# frozen_string_literal: true

class <%= @migration_class_name %> < ActiveRecord::Migration<%= ActiveRecord::VERSION::MAJOR < 5 ? '' : '[5.0]' %>
  def up
    execute <<-SQL
    CREATE OR REPLACE VIEW <%= view_name %> AS
      SELECT
        tag_name,
        COUNT(*) AS taggings_count
      FROM (
        SELECT UNNEST
          (<%= source_columns.join(' || ') %>) AS tag_name
        FROM
          <%= source_table_name %>
      ) subquery
      GROUP BY
        tag_name;
    SQL
  end

  def down
    execute <<-SQL
      DROP VIEW <%= view_name %>;
    SQL
  end
end