jam-cloud/ruby/lib/jam_ruby/models/active_music_session.rb

module JamRuby
  class ActiveMusicSession < ActiveRecord::Base

    @@log = Logging.logger[ActiveMusicSession]

    self.primary_key = 'id'

    self.table_name = 'active_music_sessions'

    attr_accessor :legal_terms, :max_score

    belongs_to :claimed_recording, :class_name => "JamRuby::ClaimedRecording", :foreign_key => "claimed_recording_id", :inverse_of => :playing_sessions
    belongs_to :claimed_recording_initiator, :class_name => "JamRuby::User", :inverse_of => :playing_claimed_recordings, :foreign_key => "claimed_recording_initiator_id"

    has_one :music_session, :class_name => "JamRuby::MusicSession", :foreign_key => 'music_session_id'
    has_one :mount, :class_name => "JamRuby::IcecastMount", :inverse_of => :music_session, :foreign_key => 'music_session_id'
    belongs_to :creator, :class_name => 'JamRuby::User', :foreign_key => :user_id

    has_many :connections, :class_name => "JamRuby::Connection", foreign_key: :music_session_id
    has_many :users, :through => :connections, :class_name => "JamRuby::User"
    has_many :recordings, :class_name => "JamRuby::Recording", :inverse_of => :music_session, foreign_key: :music_session_id
    has_many :chats, :class_name => "JamRuby::ChatMessages", :foreign_key => "session_id"
    validates :creator, :presence => true
    validate :creator_is_musician
    validate :no_new_playback_while_playing

    after_create :started_session

    after_destroy do |obj|
      JamRuby::MusicSession.removed_music_session(obj.id)
    end

    #default_scope :select => "*, 0 as score"

    def attributes
      super.merge('max_score' => self.max_score)
    end

    def max_score
      nil unless has_attribute?(:max_score)
      read_attribute(:max_score).to_i
    end

    before_create :create_uuid
    def create_uuid
       #self.id = SecureRandom.uuid
    end

    def before_destroy
      self.mount.destroy if self.mount
    end

    def creator_is_musician
      unless creator.musician?
        errors.add(:creator, ValidationMessages::MUST_BE_A_MUSICIAN)
      end
    end

    def no_new_playback_while_playing
      # if we previous had a claimed recording and are trying to set one
      # and if also the previous initiator is different than the current one... it's a no go
      if !claimed_recording_id_was.nil? && !claimed_recording_id.nil? &&
          claimed_recording_initiator_id_was != claimed_recording_initiator_id
          errors.add(:claimed_recording, ValidationMessages::CLAIMED_RECORDING_ALREADY_IN_PROGRESS)
      end
    end

    # returns an array of client_id's that are in this session
    # if as_musician is nil, all connections in the session ,regardless if it's a musician or not or not
    # you can also exclude a client_id from the returned set by setting exclude_client_id
    def get_connection_ids(options = {})
      as_musician = options[:as_musician]
      exclude_client_id = options[:exclude_client_id]

      where = { :music_session_id => self.id }
      where[:as_musician] = as_musician unless as_musician.nil?

      exclude = "client_id != '#{exclude_client_id}'"unless exclude_client_id.nil?

      Connection.select(:client_id).where(where).where(exclude).map(&:client_id)
    end

    # This is a little confusing. You can specify *BOTH* friends_only and my_bands_only to be true
    # If so, then it's an OR condition. If both are false, you can get sessions with anyone.
    def self.index(current_user, options = {})
      participants = options[:participants]
      genres = options[:genres]
      keyword = options[:keyword]
      friends_only = options[:friends_only].nil? ? false : options[:friends_only]
      my_bands_only = options[:my_bands_only].nil? ? false : options[:my_bands_only]
      as_musician = options[:as_musician].nil? ? true :  options[:as_musician]

