module Awspec::Helper
  module Finder
    module Ec2
      def find_ec2(id)
        # instance_id or tag:Name

        # First tries to search by using an educated guess, based on the
        # references below:
        # https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/resource-ids.html
        # https://docs.chef.io/inspec/resources/aws_ec2_instance/
        # This should be faster then just first trying ID when the parameter is
        # clearly not one

        # https://medium.com/@Bakku1505/ruby-start-with-end-with-vs-regular-expressions-59728be0859e
        if id.start_with?('i-') && id.length == 19 && id =~ /^i-[0-9a-f]/
          begin
            res = ec2_client.describe_instances({
                                                  instance_ids: [id]
                                                })
          rescue Aws::EC2::Errors::InvalidInstanceIDNotFound, Aws::EC2::Errors::InvalidInstanceIDMalformed => e
            res = ec2_client.describe_instances({
                                                  filters: [{ name: 'tag:Name', values: [id] }]
                                                })
          end
        else
          begin
            res = ec2_client.describe_instances({
                                                  filters: [{ name: 'tag:Name', values: [id] }]
                                                })
          rescue Aws::EC2::Errors::InvalidInstanceIDNotFound, Aws::EC2::Errors::InvalidInstanceIDMalformed => e
            res = ec2_client.describe_instances({
                                                  instance_ids: [id]
                                                })
            if res.reservations.count > 1
              STDERR.puts "Warning: '#{id}' unexpectedly identified as a valid instance ID during fallback search"
            end
          end
        end

        return nil if res.reservations.count == 0
        return res.reservations.first.instances.single_resource(id) if res.reservations.count == 1
        raise Awspec::DuplicatedResourceTypeError, dup_ec2_instance(id) if res.reservations.count > 1
        raise "Unexpected condition of having reservations = #{res.reservations.count}"
      end

      def dup_ec2_instance(id)
        "Duplicate instances matching id or tag #{id}"
      end

      def find_ec2_attribute(id, attribute)
        res = ec2_client.describe_instance_attribute({
                                                       instance_id: id, attribute: attribute
                                                     })
      end

      def find_ec2_credit_specifications(id)
        res = ec2_client.describe_instance_credit_specifications({
                                                                   instance_ids: [id]
                                                                 })
        res.instance_credit_specifications.first if res.instance_credit_specifications.count == 1
      end

      def find_ec2_status(id)
        res = ec2_client.describe_instance_status({
                                                    instance_ids: [id]
                                                  })
        res.instance_statuses.first if res.instance_statuses.count == 1
      end

      # find_internet_gateway find_vpn_gateway find_customer_gateway
      gateway_types = %w(internet vpn customer transit)
      gateway_types.each do |type|
        define_method 'find_' + type + '_gateway' do |*args|
          gateway_id = args.first
          method_name = 'describe_' + type + '_gateways'
          res = ec2_client.send(
            method_name,
            { filters: [{ name: type + '-gateway-id', values: [gateway_id] }] }
          )
          resource = res[type + '_gateways'].single_resource(gateway_id)
          return resource if resource
          res = ec2_client.send(
            method_name,
            { filters: [{ name: 'tag:Name', values: [gateway_id] }] }
          )
          res[type + '_gateways'].single_resource(gateway_id)
        end
      end

      def find_vpn_connection(vpn_connection_id)
        res = ec2_client.describe_vpn_connections({
                                                    filters: [
                                                      {
                                                        name: 'vpn-connection-id',
                                                        values: [vpn_connection_id]
                                                      }
                                                    ]
                                                  })
        resource = res.vpn_connections.single_resource(vpn_connection_id)
        return resource if resource
        res = ec2_client.describe_vpn_connections({
                                                    filters: [
                                                      {
                                                        name: 'tag:Name',
                                                        values: [vpn_connection_id]
                                                      }
                                                    ]
                                                  })
        res.vpn_connections.single_resource(vpn_connection_id)
      end

