// ==UserScript==
// @name           SO Question rep reduction estimator
// @namespace      http://www.shog9.com/greasemonkey/scripts
// @author         Joshua Heyer
// @version        2.0
// @include        http://stackoverflow.com/users/*
// @include        http://meta.stackoverflow.com/users/*
// @include        http://serverfault.com/users/*
// @include        http://superuser.com/users/*
// ==/UserScript==


var script = document.createElement("script");
script.type = "text/javascript";
script.textContent = "(" + fakeRecalc.toString() + ")()";
document.body.appendChild(script);

function fakeRecalc()
{
   var initialRep = Number($(".summaryinfo>.summarycount").text().replace(/,/g, ''));
   $("<button title='Perform a rough estimate of what this reputation will be after the rep reward for question upvotes is reduced to 5 (will not work once this change is actually implemented!)'>Estimate Rep Reduction</button>")
      .appendTo(".summaryinfo:first")
      .click(DoRecalc);

   function DoRecalc()
   {
      $(".summaryinfo>.summarycount")
         .css({color: "yellow"});
      $(".summaryinfo:first")
         .append("<br><small><i>Ignores mitigating factors such as the daily rep cap: actual rep following the official recalc may be greater...</i></small>");
      
      var userID = /^\/users\/(\d+)/.exec(window.location.pathname)[1];
      var joinDate = isoDateStringToDate($(".user-details>tbody>tr:eq(1)>td:eq(1)>span").attr("title"));

      // round back to start of day (in UTC)
      joinDate = new Date(joinDate.valueOf() - joinDate.valueOf()%(24*60*60*1000));

      LoadNext(joinDate);

      function LoadNext(start)
      {
         var next = new Date(start);
         next.setUTCDate(next.getUTCDate()+90);
         $.getJSON("/users/rep-graph/"+userID+'/'+start.valueOf()+'/'+(next-1).valueOf()+'/',
            function(data)
            {
               AccumulateRep(data);
               if ( next < (new Date()) )
                  LoadNext(next);
               else
                  $(".summaryinfo>.summarycount")
                     .css("color", "green")
                     .append("<br>Difference: " + ((totalGain + totalLoss)-initialRep));
            }
         );

      }

      var totalGain = 0;
      var totalLoss = 0;
      function AccumulateRep(repData)
      {
         var newRepGain = 0;
         var newRepLoss = 0;
         repData.forEach(function(post)
         {
            var gain = post.IsQ ? post.Gain / 2 : post.Gain;
            newRepGain += gain;
            newRepLoss += post.Loss;
         });
         totalGain += newRepGain;
         totalLoss += newRepLoss;
         $(".summaryinfo>.summarycount").html( (totalGain + totalLoss) + "<span style='font-size:10pt'><br>+" + totalGain + ", " + totalLoss + "</span>");
      }
   }   

   // cribbed from: http://stackoverflow.com/questions/436374/how-can-i-convert-datetime-microformat-to-local-time-in-javascript/436562#436562
   function isoDateStringToDate(datestr) 
   {
     if (! this.re) {
       // The date in YYYY-MM-DD or YYYYMMDD format
       var datere = "(\\d{4})-?(\\d{2})-?(\\d{2})";
       // The time in HH:MM:SS[.uuuu] or HHMMSS[.uuuu] format
       var timere = "(\\d{2}):?(\\d{2}):?(\\d{2}(?:\\.\\d+)?)";
       // The timezone as Z or in +HH[:MM] or -HH[:MM] format
       var tzre = "(Z|(?:\\+|-)\\d{2}(?:\\:\\d{2})?)?";
       this.re = new RegExp("^" + datere + "[ T]" + timere + tzre + "$");
     }

     var matches = this.re.exec(datestr);
     if (! matches)
       return null;

     var year = matches[1];
     var month = matches[2] - 1;
     var day = matches[3];
     var hour = matches[4];
     var minute = matches[5];
     var second = Math.floor(matches[6]);
     var ms = matches[6] - second;
     var tz = matches[7];
     var ms = 0;
     var offset = 0;

     if (tz && tz != "Z") {
       var tzmatches = tz.match(/^(\+|-)(\d{2})(\:(\d{2}))$/);
       if (tzmatches) {
         offset = Number(tzmatches[2]) * 60 + Number(tzmatches[4]);
         if (tzmatches[1] == "-")
           offset = -offset;
       }
     }

     offset *= 60 * 1000;
     var dateval = Date.UTC(year, month, day, hour, minute, second, ms) - offset;

     return new Date(dateval);
   }
}