Module: Lexorank::Rankable::InstanceMethods

Defined in:
lib/lexorank/rankable.rb

Instance Method Summary collapse

Instance Method Details

#move_to(position) ⇒ Object 



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# File 'lib/lexorank/rankable.rb', line 48

def move_to(position)
  collection = self.class.ranked
  if self.class.ranking_group_by.present?
    collection = collection.where("#{self.class.ranking_group_by}": send(self.class.ranking_group_by))
  end

  # exceptions:
  #   move to the beginning (aka move to position 0)
  #   move to end (aka position = collection.size - 1)
  # when moving to the end of the collection the offset and limit statement automatically handles
  # that 'after' is nil which is the same like [collection.last, nil]
  before, after =
    if position == 0
      [nil, collection.first]
    else
      # if item is currently in front of the index we just use position otherwise position - 1
      # if the item has no rank we use position - 1
      position -= 1 if !self.send(self.class.ranking_column) || collection.map(&:id).index(self.id) > position
      collection.offset(position).limit(2)
    end

  rank =
    if self == after && self.send(self.class.ranking_column).present?
      self.send(self.class.ranking_column)
    else
      value_between(before&.send(self.class.ranking_column), after&.send(self.class.ranking_column))
    end

  self.send("#{self.class.ranking_column}=", rank)
end

#move_to!(position) ⇒ Object 



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# File 'lib/lexorank/rankable.rb', line 79

def move_to!(position)
  move_to(position)
  save
end

#move_to_top ⇒ Object 



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# File 'lib/lexorank/rankable.rb', line 44

def move_to_top
  move_to(0)
end

#move_to_top! ⇒ Object 



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# File 'lib/lexorank/rankable.rb', line 84

def move_to_top!
  move_to!(0)
end