vlinkColor;

// color of dead links:
var dead_link_color = document.fgColor;
//var dead_link_color = document.linkColor;
//var dead_link_color = document.vlinkColor;

// default attributes for pop-up text
var popup_att_default = 'BGCOLOR="#FFFFCC"';
//var popup_att_default = 'BGCOLOR="#FF6666"';
var dead_link_popup = false;

// default attributes for status text
var dead_link_status = false;

// shall titles be poped up?
var title_popup = false;

// shall titles be displayed in the status bar?
var title_status = true;


//
// Initializations
//

var h_hist = histValue ();

var h_hist_empty = (h_hist == "");

addHist();

var h_no_link = true;

var h_popnb = 1;

var popupText = null;

var statusText = null;

var popupAtt = "";

if (typeof(titleArray) == "undefined")
    titleArray = new Array ();

if (typeof(popupAttArray) == "undefined")
    popupAttArray = new Array ();


// Basic cookie manipulation functions.

function h_cookieVal (name) 
// Returns the value of the cookie _name_.
   {

function h_cookieVal2 (offset) 
   {

   var end = document.cookie.indexOf (";", offset);

   if (end == -1)

      end = document.cookie.length;

   return unescape(document.cookie.substring(offset, end));

   }

   var prefix = name + "=";

   var prefix_len = prefix.length;

   var cookie_len = document.cookie.length;

   var i = 0;

   while (i < cookie_len ) 
      {

      var j = i + prefix_len;

      if (document.cookie.substring(i, j) == prefix)

         return h_cookieVal2 (j);

      i = document.cookie.indexOf(" ", i) + 1;

      if (i == 0) break; 

      }

   return "";

   }


function h_setCookie (name, value) 
// Sets the cookie _name_ with value _value_.
   {

   var arg = h_setCookie.arguments;

   var arg_len = h_setCookie.arguments.length;

   var expires = (arg_len > 2) ? arg[2] : null;

   var path = (arg_len > 3) ? arg[3] : null;

   var domain = (arg_len > 4) ? arg[4] : null;

   var secure = (arg_len > 5) ? arg[5] : false;

   document.cookie = name + "=" + escape (value) +

        ((expires == null) ? "" : ("; expires=" + expires.toGMTString())) +

        ((path == null) ? "" : ("; path=" + path)) +

        ((domain == null) ? "" : ("; domain=" + domain)) +

        ((secure == true) ? "; secure" : "");

   }


function h_deleteCookie (name) 
// Deletes the cookie _name_.
   {

   var expires = new Date ();

   expires.setTime (expires.getTime() - 1000000000);  

   var val = h_cookieVal (name);

   document.cookie = name + "=" + val + "; expires=" + expires.toGMTString();

   }


// Other basic functions


function h_thisFile ()
// Returns the file name of the current window location
   {

   var url = window.location.href;

   var i = url.lastIndexOf ('/');

   return (url.substring (i +1, url.length));

   }

function h_show(object) 
// Sets the visibility attribute to visible
   { 

   if (document.layers && document.layers[object]) 

      document.layers[object].visibility = 'visible'; 

   else if (document.all) 
      { document.all[object].style.visibility = 'visible'; document.all[object].style.zIndex = 100; } 

   }


function h_hide(object) 
// Sets the visibility attribute to hidden
   { 

   if (document.layers && document.layers[object]) 

      document.layers[object].visibility = 'hidden'; 

   else if (document.all) 
      document.all[object].style.visibility = 'hidden'; 

   }


function h_member (ident, str)
// Returns true if _ident_ belongs to the string _str_.
   {

   if (str.indexOf(ident) != -1) return (true);

   else return(false);

   }


// Functions for identifiers manipulation


function makeIdent (lfile)
// Produces the identifier to be used in the history.
   {

   var i = lfile.lastIndexOf ('/');

   var file = lfile.substring (i +1, lfile.length);

   var dot = file.lastIndexOf ('.');

   if (dot == -1) return (file + '?');

   var suffix = file.substring (dot +1, file.length);

   var prefix = file.substring (0, dot);

   switch (suffix) 
      {

      case "html" : 
         return (prefix);

      case "htm" : 
         return (prefix + '|');

      default : 
         return (file + '?');

      } 

   }

function makeFileName (ident)
// Returns the file name corresponding to _ident_.
   {

   var end = ident.length -1;

   switch (ident.charAt (end) ) 
      {

      case "?" :
         return (ident.substring(0, end));

      case "|" :
         return (ident.substring(0, end) + ".htm");

      default :
         return (ident + ".html");

