# frozen_string_literal: true

module Database
  module MultipleDatabases
    def skip_if_multiple_databases_not_setup
      skip 'Skipping because multiple databases not set up' unless Gitlab::Database.has_config?(:ci)
    end

    # The usage of this method switches temporarily used `connection_handler`
    # allowing full manipulation of ActiveRecord::Base connections without
    # having side effects like:
    # - misaligned transactions since this is managed by `BeforeAllAdapter`
    # - removal of primary connections
    #
    # The execution within a block ensures safe cleanup of all allocated resources.
    #
    # rubocop:disable Database/MultipleDatabases
    def with_reestablished_active_record_base(reconnect: true)
      connection_classes = ActiveRecord::Base.connection_handler.connection_pool_names.map(&:constantize).to_h do |klass|
        [klass, klass.connection_db_config]
      end

      original_handler = ActiveRecord::Base.connection_handler
      new_handler = ActiveRecord::ConnectionAdapters::ConnectionHandler.new
      ActiveRecord::Base.connection_handler = new_handler

      if reconnect
        connection_classes.each { |klass, db_config| klass.establish_connection(db_config) }
      end

      yield
    ensure
      ActiveRecord::Base.connection_handler = original_handler
      new_handler&.clear_all_connections!
    end
    # rubocop:enable Database/MultipleDatabases
  end

  module ActiveRecordBaseEstablishConnection
    def establish_connection(*args)
      # rubocop:disable Database/MultipleDatabases
      if connected? && connection&.transaction_open? && ActiveRecord::Base.connection_handler == ActiveRecord::Base.default_connection_handler
        raise "Cannot re-establish '#{self}.establish_connection' within an open transaction (#{connection&.open_transactions.to_i}). " \
          "Use `with_reestablished_active_record_base` instead or add `:reestablished_active_record_base` to rspec context."
      end
      # rubocop:enable Database/MultipleDatabases

      super
    end
  end
end

RSpec.configure do |config|
  config.around(:each, :reestablished_active_record_base) do |example|
    with_reestablished_active_record_base(reconnect: example.metadata.fetch(:reconnect, true)) do
      example.run
    end
  end
end

ActiveRecord::Base.singleton_class.prepend(::Database::ActiveRecordBaseEstablishConnection) # rubocop:disable Database/MultipleDatabases
