filter_best_posts.rb

class FilterBestPosts

  attr_accessor :filtered_posts, :posts

  def initialize(topic, filtered_posts, limit, options={})
    @filtered_posts = filtered_posts
    @topic = topic
    @limit = limit
    options.each do |key, value|
        self.instance_variable_set("@#{key}".to_sym, value)
    end
    filter
  end

  def filter
    @posts =  if @min_replies && @topic.posts_count < @min_replies + 1
                []
              else
                filter_posts_liked_by_moderators
                setup_posts
                filter_posts_based_on_trust_level
                filter_posts_based_on_score
                sort_posts
              end
  end

  private

  def filter_posts_liked_by_moderators
    return unless @only_moderator_liked
    liked_by_moderators = PostAction.where(post_id: @filtered_posts.pluck(:id), post_action_type_id: PostActionType.types[:like])
    liked_by_moderators = liked_by_moderators.joins(:user).where('users.moderator').pluck(:post_id)
    @filtered_posts = @filtered_posts.where(id: liked_by_moderators)
  end

  def setup_posts
    @posts = @filtered_posts.order('percent_rank asc, sort_order asc').where("post_number > 1")
    @posts = @posts.includes(:reply_to_user).includes(:topic).joins(:user).limit(@limit)
  end

  def filter_posts_based_on_trust_level
    return unless @min_trust_level.try('>',0)
      @posts = if @bypass_trust_level_score.try('>',0)
                  @posts.where('COALESCE(users.trust_level,0) >= ? OR posts.score >= ?',
                              @min_trust_level,
                              @bypass_trust_level_score)
                else
                  @posts.where('COALESCE(users.trust_level,0) >= ?', @min_trust_level)
                end
  end

  def filter_posts_based_on_score
    return unless @min_score.try('>',0)
    @posts = @posts.where('posts.score >= ?', @min_score)
  end

  def sort_posts
    @posts.to_a.sort!{|a,b| a.post_number <=> b.post_number}
  end

end