// http://home.earthlink.net/~bhami/rosetta.js
// Copyright (c) 2001-2003 Bruce A. Hamilton <bhami@pobox.com>.
// All rights reserved. Non-commercial use only.
// Includes enhancements by M…rten Svantesson <msv@kth.se>
//
var osBox;
var osHowMany;
var taskHowMany;
var mytable;
var whichOSes;
var indexOSes = new Array();

// ----------------------------------------
// init
// ----------------------------------------
function init() {
  var splitOSes;

  mytable = document.getElementById("Rosetta");
  osBox = document.getElementById("OSSystemBox");
  taskHowMany = mytable.rows.length - 1;
  whichOSes = getCookie("whichOSes");
  if (whichOSes == "") {
      whichOSes = null;
  }
  if (whichOSes) {
      splitOSes = whichOSes.split(",");
      for (var i = 0; i < splitOSes.length; i++) {
        indexOSes[splitOSes[i]] = true;
      }
  }
  initOSBox();
} // init

// ----------------------------------------
// initOSBox
// ----------------------------------------
function initOSBox() {
  osHowMany = mytable.rows[0].cells.length-2;
  for (var i = 0; i < osHowMany; i++) {
    var rowHeader = mytable.rows[0].cells[i+1].childNodes[0].childNodes[0].nodeValue;
    addOption(rowHeader, i);
  }
} // initOSBox

// ----------------------------------------
// addOption
// ----------------------------------------
function addOption(optText, itemNum) {
  osBox.options[itemNum] = new Option(optText, optText, false, false);
// make the OS appear selected, since the page starts with all
// selected (until we implement a cookie scheme)
  if ((!whichOSes) || indexOSes[itemNum]) {
      osBox.options[itemNum].selected = true;
  } else if (whichOSes) {
      for (var i = 0; i < taskHowMany+1; i++) {
         mytable.rows[i].cells[itemNum+1].style.display = "none";
      }
  }
}

// ----------------------------------------
// setOS
// ----------------------------------------
function setOS() {
  for (var i = 0; i < osHowMany; i++) {
    osBox.options[i].selected = true;
  }
} // setOS

// ----------------------------------------
// clearOS
// ----------------------------------------
function clearOS() {
  for (var i = 0; i < osHowMany; i++) {
    osBox.options[i].selected = false;
  }
} // clearOS

// ----------------------------------------
// SCANOS
// ----------------------------------------
function scanTable(remember) {
 var j,i;

 if (osBox.selectedIndex == -1) {
   alert ("Select at least one Operating System.");
   return;
 }

 // loop on each task and set visibility

 whichOSes = "";
 for (j = 0; j < osHowMany; j++) {
     if (osBox.options[j].selected) {
         for (i = 0; i < taskHowMany+1; i++) {
             mytable.rows[i].cells[j+1].style.display = "";
         }
         whichOSes = whichOSes + j + ",";
     } else {
         for (i = 0; i < taskHowMany+1; i++) {
             mytable.rows[i].cells[j+1].style.display = "none";
         }
     }
 }
 whichOSes = whichOSes.substring(0, (whichOSes.length-1));
 forever = new Date("December 31, 2040");
 if (remember == 1) {
     setCookie("whichOSes", whichOSes, forever);
 }
} // scanTable

// blatantly stolen from http://www.webreference.com/js/column8/functions.html

/*
   name - name of the cookie
   value - value of the cookie
   [expires] - expiration date of the cookie
     (defaults to end of current session)
   [path] - path for which the cookie is valid
     (defaults to path of calling document)
   [domain] - domain for which the cookie is valid
     (defaults to domain of calling document)
   [secure] - Boolean value indicating if the cookie transmission requires
     a secure transmission
   * an argument defaults when it is assigned null as a placeholder
   * a null placeholder is not required for trailing omitted arguments
*/

function setCookie(name, value, expires, path, domain, secure) {
  var curCookie = name + "=" + escape(value) +
      ((expires) ? "; expires=" + expires.toGMTString() : "") +
      ((path) ? "; path=" + path : "") +
      ((domain) ? "; domain=" + domain : "") +
      ((secure) ? "; secure" : "");
  document.cookie = curCookie;
}


/*
  name - name of the desired cookie
  return string containing value of specified cookie or null
  if cookie does not exist
*/

function getCookie(name) {
  var dc = document.cookie;
  var prefix = name + "=";
  var begin = dc.indexOf("; " + prefix);
  if (begin == -1) {
    begin = dc.indexOf(prefix);
    if (begin != 0) return null;
  } else
    begin += 2;
  var end = document.cookie.indexOf(";", begin);
  if (end == -1)
    end = dc.length;
  return unescape(dc.substring(begin + prefix.length, end));
}


/*
   name - name of the cookie
   [path] - path of the cookie (must be same as path used to create cookie)
   [domain] - domain of the cookie (must be same as domain used to
     create cookie)
   path and domain default if assigned null or omitted if no explicit
     argument proceeds
*/

function deleteCookie(name, path, domain) {
  if (getCookie(name)) {
    document.cookie = name + "=" +
    ((path) ? "; path=" + path : "") +
    ((domain) ? "; domain=" + domain : "") +
    "; expires=Thu, 01-Jan-70 00:00:01 GMT";
  }
}

// date - any instance of the Date object
// * hand all instances of the Date object to this function for "repairs"

function fixDate(date) {
  var base = new Date(0);
  var skew = base.getTime();
  if (skew > 0)
    date.setTime(date.getTime() - skew);
}