discourse/app/models/concerns/positionable.rb

37 lines
979 B
Ruby

module Positionable
extend ActiveSupport::Concern
included do
before_save do
self.position ||= self.class.count
end
end
def move_to(position_arg)
position = [[position_arg, 0].max, self.class.count - 1].min
if self.position.nil? || position > (self.position)
DB.exec "
UPDATE #{self.class.table_name}
SET position = position - 1
WHERE position > :current_position and position <= :new_position",
current_position: self.position, new_position: position
elsif position < self.position
DB.exec "
UPDATE #{self.class.table_name}
SET position = position + 1
WHERE position >= :new_position and position < :current_position",
current_position: self.position, new_position: position
else
# Not moving to a new position
return
end
DB.exec "
UPDATE #{self.class.table_name}
SET position = :position
WHERE id = :id", id: id, position: position
end
end