module JamRuby
  class Feed < ActiveRecord::Base

    belongs_to :recording, class_name: "JamRuby::Recording", inverse_of: :feed, foreign_key: 'recording_id'
    belongs_to :music_session_history, class_name: "JamRuby::MusicSessionHistory", inverse_of: :feed, foreign_key: 'music_session_id'

    def self.index(params = {start:0, limit:20, sort: 'date'})

      start = params[:start]
      start ||= 0

      limit = params[:limit]
      limit ||= 20

      # validate sort
      sort = params[:sort]
      sort ||= 'date'
      raise "not valid sort #{sort}" unless ['date', 'plays', 'likes'].include?(sort)

      query = Feed.includes(:recording).includes(:music_session_history).offset(start).limit(limit)
      if sort == 'date'
        query = query.order('id DESC')
      elsif sort == 'plays'
        query = query.
        query = query.order('(COALESCE(recording., '')')
      end

      query
    end
  end
end