Class: IncomeTax::Countries::Germany

Inherits:
Models::Generic show all
Defined in:
lib/income_tax/countries/germany.rb

Constant Summary collapse

SOLIDARITY = 
Rate("5.5%")

Instance Attribute Summary

Attributes inherited from Models::Generic

#gross_income, #net_income, #options, #rate, #taxes

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Models::Generic

#based_on?, #cast_value, #cast_values, currency, #initialize, #inspect, lazy, #location_name, method_added, name, names, new, other_names, register, register_on, #set_default_options, #setup, #validate, wants_options

Constructor Details

This class inherits a constructor from IncomeTax::Models::Generic

Class Method Details

.first_year ⇒ Object 



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# File 'lib/income_tax/countries/germany.rb', line 36

def self.first_year
  @first_year ||= tax_years.to_a.first.first
end

.load_rates(path) ⇒ Object 



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# File 'lib/income_tax/countries/germany.rb', line 17

def self.load_rates(path)
  File.read(path).lines[1..-1].each do |line|
    year, e0, e1, e2, e3, s1, s2, s3, a1, b1, a2, b2, b3, b4 = parse_line(line)
    e4 = 1/0.0

    tax_years[year] = [
      [ 0,      e0, 0,  Rate("0%"), Rate("0%")                                           ],
      [ e0+1,   e1, 0,  Rate(b1),   Rate((a1 * (e1 - e0) / 10_000 + b1*10_000) / 10_000) ],
      [ e1+1,   e2, s1, Rate(b2),   Rate((a2 * (e2 - e1) / 10_000 + b2*10_000) / 10_000) ],
      [ e2+1,   e3, s2, Rate(b3),   Rate(b3)                                             ],
      [ e3+1,   e4, s3, Rate(b4),   Rate(b4)                                             ]
    ]
  end
end

.parse_line(line) ⇒ Object 



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# File 'lib/income_tax/countries/germany.rb', line 10

def self.parse_line(line)
  line.chomp.split("\t").map do |entry|
    next 1/0.0 if entry == "–"
    entry.include?(?.) ? Rational(entry) : Integer(entry)
  end
end

.tax_year(year) ⇒ Object 



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# File 'lib/income_tax/countries/germany.rb', line 40

def self.tax_year(year)
  year = first_year if year < first_year
  tax_years[year] || tax_year(year - 1)
end

.tax_years ⇒ Object 



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# File 'lib/income_tax/countries/germany.rb', line 32

def self.tax_years
  @tax_years ||= {}
end

Instance Method Details

#calculate_gross ⇒ Object 



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# File 'lib/income_tax/countries/germany.rb', line 84

def calculate_gross
  income  = gross_income.to_i
  income /= 2 if married?

  lower, upper, fixed, lower_rate, upper_rate = zones.detect { |l,u,*| income.between?(l,u) }
  step   = (upper_rate - lower_rate) / (upper - lower + 1)
  steps  = (income - lower + 1)
  rate   = lower_rate + Rate(step * steps)
  @taxes = rate.gross_taxes(steps).to_i + fixed

  @taxes *= 2 if married?
  @taxes += SOLIDARITY.gross_taxes(@taxes)
end

#calculate_net ⇒ Object 



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# File 'lib/income_tax/countries/germany.rb', line 68

def calculate_net
  income  = net_income.to_i
  income /= 2 if married?

  case income
  when 0 .. for_range(zones[0][1])               then @taxes = 0
  when 0 .. for_range(zones[1][1] - zones[2][2]) then @taxes = net_taxes(income, *zones[1], zones[2][2])
  when 0 .. for_range(zones[2][1] - zones[3][2]) then @taxes = net_taxes(income, *zones[2], zones[3][2])
  when 0 .. for_range(zones[3][1] - zones[4][2]) then @taxes = net_taxes(income, *zones[3], zones[4][2])
  else                                                @taxes = net_taxes(income, *zones[4], zones[4][2])
  end

  @taxes *= 2 if married?
  @taxes += SOLIDARITY.net_taxes(income)
end

#for_range(value) ⇒ Object 



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# File 'lib/income_tax/countries/germany.rb', line 64

def for_range(value)
  value.to_f.nan? ? 1/0.0 : value
end

#net_taxes(income, lower, upper, lower_taxes, lower_rate, upper_rate, upper_taxes) ⇒ Object 



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# File 'lib/income_tax/countries/germany.rb', line 49

def net_taxes(income, lower, upper, lower_taxes, lower_rate, upper_rate, upper_taxes)
  lower_income = lower - lower_taxes
  upper_income = upper - upper_taxes
  steps        = income - lower_income

  if upper_rate > lower_rate
    step = (upper_rate - lower_rate) / (upper_income - lower_income)
    rate = lower_rate + Rate(step * steps)
  else
    rate = lower_rate
  end

  rate.net_taxes(steps).to_i + lower_taxes
end

#zones ⇒ Object 



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# File 'lib/income_tax/countries/germany.rb', line 45

def zones
  @zones ||= self.class.tax_year(tax_year)
end