package aws

import (
	"fmt"
	"log"
	"testing"

	"github.com/aws/aws-sdk-go/service/elb"
	"github.com/hashicorp/terraform/helper/resource"
	"github.com/hashicorp/terraform/terraform"
)

func TestAccAWSELBAttachment_basic(t *testing.T) {
	var conf elb.LoadBalancerDescription

	testCheckInstanceAttached := func(count int) resource.TestCheckFunc {
		return func(*terraform.State) error {
			if len(conf.Instances) != count {
				return fmt.Errorf("instance count does not match")
			}
			return nil
		}
	}

	resource.Test(t, resource.TestCase{
		PreCheck:      func() { testAccPreCheck(t) },
		IDRefreshName: "aws_elb.bar",
		Providers:     testAccProviders,
		CheckDestroy:  testAccCheckAWSELBDestroy,
		Steps: []resource.TestStep{
			resource.TestStep{
				Config: testAccAWSELBAttachmentConfig1,
				Check: resource.ComposeTestCheckFunc(
					testAccCheckAWSELBExists("aws_elb.bar", &conf),
					testCheckInstanceAttached(1),
				),
			},

			resource.TestStep{
				Config: testAccAWSELBAttachmentConfig2,
				Check: resource.ComposeTestCheckFunc(
					testAccCheckAWSELBExists("aws_elb.bar", &conf),
					testCheckInstanceAttached(2),
				),
			},

			resource.TestStep{
				Config: testAccAWSELBAttachmentConfig3,
				Check: resource.ComposeTestCheckFunc(
					testAccCheckAWSELBExists("aws_elb.bar", &conf),
					testCheckInstanceAttached(2),
				),
			},

			resource.TestStep{
				Config: testAccAWSELBAttachmentConfig4,
				Check: resource.ComposeTestCheckFunc(
					testAccCheckAWSELBExists("aws_elb.bar", &conf),
					testCheckInstanceAttached(0),
				),
			},
		},
	})
}

// remove and instance and check that it's correctly re-attached.
func TestAccAWSELBAttachment_drift(t *testing.T) {
	var conf elb.LoadBalancerDescription

	deregInstance := func() {
		conn := testAccProvider.Meta().(*AWSClient).elbconn

		deRegisterInstancesOpts := elb.DeregisterInstancesFromLoadBalancerInput{
			LoadBalancerName: conf.LoadBalancerName,
			Instances:        conf.Instances,
		}

		log.Printf("[DEBUG] deregistering instance %s from ELB", conf.Instances[0].InstanceId)

		_, err := conn.DeregisterInstancesFromLoadBalancer(&deRegisterInstancesOpts)
		if err != nil {
			t.Fatalf("Failure deregistering instances from ELB: %s", err)
		}

	}

	testCheckInstanceAttached := func(count int) resource.TestCheckFunc {
		return func(*terraform.State) error {
			if len(conf.Instances) != count {
				return fmt.Errorf("instance count does not match")
			}
			return nil
		}
	}

	resource.Test(t, resource.TestCase{
		PreCheck:      func() { testAccPreCheck(t) },
		IDRefreshName: "aws_elb.bar",
		Providers:     testAccProviders,
		CheckDestroy:  testAccCheckAWSELBDestroy,
		Steps: []resource.TestStep{
			resource.TestStep{
				Config: testAccAWSELBAttachmentConfig1,
				Check: resource.ComposeTestCheckFunc(
					testAccCheckAWSELBExists("aws_elb.bar", &conf),
					testCheckInstanceAttached(1),
				),
			},

			// remove an instance from the ELB, and make sure it gets re-added
			resource.TestStep{
				Config:    testAccAWSELBAttachmentConfig1,
				PreConfig: deregInstance,
				Check: resource.ComposeTestCheckFunc(
					testAccCheckAWSELBExists("aws_elb.bar", &conf),
					testCheckInstanceAttached(1),
				),
			},
		},
	})
}

// add one attachment
const testAccAWSELBAttachmentConfig1 = `
resource "aws_elb" "bar" {
  availability_zones = ["us-west-2a", "us-west-2b", "us-west-2c"]

  listener {
    instance_port     = 8000
    instance_protocol = "http"
    lb_port           = 80
    lb_protocol       = "http"
  }
}

resource "aws_instance" "foo1" {
  # us-west-2
  ami           = "ami-043a5034"
  instance_type = "t1.micro"
}

resource "aws_elb_attachment" "foo1" {
  elb      = "${aws_elb.bar.id}"
  instance = "${aws_instance.foo1.id}"
}
`

// add a second attachment
const testAccAWSELBAttachmentConfig2 = `
resource "aws_elb" "bar" {
  availability_zones = ["us-west-2a", "us-west-2b", "us-west-2c"]

  listener {
    instance_port     = 8000
    instance_protocol = "http"
    lb_port           = 80
    lb_protocol       = "http"
  }
}

resource "aws_instance" "foo1" {
  # us-west-2
  ami           = "ami-043a5034"
  instance_type = "t1.micro"
}

resource "aws_instance" "foo2" {
  # us-west-2
  ami           = "ami-043a5034"
  instance_type = "t1.micro"
}

resource "aws_elb_attachment" "foo1" {
  elb      = "${aws_elb.bar.id}"
  instance = "${aws_instance.foo1.id}"
}

resource "aws_elb_attachment" "foo2" {
  elb      = "${aws_elb.bar.id}"
  instance = "${aws_instance.foo2.id}"
}
`

// swap attachments between resources
const testAccAWSELBAttachmentConfig3 = `
resource "aws_elb" "bar" {
  availability_zones = ["us-west-2a", "us-west-2b", "us-west-2c"]

  listener {
    instance_port     = 8000
    instance_protocol = "http"
    lb_port           = 80
    lb_protocol       = "http"
  }
}

resource "aws_instance" "foo1" {
  # us-west-2
  ami           = "ami-043a5034"
  instance_type = "t1.micro"
}

resource "aws_instance" "foo2" {
  # us-west-2
  ami           = "ami-043a5034"
  instance_type = "t1.micro"
}

resource "aws_elb_attachment" "foo1" {
  elb      = "${aws_elb.bar.id}"
  instance = "${aws_instance.foo2.id}"
}

resource "aws_elb_attachment" "foo2" {
  elb      = "${aws_elb.bar.id}"
  instance = "${aws_instance.foo1.id}"
}
`

// destroy attachments
const testAccAWSELBAttachmentConfig4 = `
resource "aws_elb" "bar" {
  availability_zones = ["us-west-2a", "us-west-2b", "us-west-2c"]

  listener {
    instance_port     = 8000
    instance_protocol = "http"
    lb_port           = 80
    lb_protocol       = "http"
  }
}
`