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