gistfile1.rb

class Timeline
  attr_reader :data

  def initialize(order)
    @order = order
    @dt = @order.track_from..@order.track_to
  end
  
  def create_reports!
    load_data(:channel_id => @order.channel_id, :video_id => @order.video_id)

    remove_isolated_sequences!
    remove_short_sequences!

    sequences.each { |sequence|
      @order.reports.create(:sequence_start => sequence.min, :sequence_end => sequence.max)
    }
  end

  def load_data(conditions)
    @data = Broadcast.find(:all,
      :select => "dt, MAX(percentage) AS percentage",
      :group => "dt",
      :order => "dt",
      :conditions => conditions.merge(:dt => @dt.min..@dt.max)
      )
    @actual_range = @data.map(&:dt)
    @actual_range = @dt if @actual_range.empty?
  end

  def min; @actual_range.min; end
  def max; @actual_range.max; end

  MIN_GAP = 2

  def remove_isolated_sequences!
    filt = []
    @data.each_with_index do |cur, index|
      prv = @data[index - 1] || ({'dt' => min - 10})
      nxt = @data[index + 1] || ({'dt' => max + 10})
      # удаляем изолированные "всплески", шумы
      p1 = cur['dt'] - prv['dt']
      p2 = nxt['dt'] - cur['dt']

      if p1 >= MIN_GAP && p2 >= MIN_GAP
        next
      end
      filt.push(cur)
    end
    @data = filt
  end

  MIN_SEQ_SIZE = 3

  def remove_short_sequences!
    current_seq = []
    seq = []
    @data.each_with_index do |cur, index|
      prv = @data[index - 1]
      if cur['dt'] - prv['dt'] >= MIN_GAP # конец секции
        if current_seq.size <= MIN_SEQ_SIZE
          seq += current_seq
        end
        current_seq = []
      end
      current_seq.push(index)
    end
    filt = []
    @data.each_with_index do |cur, index|
      next if seq.include?(index)
      filt.push(cur)
    end
    @data = filt
  end

  MIN_SEQ_DISTANCE = 60
  MIN_SEQ_DURATION = 10

  def sequences
    unless defined?(@sequences)
      @sequences = []
      current_seq = []
      @data.each_with_index { |cur, index|
        prv = @data[index - 1]
        if cur['dt'] - prv['dt'] >= MIN_SEQ_DISTANCE
          @sequences.push current_seq if current_seq.size >= MIN_SEQ_DURATION
          current_seq = []
        end
        current_seq.push cur['dt']
      }
      @sequences.push current_seq if current_seq.size >= MIN_SEQ_DURATION
    end
    @sequences
  end
end