gistfile1.txt

  def is_payer_active_in_range(payer, range)
    active_history = payer.active_history
    # list of value and updated_at
    prev_active = false
    prev_time = 0

    # cases: updated during, updated only before, updated only after, updated before and after but not during

    for update in active_history:
      current_active = update.value
      current_time = update.updated_at
      if (current_active or prev_active) and range.start <= current_time and range.end > current_time:
        return true
      if prev_time < range.start and current_time > range.end:
        return prev_active

      prev_active = current_active
      prev_time = current_time

    return prev_active
  end

  # type: e.g. hospital, dept
  # id: unique id for type
  # range: date range
  # filters: whatever
  def patient_payers(type, id, range, filters)
    patients = patients(type, id, range, filters)
    payers_count = {}
    for patient in patients:
      patient_payers = patient.patient_payers()
      for payer in patient_payers:
        if is_payer_active_in_range(payer, range):
          if payer not in payers_count:
            payers_count[payer.name()] = 0
          payers_count[payer.name()] += 1
    return payers_count
  end