# 10.0.0.0/24 & fd09:8d46:0b26::/48 - phys clients (lan).
# 10.0.1.0/24 - vpn clients.
{
  config,
  const,
  lib,
  util,
  ...
}:
let
  internal = "10.0.0.1"; # Lan host IP address.
  internal6 = "fd09:8d46:b26:0:8079:82ff:fe1a:916a"; # Lan host IP6 address.

  lan = "br0"; # Lan interface.
  wan = "enp8s0"; # Wan interface.
in
{
  # Disable systemd-resolved for DNS server.
  services.resolved.enable = false;

  # NOTE: Debugging.
  # systemd.services."systemd-networkd".environment.SYSTEMD_LOG_LEVEL = "debug";

  # Wan configuration.
  # REF: https://nixos.wiki/wiki/Systemd-networkd
  # REF: man 5 systemd.network
  # REF: Wifi config: https://openwrt.org/docs/guide-user/network/wifi/wifiextenders/bridgedap#wireless_access_point_-_dumb_access_point
  systemd.network = {
    enable = true;
    networks = {
      "10-${wan}" = {
        matchConfig.Name = wan;
        linkConfig.RequiredForOnline = "carrier";
        dhcpV4Config = {
          ClientIdentifier = "mac";
          UseDNS = false;
          UseRoutes = true;
        };
        dhcpV6Config = {
          DUIDRawData = "00:03:00:01:a8:a1:59:47:fd:a2";
          DUIDType = "vendor";
          UseDNS = false;
          WithoutRA = "solicit";
          # PrefixDelegationHint = "::/56";
        };
        networkConfig = {
          DHCP = "yes";
          DNS = "1.1.1.1";
          IPv6AcceptRA = true;
          IPv6SendRA = false;
          DHCPPrefixDelegation = true;
        };
        dhcpPrefixDelegationConfig = {
          UplinkInterface = ":self";
          SubnetId = 0;
          Announce = false;
        };
      };
      "20-enp6s0f0" = {
        linkConfig.RequiredForOnline = "enslaved";
        matchConfig.Name = "enp6s0f0";
        networkConfig.Bridge = lan;
      };
      "20-enp6s0f1" = {
        linkConfig.RequiredForOnline = "enslaved";
        matchConfig.Name = "enp6s0f1";
        networkConfig.Bridge = lan;
      };
      "20-enp7s0f0" = {
        linkConfig.RequiredForOnline = "enslaved";
        matchConfig.Name = "enp7s0f0";
        networkConfig.Bridge = lan;
      };
      "20-enp7s0f1" = {
        linkConfig.RequiredForOnline = "enslaved";
        matchConfig.Name = "enp7s0f1";
        networkConfig.Bridge = lan;
      };
      "30-${lan}" = {
        matchConfig.Name = lan;
        linkConfig.RequiredForOnline = "carrier";
        address = [
          "${internal}/24"
          # "${internal6}/48"
        ];
        networkConfig = {
          DHCPPrefixDelegation = true;
          DHCPServer = true;
          IPv6AcceptRA = false;
          IPv6SendRA = true;
        };
        ipv6SendRAConfig = {
          EmitDNS = true;
          DNS = internal6;
        };
        ipv6Prefixes = [
          {
            Assign = true;
            Prefix = "${internal6}/64";
          }
        ];
        dhcpPrefixDelegationConfig = {
          Announce = true;
          SubnetId = 1;
          UplinkInterface = wan;
        };
        dhcpServerConfig = {
          DNS = internal;
          DefaultLeaseTimeSec = "12h";
          EmitDNS = true;
          EmitNTP = true;
          EmitRouter = true;
          EmitTimezone = true;
          MaxLeaseTimeSec = "24h";
          PoolOffset = 100;
          PoolSize = 150;
          ServerAddress = "${internal}/24";
          Timezone = const.timeZone;
          UplinkInterface = wan;
        };
        dhcpServerStaticLeases =
          let
            mkStatic = Address: MACAddress: { inherit Address MACAddress; };
          in
          [
            # TODO: Add pocket.
            (mkStatic "10.0.0.2" "9c:9d:7e:8e:3d:c7") # Wifi AP.
            (mkStatic "10.0.0.3" "d8:bb:c1:cc:da:30") # Desktop.
            (mkStatic "10.0.0.4" "2c:be:eb:52:53:2b") # Phone.
            (mkStatic "10.0.0.5" "14:85:7f:eb:6c:25") # Work.
            (mkStatic "10.0.0.6" "08:38:e6:31:54:b6") # Tablet.
            (mkStatic "10.0.0.7" "2c:f0:5d:3b:07:78") # Dasha.
            (mkStatic "10.0.0.8" "ac:5f:ea:ef:b5:05") # Dasha phone.
            (mkStatic "10.0.0.9" "10:b1:df:ea:18:57") # Laptop.
            (mkStatic "10.0.0.10" "9c:1c:37:62:3f:d5") # Printer.
            (mkStatic "10.0.0.11" "dc:a6:32:f5:77:95") # RPi.
            (mkStatic "10.0.0.12" "ec:9c:32:ad:bc:4a") # Camera.
            (mkStatic "10.0.0.13" "c0:a5:e8:b5:d9:16") # Max.
          ];
      };
    };

    netdevs = {
      "10-${lan}" = {
        netdevConfig = {
          Kind = "bridge";
          Name = lan;
        };
      };
    };
  };

  networking = {
    dhcpcd.enable = false;
    useDHCP = false;
    useNetworkd = true;
    networkmanager.enable = lib.mkForce false;
    firewall = {
      enable = true;
      extraCommands = util.trimTabs ''
        				# Wan access for 10.0.0.0/24 subnet.
        				iptables -t nat -A POSTROUTING -s 10.0.0.0/24 -d 0/0 -o ${wan} -j MASQUERADE

        				# Full access from Lan.
        				iptables  -I INPUT -j ACCEPT -i ${lan} -d ${internal}
        				ip6tables -I INPUT -j ACCEPT -i ${lan} -d ${internal6}

        				# Public email server.
        				ip46tables -I INPUT -j ACCEPT -i ${wan} -p tcp --dport 25

        				# Public VPN service.
        				ip46tables -I INPUT -j ACCEPT -i ${wan} -p udp --dport 22145
        				iptables -I INPUT -j ACCEPT -s 10.0.1.0/24 -d ${internal}

        				# Public Nginx.
        				ip46tables -I INPUT -j ACCEPT -i ${wan} -p tcp --dport 443

        				# Deluge torrenting ports.
        				ip46tables -I INPUT -j ACCEPT -i ${wan} -p tcp --dport 54630
        				ip46tables -I INPUT -j ACCEPT -i ${wan} -p udp --dport 54630
        				ip46tables -I INPUT -j ACCEPT -i ${wan} -p tcp --dport 54631
        				ip46tables -I INPUT -j ACCEPT -i ${wan} -p udp --dport 54631

        				# Terraria server.
        				ip46tables -I INPUT -j ACCEPT -i ${wan} -p tcp --dport 22777

        				# Mumble.
        				ip46tables -I INPUT -j ACCEPT -i ${wan} -p tcp --dport 22666
        				ip46tables -I INPUT -j ACCEPT -i ${wan} -p udp --dport 22666

        				# Public SSH access.
        				# ip46tables -I INPUT -j ACCEPT -i ${wan} -p tcp --dport 22143
        			'';
    };
  };
}