{ ... }:
{
  flake.modules.nixos.backup = 
  { pkgs, config, lib, ... }:
  let
    aqback-create = pkgs.writeShellScriptBin "aqback-create" ''
      ${pkgs.borgbackup}/bin/borg create --stats \
        ${lib.concatStringsSep " " config.aquaticConfig.backup.extra} \
        ${config.aquaticConfig.backup.repo}::{hostname}-{now} \
        ${lib.concatStringsSep " " config.aquaticConfig.backup.dirs}
    '';
    aqback-prune = pkgs.writeShellScriptBin "aqback-prune" ''
      ${pkgs.borgbackup}/bin/borg prune -s \
        --keep-last 4 \
        --keep-hourly ${config.aquaticConfig.backup.keep.hourly} \
        --keep-daily ${config.aquaticConfig.backup.keep.daily} \
        --keep-weekly ${config.aquaticConfig.backup.keep.weekly} \
        --keep-monthly ${config.aquaticConfig.backup.keep.monthly} \
        --keep-yearly ${config.aquaticConfig.backup.keep.yearly} \
        ${config.aquaticConfig.backup.repo}
    '';
    aqback-compact = pkgs.writeShellScriptBin "aqback-compact" ''
      ${pkgs.borgbackup}/bin/borg compact ${config.aquaticConfig.backup.repo}
    '';
    notify-backup-failure = pkgs.writeShellScriptBin "notify-backup-failure" ''
      ${pkgs.curl}/bin/curl -s \
        -H "Title: Backup Error" \
        -H "Tags: warning" \
        -d "${config.networking.hostName} - $1 failed" \
        http://192.168.0.80:4351/etc-notifications
    '';
  in
  {
    options.aquaticConfig.backup = {
      enable = lib.mkEnableOption "Enable Backups";
      repo = lib.mkOption {
        description = "Where to backup to";
      };
      dirs = lib.mkOption {
        type = lib.types.listOf lib.types.str;
        default = [];
        description = "What to backup";
      };
      extra = lib.mkOption {
        type = lib.types.listOf lib.types.str;
        default = [];
        description = "Extra arguments for backup";
      };
      frequency = {
        create = lib.mkOption {
          default="*:0/15";
          description = "How often to create a backup";
        };
        prune = lib.mkOption {
          default="0/2:07:0";
          description = "How often to prune backups";
        };
        compact = lib.mkOption {
          default="*-*-1,14 01:07:00";
          description = "How often compact backups";
        };
      };
      keep = {
        hourly = lib.mkOption {
          default="24";
          description = "How many hourly backups to keep";
        };
        daily = lib.mkOption {
          default="7";
          description = "How many daily backups to keep";
        };
        weekly = lib.mkOption {
          default="4";
          description = "How many weekly backups to keep";
        };
        monthly = lib.mkOption {
          default="6";
          description = "How many monthly backups to keep";
        };
        yearly = lib.mkOption {
          default="3";
          description = "How many yearly backups to keep";
        };
      };
    };

    config = { 

      environment.systemPackages = [
        aqback-create
        aqback-prune
        aqback-compact
        pkgs.borgbackup
      ];

      systemd = {
        services = {
          backup-create = {
            enable = true;
            description = "Create a backup";
            serviceConfig = {
              Type = "simple";
              OnFailure = "backup-notify@%n.service";
              ExecStart = "${pkgs.util-linux}/bin/flock /var/lock/borg-backup.lock ${aqback-create}/bin/aqback-create";
            };
          };
          backup-prune = {
            enable = true;
            description = "Prune old backups";
            serviceConfig = {
              Type = "simple";
              OnFailure = "backup-notify@%n.service";
              ExecStart = "${pkgs.util-linux}/bin/flock /var/lock/borg-backup.lock ${aqback-prune}/bin/aqback-prune";
            };
          };
          backup-compact = {
            enable = true;
            description = "Compact backup repo";
            serviceConfig = {
              Type = "simple";
              OnFailure = "backup-notify@%n.service";
              ExecStart = "${pkgs.util-linux}/bin/flock /var/lock/borg-backup.lock ${aqback-compact}/bin/aqback-compact";
            };
          };
          "backup-notify@" = {
            description = "Notify on backup failure";
            serviceConfig = {
              Type = "oneshot";
              ExecStart = "${notify-backup-failure}/bin/notify-backup-failure %i";
            };
          };
        };
        timers = {
          backup-create = {
            wantedBy = [ "timers.target" ];
            timerConfig = {
              OnCalendar = "${config.aquaticConfig.backup.frequency.create}";
              Persistent=true;
              Unit = "backup-create.service";
            };
          };
          backup-prune = {
            wantedBy = [ "timers.target" ];
            timerConfig = {
              OnCalendar = "${config.aquaticConfig.backup.frequency.prune}";
              Persistent=true;
              Unit = "backup-prune.service";
            };
          };
          backup-compact = {
            wantedBy = [ "timers.target" ];
            timerConfig = {
              OnCalendar= "${config.aquaticConfig.backup.frequency.compact}";
              Persistent=true;
              Unit = "backup-compact.service";
            };
          };
        };
      };
    };
  };
}