forecast.rb

class Forecast < ActiveRecord::Base
  include ForecastGenerator

  belongs_to :cruise

  serialize :result, JSON

  def generate(cruise = nil, length, initial_data_length)
    length ||=  defaults[:length_months]
    initial_data_length ||= defaults[:initial_data_length]

    data = self.class.get_initial_data(cruise, initial_data_length)

    ForecastGenerator::Seasoned.new(data).foracast(length)
  end

  def defaults
    self.class.defaults
  end


  class << self

    def get_initial_data(cruise = nil, length)
      initial_length ||=  defaults[:initial_data_length]

      Enquiry.where.not(booking_status: 'Cancelled')
             .select("DATE_TRUNC('month', created_at) as month, count(*) as count_enq")
             .group("month")
             .order("month")
             .where("created_at > DATE_TRUNC('month', CURRENT_DATE) - INTERVAL '#{initial_length} months'")
             .where(cruise_id: cruise)
             .map{ |q| {month: q.month, count: q.count_enq }}
    end

    def defaults
      ForecastGenerator.defaults
    end

  end
end