data "aws_availability_zones" "available" {
  state = "available"
}

resource "aws_ram_resource_share_accepter" "accept_tgw_share" {
  count     = var.accept_invitation ? 1 : 0
  share_arn = var.share_arn
}

resource "aws_ec2_transit_gateway_vpc_attachment" "attach_tgw" {
  depends_on = [aws_ram_resource_share_accepter.accept_tgw_share]

  subnet_ids         = var.subnets
  transit_gateway_id = var.tgw_id
  vpc_id             = var.vpc_id

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

# The VPC automatically tells the TGW about its network, but the
# VPCs themselves need to know what all to send to the TGW. For
# our purposes, it's only RFC1918 addresses. In fact, just 
# 10.0.0.0/8 for now.
resource "aws_route" "route_to_10" {
  for_each = toset(var.route_tables)

  route_table_id         = each.value
  destination_cidr_block = "10.0.0.0/8"
  transit_gateway_id     = var.tgw_id
}