spree/spree

class FixSpreeStockItemUniqueIndex < ActiveRecord::Migration[6.1]
  def change
    remove_index :spree_stock_items, name: 'stock_item_by_loc_var_id_deleted_at' if index_exists?(:spree_stock_items, [:stock_location_id, :variant_id], name: 'stock_item_by_loc_var_id_deleted_at')

    unless index_exists?(:spree_stock_items, ['variant_id', 'stock_location_id'], name: 'index_spree_stock_items_unique_without_deleted_at')
      # MySQL doesn't support partial indexes
      if ActiveRecord::Base.connection.adapter_name == 'Mysql2'
        reversible do |dir|
          dir.up do
            execute <<-SQL
              CREATE UNIQUE INDEX index_spree_stock_items_unique_without_deleted_at
              ON spree_stock_items(
                stock_location_id,
                variant_id,
                (COALESCE(deleted_at, CAST('1970-01-01' AS DATETIME)))
              );
            SQL
          end

          dir.down do
            remove_index :spree_stock_items, name: :index_spree_stock_items_unique_without_deleted_at
          end
        end
      else
        add_index(
          :spree_stock_items,
          ['variant_id', 'stock_location_id'],
          name: 'index_spree_stock_items_unique_without_deleted_at',
          unique: true,
          where: 'deleted_at IS NULL',
        )
      end
    end
  end
end