Class: SolidusPromotions::Calculators::DistributedAmount

Inherits:
Spree::Calculator
  • Object
show all
Includes:
PromotionCalculator
Defined in:
app/models/solidus_promotions/calculators/distributed_amount.rb

Overview

A calculator that distributes a fixed discount amount across line items based on their value.

This calculator takes a preferred total discount amount and distributes it proportionally across applicable line items based on their prices. More expensive line items receive a greater share of the discount.

Examples:

# Given a $30 discount and line items worth $100, $50, and $50:
# - $100 line item receives $15 discount (50% of total value)
# - $50 line item receives $7.50 discount (25% of total value)
# - $50 line item receives $7.50 discount (25% of total value)

Instance Method Summary collapse

Methods included from PromotionCalculator

#description

Instance Method Details

#compute_line_item(line_item) ⇒ BigDecimal

Computes the weighted discount amount for a specific line item.

The discount is calculated by distributing the preferred amount across all applicable line items, weighted by their prices. Returns 0 if:

  • The line item is nil

  • The currency doesn’t match the preferred currency

  • The line item is not in the list of applicable line items

Examples:

Computing discount for a line item

calculator = DistributedAmount.new(preferred_amount: 20, preferred_currency: 'USD')
# Assuming there are 2 line items: one at $80, one at $20
calculator.compute_line_item(expensive_line_item) # => 16.0 (80% of 20)
calculator.compute_line_item(cheaper_line_item)   # => 4.0 (20% of 20)

Parameters:

  • line_item (Spree::LineItem) —

    The line item to calculate the discount for

Returns:

  • (BigDecimal) —

    The weighted discount amount for this line item

See Also:



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# File 'app/models/solidus_promotions/calculators/distributed_amount.rb', line 43

def compute_line_item(line_item)
  return Spree::ZERO unless line_item
  return Spree::ZERO unless preferred_currency.casecmp(line_item.currency).zero?

  distributable_line_items = calculable.applicable_line_items(line_item.order)
  return Spree::ZERO unless line_item.in?(distributable_line_items)

  DistributedAmountsHandler.new(
    distributable_line_items,
    preferred_amount
  ).amount(line_item)
end