fixin.me/app/models/quantity.rb

66 lines
1.9 KiB
Ruby

class Quantity < ApplicationRecord
belongs_to :user, optional: true
belongs_to :parent, optional: true, class_name: "Quantity"
has_many :subquantities, class_name: "Quantity", inverse_of: :parent,
dependent: :restrict_with_error
validate if: ->{ parent.present? } do
errors.add(:parent, :user_mismatch) unless user == parent.user
end
validates :name, presence: true, length: {maximum: type_for_attribute(:name).limit}
validates :description, length: {maximum: type_for_attribute(:description).limit}
scope :defaults, ->{ where(user: nil) }
scope :ordered, ->{
cte = Arel::Table.new('cte')
numbered = Arel::Table.new('numbered')
Quantity.with(numbered: numbered(:parent_id, :name)).with_recursive(
cte:
[
Arel::SelectManager.new.project(
numbered[Arel.star],
numbered.cast(numbered[:child_number], 'BINARY').as('path')
).from(numbered).where(numbered[:parent_id].eq(nil)),
Arel::SelectManager.new.project(
numbered[Arel.star],
cte[:path].concat(numbered[:child_number])
).from(numbered).join(cte).on(numbered[:parent_id].eq(cte[:id]))
]
).select(cte[Arel.star]).from(cte).order(cte[:path])
}
scope :numbered, ->(parent_column, order_column){
select(
arel_table[Arel.star],
Arel::Nodes::NamedFunction.new(
'LPAD',
[
Arel::Nodes::NamedFunction.new(
'ROW_NUMBER', []
).over(
Arel::Nodes::Window.new.partition(parent_column).order(order_column)
),
Arel::SelectManager.new.project(
Arel::Nodes::NamedFunction.new(
'LENGTH', [Arel::Nodes::NamedFunction.new('COUNT', [Arel.star])]
)
),
Arel::Nodes.build_quoted('0')
],
).as('child_number')
)
}
def to_s
name
end
def movable?
subunits.empty?
end
def default?
parent_id.nil?
end
end