# frozen_string_literal: true

class AddPartitionsView < ActiveRecord::Migration[6.0]
  DOWNTIME = false

  def up
    execute(<<~SQL)
      CREATE OR REPLACE VIEW postgres_partitions AS
      SELECT
        pg_namespace.nspname::text || '.'::text || pg_class.relname::text AS identifier,
        pg_class.oid AS oid,
        pg_namespace.nspname AS schema,
        pg_class.relname AS name,
        parent_namespace.nspname::text || '.'::text || parent_class.relname::text AS parent_identifier,
        pg_get_expr(pg_class.relpartbound, pg_inherits.inhrelid) AS condition
      FROM pg_class
      INNER JOIN pg_namespace
      ON pg_namespace.oid = pg_class.relnamespace
      INNER JOIN pg_inherits
      ON pg_class.oid = pg_inherits.inhrelid
      INNER JOIN pg_class parent_class
      ON pg_inherits.inhparent = parent_class.oid
      INNER JOIN pg_namespace parent_namespace
      ON parent_class.relnamespace = parent_namespace.oid
      WHERE pg_class.relispartition
      AND pg_namespace.nspname IN (
        current_schema(),
        'gitlab_partitions_dynamic',
        'gitlab_partitions_static'
      )
    SQL
  end

  def down
    execute(<<~SQL)
      DROP VIEW IF EXISTS postgres_partitions
    SQL
  end
end