forecasts_controller.rb

class ForecastsController < ApplicationController
  include ForecastsHelper

  layout 'forecasts'
  before_action :set_dates, :set_chart_data, only: [:index, :table]

  def index
    respond_to do |format|
      format.html
      format.csv  {
        Delayed::Job.enqueue ForecastCSV.new(@forecast_chart, current_user.id)
        render :json =>{"msg"=>"ok"}
      }
    end
  end

  def table
    @forecast = @forecast_chart.detect{|c| c[:name] == 'forecast' }[:data]
  end

  def show
  end

  def create
  end

  private

  def set_chart_data
    @data_chart = {}
    data, forecast, forecast_trend = get_data

    1.upto(@data_dates.count) { |i| @data_chart[@data_dates[i-1]] = data[i-1] }
    @forecast_chart = [ {name: 'forecast', data: forecast }, 
                        {name: 'trend', data: forecast_trend} ]
  end

  def set_dates
    @data_date_range = (DateTime.now - 3.years)..DateTime.now - 1.month
    @data_dates   = @data_date_range.map(&:beginning_of_month).uniq.map { |d| format_date(d) }
    @forecast_end = params[:forecast_end].try(:to_date) || DateTime.now + 3.years
    @months_count = months(DateTime.now..@forecast_end - 1.month).count
  end

  def get_data
    fake_data = ForecastGenerator::Seasoned.get_raw_data
    data = months(@data_date_range).zip(fake_data).to_h

    forecast_manager = ForecastGenerator::Seasoned.new(data)

    forecast = forecast_manager.forecast(@months_count)
    trend    = forecast_manager.forecast_trend_with_dates(@months_count)

    [fake_data, forecast, trend]
  end

  def forecast_params
    params[:forecast]
  end

end