require 'open_food_network/scope_variant_to_hub'

# Responsible for estimating prices and fees for subscriptions
# Used by SubscriptionForm as part of the create/update process
# The values calculated here are intended to be persisted in the db

class SubscriptionEstimator
  def initialize(subscription)
    @subscription = subscription
  end

  def estimate!
    assign_price_estimates
    assign_fee_estimates
  end

  private

  attr_accessor :subscription

  delegate :subscription_line_items, :shipping_method, :payment_method, :shop, to: :subscription

  def assign_price_estimates
    subscription_line_items.each do |item|
      item.price_estimate =
        price_estimate_for(item.variant, item.price_estimate_was)
    end
  end

  def price_estimate_for(variant, fallback)
    return fallback unless fee_calculator && variant
    scoper.scope(variant)
    fees = fee_calculator.indexed_fees_for(variant)
    (variant.price + fees).to_d
  end

  def fee_calculator
    return @fee_calculator unless @fee_calculator.nil?
    next_oc = subscription.schedule.andand.current_or_next_order_cycle
    return nil unless shop && next_oc
    @fee_calculator = OpenFoodNetwork::EnterpriseFeeCalculator.new(shop, next_oc)
  end

  def scoper
    OpenFoodNetwork::ScopeVariantToHub.new(shop)
  end

  def assign_fee_estimates
    subscription.shipping_fee_estimate = shipping_fee_estimate
    subscription.payment_fee_estimate = payment_fee_estimate
  end

  def shipping_fee_estimate
    shipping_method.calculator.compute(subscription)
  end

  def payment_fee_estimate
    payment_method.calculator.compute(subscription)
  end
end