      def find_nat_gateway(gateway_id)
        # nat_gateway_id or tag:Name
        begin
          res = ec2_client.describe_nat_gateways({
                                                   nat_gateway_ids: [gateway_id]
                                                 })
        rescue
          res = ec2_client.describe_nat_gateways({
                                                   filter: [{ name: 'tag:Name', values: [gateway_id] }]
                                                 })
        end
        if res.nat_gateways.count == 1
          res.nat_gateways.single_resource(gateway_id)
        elsif res.nat_gateways.count > 1
          raise Awspec::DuplicatedResourceTypeError, "Duplicate nat_gateways matching id or tag #{gateway_id}"
        end
      end

      def find_network_interface(interface_id)
        res = ec2_client.describe_network_interfaces({
                                                       filters: [
                                                         {
                                                           name: 'network-interface-id',
                                                           values: [interface_id]
                                                         }
                                                       ]
                                                     })
        resource = res.network_interfaces.single_resource(interface_id)
        return resource if resource
        res = ec2_client.describe_network_interfaces({
                                                       filters: [{ name: 'tag:Name', values: [interface_id] }]
                                                     })
        res.network_interfaces.single_resource(interface_id)
      end

      def select_ec2_by_vpc_id(vpc_id)
        res = ec2_client.describe_instances({
                                              filters: [{ name: 'vpc-id', values: [vpc_id] }]
                                            })
        instances = []
        res.reservations.each do |reservation|
          reservation.instances.each do |instance|
            instances.push(instance)
          end
        end
        instances
      end

      def select_eip_by_instance_id(id)
        res = ec2_client.describe_addresses({
                                              filters: [{ name: 'instance-id', values: [id] }]
                                            })
        res.addresses
      end

      def select_eip_by_public_ip(id)
        res = ec2_client.describe_addresses({
                                              filters: [{ name: 'public-ip', values: [id] }]
                                            })
        res.addresses
      end

      def select_network_interface_by_instance_id(id)
        res = ec2_client.describe_network_interfaces({
                                                       filters: [{ name: 'attachment.instance-id', values: [id] }]
                                                     })
        res.network_interfaces
      end

      def select_nat_gateway_by_vpc_id(vpc_id)
        res = ec2_client.describe_nat_gateways({
                                                 filter: [{ name: 'vpc-id', values: [vpc_id] }]
                                               })
        res.nat_gateways
      end

      def select_internet_gateway_by_vpc_id(vpc_id)
        res = ec2_client.describe_internet_gateways({
                                                      filters: [{ name: 'attachment.vpc-id', values: [vpc_id] }]
                                                    })
        res.internet_gateways
      end

      def select_network_interface_by_vpc_id(vpc_id)
        res = ec2_client.describe_network_interfaces({
                                                       filters: [{ name: 'vpc-id', values: [vpc_id] }]
                                                     })
        res.network_interfaces
      end

      def find_launch_template(id)
        # launch_template_id or launch_template_name
        begin
          res = ec2_client.describe_launch_templates({
                                                       launch_template_ids: [id]
                                                     })
        rescue
          res = ec2_client.describe_launch_templates({
                                                       launch_template_names: [id]
                                                     })
        end
        res.launch_templates.single_resource(id)
      end

      def find_launch_template_versions(id)
        # launch_template_id or launch_template_name
        res = ec2_client.describe_launch_template_versions({
                                                             launch_template_id: id
                                                           })
      rescue
        res = ec2_client.describe_launch_template_versions({
                                                             launch_template_name: id
                                                           })
      end

      def find_tgw_attachments_by_tgw_id(tgw_id)
        res = ec2_client.describe_transit_gateway_attachments({
                                                                filters: [
                                                                  { name: 'transit-gateway-id', values: [tgw_id] }
                                                                ]
                                                              })
        res.transit_gateway_attachments
      end
    end
  end
end