{ lib, hostname, config, ... }:

let
  inherit (lib) mkEnableOption mkOption mkIf types;
  inherit (builtins) readFile fromTOML fromJSON;
  secrets = config.age.secrets;
  cfg = config.networking.private-wireguard;
  port = 51871;
  wgcfg = fromTOML (readFile ./../configs/wireguard.toml);
  allPeers = wgcfg.peers;
  thisPeer = allPeers."${hostname}" or null;
  otherPeers = lib.filterAttrs (n: v: n != hostname) allPeers;
in {
  options.networking.private-wireguard = {
    enable = mkEnableOption "Enable private wireguard vpn connection";
  };

  config = lib.mkIf cfg.enable {
    networking = {
      wireguard.interfaces.wg0 = {
        listenPort = port;
        privateKeyFile =
          secrets."network/${config.networking.hostName}/wireguard_privatekey".path;
        ips = [
          "${wgcfg.subnet4}.${toString thisPeer.ipv4}/${toString wgcfg.mask4}"
        ];

        peers = lib.mapAttrsToList (name: peer:
          {
            allowedIPs = [
              "${wgcfg.subnet4}.${toString peer.ipv4}/${toString wgcfg.mask4}"
            ];
            publicKey = peer.key;
          } // lib.optionalAttrs (peer ? externalIp) {
            endpoint = "${peer.externalIp}:${toString port}";
          } // lib.optionalAttrs (!(thisPeer ? externalIp)) {
            persistentKeepalive = 10;
          }) otherPeers;
      };
    };
  };
}