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'

    FIXNUM_MAX = (2**(0.size * 8 -2) -1)
    SORT_TYPES = ['date', 'plays', 'likes']
    TIME_RANGES = { "today" => 1 , "week" => 7, "month" => 30, "all" => 0}
    TYPE_FILTERS = ['music_session_history', 'recording', 'all']

    def self.index(user, params = {})
      limit = params[:limit]
      limit ||= 20
      limit = limit.to_i

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

      start = params[:start].presence
      if sort == 'date'
        start ||= FIXNUM_MAX
      else
        start ||= 0
      end
      start = start.to_i

      time_range = params[:time_range]
      time_range ||= 'month'
      raise "not valid time_range #{time_range}" unless TIME_RANGES.has_key?(time_range)

      type_filter = params[:type]
      type_filter ||= 'all'
      raise "not valid type #{type_filter}" unless TYPE_FILTERS.include?(type_filter)

      target_user = params[:user]
      target_band = params[:band]

      #query = Feed.includes([:recording]).includes([:music_session_history]).limit(limit)
      query = Feed.joins("LEFT OUTER JOIN recordings ON recordings.id = feeds.recording_id")
                  .joins("LEFT OUTER JOIN music_sessions_history ON music_sessions_history.id = feeds.music_session_id")
                  .limit(limit)

      # handle sort
      if sort == 'date'
        query = query.where("feeds.id < #{start}")
        query = query.order('feeds.id DESC')
      elsif sort == 'plays'
        query = query.offset(start)
        query = query.order("COALESCE(recordings.play_count, music_sessions_history.play_count) DESC ")
      elsif sort == 'likes'
        query = query.offset(start)
        query = query.order("COALESCE(recordings.like_count, music_sessions_history.like_count) DESC ")
      else
        raise "sort not implemented: #{sort}"
      end

      # handle time range
      days = TIME_RANGES[time_range]
      if days > 0
        query = query.where("feeds.created_at > NOW() - '#{days} day'::INTERVAL")
      end

      # handle type filters
      if type_filter == 'music_session_history'
        query = query.where('feeds.music_session_id is not NULL')
      elsif type_filter == 'recording'
        query = query.where('feeds.recording_id is not NULL')
      end


      if target_user

        if target_user != user.id
          require_public_recordings = "claimed_recordings.is_public = TRUE AND"
          require_public_sessions = "music_sessions_history.fan_access = TRUE AND"
        end

        query = query.joins("LEFT OUTER JOIN claimed_recordings ON recordings.id = claimed_recordings.recording_id AND #{require_public_recordings} (claimed_recordings.user_id = '#{target_user}' OR (recordings.band_id IN (SELECT band_id FROM bands_musicians where user_id='#{target_user}')))")
        query = query.joins("LEFT OUTER JOIN music_sessions_user_history ON music_sessions_history.id = music_sessions_user_history.music_session_id AND #{require_public_sessions} music_sessions_user_history.user_id = '#{target_user}'")
        query = query.group("feeds.id, feeds.recording_id, feeds.music_session_id, feeds.created_at, feeds.updated_at, recordings.id, music_sessions_history.id")
        if sort == 'plays'
          query = query.group("COALESCE(recordings.play_count, music_sessions_history.play_count)")
        elsif sort == 'likes'
          query = query.group("COALESCE(recordings.like_count, music_sessions_history.like_count)")
        end
        query = query.where('recordings.id is NULL OR claimed_recordings.id IS NOT NULL')
        query = query.where('music_sessions_history.id is NULL OR music_sessions_user_history.id IS NOT NULL')

      elsif target_band

        unless Band.find(target_band).users.include?(user)
          require_public_recordings = "claimed_recordings.is_public = TRUE AND"
          require_public_sessions = "music_sessions_history.fan_access = TRUE AND"
        end

        query = query.joins("LEFT OUTER JOIN claimed_recordings ON recordings.id = claimed_recordings.recording_id AND #{require_public_recordings} recordings.band_id = '#{target_band}'")
        query = query.where("music_sessions_history IS NULL OR #{require_public_sessions} music_sessions_history.band_id = '#{target_band}'")
        query = query.group("feeds.id, feeds.recording_id, feeds.music_session_id, feeds.created_at, feeds.updated_at, recordings.id, music_sessions_history.id")
        if sort == 'plays'
          query = query.group("COALESCE(recordings.play_count, music_sessions_history.play_count)")
        elsif sort == 'likes'
          query = query.group("COALESCE(recordings.like_count, music_sessions_history.like_count)")
        end
        query = query.where('recordings.id is NULL OR claimed_recordings.id IS NOT NULL')
        #query = query.where('music_sessions_history.id is NULL OR music_sessions_user_history.id IS NOT NULL')
      else
        query = query.joins('LEFT OUTER JOIN claimed_recordings ON recordings.id = claimed_recordings.recording_id AND claimed_recordings.is_public = TRUE')
        query = query.joins("LEFT OUTER JOIN music_sessions_user_history ON music_sessions_history.id = music_sessions_user_history.music_session_id AND music_sessions_history.fan_access = TRUE")
        query = query.group("feeds.id, feeds.recording_id, feeds.music_session_id, feeds.created_at, feeds.updated_at, recordings.id, music_sessions_history.id")
        if sort == 'plays'
          query = query.group("COALESCE(recordings.play_count, music_sessions_history.play_count)")
        elsif sort == 'likes'
          query = query.group("COALESCE(recordings.like_count, music_sessions_history.like_count)")
        end
        query = query.where('recordings.id is NULL OR claimed_recordings.is_public = TRUE')
        query = query.where('music_sessions_history.id is NULL OR music_sessions_user_history.id IS NOT NULL')
      end




      if params[:hash]
        if query.length == 0
          { query:query, next: nil}
        elsif query.length < limit
          { query:query, next: nil}
        else
          if sort == 'date'
            { query:query, next: query.last.id}
          else
            { query:query, next: start + limit}
          end
        end
      else
        if query.length == 0
          [query, nil]
        elsif query.length < limit
          [query, nil]
        else
          if sort == 'date'
            [query, query.last.id]
          else
            [query, start + limit]
          end
        end
      end
    end
  end
end