      query = ActiveMusicSession
      .joins(
          %Q{
            INNER JOIN
              music_sessions
            ON
              active_music_sessions.id = music_sessions.id
          }
      )
      .joins(
          %Q{
            INNER JOIN
              connections
            ON
              active_music_sessions.id = connections.music_session_id
          }
      )
      .joins(
          %Q{
            LEFT OUTER JOIN 
              friendships 
            ON 
              connections.user_id = friendships.user_id 
            AND 
              friendships.friend_id = '#{current_user.id}'
          }
      )
      .joins(
          %Q{
            LEFT OUTER JOIN
              invitations
            ON
              invitations.music_session_id = active_music_sessions.id
            AND
              invitations.receiver_id = '#{current_user.id}'
          }
      )
      .group(
          %Q{
            active_music_sessions.id
          }
      )
      .order(
          %Q{
            SUM(CASE WHEN invitations.id IS NULL THEN 0 ELSE 1 END) DESC, 
            SUM(CASE WHEN friendships.user_id IS NULL THEN 0 ELSE 1 END) DESC, 
            active_music_sessions.created_at DESC
          }
      )

      if as_musician
        query = query.where(
            %Q{
                musician_access = true
              OR
                invitations.id IS NOT NULL
            }
        )
      else
        # if you are trying to join the session as a fan/listener,
        # we have to have a mount, fan_access has to be true, and we have to allow for the reload of icecast to have taken effect
        query = query.joins('INNER JOIN icecast_mounts ON icecast_mounts.music_session_id = active_music_sessions.id INNER JOIN icecast_servers ON icecast_mounts.icecast_server_id = icecast_servers.id')
        query = query.where('music_sessions.fan_access = true')
        query = query.where("(active_music_sessions.created_at < icecast_servers.config_updated_at)")
      end

      query = query.where("music_sessions.description like '%#{keyword}%'") unless keyword.nil?
      query = query.where("connections.user_id" => participants.split(',')) unless participants.nil?
      query = query.where("music_sessions.genre_id in (?)", genres) unless genres.nil?

      if my_bands_only
        query = query.joins(
            %Q{
            LEFT OUTER JOIN
              bands_musicians
            ON
              bands_musicians.user_id = '#{current_user.id}'
          }
        )
      end

      if my_bands_only || friends_only
        query = query.where(
            %Q{
            #{friends_only ? "friendships.user_id IS NOT NULL" : "false"}
            OR
              #{my_bands_only ? "bands_musicians.band_id = music_sessions.band_id" : "false"}
            }
        )
      end

      return query
    end

    # This is a little confusing. You can specify *BOTH* friends_only and my_bands_only to be true
    # If so, then it's an OR condition. If both are false, you can get sessions with anyone.
    # note, this is mostly the same as above but includes paging through the result and and scores.
    # thus it needs the client_id...
    def self.nindex(current_user, options = {})
      client_id = options[:client_id]
      participants = options[:participants]
      genres = options[:genres]
      keyword = options[:keyword]
      friends_only = options[:friends_only].nil? ? false : options[:friends_only]
      my_bands_only = options[:my_bands_only].nil? ? false : options[:my_bands_only]
      as_musician = options[:as_musician].nil? ? true :  options[:as_musician]
      offset = options[:offset]
      limit = options[:limit]

      connection = Connection.where(client_id: client_id).first!
      locidispid = connection.locidispid

      query = ActiveMusicSession
      .select("active_music_sessions.*, max(coalesce(current_scores.score, 1000)) as max_score")  # 1000 is higher than the allowed max of 999
      .joins(
          %Q{
            INNER JOIN
              music_sessions
            ON
              active_music_sessions.id = music_sessions.id
          }
      )
      .joins(
          %Q{
            INNER JOIN
              connections
            ON
              active_music_sessions.id = connections.music_session_id
          }
      )
      .joins(
          %Q{
            LEFT OUTER JOIN
              current_scores
            ON
              current_scores.alocidispid = connections.locidispid
            AND
              current_scores.blocidispid = #{locidispid}
          }
      )
      .joins(
          %Q{
            LEFT OUTER JOIN
              friendships
            ON
              connections.user_id = friendships.user_id
            AND
              friendships.friend_id = '#{current_user.id}'
          }
      )
      .joins(
          %Q{
            LEFT OUTER JOIN
              invitations
            ON
              invitations.music_session_id = active_music_sessions.id
            AND
              invitations.receiver_id = '#{current_user.id}'
          }
      )
      .group(
          %Q{
            active_music_sessions.id
          }
      )
      .order(
          %Q{
            SUM(CASE WHEN invitations.id IS NULL THEN 0 ELSE 1 END) DESC,
            SUM(CASE WHEN friendships.user_id IS NULL THEN 0 ELSE 1 END) DESC,
            active_music_sessions.created_at DESC
          }
      )

