/* jFeed : jQuery feed parser plugin
 * Copyright (C) 2007 Jean-François Hovinne - http://www.hovinne.com/
 * Dual licensed under the MIT (MIT-license.txt)
 * and GPL (GPL-license.txt) licenses.
 */

jQuery.getFeed = function(options) {

    options = jQuery.extend({
    
        url: null,
        data: null,
        success: null
        
    }, options);

    if(options.url) {

        $.ajax({
            type: 'GET',
            url: options.url,
            data: options.data,
            dataType: 'xml',
            success: function(xml) {
                var feed = new JFeed(xml);
                if(jQuery.isFunction(options.success)) options.success(feed);
            }
        });
    }
};

function JFeed(xml) {
    if(xml) this.parse(xml);
};

JFeed.prototype = {

    type: '',
    version: '',
    title: '',
    link: '',
    description: '',
    parse: function(xml) {
        
        if(jQuery('channel', xml).length == 1) {
        
            this.type = 'rss';
            var feedClass = new JRss(xml);

        } else if(jQuery('feed', xml).length == 1) {
        
            this.type = 'atom';
            var feedClass = new JAtom(xml);
        }
        
        if(feedClass) jQuery.extend(this, feedClass);
    }
};

function JFeedItem() {};

JFeedItem.prototype = {

    title: '',
    link: '',
    description: '',
    updated: '',
    id: ''
};

function JAtom(xml) {
    this._parse(xml);
};

JAtom.prototype = {
    
    _parse: function(xml) {
    
        var channel = jQuery('feed', xml).eq(0);

        this.version = '1.0';
        this.title = jQuery(channel).find('title:first').text();
        this.link = jQuery(channel).find('link[rel=alternate]').attr('href'); 
        this.description = jQuery(channel).find('subtitle:first').text();
        this.language = jQuery(channel).attr('xml:lang');
        this.updated = jQuery(channel).find('updated:first').text();
        
        this.items = new Array();
        
        var feed = this;
        
        jQuery('entry', xml).each( function() {
        
            var item = new JFeedItem();
            
            item.title = jQuery(this).find('title').eq(0).text();
            item.link = jQuery(this).find('link[rel=alternate]').eq(0).attr('href');
            item.description = jQuery(this).find('summary').eq(0).text();
			item.author = jQuery(this).find('author name').eq(0).text();
            item.updated = formatDate(W3CToIETFDate(jQuery(this).find('updated').eq(0).text()));
            item.id = jQuery(this).find('id').eq(0).text();
            
            feed.items.push(item);
        });
    }
};

function JRss(xml) {
    this._parse(xml);
};

JRss.prototype  = {
    
    _parse: function(xml) {
    
        if(jQuery('rss', xml).length == 0) this.version = '1.0';
        else this.version = jQuery('rss', xml).eq(0).attr('version');

        var channel = jQuery('channel', xml).eq(0);
    
        this.title = jQuery(channel).find('title:first').text();
        this.link = jQuery(channel).find('link:first').text();
        this.description = jQuery(channel).find('description:first').text();
        this.language = jQuery(channel).find('language:first').text();
        this.updated = jQuery(channel).find('lastBuildDate:first').text();
    
        this.items = new Array();
        
        var feed = this;
        
        jQuery('item', xml).each( function() {
        
            var item = new JFeedItem();
            
            item.title = jQuery(this).find('title').eq(0).text();
            item.link = jQuery(this).find('link').eq(0).text();
            item.description = jQuery(this).find('description').eq(0).text();
			item.author = jQuery(this).find('author name').eq(0).text();
            item.updated = formatDate(jQuery(this).find('pubDate').eq(0).text());
            item.id = jQuery(this).find('guid').eq(0).text();
            
            feed.items.push(item);
        });
    }
};


// Handy conversion values.
var HOURS_TO_MINUTES = 60;
var MINUTES_TO_SECONDS = 60;
var HOURS_TO_SECONDS = MINUTES_TO_SECONDS * HOURS_TO_MINUTES;
var SECONDS_TO_MILLISECONDS = 1000;
var MINUTES_TO_MILLISECONDS = MINUTES_TO_SECONDS * SECONDS_TO_MILLISECONDS;
var HOURS_TO_MILLISECONDS = HOURS_TO_MINUTES * MINUTES_TO_MILLISECONDS;


