class Weight

# File lib/weight_conversion.rb, line 7
def initialize(value=0.0, unit='lb')
   self.value = value
   self.unit = unit
end

# File lib/weight_conversion.rb, line 68
def *(other)
   raise TypeError, 'You can only multiply by a number' unless other.is_a?(Numeric)
   self.class.new(value * other, unit)
end

# File lib/weight_conversion.rb, line 48
def +(other)
   return if is_not_weight?(other)
   self.class.new(value + other_value(other), unit)
end

# File lib/weight_conversion.rb, line 53
def -(other)
   return if is_not_weight?(other)
   self.class.new(value - other_value(other), unit)
end

# File lib/weight_conversion.rb, line 73
def /(other)
   raise TypeError, 'You can only divide by a number' unless other.is_a?(Numeric)
   self.class.new(value / other, unit)
end

# File lib/weight_conversion.rb, line 58
def <=>(other)
   return if is_not_weight?(other)
   self.to_gms <=> other.to_gms
end

# File lib/weight_conversion.rb, line 63
def ==(other)
   return if is_not_weight?(other)
   self.to_gms  == other.to_gms
end

# File lib/weight_conversion.rb, line 44
def to_f
   value.round(4).to_f
end

# File lib/weight_conversion.rb, line 24
def to_gms
   data_in_grams.round(4)
end

# File lib/weight_conversion.rb, line 40
def to_i
   value.round
end

# File lib/weight_conversion.rb, line 36
def to_kgs
   (data_in_grams / grams_per_kilogram).round(4)
end

# File lib/weight_conversion.rb, line 32
def to_lbs
   (data_in_grams / grams_per_pound).round(4)
end

# File lib/weight_conversion.rb, line 28
def to_ozs
   (data_in_grams / grams_per_ounce).round(4)
end

# File lib/weight_conversion.rb, line 12
def translated
 I18n.t("weight.units.#{unit}")
end

# File lib/weight_conversion.rb, line 20
def unit
   @input_unit
end

# File lib/weight_conversion.rb, line 16
def value
   @input_value
end

# File lib/weight_conversion.rb, line 92
def allowed_units
   [:gm, :oz, :lb, :kg]
end

# File lib/weight_conversion.rb, line 109
def data_in_grams
   case unit
   when :gm
      value
   when :oz
      value * grams_per_ounce
   when :lb
      value * grams_per_pound
   when :kg
      value * grams_per_kilogram
   else
      raise TypeError, 'Unit is not valid.'
   end
end

# File lib/weight_conversion.rb, line 132
def grams_per_kilogram
   1000
end

# File lib/weight_conversion.rb, line 124
def grams_per_ounce
   28.34952
end

# File lib/weight_conversion.rb, line 128
def grams_per_pound
   453.5923
end

# File lib/weight_conversion.rb, line 136
def is_not_weight?(other)
   return false if other.is_a?(Weight)
   raise TypeError, 'Not a Weight class.'
   return true
end

# File lib/weight_conversion.rb, line 96
def other_value(other)
   case unit
   when :gm
      other.to_gms
   when :oz
      other.to_ozs
   when :lb
      other.to_lbs
   when :kg
      other.to_kgs
   end
end

# File lib/weight_conversion.rb, line 86
def unit=(unit)
   unit = unit.to_s.downcase.to_sym
   raise ArgumentError, "Allowed unit types #{allowed_units.inspect}" unless allowed_units.include?(unit)
   @input_unit = unit
end

# File lib/weight_conversion.rb, line 80
def value=(value)
   raise TypeError, 'Value cannot be negative' if value < 0
   raise TypeError, 'Value must be Numeric' unless value.is_a? Numeric
   @input_value = value
end