      if (offset)
        query = query.offset(offset)
      end

      if (limit)
        query = query.limit(limit)
      end

      if as_musician
        query = query.where(
            %Q{
                musician_access = true
              OR
                music_sessions.user_id = '#{current_user.id}'
              OR
                invitations.id IS NOT NULL
            }
        )
      else
        # if you are trying to join the session as a fan/listener,
        # we have to have a mount, fan_access has to be true, and we have to allow for the reload of icecast to have taken effect
        query = query.joins('INNER JOIN icecast_mounts ON icecast_mounts.music_session_id = active_music_sessions.id INNER JOIN icecast_servers ON icecast_mounts.icecast_server_id = icecast_servers.id')
        query = query.where('music_sessions.fan_access = true')
        query = query.where("(active_music_sessions.created_at < icecast_servers.config_updated_at)")
      end

      query = query.where("music_sessions.description like '%#{keyword}%'") unless keyword.nil?
      query = query.where("connections.user_id" => participants.split(',')) unless participants.nil?
      query = query.where("music_sessions.genre_id in (?)", genres) unless genres.nil?

      if my_bands_only
        query = query.joins(
            %Q{
            LEFT OUTER JOIN
              bands_musicians
            ON
              bands_musicians.user_id = '#{current_user.id}'
          }
        )
      end

      if my_bands_only || friends_only
        query = query.where(
            %Q{
            #{friends_only ? "friendships.user_id IS NOT NULL" : "false"}
            OR
              #{my_bands_only ? "bands_musicians.band_id = music_sessions.band_id" : "false"}
            }
        )
      end

      return query
    end

    # initialize the two temporary tables we use to drive ams_index and ams_users
    def self.ams_init(current_user, options = {})
      client_id = options[:client_id]

      connection = Connection.where(user_id: current_user.id, client_id: client_id).first!
      my_locidispid = connection.locidispid
      # 13 is an average audio gear value we use if they have not qualified any gear
      my_audio_latency = connection.last_jam_audio_latency || current_user.last_jam_audio_latency || 13
      locidispid_expr = my_locidispid ? "#{my_locidispid}::bigint" : '0::bigint'

      self.connection.execute("select ams_index('#{current_user.id}'::varchar, #{locidispid_expr}, #{my_audio_latency}::integer)").check
    end

    # Generate a list of music sessions (that are active) filtered by genre, language, keyword, and sorted
    # (and tagged) by rsvp'd (1st), invited (2nd), and musician can join (3rd). within a group tagged the
    # same, sorted by score. date seems irrelevant as these are active sessions. ams_init must be called
    # first.
    def self.ams_query(current_user, options = {})
      session_id = options[:session_id]
      client_id = options[:client_id]
      genre = options[:genre]
      lang = options[:lang]
      keyword = options[:keyword]
      offset = options[:offset]
      limit = options[:limit]
      day = options[:day]
      timezone_offset = options[:timezone_offset]

      query = MusicSession
        .select('music_sessions.*')

      # this is not really needed when ams_music_session_tmp is joined
      # unless there is something specific we need out of active_music_sessions
      # query = query.joins(
      #   %Q{
      #     INNER JOIN
      #       active_music_sessions
      #     ON
      #       active_music_sessions.id = music_sessions.id
      #   }
      # )
      # .select('1::integer as tag, 15::integer as latency')

      # integrate ams_music_session_tmp into the processing
      # then we can join ams_music_session_tmp and not join active_music_sessions
      query = query.joins(
        %Q{
          INNER JOIN
            ams_music_session_tmp
          ON
            ams_music_session_tmp.music_session_id = music_sessions.id
        }
      )
      .select('ams_music_session_tmp.tag, ams_music_session_tmp.latency')

      query = query.order(
        %Q{
          tag, latency, music_sessions.id
        }
      )
      .group(
        %Q{
          tag, latency, music_sessions.id
        }
      )

      # if not specified, default offset to 0
      offset ||= 0
      offset = offset.to_i
      # if not specified, default limit to 20
      limit ||= 20
      limit = limit.to_i

      query = query.offset(offset)
      query = query.limit(limit)
      query = query.where("music_sessions.genre_id = ?", genre) unless genre.blank?
      query = query.where('music_sessions.language = ?', lang) unless lang.blank?
      query = query.where('music_sessions.id = ?', session_id) unless session_id.blank?
      query = query.where("(description_tsv @@ to_tsquery('jamenglish', ?))",  ActiveRecord::Base.connection.quote(keyword) + ':*') unless keyword.blank?