function formatDate(date) {
    var pubDate = new Date(date).getTime();
    var nowTime = new Date().getTime();
    var diff = (nowTime-pubDate)/1000;
    //alert(date + " -> " + pubDate);
    if(diff < (5*MINUTES_TO_SECONDS)){
	    pubDate = "less than 5 minutes ago"
    }else if(diff < (HOURS_TO_SECONDS)){
	    diff = Math.round(diff/MINUTES_TO_SECONDS);
	    pubDate = "about "+diff+" minutes ago";
    }else if(diff < (1.75 * HOURS_TO_SECONDS)){
	    diff = Math.round((diff-HOURS_TO_SECONDS)/HOURS_TO_MINUTES);
	    pubDate = "1 hour "+diff+" minutes ago";
    }else if(diff < (24 * HOURS_TO_SECONDS)){
	    diff = Math.round(diff/HOURS_TO_SECONDS);
	    pubDate = "about "+diff+" hours ago";
    }else if(diff < (24 * HOURS_TO_SECONDS)){
	    diff = Math.round((diff-(24 * HOURS_TO_SECONDS))/HOURS_TO_SECONDS);
	    pubDate = "1 day "+diff+" hours ago";
    }else{
	    diff = Math.round(diff/(24 * HOURS_TO_SECONDS));
	    pubDate = "about "+diff+" days ago";
    }
   return pubDate;
}

function debug(s) {
    //alert(s);
}

function W3CToIETFDate(dateString) {
  // Converts a W3C-DTF (subset of ISO 8601) date string to an IETF date string.
  // W3C-DTF is described in this note: http://www.w3.org/TR/NOTE-datetime
  // IETF is obtained via the Date object's toUTCString() method.  The object's
  // toString() method is insufficient because it spells out timezones on Win32
  // (f.e. "Pacific Standard Time" instead of "PST"), which Mail doesn't grok.
  // For info, see http://lxr.mozilla.org/mozilla/source/js/src/jsdate.c#1526.

  var parts = dateString.match(/(\d\d\d\d)(-(\d\d))?(-(\d\d))?(T(\d\d):(\d\d)(:(\d\d)(\.(\d+))?)?(Z|([+-])(\d\d):(\d\d))?)?/);
  debug("date parts: " + parts);

  // Here's an example of a W3C-DTF date string and what .match returns for it.
  //  date: 2003-05-30T11:18:50.345-08:00
  //  date.match returns array values:
  //   0: 2003-05-30T11:18:50-08:00,
  //   1: 2003,
  //   2: -05,
  //   3: 05,
  //   4: -30,
  //   5: 30,
  //   6: T11:18:50-08:00,
  //   7: 11,
  //   8: 18,
  //   9: :50,
  //   10: 50,
  //   11: .345,
  //   12: 345,
  //   13: -08:00,
  //   14: -,
  //   15: 08,
  //   16: 00

  // Create a Date object from the date parts.  Note that the Date object
  // apparently can't deal with empty string parameters in lieu of numbers,
  // so optional values (like hours, minutes, seconds, and milliseconds)
  // must be forced to be numbers.
  var date = new Date(parts[1], parts[3]-1, parts[5], parts[7] || 0,
                      parts[8] || 0, parts[10] || 0, parts[12] || 0);

  // We now have a value that the Date object thinks is in the local timezone
  // but which actually represents the date/time in the remote timezone
  // (f.e. the value was "10:00 EST", and we have converted it to "10:00 PST"
  // instead of "07:00 PST").  We need to correct that.  To do so, we're going
  // to add the offset between the remote timezone and UTC (to convert the value
  // to UTC), then add the offset between UTC and the local timezone (to convert
  // the value to the local timezone).

  // Ironically, W3C-DTF gives us the offset between UTC and the remote timezone
  // rather than the other way around, while the getTimezoneOffset() method
  // of a Date object gives us the offset between the local timezone and UTC
  // rather than the other way around.  Both of these are the additive inverse
  // (i.e. -x for x) of what we want, so we have to invert them to use them
  // by multipying by -1
  // (f.e. if "the offset between UTC and the remote timezone" is -5 hours,
  // then "the offset between the remote timezone and UTC" is -5*-1 = 5 hours).

  // Note that if the timezone portion of the date/time string is absent
  // (which violates W3C-DTF, although ISO 8601 allows it), we assume the value
  // to be in UTC.

  // The offset between the remote timezone and UTC in milliseconds.
  var remoteToUTCOffset = 0;
  if (parts[13] && parts[13] != "Z") {
    var direction = (parts[14] == "+" ? 1 : -1);
    if (parts[15])
      remoteToUTCOffset += direction * parts[15] * HOURS_TO_MILLISECONDS;
    if (parts[16])
      remoteToUTCOffset += direction * parts[16] * MINUTES_TO_MILLISECONDS;
  }
  remoteToUTCOffset = remoteToUTCOffset * -1; // invert it
  debug("date remote to UTC offset: " + remoteToUTCOffset);

  // The offset between UTC and the local timezone in milliseconds.
  var UTCToLocalOffset = date.getTimezoneOffset() * MINUTES_TO_MILLISECONDS;
  UTCToLocalOffset = UTCToLocalOffset * -1; // invert it
  debug("date UTC to local offset: " + UTCToLocalOffset);

  date.setTime(date.getTime() + remoteToUTCOffset + UTCToLocalOffset);

  debug("date string: " + date.toUTCString());

  return date.toUTCString();
}