blood_pressure.rb

class Readings::BloodPressure < Readings::Base

  has_data_fields [:diastolic, :systolic]

  validates :diastolic, :numericality => {:greater_than => 0}
  validates :systolic, :numericality => {:greater_than => 0}

  def self.display_name
    "Blood Pressure"
  end

  def self.get_data_for(raw_data)
    { :systolic => [], :diastolic => [] }.tap do |series|
      raw_data.each do |d|
        series[:systolic] << [d.reading_date.to_time.to_i * 1000, d.systolic]
        series[:diastolic] << [d.reading_date.to_time.to_i * 1000, d.diastolic]
      end
    end
  end

  def self.get_display_value(raw_data)
    # Monthly average
    # FIXME: If the pairs are uneven, can't use raw_data.count
    display_value = ""
    sums = {:systolic => 0, :diastolic => 0}
    raw_data.each do |d|
      sums[:diastolic] += d.diastolic
      sums[:systolic] += d.systolic
    end

    sums.each_with_index do |(context, sum), index|
      display_value += (sum / raw_data.count).to_s unless raw_data.count == 0
      display_value += "/" if index < sums.length - 1
    end

    display_value
  end

  def high_diastolic?
    diastolic > 100
  end

  def high_systolic?
    systolic > 150
  end

  def hypertension?
    high_diastolic? && high_systolic?
  end

end