// ==UserScript==
// @name           Helgon.net avatars in user listings
// @namespace      http://www.lysator.liu.se/~jhs/userscript
// @description    Show avatars next to user names on Helgon.net user listings.
// @include        http://*helgon.net/*.asp*
// ==/UserScript==

// every sex listed in here with a true value will get avatars shown in lists:
var show = { T:true, O:true, K:true };

var poll = 7 * 24 * 60 * 60 * 1000; // refetch image URLs weekly
var purl = '/userinfo/userinfo.asp?ID='; // profile URL link
var host = 'http://' + location.host;

// XPath expression to match all profile links we want to link images to
var profile_links = '//a[starts-with(@href,"'+ purl +'")]' + sexpath( show );

// regexps for detecting profile URLs and for parsing profile content data
var id_re = new RegExp( '<img[^>]* src=.?http://g\\.helgon\\.net/u/.{6,10}' +
			'([0-9A-F-]{36}).{1,3}\\.jpg', 'i' ); // (image uid)
var tags = '(?:<[^>]*>)*';
var headline_re = new RegExp( '<font class="largeheadline"> ?'+ tags +
			      '([^\\s<]*)'+ tags +' (.)(\\d+)'+ tags +
			      '([^<]*) i ([^<]*)', 'i' );
// (name, sex, age, city, region)

// extend the profile-link xpath to become gender specific (based on `show')
function sexpath( show )
{
  var on = 0, sex, y, n;
  for( sex in show )
    if( !show[sex] )
      n = sex;
    else
    {
      on++;
      y = sex;
    }
  switch( on )
  {
    case 0: return '[0=1]';
    case 1: return     '[starts-with(following-sibling::text()," '+ y +'")]';
    case 2: return '[not(starts-with(following-sibling::text()," '+ n +'"))]';
    case 3: return '';
  }
}


// generic support functions:

// Returns a function that calls `f' in the context of `self'. `f' gets called
// with `args' concatenated to its arguments array, when the returned function
// is called. Fuzzy? A really spaced-out "hello world" example:
// make_caller( function( h, w ){ alert( h+this.s+w ); }, ['World!'], {s:' '} )
// ( 'Hello' );
function make_caller( f, args, self )
{
  return function()
  {
    args = Array.prototype.slice.call( arguments ).concat( args||[] );
    f.apply( self||f, args );
  };
}

// Fetch a web page and call cb( http_response, args[0], ..., args[N] )
function get( url, cb, args )
{
  //if( args ) cb = make_caller( cb, args );
  GM_xmlhttpRequest( { method:'GET', url:url, onload:cb } );
}

// list nodes matching this expression, optionally relative to the node `root'
function $x( xpath, root )
{
  var doc = root ? root.evaluate ? root : root.ownerDocument : document;
  var got = doc.evaluate( xpath, root||doc, null, 0, null ), next, result = [];
  while( next = got.iterateNext() )
    result.push( next );
  return result;
}

// run the passed cb( node, index ) on all nodes matching the expression
function foreach( xpath, cb )
{
  var nodes = $x( xpath ), i, e = 0;
  for( i=0; i<nodes.length; i++ )
    e += cb( nodes[i], i ) || 0;
  return e;
}


// user profile data handling support code

function Users(){}

// user data storage, in JSON encoded form
eval( 'var cache = '+ GM_getValue( 'users', '{}' ) );

Users.save_all = function()
{
  GM_setValue( 'users', cache.toSource() );
};

Users.save = function( user )
{
  cache[ user.id ] = user.encode();
  if( Users.defer_save ) clearTimeout( Users.defer_save );
  Users.defer_save = setTimeout( Users.save_all, 2e3 ); // save in two seconds
};

Users.get = function( id )
{
  var u = cache[ id ];
  if( u )
    return u && new User( id, u );
}

Users.id_from_url = function( url )
{
  var id = /\d+$/.exec( url );
  return id && parseInt( id[0], 10 );
};

