Class: Calculator::Vat

Inherits:
Calculator
  • Object
show all
Defined in:
app/models/calculator/vat.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 = default_rates) ⇒ Object 



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# File 'app/models/calculator/vat.rb', line 21

def self.calculate_tax(order, rates=default_rates)
  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 { | vat_rate | vat_rate.tax_category_id == tax_category.id } if cache_hack
    next unless rate = rates.find { | vat_rate | vat_rate.tax_category == tax_category } unless cache_hack
    taxable_totals[tax_category] ||= 0
    taxable_totals[tax_category] += line_item.price * rate.amount * line_item.quantity
  end

  return 0 if taxable_totals.empty?
  tax = 0
  taxable_totals.values.each do |total|
    tax += total
  end
  tax
end

.calculate_tax_on(product_or_variant) ⇒ Object

TODO: Refactor this method after integrating #54 to use default address



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# File 'app/models/calculator/vat.rb', line 45

def self.calculate_tax_on(product_or_variant)
  vat_rates = default_rates

  return 0 if vat_rates.nil?
  return 0 unless tax_category = product_or_variant.is_a?(Product) ? product_or_variant.tax_category : product_or_variant.product.tax_category
  return 0 unless rate = vat_rates.find { | vat_rate | vat_rate.tax_category_id == tax_category.id }

  (product_or_variant.is_a?(Product) ? product_or_variant.price : product_or_variant.price) * rate.amount
end

.default_rates ⇒ Object

list the vat rates for the default country



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# File 'app/models/calculator/vat.rb', line 13

def self.default_rates
  origin = Country.find(Spree::Config[:default_country_id])
  calcs = Calculator::Vat.includes(:calculable => :zone).select {
    |vat| vat.calculable.zone.country_list.include?(origin)
  }
  calcs.collect { |calc| calc.calculable }
end

.description ⇒ Object 



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

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

.register ⇒ Object 



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

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

Instance Method Details

#compute(order) ⇒ Object

computes vat for line_items associated with order, and tax rate



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# File 'app/models/calculator/vat.rb', line 56

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.price * rate.amount * line_item.quantity)
  }
end