# fwupd daemon.
{
  config,
  lib,
  pkgs,
  ...
}:
let
  cfg = config.services.fwupd;

  format = pkgs.formats.ini {
    listToValue = l: lib.concatStringsSep ";" (map (s: lib.generators.mkValueStringDefault { } s) l);
    mkKeyValue = lib.generators.mkKeyValueDefault { } "=";
  };

  customEtc = {
    "fwupd/fwupd.conf" = {
      source = format.generate "fwupd.conf" (
        {
          fwupd = cfg.daemonSettings;
        }
        // lib.optionalAttrs (lib.length (lib.attrNames cfg.uefiCapsuleSettings) != 0) {
          uefi_capsule = cfg.uefiCapsuleSettings;
        }
      );
      # fwupd tries to chmod the file if it doesn't have the right permissions
      mode = "0640";
    };
  };

  originalEtc =
    let
      mkEtcFile = n: lib.nameValuePair n { source = "${cfg.package}/etc/${n}"; };
      etcFiles = lib.filter (
        f: config.boot.loader.grub.enable || f != "grub.d/35_fwupd"
      ) cfg.package.filesInstalledToEtc;
    in
    lib.listToAttrs (map mkEtcFile etcFiles);
  extraTrustedKeys =
    let
      mkName = p: "pki/fwupd/${baseNameOf p}";
      mkEtcFile = p: lib.nameValuePair (mkName p) { source = p; };
    in
    lib.listToAttrs (map mkEtcFile cfg.extraTrustedKeys);

  enableRemote = base: remote: {
    "fwupd/remotes.d/${remote}.conf" = {
      source = pkgs.runCommand "${remote}-enabled.conf" { } ''
        sed "s,^Enabled=false,Enabled=true," \
        "${base}/etc/fwupd/remotes.d/${remote}.conf" > "$out"
      '';
    };
  };
  remotes =
    (lib.foldl' (
      configFiles: remote: configFiles // (enableRemote cfg.package remote)
    ) { } cfg.extraRemotes)
    // (
      # We cannot include the file in $out and rely on filesInstalledToEtc
      # to install it because it would create a cyclic dependency between
      # the outputs. We also need to enable the remote,
      # which should not be done by default.
      lib.optionalAttrs (cfg.daemonSettings.TestDevices or false) (
        enableRemote cfg.package.installedTests "fwupd-tests"
      )
    );

in
{

  ###### interface
  options = {
    services.fwupd = {
      enable = lib.mkOption {
        type = lib.types.bool;
        default = false;
        description = ''
          Whether to enable fwupd, a DBus service that allows
          applications to update firmware.
        '';
      };

      extraTrustedKeys = lib.mkOption {
        type = lib.types.listOf lib.types.path;
        default = [ ];
        example = lib.literalExpression "[ /etc/nixos/fwupd/myfirmware.pem ]";
        description = ''
          Installing a public key allows firmware signed with a matching private key to be recognized as trusted, which may require less authentication to install than for untrusted files. By default trusted firmware can be upgraded (but not downgraded) without the user or administrator password. Only very few keys are installed by default.
        '';
      };

      extraRemotes = lib.mkOption {
        type = with lib.types; listOf str;
        default = [ ];
        example = [ "lvfs-testing" ];
        description = ''
          Enables extra remotes in fwupd. See `/etc/fwupd/remotes.d`.
        '';
      };

      package = lib.mkPackageOption pkgs "fwupd" { };

      daemonSettings = lib.mkOption {
        type = lib.types.submodule {
          freeformType = format.type.nestedTypes.elemType;
          options = {
            DisabledDevices = lib.mkOption {
              type = lib.types.listOf lib.types.str;
              default = [ ];
              example = [ "2082b5e0-7a64-478a-b1b2-e3404fab6dad" ];
              description = ''
                List of device GUIDs to be disabled.
              '';
            };

            DisabledPlugins = lib.mkOption {
              type = lib.types.listOf lib.types.str;
              default = [ ];
              example = [ "udev" ];
              description = ''
                List of plugins to be disabled.
              '';
            };