      }

   }


// Functions for history manipulation


function setHist (value)
// Sets the history to  _value_.
   {
  
   var name = hist_cookie_name;

   var exp_date = new Date (); 

   exp_date.setTime(exp_date.getTime() + (24 * 60 * 60 * 1000 * 365)); 
   // The expiration date of the cookie (here: 1 year after it is set).

   h_setCookie (name, value, exp_date);  

   return false;

   }


function histValue ()
// Returns the value of the history.
   {
  
   var name = hist_cookie_name;

   return h_cookieVal (name);

   }


function histArray ()
// Returns an array containing the history.
   {

   h = new Array ();

   var ind = 0;

   var i = 0;

   var j = h_hist.indexOf ('*', i+1);

   while (j != -1)
      {

      h[ind] = makeFileName ( h_hist.substring( i+1, j));

      ind++;

      i = j;

      j = h_hist.indexOf ('*', i+1);

      }

   return (h);

}

// End user functions for text or file (or whatever)  specification
// These functions can also be used inside conditions.


function firstCond (otherwise, items_and_conds)
// _items_and_conds_ is of the form:
//     item1, cond1, item2, cond2, item3, cond3,...
// items can be file names or text, or whatever
// Returns the first item _itemi_ such that _condi_ holds.
// If no condition is satisfied then returns _otherwise.
   {

   var arg = firstCond.arguments;

   var arg_len = firstCond.arguments.length;

   for (var i=1 ; i<arg_len ; i=i+2)
      if ( arg[i+1] )
         return (arg[i]);

   return (arg[0]);

   }


function random (items)
// Randomly selects an item in _items_. 
   {

   var arg = random.arguments;

   var arg_len = random.arguments.length;

   var select = Math.floor (Math.random () * (arg_len) );

   if (select == arg_len) select = arg_len - 1;

   return (arg[select]);

   }


function randomCond (otherwise, items_and_conds)
// Randomly selects an item _itemi_  such that _condi_ holds.
// If no condition is satisfied then returns _otherwise__.
   {

   var arg = randomCond.arguments;

   var arg_len = randomCond.arguments.length;

   nv = new Array (arg_len - 1);

   var nbnv = 0;

   for (var i = 1 ; i < arg_len ; i=i+2)

      if ( arg[i+1] )
         {

         nv[nbnv] = i;

         nbnv++;

         }

   if (nbnv ==0) return (otherwise);

   else
      {

      var select = Math.ceil (Math.random () * (nbnv) );

      if (select == 0) select = 1;

      return (arg[ nv[select -1] ]);

      }
   
   }


// End user functions for file specification
// These functions can also be used inside conditions.

function hist (rank)
// Returns the page (file name) element of rank _rank_ in the history.
// If _rank_ = 0, Hist(rank) returns the current page 
// (last element of the history.
// If _rank_ is negative, the rank is counted in reverse from the last element 
// in the history.
   {

   if (rank > 0) 
      {

      var end = h_hist.length-1;

      var j = 0;

      var k = h_hist.indexOf ('*', j +1);

      for (var i=rank ; i>1 ; i--)
         {

         if (j >= end) break;

         j = k;

         k = h_hist.indexOf ('*', j +1);

         }

      if (j >= end) return (null);

      var ident = h_hist.substring (j+1, k);

      return (makeFileName (ident) );

      }

   if (rank <= 0) 
      {

      var j = h_hist.length -1;

      var k = h_hist.lastIndexOf ('*', j-1);

      for (var i=rank ; i<0 ; i++)
         {

         if (j <= 0) break;

         j = k;

         k = h_hist.lastIndexOf ('*', j-1);

         }

      if (j <= 0) return (null);

      var ident = h_hist.substring (k+1, j);

      return (makeFileName (ident) );

      }

   }

function histRank(file)
// Returns a javascript array containing the indices where 
// _file_ appears in the history.
   {

   var ident = makeIdent (file);

   indarray = new Array ();

   var i = 0;  var j = 0; var ind = 1;

   var k = h_hist.indexOf ('*', j +1);
   
   while (k != -1)
      {

      if (h_hist.substring (j+1, k) == ident)
         {

          indarray[i] = ind;

          i++;

          }

      j = k;

      k = h_hist.indexOf ('*', j +1);

      ind++;

      }

   return (indarray);

