Module: HasSet::ClassMethods

Defined in:
lib/has_set.rb

Instance Method Summary collapse

Instance Method Details

#has_set(set_name, options = {}) ⇒ Object

Use like this:

class Person < ActiveRecord::Base
  has_set :interests
end



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# File 'lib/has_set.rb', line 17

def has_set(set_name, options = {})
  
  set_column = options.has_key?(:column_name) ? options[:column_name].to_s : "#{set_name}_bitfield"
  
  begin
    enum_class = options.has_key?(:enum_class) ? options[:enum_class] : Object.const_get(set_name.to_s.camelcase)
  rescue NameError => ne
    raise NameError, "There ist no class to take the set entries from (#{ne.message})."
  end
  
  # Extend enum_class with field_name method
  enum_class.class_eval <<-EOF
    def field_name
      '#{set_name.to_s.singularize}_' + self.name.underscore
    end
  EOF
  
  define_method("#{set_name}=") do |set_elements|
    self[set_column] = 0
    unless set_elements.blank?
      if set_elements.kind_of? String
        set_elements = set_elements.split(",").collect do |element|
          element.strip!
          enum_class.const_get(element)
        end
      end
      [set_elements].flatten.each do |element|
        unless element.kind_of? enum_class
          raise ArgumentError, "You must provide an element of the #{enum_class} Enumeration. You provided an element of the class #{element.class}."
        end
        
        2**element.bitfield_index & self[set_column] == 2**element.bitfield_index ? next : self[set_column] += 2**element.bitfield_index
      end
    end
  end
  
  define_method(set_name) do
    if self[set_column] == 0
      return []
    else
      set_elements = enum_class.values.inject([]) do |set_elements, enum_element|
        set_elements << enum_element if send("#{set_name.to_s.singularize}_#{enum_element.name.underscore}?")
        set_elements
      end
      # special to_s method for element-array
      class <<set_elements
        def to_s
          self.collect { |element| "#{element.name}" }.join(", ")
        end
      end
      return set_elements
    end
  end
  
  # TODO: This should be a class method
  define_method("available_#{set_name.to_s}") do
    self.methods.grep(/#{set_name.to_s.singularize}_\w+[^\?=]$/).sort
  end
  
  enum_class.values.each do |enum|
    define_method("#{set_name.to_s.singularize}_#{enum.name.underscore}?") do
      2**enum.bitfield_index & self[set_column] == 2**enum.bitfield_index ? true : false
    end
    
    alias_method :"#{set_name.to_s.singularize}_#{enum.name.underscore}", :"#{set_name.to_s.singularize}_#{enum.name.underscore}?"
    
    define_method("#{set_name.to_s.singularize}_#{enum.name.underscore}=") do |true_or_false|
      current_value = (2**enum.bitfield_index & self[set_column] == 2**enum.bitfield_index)
      true_or_false = true  if true_or_false.to_s == "true" || (true_or_false.respond_to?(:to_i) && true_or_false.to_i == 1)
      true_or_false = false if true_or_false.to_s == "false" || (true_or_false.respond_to?(:to_i) && true_or_false.to_i == 0)

      if current_value != true_or_false
        true_or_false ? self[set_column] += 2**enum.bitfield_index : self[set_column] -= 2**enum.bitfield_index
      end
    end
  end
end