/* comment */

comment = {
   _id: "itsid"
   _rev : "",
   link_id: "id of item you comment",
   parent: "id of parent"n
   children: "comment children",
}

/* map function */
function(doc) {
  if (doc.kind == "comment") {
      emit(doc.link_id, doc);
  }
} 

/* reduce */
function (key, values) {
  var idx_comments = {};
  var comments = [];
  for (var i=0; i<values.length; i++) {
    if (values[i]) {
        idx_comments[values[i]['_id']] = values[i];
        if (!values[i]['parent'])
              comments.push(values[i]);
    }     
  }

   function iter_comments(lcomments) {
     for (var i=0; i<lcomments.length; i++) {
       var comment = lcomments[i] || [];
       var thread=[];
       if (comment['children'] && comment['children'].length > 0) {

         for (var j=0; j<comment['children'].length; j++) {
            thread.push(idx_comments[comment['children'][j]]);
         }
         if (thread && thread.length >0) {
           comment['thread'] = iter_comments(thread);
         } else {
           comment['thread'] = null;
         }
        }
        lcomments[i] = comment
      }
      return lcomments;
    }
    tmp = iter_comments(comments);
    return tmp;
}


/* rereduce */
function(key, values) {
  function cmp(a, b) {
    if (a['created'] > b['created'])
        return true;
    return false;
  }
  function swap(arr, i, j) {
    var tmp = arr[i];
    arr[i] = arr[j];
    arr[j] = tmp;
  }
  function partition(arr, start, end, pivot) {
    var pval = arr[pivot];
    swap(arr, pivot, end--);
    while (start < end) {
      if (cmp(arr[start], pval) {
        swap(arr, start, pivot);
        pivot++;
      }
    }
    swap(arr, pivot, end+1);
    return pivot;
  }
  
  function qsort(arr, start, end) {
    if (start < end) {
        var pivot = partition(arr, start, end, start);
        qsort(arr, start, pivot);
        qsort(arr, pivot+1, end)
    }
  }
  
  function iter_comments(comments) {
    qsort(comments, 0, comments.length-1);
    for (var i=0; i<comments.length; i++) {
        comment = comments[i];
        if (comment['thread'] and comment['thread']>1)
            comment['thread'] = iter_comments(comment['thread']);
        comments[i] = comment;

    }
    return comments;
  }
  return iter_comments(values);
}