   }


function firstVisited (files)
// Returns the page (file name) in _files_ that was visited first.
// Returns null if none of _files_ were visited.
   {

   var arg = firstVisited.arguments;

   var arg_len = firstVisited.arguments.length;

   var max_val = h_hist.length;

   var max_file = null;

   for (var i=0 ; i<arg_len ; i++)
      {   

      var ident = makeIdent (arg[i]);

      var j = h_hist.indexOf ('*' + ident + '*');

      if (j != -1 && j < max_val)
         {

         max_val = j;

         max_file = arg[i];

         }

      }

   return (max_file);

   }


function lastVisited (files)
// Returns the page (file name) in _files_ that was last visited.
// Returns null if none of _files_ were visited.
   {

   var arg = lastVisited.arguments;

   var arg_len = lastVisited.arguments.length;

   var max_val = -1;

   var max_file = null;

   for (var i=0 ; i<arg_len ; i++)   
      {

      var ident = makeIdent(arg[i]);

      var j = h_hist.lastIndexOf('*' + ident + '*')

      if (j > max_val)
         {

         max_val = j;

         max_file = arg[i];

         }

      }

   return (max_file);

   }


function firstNotVisited (otherwise_target, targets)
// Returns the first page not visited in the arguments _targets_. 
// If all pages in _targets_ are visited then returns  _otherwise_target_.
   {

   var arg = firstNotVisited.arguments;

   var arg_len = firstNotVisited.arguments.length;

   for (var i=1 ; i<arg_len ; i++)
      if ( ! (visited (arg[i]) ) )
          return (arg[i]);

   return (arg[0]);

   }
   

function randomNotVisited (otherwise_file, files)
// Randomly selects a non visited page in _files_.
// If all pages in _targets_ are visited then returns  _otherwise_target_.
   {

   var arg = randomNotVisited.arguments;

   var arg_len = randomNotVisited.arguments.length;

   nv = new Array (arg_len - 1);

   var nbnv = 0;

   for (var i = 1 ; i < arg_len ; i++)

      if (! visited(arg[i]))
         {

         nv[nbnv] = i;

         nbnv++;

         }

   if (nbnv == 0) return (otherwise_file);

   else
      {

      var select = Math.ceil (Math.random () * (nbnv) );

      if (select == 0) select = 1;

      return (arg[ nv[select -1] ]);

      }
   
   }

function randomNotVisitedNotLinked (otherwise_file, files)
// Randomly selects a non visited and non linked  page in _files_.
// If all pages in _targets_ are visited then returns  _otherwise_target_.
   {

   var arg = randomNotVisitedNotLinked.arguments;

   var arg_len = randomNotVisitedNotLinked.arguments.length;

   nv = new Array (arg_len - 1);

   var nbnv = 0;

   for (var i = 1 ; i < arg_len ; i++)
      if (! visited(arg[i]) && ! linked(arg[i]))
         {

         nv[nbnv] = i;

         nbnv++;

         }

   if (nbnv == 0) return (otherwise_file);

   else
      {

      var select = Math.ceil (Math.random () * (nbnv) );

      if (select == 0) select = 1;

      return (arg[ nv[select -1] ]);

      }
   
   }


// Other end user functions for building conditions

function visited (files)
// Returns true if all pages in _files_ belong to the history.
   {

   var arg = visited.arguments;

   var arg_len = visited.arguments.length;

   for (var i=0 ; i<arg_len ; i++)
      {

      var ident = makeIdent (arg[i]);

      if ( ! h_member('*' + ident + '*', h_hist) ) 

          return (false);

      }

   return (true);

   }


function orVisited (files)
// Returns true if at least one of the pages in _files_ belong to the history.
   {

   var arg = orVisited.arguments;

   var arg_len = orVisited.arguments.length;

   for (var i=0 ; i<arg_len ; i++)
      {

      var ident = makeIdent (arg[i]);

      if ( h_member('*' + ident + '*', h_hist) ) 

          return (true);

      }

   return (false);

   }

function visitedFrom (file)
// Returns true if _file_ was visited immediately after the current page.
// if 2 arguments, tests _file_ was visited from the second file argument.
   {

   var arg = visitedFrom.arguments;

   var arg_len = visitedFrom.arguments.length;

   var offset = "*" + makeIdent (file) + "*";

   if (arg_len == 1)

      offset = "*" + makeIdent ( h_thisFile() ) + offset;

   else

      offset = "*" + makeIdent (arg[1]) + offset;

   return ( h_member(offset, h_hist) );

