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

let
  cfg = config.services.desktopManager.lomiri;
in {
  options.services.desktopManager.lomiri = {
    enable = lib.mkEnableOption ''
      the Lomiri graphical shell (formerly known as Unity8)
    '';
  };

  config = lib.mkIf cfg.enable {
    environment = {
      systemPackages = (with pkgs; [
        glib # XDG MIME-related tools identify it as GNOME, add gio for MIME identification to work
        libayatana-common
        ubports-click
      ]) ++ (with pkgs.lomiri; [
        hfd-service
        history-service
        libusermetrics
        lomiri
        lomiri-calculator-app
        lomiri-camera-app
        lomiri-clock-app
        lomiri-content-hub
        lomiri-docviewer-app
        lomiri-download-manager
        lomiri-filemanager-app
        lomiri-gallery-app
        lomiri-polkit-agent
        lomiri-schemas # exposes some required dbus interfaces
        lomiri-session # wrappers to properly launch the session
        lomiri-sounds
        lomiri-system-settings
        lomiri-terminal-app
        lomiri-thumbnailer
        lomiri-url-dispatcher
        lomiri-wallpapers
        mediascanner2 # TODO possibly needs to be kicked off by graphical-session.target
        morph-browser
        qtmir # not having its desktop file for Xwayland available causes any X11 application to crash the session
        suru-icon-theme
        telephony-service
        teleports
      ]);

      # To override the default keyboard layout in Lomiri
      etc.${pkgs.lomiri.lomiri.passthru.etcLayoutsFile}.text = lib.strings.replaceStrings [","] ["\n"] config.services.xserver.xkb.layout;
    };

    hardware = {
      bluetooth.enable = lib.mkDefault true;
    };

    networking.networkmanager.enable = lib.mkDefault true;

    systemd.packages = with pkgs.lomiri; [
      hfd-service
      lomiri-download-manager
    ];

    services.dbus.packages = with pkgs.lomiri; [
      hfd-service
      libusermetrics
      lomiri-download-manager
    ];

    fonts.packages = with pkgs; [
      # Applications tend to default to Ubuntu font
      ubuntu-classic
    ];

    # Copy-pasted basic stuff
    hardware.graphics.enable = lib.mkDefault true;
    fonts.enableDefaultPackages = lib.mkDefault true;
    programs.dconf.enable = lib.mkDefault true;

    # Xwayland is partly hardcoded in Mir so it can't really be fully turned off, and it must be on PATH for X11 apps *and Lomiri's web browser* to work.
    # Until Mir/Lomiri can be properly used without it, force it on so everything behaves as expected.
    programs.xwayland.enable = lib.mkForce true;

    services.accounts-daemon.enable = true;

    services.ayatana-indicators = {
      enable = true;
      packages = (with pkgs; [
        ayatana-indicator-datetime
        ayatana-indicator-display
        ayatana-indicator-messages
        ayatana-indicator-power
        ayatana-indicator-session
      ] ++ lib.optionals config.hardware.bluetooth.enable [
        ayatana-indicator-bluetooth
      ] ++ lib.optionals (config.hardware.pulseaudio.enable || config.services.pipewire.pulse.enable) [
        ayatana-indicator-sound
      ]) ++ (with pkgs.lomiri; [
        telephony-service
      ] ++ lib.optionals config.networking.networkmanager.enable [
        lomiri-indicator-network
      ]);
    };

    services.udisks2.enable = true;
    services.upower.enable = true;
    services.geoclue2.enable = true;

    services.gnome.evolution-data-server = {
      enable = true;
      plugins = with pkgs; [
        # TODO: lomiri.address-book-service
      ];
    };

    services.telepathy.enable = true;

    services.displayManager = {
      defaultSession = lib.mkDefault "lomiri";
      sessionPackages = with pkgs.lomiri; [ lomiri-session ];
    };

    services.xserver = {
      enable = lib.mkDefault true;
      displayManager.lightdm = {
        enable = lib.mkDefault true;
        greeters.lomiri.enable = lib.mkDefault true;
      };
    };

    environment.pathsToLink = [
      # Configs for inter-app data exchange system
      "/share/lomiri-content-hub/peers"
      # Configs for inter-app URL requests
      "/share/lomiri-url-dispatcher/urls"
      # Splash screens & other images for desktop apps launched via lomiri-app-launch
      "/share/lomiri-app-launch"
      # TODO Try to get maliit stuff working
      "/share/maliit/plugins"
      # At least the network indicator is still under the unity name, due to leftover Unity-isms
      "/share/unity"
      # Data
      "/share/locale" # TODO LUITK hardcoded default locale path, fix individual apps to not rely on it
      "/share/sounds"
      "/share/wallpapers"
    ];

    systemd.user.services = {
      # Unconditionally run service that collects system-installed URL handlers before LUD
      # TODO also run user-installed one?
      "lomiri-url-dispatcher-update-system-dir" = {
        description = "Lomiri URL dispatcher system directory updater";
        wantedBy = [ "lomiri-url-dispatcher.service" ];
        before = [ "lomiri-url-dispatcher.service" ];
        serviceConfig = {
          Type = "oneshot";
          ExecStart = "${pkgs.lomiri.lomiri-url-dispatcher}/libexec/lomiri-url-dispatcher/lomiri-update-directory /run/current-system/sw/share/lomiri-url-dispatcher/urls/";
        };
      };

      "lomiri-polkit-agent" = rec {
        description = "Lomiri Polkit agent";
        wantedBy = [ "lomiri.service" "lomiri-full-greeter.service" "lomiri-full-shell.service" "lomiri-greeter.service" "lomiri-shell.service" ];
        after = [ "graphical-session.target" ];
        partOf = wantedBy;
        serviceConfig = {
          Type = "simple";
          Restart = "always";
          ExecStart = "${pkgs.lomiri.lomiri-polkit-agent}/libexec/lomiri-polkit-agent/policykit-agent";
        };
      };
    };

    systemd.services = {
      "dbus-com.lomiri.UserMetrics" = {
        serviceConfig = {
          Type = "dbus";
          BusName = "com.lomiri.UserMetrics";
          User = "usermetrics";
          StandardOutput = "syslog";
          SyslogIdentifier = "com.lomiri.UserMetrics";
          ExecStart = "${pkgs.lomiri.libusermetrics}/libexec/libusermetrics/usermetricsservice";
        } // lib.optionalAttrs (!config.security.apparmor.enable) {
          # Due to https://gitlab.com/ubports/development/core/libusermetrics/-/issues/8, auth must be disabled when not using AppArmor, lest the next database usage breaks
          Environment = "USERMETRICS_NO_AUTH=1";
        };
      };
    };

    users.users.usermetrics = {
      group = "usermetrics";
      home = "/var/lib/usermetrics";
      createHome = true;
      isSystemUser = true;
    };

    users.groups.usermetrics = { };
  };

  meta.maintainers = lib.teams.lomiri.members;
}