class ConsumerRef < ServerSide::Model(:consumer_refs)
  def self.signaled_node_ids(channel_id)
    transaction do
      node_ids, ref_ids = [], []
      filter(:channel_id => channel_id, :signaled => true).each do |r|
        ref_ids << r[:id]
        node_ids << r[:node_id]
      end
      filter(:id => ref_ids).update(:signaled => false)
      node_ids
    end
  end
  
  def self.signal_by_node_id(node_id)
    filter(:node_id => node_id).update(:signaled => true)
  end
  
  def self.signal_by_channel_id(channel_id)
    filter(:channel_id => channel_id).update(:signaled => true)
  end
  
  def self.remove_by_channel_id(channel_id)
    filter(:channel_id => channel_id).delete
  end
  
  def self.minimum_sample_rate(node_id)
    filter(:node_id => node_id).minimum(:sample_rate)
  end

  def self.add_or_update(channel_id, node_id, sample_rate)
    ref = find(:channel_id => channel_id, :node_id => node_id)
    if ref
      if ref[:sample_rate] != sample_rate
        ref.set(:sample_rate => sample_rate, :signaled => true)
      end
    else
      ref = create(
        :channel_id => channel_id,
        :node_id => node_id,
        :sample_rate => sample_rate
        :signaled => true
      )
    end
    ref
  end
end

class Channel < ServerSide::Model(:channels)
  def self.compile_consumer_events(channel_id)
    ConsumerRef.signaled_node_ids(channel_id).inject([]) do |events, node_id|
      node = Node[node_id]
      events << ChannelEvent.state_changed(node)
    end
  end
  
  before_delete do
    transaction do
      ConsumerRef.delete_by_channel_id(id)
      ProducerRef.delete_by_channel_id(id)
      Node.filter(:producer_id => id).update(:producer_id => nil)
      ...etc...
    end
  end
  
  one_to_many :produced_nodes, :class => Node, :key => {:producer_id => :id}
  
  def consumed_nodes
    Node.join(:consumer_refs, :node_id => :id).
      filter(:consumer_refs__channel_id => @pkey)
  end
  
  def self.stale
    filter(:stamp.LESS_THAN(Time.now - STALE_PERIOD))
  end
  
  def self.delete_stale
    db.transaction {stale.delete}
  end
  
  def touch
    set(:stamp => Time.ticks)
  end
  
  def touch_produced_nodes
    t = Time.now
    produced_nodes.each {|n| n.touch(t)}
  end
  
  def signal_subscribed_nodes
    ConsumerNodeRef.signal_by_channel_id(id)
  end
  
  def subscribe(paths, sample_rate = nil)
    Node.filter(:path => paths).each do |node|
      ConsumerNodeRef.add_or_update(id, node.id, sample_rate)
      node.update_tracking
    end
  end
  
  def mount(path)
    Node.mount_subtree(path, id)
  end
end

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