   }


function linked (files)
// Returns true if all pages in _files_ are linked above in the document.
   {

   var arg = linked.arguments;

   var arg_len = linked.arguments.length;

   var nb_links = document.links.length;

   var l_list = "*";

   for (var i=0 ; i<nb_links ; i++)
      l_list = l_list + makeIdent(document.links[i].toString()) + "*";

   for (var i=0 ; i<arg_len ; i++)
      {

      var ident = makeIdent (arg[i]);

      if ( ! h_member('*' + ident + '*', l_list) ) 

          return (false);

      }

   return (true);

   }


function nbVisits (file)
// Returns how many times _page_ was already visited.
   {

   var nb_visits = 0;

   var ident = makeIdent (file);

   var i = h_hist.indexOf ('*' + ident + '*');

   while (i != -1)
      {

      nb_visits++;

      i = h_hist.indexOf ('*' + ident + '*',i+1);

      }

   return (nb_visits);

   }
        

function nbDiffVisited ()
// Returns the number of different pages already visited.
   {

   var nbpages = 0;

   var i = 0;

   while ( i < h_hist.length)
      {

      var next = h_hist.indexOf ('*', i+1);

      if (next == -1) break;

      var h_ident = h_hist.substring (i, next +1);

      if (h_hist.indexOf(h_ident) == i)

         nbpages++;

      i = next;

      }

   return (nbpages);

   }


function nbVisited ()
// Returns the number of pages already visited, 
// i.e., the length of the history.
   {

   var nbVisited = 0;

   var i = h_hist.indexOf ('*');

      i = h_hist.indexOf ('*', i+1);

   while ( i != -1)
      {

      i = h_hist.indexOf ('*', i+1);

      nbVisited++;

      }

   return (nbVisited);

   }

function nbDiffVisitedIn (files)
// Returns how many pages in _files_ were already visited.
   {

   var nbpages = 0;

   var arg = nbDiffVisitedIn.arguments;

   var arg_len = nbDiffVisitedIn.arguments.length;

   for (var i=0 ; i<arg_len ; i++)
      {
        
      var ident = makeIdent (arg[i]);

      if (h_member('*' + ident + '*', h_hist)) 

         nbpages++;

      }

   return (nbpages);

   }


// End-user functions for history munipulation


function initHist (file)
// Initialises the history with the current window or _file_ identifier.
   {

   if (initHist.arguments.length == 0)
      
      h_hist = '*' + makeIdent( h_thisFile() ) + '*';  
      
   else

      h_hist = '*' + makeIdent(file) + '*';  

   setHist (h_hist);

   }


function addHist (file)
// Adds the current window or _file_ identifier to the history.
   {

   if (h_hist.charAt (h_hist.length -1) != "*") h_hist = h_hist + '*';

   if (addHist.arguments.length == 0)

      h_hist = h_hist + makeIdent( h_thisFile() ) + '*';

   else

      h_hist = h_hist + makeIdent(file) + '*';

   setHist (h_hist);

   }


function deleteHist ()
// Deletes the history.
   {

   var name = hist_cookie_name;

   h_deleteCookie (name);

   h_hist = "";

   }


function histEmpty ()
// Returns true if the history is empty.
   {

   return (h_hist_empty);

   }


// End-user functions for writing and linking


function cond (yes_javascript_code, condd, no_javascript_code)
// Conditional function.
// _yes_javascript_code_ is  executed if cond holds.
// _no_javascript_code_, if specified,  is executed if cond does not hold.
   {

   if (condd)

      document.write("<SCRIPT type='text/javascript'>" +  yes_javascript_code + "</SCRIPT>");

   else

      if ( typeof(no_javascript_code) == "string" )

         document.write("<SCRIPT type='text/javascript'>" + no_javascript_code + "</SCRIPT>");

   }


function hWrite (text)
// Writes _text_ with possibly popup or/and status text if specified
   {

   if (popupText == null && statusText == null)
      document.write(text);

   else 
      {
         var tmp = document.linkColor;
         document.linkColor = hWrite_color;

         document.write ("<A HREF='javascript:void(0)' onMouseOver='"); 

      if (statusText != null)
         document.write("window.status=" + '"' + statusText + '";');

      if (popupText != null)
         document.write ("h_show(" + '"pop' + h_popnb.toString() + '"' + ");");

      document.write(" return true;' onMouseOut='");

      if (statusText != null)
         document.write('window.status="";');

      if (popupText != null)
         document.write("h_hide(" + '"pop' + h_popnb.toString() + '"' + ");");

         document.write(" return true'>" + text + "</A>");

      if (popupText != null)
         document.write("<SPAN ID=" + '"pop' + h_popnb.toString() + '"' + " CLASS='popup'><TABLE " + popupAtt + " " + popup_att_default + "><TR><TD>" + popupText + "</TD></TR></TABLE></SPAN>");     

   document.linkColor = tmp;
   popupText = null;
   statusText = null;
   popupAtt = "";
         }
 }         
      

function condWrite (yes_text, condd, no_text)
// Conditional write.
// _yes_text_ is the text to be written if cond holds.
// _no_text_, if specified, is the text to be written if cond does not hold.
   {

   if (condd)
      document.write (yes_text);
        
   else
      if ( typeof(no_text) == "string" )
         document.write (no_text);