            EspLocation = lib.mkOption {
              type = lib.types.path;
              default = config.boot.loader.efi.efiSysMountPoint;
              defaultText = lib.literalExpression "config.boot.loader.efi.efiSysMountPoint";
              description = ''
                The EFI system partition (ESP) path used if UDisks is not available
                or if this partition is not mounted at /boot/efi, /boot, or /efi
              '';
            };

            TestDevices = lib.mkOption {
              internal = true;
              type = lib.types.bool;
              default = false;
              description = ''
                Create virtual test devices and remote for validating daemon flows.
                This is only intended for CI testing and development purposes.
              '';
            };
          };
        };
        default = { };
        description = ''
          Configurations for the fwupd daemon.
        '';
      };

      uefiCapsuleSettings = lib.mkOption {
        type = lib.types.submodule {
          freeformType = format.type.nestedTypes.elemType;
        };
        default = { };
        description = ''
          UEFI capsule configurations for the fwupd daemon.
        '';
      };
    };
  };

  imports = [
    (lib.mkRenamedOptionModule
      [ "services" "fwupd" "blacklistDevices" ]
      [ "services" "fwupd" "daemonSettings" "DisabledDevices" ]
    )
    (lib.mkRenamedOptionModule
      [ "services" "fwupd" "blacklistPlugins" ]
      [ "services" "fwupd" "daemonSettings" "DisabledPlugins" ]
    )
    (lib.mkRenamedOptionModule
      [ "services" "fwupd" "disabledDevices" ]
      [ "services" "fwupd" "daemonSettings" "DisabledDevices" ]
    )
    (lib.mkRenamedOptionModule
      [ "services" "fwupd" "disabledPlugins" ]
      [ "services" "fwupd" "daemonSettings" "DisabledPlugins" ]
    )
    (lib.mkRemovedOptionModule [ "services" "fwupd" "enableTestRemote" ]
      "This option was removed after being removed upstream. It only provided a method for testing fwupd functionality, and should not have been exposed for use outside of nix tests."
    )
  ];

  ###### implementation
  config = lib.mkIf cfg.enable {
    # Disable test related plug-ins implicitly so that users do not have to care about them.
    services.fwupd.daemonSettings = {
      EspLocation = lib.mkDefault config.boot.loader.efi.efiSysMountPoint;
    };

    environment.systemPackages = [ cfg.package ];

    # customEtc overrides some files from the package
    environment.etc = originalEtc // customEtc // extraTrustedKeys // remotes;

    services.dbus.packages = [ cfg.package ];

    services.udev.packages = [ cfg.package ];

    # required to update the firmware of disks
    services.udisks2.enable = true;

    systemd = {
      packages = [ cfg.package ];

      # fwupd looks for its EFI app in /run/fwupd-efi so that signed variants can
      # be placed next to it; `C+` keeps those signed files across a rebuild.
      tmpfiles.rules = [
        "C+ /run/fwupd-efi - - - - ${cfg.package.fwupd-efi}/libexec/fwupd/efi"
      ];

      # The upstream unit runs as User=fwupd-refresh; ensure it can take
      # ownership of /var/lib/fwupd.
      services.fwupd-refresh.serviceConfig = {
        StateDirectory = "fwupd";
        # Better for debugging, upstream sets stderr to null for some reason..
        StandardError = "inherit";
      };

      timers.fwupd-refresh.wantedBy = [ "timers.target" ];
    };

    users.users.fwupd-refresh = {
      isSystemUser = true;
      group = "fwupd-refresh";
    };
    users.groups.fwupd-refresh = { };

    security.polkit = {
      enable = true;
      # fwupd-refresh.service has no seat, so polkit denies these actions.
      # Upstream's TrustedUids needs a static uid which we only allocate at
      # activation time, so grant access via a rule on the user name instead.
      extraConfig = ''
        polkit.addRule(function(action, subject) {
          if ((action.id == "org.freedesktop.fwupd.get-remotes" ||
               action.id == "org.freedesktop.fwupd.refresh-remote") &&
              subject.user == "fwupd-refresh") {
            return polkit.Result.YES;
          }
        });
      '';
    };
  };

  meta = {
    maintainers = pkgs.fwupd.meta.maintainers;
  };
}