package aws

import (
	"fmt"
	"testing"

	"github.com/hashicorp/terraform/helper/resource"
	"github.com/hashicorp/terraform/terraform"
	"github.com/mitchellh/goamz/ec2"
)

func TestAccAWSInternetGateway(t *testing.T) {
	var v, v2 ec2.InternetGateway

	testNotEqual := func(*terraform.State) error {
		if len(v.Attachments) == 0 {
			return fmt.Errorf("IG A is not attached")
		}
		if len(v2.Attachments) == 0 {
			return fmt.Errorf("IG B is not attached")
		}

		id1 := v.Attachments[0].VpcId
		id2 := v2.Attachments[0].VpcId
		if id1 == id2 {
			return fmt.Errorf("Both attachment IDs are the same")
		}

		return nil
	}

	resource.Test(t, resource.TestCase{
		PreCheck:     func() { testAccPreCheck(t) },
		Providers:    testAccProviders,
		CheckDestroy: testAccCheckInternetGatewayDestroy,
		Steps: []resource.TestStep{
			resource.TestStep{
				Config: testAccInternetGatewayConfig,
				Check: resource.ComposeTestCheckFunc(
					testAccCheckInternetGatewayExists(
						"aws_internet_gateway.foo", &v),
				),
			},

			resource.TestStep{
				Config: testAccInternetGatewayConfigChangeVPC,
				Check: resource.ComposeTestCheckFunc(
					testAccCheckInternetGatewayExists(
						"aws_internet_gateway.foo", &v2),
					testNotEqual,
				),
			},
		},
	})
}

func testAccCheckInternetGatewayDestroy(s *terraform.State) error {
	conn := testAccProvider.ec2conn

	for _, rs := range s.Resources {
		if rs.Type != "aws_internet_gateway" {
			continue
		}

		// Try to find the resource
		resp, err := conn.DescribeInternetGateways(
			[]string{rs.ID}, ec2.NewFilter())
		if err == nil {
			if len(resp.InternetGateways) > 0 {
				return fmt.Errorf("still exist.")
			}

			return nil
		}

		// Verify the error is what we want
		ec2err, ok := err.(*ec2.Error)
		if !ok {
			return err
		}
		if ec2err.Code != "InvalidInternetGatewayID.NotFound" {
			return err
		}
	}

	return nil
}

func testAccCheckInternetGatewayExists(n string, ig *ec2.InternetGateway) resource.TestCheckFunc {
	return func(s *terraform.State) error {
		rs, ok := s.Resources[n]
		if !ok {
			return fmt.Errorf("Not found: %s", n)
		}

		if rs.ID == "" {
			return fmt.Errorf("No ID is set")
		}

		conn := testAccProvider.ec2conn
		resp, err := conn.DescribeInternetGateways(
			[]string{rs.ID}, ec2.NewFilter())
		if err != nil {
			return err
		}
		if len(resp.InternetGateways) == 0 {
			return fmt.Errorf("InternetGateway not found")
		}

		*ig = resp.InternetGateways[0]

		return nil
	}
}

const testAccInternetGatewayConfig = `
resource "aws_vpc" "foo" {
	cidr_block = "10.1.0.0/16"
}

resource "aws_internet_gateway" "foo" {
	vpc_id = "${aws_vpc.foo.id}"
}
`

const testAccInternetGatewayConfigChangeVPC = `
resource "aws_vpc" "foo" {
	cidr_block = "10.1.0.0/16"
}

resource "aws_vpc" "bar" {
	cidr_block = "10.2.0.0/16"
}

resource "aws_internet_gateway" "foo" {
	vpc_id = "${aws_vpc.bar.id}"
}
`