#!/usr/bin/awk -f
# Transform docker-compose.yml to use an external overlay network for all services
# - Remove top-level networks definition
# - Remove per-service networks block (including ipv4_address and sysnet refs)
# - Insert per-service networks: [argus-sys-net]
# - Append external networks mapping at the end

BEGIN{
  in_top_networks=0; in_services=0; in_service=0; svc_indent=0; curr_name="";
}

function is_service_header(line){ return svc_name(line)!=""; }
function svc_name(line,   m){ if (match(line, /^  ([A-Za-z0-9_-]+):[ ]*$/, m)) return m[1]; return ""; }

function indent_len(s,   n){ n=match(s,/[^ ]/)-1; if(n<0) n=0; return n; }

{
  # Detect entry into top-level sections
  if ($0 ~ /^[A-Za-z0-9_-]+:[ ]*$/ && $0 !~ /^\s/) {
    in_services = ($0 ~ /^services:[ ]*$/);
    # If a new top-level section starts, stop skipping top networks
    in_top_networks = 0;
  }

  # Handle removal of initial top-level 'networks:' block
  if ($0 ~ /^networks:[ ]*$/ && $0 !~ /^\s/) {
    in_top_networks = 1; next;
  }
  if (in_top_networks) {
    # skip until next top-level section (non-indented key)
    next;
  }

  if (in_services) {
    # Track service boundaries
    if (is_service_header($0)) {
      in_service=1; svc_indent=2; networks_inserted=0; curr_name=svc_name($0); print; next;
    }
    if (in_service) {
      # If line is indented <= service indent, we've left this service
      if (indent_len($0) <= svc_indent && $0 !~ /^\s*$/) {
        in_service=0;
      }
    }

    if (in_service) {
      # Skip any existing networks block under the service
      if ($0 ~ /^\s{4}networks:[ ]*$/) { skipping_nets=1; next; }
      if (skipping_nets) {
        if (indent_len($0) <= 4) { skipping_nets=0; }
        else next;
      }

      # After container_name or image, inject networks once
      if (!networks_inserted && ($0 ~ /^\s{4}container_name:/ || $0 ~ /^\s{4}image:/)) {
        print; 
        print "    networks:";
        print "      - argus-sys-net";
        networks_inserted=1; next;
      }
      # no host port injection; bind serves DNS inside overlay only
    }
  }

  print;
}

END{
  print "";
  print "networks:";
  print "  argus-sys-net:";
  print "    external: true";
  print "    name: ${OVERLAY_NET_NAME:-argus-sys-net}";
}