package aws

import (
	"fmt"
	"math/rand"
	"testing"
	"time"

	"github.com/hashicorp/terraform/helper/resource"
	"github.com/hashicorp/terraform/terraform"

	"github.com/hashicorp/aws-sdk-go/aws"
	"github.com/hashicorp/aws-sdk-go/gen/rds"
)

func TestAccAWSDBInstance(t *testing.T) {
	var v rds.DBInstance

	resource.Test(t, resource.TestCase{
		PreCheck:     func() { testAccPreCheck(t) },
		Providers:    testAccProviders,
		CheckDestroy: testAccCheckAWSDBInstanceDestroy,
		Steps: []resource.TestStep{
			resource.TestStep{
				Config: testAccAWSDBInstanceConfig,
				Check: resource.ComposeTestCheckFunc(
					testAccCheckAWSDBInstanceExists("aws_db_instance.bar", &v),
					testAccCheckAWSDBInstanceAttributes(&v),
					resource.TestCheckResourceAttr(
						"aws_db_instance.bar", "allocated_storage", "10"),
					resource.TestCheckResourceAttr(
						"aws_db_instance.bar", "engine", "mysql"),
					resource.TestCheckResourceAttr(
						"aws_db_instance.bar", "engine_version", "5.6.21"),
					resource.TestCheckResourceAttr(
						"aws_db_instance.bar", "instance_class", "db.t1.micro"),
					resource.TestCheckResourceAttr(
						"aws_db_instance.bar", "name", "baz"),
					resource.TestCheckResourceAttr(
						"aws_db_instance.bar", "username", "foo"),
					resource.TestCheckResourceAttr(
						"aws_db_instance.bar", "parameter_group_name", "default.mysql5.6"),
				),
			},
		},
	})
}

func testAccCheckAWSDBInstanceDestroy(s *terraform.State) error {
	conn := testAccProvider.Meta().(*AWSClient).rdsconn

	for _, rs := range s.RootModule().Resources {
		if rs.Type != "aws_db_instance" {
			continue
		}

		// Try to find the Group
		resp, err := conn.DescribeDBInstances(
			&rds.DescribeDBInstancesMessage{
				DBInstanceIdentifier: aws.String(rs.Primary.ID),
			})

		if err == nil {
			if len(resp.DBInstances) != 0 &&
				*resp.DBInstances[0].DBInstanceIdentifier == rs.Primary.ID {
				return fmt.Errorf("DB Instance still exists")
			}
		}

		// Verify the error
		newerr, ok := err.(*aws.APIError)
		if !ok {
			return err
		}
		if newerr.Code != "InvalidDBInstance.NotFound" {
			return err
		}
	}

	return nil
}

func testAccCheckAWSDBInstanceAttributes(v *rds.DBInstance) resource.TestCheckFunc {
	return func(s *terraform.State) error {

		if *v.Engine != "mysql" {
			return fmt.Errorf("bad engine: %#v", *v.Engine)
		}

		if *v.EngineVersion != "5.6.21" {
			return fmt.Errorf("bad engine_version: %#v", *v.EngineVersion)
		}

		if *v.BackupRetentionPeriod != 0 {
			return fmt.Errorf("bad backup_retention_period: %#v", *v.BackupRetentionPeriod)
		}

		return nil
	}
}

func testAccCheckAWSDBInstanceExists(n string, v *rds.DBInstance) resource.TestCheckFunc {
	return func(s *terraform.State) error {
		rs, ok := s.RootModule().Resources[n]
		if !ok {
			return fmt.Errorf("Not found: %s", n)
		}

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

		conn := testAccProvider.Meta().(*AWSClient).rdsconn

		opts := rds.DescribeDBInstancesMessage{
			DBInstanceIdentifier: aws.String(rs.Primary.ID),
		}

		resp, err := conn.DescribeDBInstances(&opts)

		if err != nil {
			return err
		}

		if len(resp.DBInstances) != 1 ||
			*resp.DBInstances[0].DBInstanceIdentifier != rs.Primary.ID {
			return fmt.Errorf("DB Instance not found")
		}

		*v = resp.DBInstances[0]

		return nil
	}
}

// Database names cannot collide, and deletion takes so long, that making the
// name a bit random helps so able we can kill a test that's just waiting for a
// delete and not be blocked on kicking off another one.
var testAccAWSDBInstanceConfig = fmt.Sprintf(`
resource "aws_db_instance" "bar" {
	identifier = "foobarbaz-test-terraform-%d"

	allocated_storage = 10
	engine = "mysql"
	engine_version = "5.6.21"
	instance_class = "db.t1.micro"
	name = "baz"
	password = "barbarbarbar"
	username = "foo"

	backup_retention_period = 0

	parameter_group_name = "default.mysql5.6"
}`, rand.New(rand.NewSource(time.Now().UnixNano())).Int())