hexo.extend.helper.register('related_posts', function (currentPost, allPosts) {
  var relatedPosts = [];
  currentPost.tags.forEach(function (tag) {
    allPosts.forEach(function (post) {
      if (isTagRelated(tag.name, post.tags)) {
        var relatedPost = {
          title: post.title,
          path: post.path,
          cover: post.cover,
          weight: 1
        };
        var index = findItem(relatedPosts, 'path', post.path);
        if (index != -1) {
          relatedPosts[index].weight += 1;
        } else {
          if (currentPost.path != post.path) {
            relatedPosts.push(relatedPost);
          };
        };
      };
    });
  });
  if (relatedPosts.length == 0) { return '' };
  var result = "";
  var limit_num = hexo.theme.config.related_post.limit || 6
  var lang = hexo.theme.config.rootConfig.language;
  var headline_lang;
  if (lang === 'zh-CN') {
    headline_lang = '相关推荐';
  } else if ( lang === 'zh-TW') {
    headline_lang = '相關推薦';
  } else {
    headline_lang = 'Recommend';
  }
    
  relatedPosts = relatedPosts.sort(compare('weight'));
  var lazy_src = hexo.theme.config.lazyload.enable ? lazy_src = 'data-src' : lazy_src = 'src'
  var lazy_class = hexo.theme.config.lazyload.enable ? lazy_class  = 'lozad' : lazy_class  = ''

  if (relatedPosts.length > 0) {
    result += '<div class="relatedPosts">'
    result += '<div class="relatedPosts_headline"><i class="fa fa-fw fa-thumbs-up" aria-hidden="true"></i><span>' + ' ' + headline_lang + '</span></div>'
    result += '<div class="relatedPosts_list">'
  
  for (var i = 0; i < Math.min(relatedPosts.length, limit_num); i++) {
 
    var cover = relatedPosts[i].cover

    result += '<div class="relatedPosts_item"><a href="' + hexo.theme.config.rootConfig.root + relatedPosts[i].path + '" title="' + relatedPosts[i].title + '">';
    result += '<img class="relatedPosts_cover '+ lazy_class + '"' + lazy_src + '="' + cover + '">';
    result += '<div class="relatedPosts_title">' + relatedPosts[i].title + '</div>';
    result += '</a></div>'
    };
    
    result += '</div><div class="clear_both"></div></div>'
  return result;

}
});
hexo.extend.helper.register('echo', function(path){
return path;
});
function isTagRelated (tagName, TBDtags) {
  var result = false;
  TBDtags.forEach(function (tag) {
      if (tagName == tag.name) {
          result = true;
      };
  })
  return result;
}
function findItem (arrayToSearch, attr, val) {
  for (var i = 0; i < arrayToSearch.length; i++) {
      if (arrayToSearch[i][attr] == val) {
          return i
      };
  };
  return -1;
}
function compare (attr) {
  return function (a, b) {
      var val1 = a[attr];
      var val2 = b[attr];
      return val2 - val1;
  }
}