32 lines
786 B
Ruby
32 lines
786 B
Ruby
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module Concern
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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)
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self.exec_sql "
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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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self.exec_sql "
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UPDATE #{self.class.table_name} t
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SET position = x.position - 1
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FROM (
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SELECT i.id, row_number()
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OVER(ORDER BY i.position asc,
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CASE WHEN i.id = :id THEN 0 ELSE 1 END ASC) AS position
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FROM #{self.class.table_name} i
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WHERE i.position IS NOT NULL
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) x
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WHERE x.id = t.id AND t.position <> x.position - 1
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", {id: id}
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end
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end
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end
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