   }

function link (target, text)
// Creates a link to file _target_ with text _text_.
   {

   if (target == null)
   {

      if (popupText == null && title_popup == true)
         if (typeof(titleArray['dead_link']) != "undefined")
             popupText = titleArray['dead_link'];

      if (statusText == null && title_status == true)
         if (typeof(titleArray['dead_link']) != "undefined")
             statusText = titleArray['dead_link'];

      if ( (popupText != null && dead_link_popup == true)
           ||
           (statusText != null && dead_link_status == true) )

         {

         var tmp = document.linkColor;
         document.linkColor = dead_link_color;

         document.write ("<A HREF='javascript:void(0)' onMouseOver='"); 

      if (statusText != null && dead_link_status == true)
         document.write("window.status=" + '"' + statusText + '";');

      if (popupText != null && dead_link_popup == true)
         document.write ("h_show(" + '"pop' + h_popnb.toString() + '"' + ")");

      document.write(" return true' onMouseOut='");

      if (statusText != null && dead_link_status == true)
         document.write('window.status="";');

      if (popupText != null && dead_link_popup == true)
         document.write ("h_hide(" + '"pop' + h_popnb.toString() + '"' + ");");

         document.write(" return true'>" + text + "</A>");

      if (popupText != null && dead_link_popup == true)
         document.write("<SPAN ID=" + '"pop' + h_popnb.toString() + '"' + " CLASS='popup'><TABLE " + popupAtt + " " + popup_att_default + "><TR><TD>" + popupText + "</TD></TR></TABLE></SPAN>");     

         document.linkColor = tmp;
         h_popnb++;
         }

      else

      switch ( dead_link_style )
         {

         case "underline" :
            document.write ('<FONT COLOR=' + '"' + dead_link_color + '">' + '<U>' + text + '</U></FONT>'); break;

         default :
            document.write ('<FONT COLOR=' + '"' + dead_link_color + '">' + text + '</FONT>');

         }

   }
   else
      {


      if (popupText == null && title_popup == true)
         if (typeof(titleArray[target]) != "undefined")
             popupText = titleArray[target];

      if (statusText == null && title_status == true)
         if (typeof(titleArray[target]) != "undefined")
             statusText = titleArray[target];

      document.write ('<A HREF=' + target);

      if (statusText != null || popupText != null)
         document.write(" onMouseOver='");

      if (statusText != null)
         document.write("window.status=" + '"' + statusText + '";');

      if (popupText != null)
        document.write("h_show(" + '"pop' + h_popnb.toString() + '"' + ");");

      if (statusText != null || popupText != null)
         document.write(" return true' onMouseOut='");

      if (statusText != null)
         document.write('window.status="";');

      if (popupText != null)
        document.write ("h_hide(" + '"pop' + h_popnb.toString() + '"' + ");");

      if (statusText != null || popupText != null)
         document.write(" return true'");

      document.write (">" + text + '</A>');
         
      if (popupText != null)
         {

         document.write("<SPAN ID=" + '"pop' + h_popnb.toString() + '"' + " CLASS='popup'><TABLE " + popupAtt + " " + popup_att_default + "><TR><TD>" + popupText + "</TD></TR></TABLE></SPAN>");  

         h_popnb++;

         }

      h_no_link = false;

      }

   popupText = null;
   statusText = null;
   popupAtt = "";

   }    


function condLink(target, text, condd, no_target, no_text)
// Creates a conditional link to target with text _text_ 
// under condition _cond_. If cond does not hold and no_text, no_target 
// are specified, then creates a link to no_target with text no_text.
   {

   if (condd)
      link (target, text);

   else 
      {
      if ( typeof(no_text) != "undefined" )
         text = no_text;

      if ( typeof(no_target) !="undefined" )
         link (no_target, text);
      }

   }    


function otherwiseLink (target, text, no_target, no_text)
// Creates a link to target with text _text_ if no other 
// link was active in the page.
// If some other link was active, uses no_target and no_text, if specified. 
   {

   condLink(target, text, h_no_link, no_target, no_text);

   }