// Future improvement: maybe parse out some optional bits like this, too?
// &nbsp;Civilstatus</font></td> <td width="30%"><font class="text1">Singel<

function User( id, data )
{
  if( typeof data == 'object' )
    this.init( id, data.u, data.s, data.a, data.n, data.c, data.r, data.t );
}

User.prototype.init = function( id, uid, sex, age, name, city, region, t )
{
  this.id = id;
  this.uid = uid;
  this.sex = sex;
  this.age = age;
  this.name = name;
  this.city = city;
  this.region = region;
  this.timestamp = t;
};

User.prototype.get_image_url = function()
{
  var prefix = this.uid.substring( 0, 3 );
  return 'http://g.helgon.net/u/%7B'+ prefix +'/%7B'+ this.uid +'%7D.jpg';
};

User.prototype.encode = function()
{
  var n = { name:'n', sex:'s', age:'a', /*city:'c', region:'r',*/ uid:'u',
	    timestamp:'t' }, u = {}, property;
  for( property in this )
    if( n[property] )
      u[n[property]] = this[property];
  return u;
};

// run cb( args[0], ... args[N] ) with the this object set to a given user (id,
// url or User object), fetching it as needed from the server or our user cache
User.apply = function( user, cb, args )
{
  var id;
  if( typeof user == 'object' ) // we got a User object
    return cb.apply( user, args );
  if( typeof user == 'string' ) // we got a url (or id)
    id = Users.id_from_url( user );
  if( typeof user == 'number' ) // we got a user id
    id = user;
  if( user = Users.get( id ) )  // we had a cached copy
  {
    cb.apply( user, args );
    if( (new Date).getTime() - user.timestamp < poll )
      return; // ...and there was no need to refresh it
    cb = 0; // refresh, but don't add the avatar again.
  }
  // okay, we need to pull the user data from the server

  var url = host + purl + id;
  // this generates a call User.parse( xhrdata, url, cb, args ) call:
  get( url, make_caller( User.parse, [url, cb, args] ) );
};

// Parse profile data, update the user cache, and optionally call the provided
// callback with the this object set to the appropriate User, passing on args.
User.parse = function( data, url, cb, args )
{
  var u = new User, html = typeof data=='string' ? data : data.responseText;
  html = html.replace( /\s+/gm, ' ' );
  u.id = Users.id_from_url( url );
  if( !u.id ) return; // probably our own profile -- just ignore it, for now
  u.uid = id_re.exec( html )[1];
  if( data = headline_re.exec( html ) ) // name, sex, age, city, region
  {
    u.name   = data[1];
    u.sex    = data[2];
    u.age    = parseInt( data[3], 10 );
    u.city   = data[4];
    u.region = data[5];
  }
  u.timestamp = (new Date).getTime();
  Users.save( u );
  if( cb )
    cb.apply( u, args||[] );
};



// avatar script

function inject_avatar_before( node ) // assumes a User this object
{
  // exit early to cop out of showing the ugly (drawn) default avatars
  if( this.uid.match( /00000000-0000-0000-0000-0000000000/ ) ) return;

  node.parentNode.style.minHeight = '60px';

  var img = document.createElement( 'img' );
  with( img )
  {
    src = this.get_image_url();
    className = 'largeimageborder';
    style.width = '40px';
    style.height = '56px';
    align = 'middle';
  }

  var a = document.createElement( 'a' );
  a.href = host + purl + this.id;
  a.appendChild( img );

  var space = document.createTextNode(' ');
  node.parentNode.insertBefore( space, node );
  node.parentNode.insertBefore( a, space );
}

function fetch_and_inject_avatar( node, n )
{
  User.apply( node.href, inject_avatar_before, [node] );
}

switch( location.pathname.toLowerCase() )
{
  case '/':
  case '/start/start.asp':
  case '/guestbook/guestbook.asp':
    break;

  case '/userinfo/userinfo.asp': // just update the cache for this user
    User.parse( document.documentElement.innerHTML, location.href );
    break;

  default:
    foreach( profile_links, fetch_and_inject_avatar );
}