{ config, lib, pkgs, ... }:

with lib;

let
  cfg = config.plasmacloud.network;
  clusterCfg = config.plasmacloud.cluster;

  # BGP peer type for FiberLB
  bgpPeerType = types.submodule {
    options = {
      address = mkOption {
        type = types.str;
        description = "Peer IP address (ToR switch, upstream router)";
        example = "192.168.1.1";
      };

      asn = mkOption {
        type = types.int;
        description = "Peer AS number";
        example = 65001;
      };

      description = mkOption {
        type = types.str;
        default = "";
        description = "Human-readable peer description";
        example = "ToR switch rack1";
      };
    };
  };

in {
  options.plasmacloud.network = {
    fiberlbBgp = {
      enable = mkEnableOption "FiberLB BGP VIP advertisement";

      vips = mkOption {
        type = types.listOf types.str;
        default = [];
        description = "VIPs to advertise via BGP (CIDR notation)";
        example = [ "203.0.113.10/32" "203.0.113.11/32" ];
      };

      peers = mkOption {
        type = types.listOf bgpPeerType;
        default = [];
        description = "BGP peers (ToR switches, upstream routers)";
        example = literalExpression ''
          [
            { address = "192.168.1.1"; asn = 65001; description = "ToR switch rack1"; }
            { address = "192.168.1.2"; asn = 65001; description = "ToR switch rack2"; }
          ]
        '';
      };

      routerId = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "BGP router ID (auto-detected from primary IP if null)";
      };
    };

    prismnetIntegration = {
      enable = mkEnableOption "PrismNET OVN integration";
    };
  };

  config = mkMerge [
    # FiberLB BGP configuration
    (mkIf cfg.fiberlbBgp.enable {
      # Assertions
      assertions = [
        {
          assertion = clusterCfg.bgp.asn > 0;
          message = "plasmacloud.cluster.bgp.asn must be configured for FiberLB BGP";
        }
        {
          assertion = (length cfg.fiberlbBgp.vips) > 0;
          message = "plasmacloud.network.fiberlbBgp.vips must contain at least one VIP";
        }
        {
          assertion = (length cfg.fiberlbBgp.peers) > 0;
          message = "plasmacloud.network.fiberlbBgp.peers must contain at least one BGP peer";
        }
      ];

      # Wire to nix-nos.bgp (Layer 1)
      nix-nos.enable = true;
      nix-nos.bgp = {
        enable = true;
        backend = "gobgp";  # FiberLB uses GoBGP
        asn = clusterCfg.bgp.asn;

        # Auto-detect router ID from primary IP or use configured value
        routerId =
          if cfg.fiberlbBgp.routerId != null
          then cfg.fiberlbBgp.routerId
          else
            # Fallback to a simple IP extraction from node config
            let
              hostname = config.networking.hostName;
              node = clusterCfg.nodes.${hostname} or null;
            in
            if node != null then node.ip else "127.0.0.1";

        peers = cfg.fiberlbBgp.peers;

        # Convert VIPs to BGP announcements
        announcements = map (vip: { prefix = vip; }) cfg.fiberlbBgp.vips;
      };

      # FiberLB service configuration (if FiberLB is enabled)
      # Note: This assumes fiberlb service is defined elsewhere
      # services.fiberlb.bgp.gobgpAddress = mkIf (config.services.fiberlb.enable or false) "127.0.0.1:50051";
    })

    # PrismNET OVN integration
    (mkIf cfg.prismnetIntegration.enable {
      # Enable OVN Controller
      virtualisation.switch.enable = true;
      virtualisation.ovn = {
        enable = true;
        controller = {
          enable = true;
          # Use Geneve encapsulation to avoid VXLAN VNI limitations and allow richer metadata
          encapType = "geneve";
          # Auto-detect IP from cluster config
          encapIp = 
            let
              hostname = config.networking.hostName;
              node = clusterCfg.nodes.${hostname} or null;
            in
            if node != null then node.ip else "127.0.0.1";
        };
      };
    })
  ];
}