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

with lib;

{

  systemd.services."notify-failed@" = {
    description = "notify that %i has failed";
    scriptArgs = "%i";
    path = [ pkgs.maxwell-notify ];
    script = ''
      unit=$1
      notify "$unit: failed. last log lines:"
      journalctl -u "$unit" -o cat -n 15 | notify
    '';
  };

  systemd.services.ydns = {
    description = "update ydns address record";
    after    = [ "network-online.target" ];
    startAt  = "*:0/30";

    serviceConfig.Type = "oneshot";
    serviceConfig.environmentFile = config.secrets.environments.ydns;

    path = with pkgs; [ curl cacert gawk iproute ];
    environment = {
      YDNS_HOST      = config.var.hostname;
      CURL_CA_BUNDLE = "${pkgs.cacert}/etc/ssl/certs/ca-bundle.crt";
    };

    script = ''
      update() {
        ret=$(curl -$1 --basic --silent \
          -u "$YDNS_USER:$YDNS_PASSWD" \
          "https://ydns.io/api/v1/update/?host=$YDNS_HOST&ip=$2" || exit 0)

        case "$ret" in
          ok)
            echo "updated successfully: $YDNS_HOST ($2)"
            ;;

          badauth)
            echo "updated failed: $YDNS_HOST (authentication failed)"
            ;;

          *)
            echo "update failed: $YDNS_HOST ($ret)"
            ;;
        esac
      }

      update 4 "$(curl -s -4 https://ydns.io/api/v1/ip)"
      update 6 "$(ip addr show mngtmpaddr | awk '/inet6/{print $2; exit}' | cut -d/ -f1)"
    '';
  };

  system.fsPackages = [ pkgs.nfs-utils ];

  systemd.mounts = lib.singleton
    {
      description = "backup NFS volume";
      after = [ "network-online.target" ];

      what    = "192.168.1.3:/maxwell";
      where   = "/mnt/backup";
      type    = "nfs";
      options = "nolock";
    };

  systemd.services.backup =
  let
    saved = pkgs.writeText "backup-saved" ''
      /etc/lvm
      /var/lib
      /home
    '';

    excluded = pkgs.writeText "backup-excluded" ''
      /var/lib/systemd
      /var/lib/udisks2
      /var/lib/postgresql
      /var/lib/matrix-synapse/media_store/url_cache
      /var/lib/matrix-synapse/media_store/url_cache_thumbnails
    '';

  in {
    description = "system backup";
    after       = [ "network-online.target" "mnt-backup.mount" ];
    bindsTo     = [ "mnt-backup.mount" ];
    startAt     = "*-*-* 03:00";  # every day at 3:00
    onFailure   = [ "notify-failed@backup.service" ];

    serviceConfig = {
      Type = "oneshot";
      PrivateTmp = true;
      LimitNOFILE = 65536;
    };

    environment.BUP_DIR = "/mnt/backup";
    path = with pkgs; [ bup git nfs-utils sudo gzip postgresql ];

    script = ''
      # mount repository
      mkdir -p "$BUP_DIR"

      # init backup
      ! test -e $BUP_DIR/bupindex && bup init

      # build indices and save
      while read -r dir; do
        name=$(basename "$dir")

        echo indexing $name...
        bup index "$dir" --exclude-from="${excluded}"
        echo done

        echo saving $name...
        bup save -n "$name" "$dir"
        echo done
      done < "${saved}"

      # postgresql backup
      dir=/tmp/postgresql
      mkdir -p "$dir"

      echo dumping databases...
      sudo -u postgres pg_dumpall | gzip > "$dir"/db.bak
      echo done

      echo saving...
      bup index "$dir"
      bup save -n postgresql "$dir" --strip-path=/tmp
      echo done

      # prune backups every week
      if test $(( $(date +%s) / 86400 % 7 )) -eq 0; then
        echo pruning...
        bup prune-older --keep-all-for 6m --keep-monthlies-for 2y --unsafe
        echo done
      fi
    '';
  };


  systemd.services.namecoin-update =
  let
    userFile = with config.services.namecoind;
      pkgs.writeText "namecoin.conf" ''
      rpcbind=${rpc.address}
      rpcport=${toString rpc.port}
      rpcuser=${rpc.user}
      rpcpassword=${rpc.password}
      '';
  in {
    description = "update namecoin names";
    after       = [ "namecoind.service" ];
    startAt     = "hourly";
    onFailure   = [ "notify-failed@namecoin-update.service" ];

    path = [ pkgs.namecoind ];
    serviceConfig.Type = "oneshot";
    serviceConfig.ExecStart = "${pkgs.haskellPackages.namecoin-update}/bin/namecoin-update ${userFile}";
  };

}