#----------------------------------------------------------------------------
# INTERNAL LB
#----------------------------------------------------------------------------
resource "aws_alb" "internal" {
  name                       = "${local.server_name_stem}-alb-internal-${var.environment}"
  security_groups            = [aws_security_group.alb_internal.id]
  internal                   = true
  subnets                    = var.public_subnets
  load_balancer_type         = "application"
  drop_invalid_header_fields = true

  access_logs {
    bucket  = "xdr-elb-${var.environment}"
    enabled = true
  }

  idle_timeout = 1200

  tags = merge(local.standard_tags, var.tags, { Name = "${local.server_name_stem}-alb-internal-${var.environment}" })
}

# Create a new target group
resource "aws_alb_target_group" "internal" {
  name     = "${local.server_name_stem}-alb-targets"
  port     = 443
  protocol = "HTTPS"
  vpc_id   = var.vpc_id

  health_check {
    protocol            = "HTTPS"
    port                = "443"
    path                = "/"
    matcher             = "200,302"
    timeout             = "4"
    interval            = "5"
    unhealthy_threshold = 2
    healthy_threshold   = 2
  }

  #stickiness {
  #  type    = "lb_cookie"
  #  enabled = false
  #}

  tags = merge(local.standard_tags, var.tags)
}

resource "aws_lb_target_group_attachment" "internal" {
  count            = local.instance_count
  target_group_arn = aws_alb_target_group.internal.arn
  target_id        = aws_instance.instance[count.index].id
  port             = 443
}

# Create a new alb listener
resource "aws_alb_listener" "https_internal" {
  load_balancer_arn = aws_alb.internal.arn
  port              = "443"
  protocol          = "HTTPS"
  ssl_policy        = "ELBSecurityPolicy-FS-1-2-Res-2020-10" # PFS, TLS1.2, and GCM; most "restrictive" policy
  certificate_arn   = aws_acm_certificate.cert_private.arn

  default_action {
    target_group_arn = aws_alb_target_group.internal.arn
    type             = "forward"
  }
}

resource "aws_lb_listener" "listener_http" {
  load_balancer_arn = aws_alb.internal.arn
  port              = "80"
  protocol          = "HTTP"

  default_action {
    type = "redirect"

    redirect {
      port        = "443"
      protocol    = "HTTPS"
      status_code = "HTTP_301"
    }
  }
}

#----------------------------------------------------------------------------
# DNS Entry
#----------------------------------------------------------------------------
module "alb_private_dns_record" {
  source = "../../submodules/dns/private_CNAME_record"

  name             = local.server_name_stem
  target_dns_names = [aws_alb.internal.dns_name]
  dns_info         = var.dns_info

  providers = {
    aws.c2 = aws.c2
  }
}

#----------------------------------------------------------------------------
# ALB Security Group
#----------------------------------------------------------------------------
resource "aws_security_group" "alb_internal" {
  vpc_id      = var.vpc_id
  name        = "${local.server_name_stem}-alb-sg-internal"
  description = "ALB for ${local.server_name_stem}"
  tags        = merge(local.standard_tags, var.tags)
}

#----------------------------------------------------------------------------
# INGRESS
#----------------------------------------------------------------------------
resource "aws_security_group_rule" "internal_http_from_local" {
  type              = "ingress"
  description       = "HTTP - Inbound from internal VPCs"
  from_port         = "80"
  to_port           = "80"
  protocol          = "tcp"
  cidr_blocks       = local.supernets
  security_group_id = aws_security_group.alb_internal.id
}

resource "aws_security_group_rule" "internal_https_from_local" {
  type              = "ingress"
  description       = "HTTPS - Inbound from internal_vpc"
  from_port         = "443"
  to_port           = "443"
  protocol          = "tcp"
  cidr_blocks       = local.supernets
  security_group_id = aws_security_group.alb_internal.id
}

#----------------------------------------------------------------------------
# EGRESS
#----------------------------------------------------------------------------
resource "aws_security_group_rule" "internal_alb_to_server" {
  type                     = "egress"
  description              = "HTTPS to the Server"
  from_port                = "443"
  to_port                  = "443"
  protocol                 = "tcp"
  source_security_group_id = aws_security_group.instance.id
  security_group_id        = aws_security_group.alb_internal.id
}