package ec2

import (
	"fmt"
	"log"

	"github.com/aws/aws-sdk-go/aws"
	"github.com/aws/aws-sdk-go/service/ec2"
	"github.com/hashicorp/aws-sdk-go-base/v2/awsv1shim/v2/tfawserr"
	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
	"github.com/hashicorp/terraform-provider-aws/internal/conns"
	"github.com/hashicorp/terraform-provider-aws/internal/tfresource"
)

func ResourceNetworkACLAssociation() *schema.Resource {
	return &schema.Resource{
		Create: resourceNetworkACLAssociationCreate,
		Read:   resourceNetworkACLAssociationRead,
		Delete: resourceNetworkACLAssociationDelete,
		Importer: &schema.ResourceImporter{
			State: schema.ImportStatePassthrough,
		},

		Schema: map[string]*schema.Schema{
			"network_acl_id": {
				Type:     schema.TypeString,
				Required: true,
				ForceNew: true,
			},
			"subnet_id": {
				Type:     schema.TypeString,
				Required: true,
				ForceNew: true,
			},
		},
	}
}

func resourceNetworkACLAssociationCreate(d *schema.ResourceData, meta interface{}) error {
	conn := meta.(*conns.AWSClient).EC2Conn()

	associationID, err := networkACLAssociationCreate(conn, d.Get("network_acl_id").(string), d.Get("subnet_id").(string))

	if err != nil {
		return err
	}

	d.SetId(associationID)

	return resourceNetworkACLAssociationRead(d, meta)
}

func resourceNetworkACLAssociationRead(d *schema.ResourceData, meta interface{}) error {
	conn := meta.(*conns.AWSClient).EC2Conn()

	association, err := FindNetworkACLAssociationByID(conn, d.Id())

	if !d.IsNewResource() && tfresource.NotFound(err) {
		log.Printf("[WARN] EC2 Network ACL Association (%s) not found, removing from state", d.Id())
		d.SetId("")
		return nil
	}

	if err != nil {
		return fmt.Errorf("error reading EC2 Network ACL Association (%s): %w", d.Id(), err)
	}

	d.Set("network_acl_id", association.NetworkAclId)
	d.Set("subnet_id", association.SubnetId)

	return nil
}

func resourceNetworkACLAssociationDelete(d *schema.ResourceData, meta interface{}) error {
	conn := meta.(*conns.AWSClient).EC2Conn()

	input := &ec2.DescribeNetworkAclsInput{
		Filters: BuildAttributeFilterList(map[string]string{
			"association.association-id": d.Id(),
		}),
	}

	nacl, err := FindNetworkACL(conn, input)

	if err != nil {
		return fmt.Errorf("error reading EC2 Network ACL for Association (%s): %w", d.Id(), err)
	}

	vpcID := aws.StringValue(nacl.VpcId)
	defaultNACL, err := FindVPCDefaultNetworkACL(conn, vpcID)

	if err != nil {
		return fmt.Errorf("error reading EC2 VPC (%s) default NACL: %w", vpcID, err)
	}

	if err := networkACLAssociationDelete(conn, d.Id(), aws.StringValue(defaultNACL.NetworkAclId)); err != nil {
		return err
	}

	return nil
}

// networkACLAssociationCreate creates an association between the specified NACL and subnet.
// The subnet's current association is replaced and the new association's ID is returned.
func networkACLAssociationCreate(conn *ec2.EC2, naclID, subnetID string) (string, error) {
	association, err := FindNetworkACLAssociationBySubnetID(conn, subnetID)

	if err != nil {
		return "", fmt.Errorf("error reading EC2 Network ACL Association for EC2 Subnet (%s): %w", subnetID, err)
	}

	input := &ec2.ReplaceNetworkAclAssociationInput{
		AssociationId: association.NetworkAclAssociationId,
		NetworkAclId:  aws.String(naclID),
	}

	log.Printf("[DEBUG] Creating EC2 Network ACL Association: %s", input)
	outputRaw, err := tfresource.RetryWhenAWSErrCodeEquals(propagationTimeout, func() (interface{}, error) {
		return conn.ReplaceNetworkAclAssociation(input)
	}, errCodeInvalidAssociationIDNotFound)

	if err != nil {
		return "", fmt.Errorf("error creating EC2 Network ACL (%s) Association: %w", naclID, err)
	}

	return aws.StringValue(outputRaw.(*ec2.ReplaceNetworkAclAssociationOutput).NewAssociationId), nil
}

// networkACLAssociationsCreate creates associations between the specified NACL and subnets.
func networkACLAssociationsCreate(conn *ec2.EC2, naclID string, subnetIDs []interface{}) error {
	for _, v := range subnetIDs {
		subnetID := v.(string)
		_, err := networkACLAssociationCreate(conn, naclID, subnetID)

		if tfresource.NotFound(err) {
			// Subnet has been deleted.
			continue
		}

		if err != nil {
			return err
		}
	}

	return nil
}

// networkACLAssociationDelete deletes the specified association between a NACL and subnet.
// The subnet's current association is replaced by an association with the VPC's default NACL.
func networkACLAssociationDelete(conn *ec2.EC2, associationID, naclID string) error {
	input := &ec2.ReplaceNetworkAclAssociationInput{
		AssociationId: aws.String(associationID),
		NetworkAclId:  aws.String(naclID),
	}

	log.Printf("[DEBUG] Deleting EC2 Network ACL Association: %s", associationID)
	_, err := conn.ReplaceNetworkAclAssociation(input)

	if tfawserr.ErrCodeEquals(err, errCodeInvalidAssociationIDNotFound) {
		return nil
	}

	if err != nil {
		return fmt.Errorf("error deleting EC2 Network ACL Association (%s): %w", associationID, err)
	}

	return nil
}

// networkACLAssociationDelete deletes the specified NACL associations for the specified subnets.
// Each subnet's current association is replaced by an association with the specified VPC's default NACL.
func networkACLAssociationsDelete(conn *ec2.EC2, vpcID string, subnetIDs []interface{}) error {
	defaultNACL, err := FindVPCDefaultNetworkACL(conn, vpcID)

	if err != nil {
		return fmt.Errorf("error reading EC2 VPC (%s) default NACL: %w", vpcID, err)
	}

	for _, v := range subnetIDs {
		subnetID := v.(string)
		association, err := FindNetworkACLAssociationBySubnetID(conn, subnetID)

		if tfresource.NotFound(err) {
			// Subnet has been deleted.
			continue
		}

		if err != nil {
			return fmt.Errorf("error reading EC2 Network ACL Association for EC2 Subnet (%s): %w", subnetID, err)
		}

		if err := networkACLAssociationDelete(conn, aws.StringValue(association.NetworkAclAssociationId), aws.StringValue(defaultNACL.NetworkAclId)); err != nil {
			return err
		}
	}

	return nil
}