      if !day.blank? && !timezone_offset.blank?
        begin
          day = Date.parse(day)
          next_day = day + 1
          timezone_offset = timezone_offset.to_i
          if timezone_offset > 0
            timezone_offset = "+#{timezone_offset}"
          end
          query = query.where("scheduled_start BETWEEN TIMESTAMP WITH TIME ZONE '#{day} 00:00:00#{timezone_offset}'
                    AND TIMESTAMP WITH TIME ZONE '#{next_day} 00:00:00#{timezone_offset}'")
        rescue Exception => e
          # do nothing. bad date probably
          @@log.warn("unable to parse  day=#{day}, timezone_offset=#{timezone_offset}, e=#{e}")
        end
      end

      return query
    end

    # returns the set of users in a music_sessions and the music_session they are in and their latency.
    # ams_init must be called first.
    # user.audio_latency / 2 , + other_user.audio_latency of them / 2, + network latency /2
    def self.ams_users
      return User.select('users.*, ams_users_tmp.music_session_id, ams_users_tmp.latency')
      .joins(
        %Q{
          INNER JOIN
            ams_users_tmp
          ON
            ams_users_tmp.user_id = users.id
        }
      )
      .order('ams_users_tmp.music_session_id, ams_users_tmp.user_id')
    end

    # wrap me in a transaction!
    # note that these queries must be actualized before the end of the transaction
    # else the temporary tables created by sms_init will be gone.
    def self.ams_index(current_user, params)
      ActiveMusicSession.ams_init(current_user, params)

      music_sessions = ActiveMusicSession.ams_query(current_user, params).all

      music_session_users = ActiveMusicSession.ams_users.all

      user_scores = {}
      music_session_users.each do |user|
        user_scores[user.id] = {latency: user.latency}
      end

      [music_sessions, user_scores]
    end

    def self.participant_create user, music_session_id, client_id, as_musician, tracks, audio_latency
      music_session = MusicSession.find(music_session_id)

      if music_session.active_music_session
        connection = nil
        active_music_session = nil
        ActiveRecord::Base.transaction do

          active_music_session = ActiveMusicSession.find(music_session_id)

          active_music_session.with_lock do # VRFS-1297
            active_music_session.tick_track_changes
            connection = ConnectionManager.new.join_music_session(user, client_id, active_music_session, as_musician, tracks, audio_latency)

            if connection.errors.any?
              # rollback the transaction to make sure nothing is disturbed in the database
              raise ActiveRecord::Rollback
            end
          end
        end

        unless connection.errors.any?
          user.update_progression_field(:first_music_session_at)
          MusicSessionUserHistory.save(music_session_id, user.id, client_id, tracks)

          if as_musician
            # send to session participants
            Notification.send_session_join(active_music_session, connection, user)

            # send "musician joined session" notification only if it's not a band session since there will be a "band joined session" notification
            if music_session.band.nil?
              Notification.send_musician_session_join(active_music_session, user)
            end
          end
        end

        connection
      else
        return_value = nil

        time = Benchmark.realtime do
          ActiveRecord::Base.transaction do

            # we need to lock the icecast server in this transaction for writing, to make sure thath IcecastConfigWriter
            # doesn't dumpXML as we are changing the server's configuraion
            icecast_server = IcecastServer.find_best_server_for_user(user) if music_session.fan_access
            icecast_server.lock! if icecast_server

            # check if we are connected to rabbitmq
            active_music_session = ActiveMusicSession.new
            active_music_session.id = music_session.id # copy the .id from music_session to active_music_session
            active_music_session.creator = user

            if music_session.fan_access
              # create an icecast mount since regular users can listen in to the broadcast
              active_music_session.mount = IcecastMount.build_session_mount(music_session, active_music_session, icecast_server)
            end

            active_music_session.save

            unless active_music_session.errors.any?
              music_session.started_at = active_music_session.created_at
              music_session.save(:validate => false)

