Class: Calculator::SalesTax

Inherits:
Calculator show all
Defined in:
app/models/calculator/sales_tax.rb

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Calculator

#available?, calculators, #description, #to_s

Class Method Details

.calculate_tax(order, rates) ⇒ Object 



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# File 'app/models/calculator/sales_tax.rb', line 12

def self.calculate_tax(order, rates)
  ActiveSupport::Deprecation.warn("please use Calculator::SalesTax#compute instead", caller)

  return 0 if rates.empty?
  # note: there is a bug with associations in rails 2.1 model caching so we're using this hack
  # (see http://rails.lighthouseapp.com/projects/8994/tickets/785-caching-models-fails-in-development)
  cache_hack = rates.first.respond_to?(:tax_category_id)
          
  taxable_totals = {}
  order.line_items.each do |line_item|
    next unless tax_category = line_item.variant.product.tax_category
    next unless rate = rates.find { | sales_rate | sales_rate.tax_category_id == tax_category.id } if cache_hack
    next unless rate = rates.find { | sales_rate | sales_rate.tax_category == tax_category } unless cache_hack

    taxable_totals[tax_category] ||= 0
    taxable_totals[tax_category] += line_item.total
  end

  return 0 if taxable_totals.empty?
  tax = 0
  rates.each do |rate|
    tax_category = rate.tax_category unless cache_hack
    tax_category = TaxCategory.find(rate.tax_category_id) if cache_hack
    next unless taxable_total = taxable_totals[tax_category]
    tax += taxable_total * rate.amount
  end
  tax
end

.description ⇒ Object 



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# File 'app/models/calculator/sales_tax.rb', line 3

def self.description
  I18n.t("sales_tax")
end

.register ⇒ Object 



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# File 'app/models/calculator/sales_tax.rb', line 7

def self.register
  super
  TaxRate.register_calculator(self)
end

Instance Method Details

#compute(order) ⇒ Object 



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# File 'app/models/calculator/sales_tax.rb', line 41

def compute(order)
  rate = self.calculable
  line_items = order.line_items.select { |i| i.product.tax_category == rate.tax_category }
  line_items.inject(0) {|sum, line_item|
    sum += line_item.total * rate.amount
  }
end