Class: ActiveMerchant::Shipping::ShipmentPacker

Inherits:
Object
  • Object
show all
Defined in:
lib/active_shipping/shipping/shipment_packer.rb

Defined Under Namespace

Classes: ExcessPackageQuantity, OverweightItem

Constant Summary collapse

EXCESS_PACKAGE_QUANTITY_THRESHOLD =
10_000

Class Method Summary collapse

Class Method Details

.pack(items, dimensions, maximum_weight, currency) ⇒ Object

items - array of hashes containing quantity, grams and price.

ex. [{:quantity => 2, :price => 1.0, :grams => 50}]

dimensions - [5.0, 15.0, 30.0] maximum_weight - maximum weight in grams currency - ISO currency code


15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
# File 'lib/active_shipping/shipping/shipment_packer.rb', line 15

def self.pack(items, dimensions, maximum_weight, currency)
  return [] if items.empty?
  packages = []

  # Naive in that it assumes weight is equally distributed across all items
  # Should raise early enough in most cases
  total_weight = 0
  items.map!(&:symbolize_keys).each do |item|
    total_weight += item[:quantity].to_i * item[:grams].to_i

    if item[:grams].to_i > maximum_weight
      raise OverweightItem, "The item with weight of #{item[:grams]}g is heavier than the allowable package weight of #{maximum_weight}g"
    end

    if total_weight > maximum_weight * EXCESS_PACKAGE_QUANTITY_THRESHOLD
      raise ExcessPackageQuantity, "Unable to pack more than #{EXCESS_PACKAGE_QUANTITY_THRESHOLD} packages"
    end
  end

  items = items.deep_dup.sort_by! { |i| i[:grams].to_i }

  state = :package_empty
  while state != :packing_finished
    case state
    when :package_empty
      package_weight, package_value = 0, 0
      state = :filling_package
    when :filling_package
      items.each do |item|
        quantity = if item[:grams].to_i <= 0
          item[:quantity].to_i
        else
          # Grab the max amount of this item we can fit into this package
          # Or, if there are fewer than the max for this item, put
          # what is left into this package
          [(maximum_weight - package_weight) / item[:grams].to_i, item[:quantity].to_i].min
        end

        item_weight = quantity * item[:grams].to_i
        item_value = quantity * Package.cents_from(item[:price])

        package_weight += item_weight
        package_value += item_value

        item[:quantity] = item[:quantity].to_i - quantity
      end

      items.reject! { |i| i[:quantity].to_i == 0 }

      state = :package_full
    when :package_full
      packages << ActiveMerchant::Shipping::Package.new(package_weight, dimensions, :value => package_value, :currency => currency)
      state = items.any? ? :package_empty : :packing_finished
    end
  end

  packages
end