class AddExternalNumbersFieldToChecks < ActiveRecord::Migration[7.2]
  def change
    reversible do |dir|
      dir.down do
        add_column :checks, :external_number, :integer
        execute <<~SQL
          UPDATE checks SET 
          external_number = printf('%d.%d.%d', external_number_1, external_number_2, external_number_3)
        SQL
        remove_column :checks, :external_number_1, :integer
        remove_column :checks, :external_number_2, :integer
        remove_column :checks, :external_number_3, :integer
      end
    end

    

    reversible do |dir|
      dir.up do
        add_column :checks, :external_number_1, :integer
        add_column :checks, :external_number_2, :integer
        add_column :checks, :external_number_3, :integer
        execute <<~SQL
        UPDATE checks SET
          external_number_1 = CAST(SUBSTRING(external_number, 1, INSTR(external_number, '.') - 1) AS integer),
          external_number_2 = CAST(SUBSTRING(SUBSTRING(external_number, INSTR(external_number, '.') + 1), 1, INSTR(SUBSTRING(external_number, INSTR(external_number, '.') + 1), '.') - 1) AS integer),
          external_number_3 = CAST(SUBSTRING(SUBSTRING(external_number, INSTR(external_number, '.') + 1), INSTR(SUBSTRING(external_number, INSTR(external_number, '.') + 1), '.') + 1) AS integer)
        SQL
        remove_column :checks, :external_number
      end
    end
  end
end