require 'agent/metrics/exception_record'

module APMInsight
  module Agent
    class SequenceBook
      attr_reader :openTracker, :rootTracker, :trackerCount, :exceptionBag, :listenFlag
      
      def initialize
        @rootTracker = nil
        #@closedTracker = @rootTracker
        @openTracker = nil
        
        @trackerCount = 0
        @closedTrackerCount = 0
        @listenFlag = -1
#        @exceptionBag = Array.new
      end
      
      def attachTracker tracker
        if tracker == nil
          return nil
        end
        
        # If RootTracker is not set, check type and set
        if @rootTracker == nil
          if !tracker.is_a?(ManageEngine::Tracker::RootTracker)
            closeSequence()
            return nil
          end
          @rootTracker = tracker
          updateListenFlag()
        end
        
        tracker.setParent(openTracker)
        @openTracker = tracker
        
        
        # Attach tracker as Sibling or Child and set nominee
#        if @closedTracker != nil
#          tracker.sibling = @closedTracker
#          @closedTracker.sibling = tracker # Nominee - if dropped/corrupted, defaults to this tracker
#          @openTracker = tracker
#          @closedTracker = nil
#        else
#          if tracker.equal?(@openTracker)
#            return nil
#          end
#          
#          @openTracker.child = tracker
#          tracker.sibling = @openTracker
#          @openTracker = tracker
#        end
        
        checkAndArrestSequence()
        
        return tracker
      end
      
      def closeTracker tracker
#        @closedTrackerCount += 1
#        @closedTracker = tracker
#        tracker.sibling = nil
#        @openTracker = nil
        @openTracker = tracker.parent;
        
        # Marks end of transaction
#        if @rootTracker == tracker
        if @openTracker == nil 
          if @listenFlag < 1 || (@listenFlag >= 1 && @trackerCount > 0)
            # if some trackers are not closed, while processing the metrics, it may go into infinite loop
#            if (@closedTrackerCount - @trackerCount) == 0
              sequenceBag = Hash.new
              sequenceBag["roottracker"] = @rootTracker
              sequenceBag["exceptions"] = @exceptionBag
              
              ManageEngine::APMObjectHolder.instance.collector.updateTransaction(@rootTracker.url, sequenceBag)
#            else
#              ManageEngine::APMObjectHolder.instance.log.warn "Some trackers are not closed, dropping the metrics for #{@rootTracker.url}"
#            end
          end
          closeSequence()
        end
      end
      
      def closeSequence
        @rootTracker = nil
        @openTracker = @closedTracker = nil
        @trackerCount = 0
        @closedTrackerCount = 0
        Thread.current[:apminsight] = nil
      end
      
      def addExceptionInfo(exception)
        begin
          if @exceptionBag == nil
            @exceptionBag = Set.new
          end
          if (@exceptionBag.size() < 10)
            exceptionRecord = ::APMInsight::Errors::ExceptionRecord.new(exception)
            @exceptionBag.add(exceptionRecord)
          end
        rescue Exception=>e
        end
      end
      
      def updateListenFlag
        if !ManageEngine::APMObjectHolder.instance.txn_util.listen?(@rootTracker.url())
          @listenFlag = 1
        end
        
        ## Check for sampling factor & for bg txn chk if enabled
      end
      
      def checkAndArrestSequence
        @trackerCount += 1
        if @trackerCount == 1000
          @listenFlag = 1
        end
        
        ## Can check for timeout
      end
      
      def createDummyTracker
        return ManageEngine::Tracker::DefaultTracker.new("dummy")
      end
      
    end
  end
end