              # save session parameters for next session
              User.save_session_settings(user, music_session)

              # auto-join this user into the newly created session
              as_musician = true
              connection = ConnectionManager.new.join_music_session(user, client_id, active_music_session, as_musician, tracks, audio_latency)

              unless connection.errors.any?
                user.update_progression_field(:first_music_session_at)
                MusicSessionUserHistory.save(active_music_session.id, user.id, client_id, tracks)

                # only send this notification if it's a band session
                unless music_session.band.nil?
                  Notification.send_band_session_join(active_music_session, music_session.band)
                end

                return_value = connection
              else
                return_value = connection
                # rollback the transaction to make sure nothing is disturbed in the database
                raise ActiveRecord::Rollback
              end
            else
              return_value = active_music_session
              # rollback the transaction to make sure nothing is disturbed in the database
              raise ActiveRecord::Rollback
            end
          end
        end

        if time > 2
          Logging.logger[self].warn "creating a music session took #{time*1000} milliseconds"
        end

        return_value
      end
    end

    # Verifies that the specified user can join this music session
    def can_join? user, as_musician
      if as_musician
        if !user.musician
          return false # "a fan can not join a music session as a musician"
          raise PermissionError, "a fan can not join a music session as a musician"
        end
        
        if self.musician_access
          if self.approval_required
            return self.invited_musicians.exists?(user)
          else
            return true
          end

        else
          # the creator can always join, and the invited users can join
          return self.creator == user || self.invited_musicians.exists?(user)
        end
      else
        # it's a fan, and the only way a fan can join is if fan_access is true
        return self.fan_access
      end

    end

    # Verifies that the specified user can see this music session
    def can_see? user
      if self.musician_access || self.fan_access
        true
      else
        self.creator == user || self.invited_musicians.exists?(user)
      end
    end

    # Verifies that the specified user can delete this music session
    def can_delete? user
      # the creator can delete
      self.creator == user
    end

    def access? user
      music_session.part_of_session? user
    end

    def most_recent_recording
      recordings.where(:music_session_id => self.id).order('created_at desc').limit(1).first
    end

    # is this music session currently recording?
    def is_recording?
      recordings.where(:duration => nil).count > 0
    end

    def is_playing_recording?
      !self.claimed_recording.nil?
    end

    def recording
      recordings.where(:duration => nil).first
    end

    # stops any active recording
    def stop_recording
      current_recording = self.recording
      current_recording.stop unless current_recording.nil?
    end

    def claimed_recording_start(owner, claimed_recording)
      self.claimed_recording = claimed_recording
      self.claimed_recording_initiator = owner
      self.save
    end

    def claimed_recording_stop
      self.claimed_recording = nil
      self.claimed_recording_initiator = nil
      self.save
    end

    def invitations
      music_session.invitations
    end

    def invited_musicians
      music_session.invited_musicians
    end

    def join_requests
      music_session.join_requests
    end

    def fan_invitations
      music_session.fan_invitations
    end

    def to_s
      description
    end

    def musician_access
      music_session.musician_access
    end

    def fan_access
      music_session.fan_access
    end

    def description
      music_session.description
    end

    def name
      music_session.name
    end

    def genre
      music_session.genre
    end

    def fan_chat
      music_session.fan_chat
    end

    def band
      music_session.band
    end

    def approval_required
      music_session.approval_required
    end

    def music_notations
      music_session.music_notations
    end

    def tick_track_changes
      self.track_changes_counter += 1
      self.save!(:validate => false)
    end

    def connected_participant_count
      Connection.where(:music_session_id => self.id, 
                       :aasm_state => Connection::CONNECT_STATE.to_s,
                       :as_musician => true)
        .count
    end

    def started_session
      raise "active_music_sessions.id must be set by caller" unless self.id
      # associate this active_music_session with the music_session formally
      session = MusicSession.find(self.id)
      session.active_music_session = self
      self.music_session = session # needed because of the Google Analytics below in some test cases
      session.scheduled_start = self.created_at unless session.scheduled_start
      session.save!

      GoogleAnalyticsEvent.track_session_duration(self)
      GoogleAnalyticsEvent.track_band_real_session(self) 
    end


    def self.sync(session_history)
      music_session = MusicSession.find_by_id(session_history.id)

      if music_session.nil?
        music_session = MusicSession.new
        music_session.id = session_history.id
      end

      music_session.user_id = session_history.creator.id
      music_session.band_id = session_history.band.id unless session_history.band.nil?
      session_history.save!
    end
  end
end