plasma-manager/modules/startup.nix

# Allows to run commands/scripts at startup (this is used by some of the other
# modules, which may need to do this, but can also be used on its own)
{ config, lib, ... }:
let
  cfg = config.programs.plasma;
  topScriptName = "run_all.sh";

  textOption = lib.mkOption {
    type = lib.types.str;
    description = "The content of the startup-script.";
  };
  priorityOption = lib.mkOption {
    type = (lib.types.ints.between 0 8);
    default = 0;
    description = "The priority for the execution of the script. Lower priority means earlier execution.";
  };
  restartServicesOption = lib.mkOption {
    type = with lib.types; listOf str;
    default = [ ];
    description = "Services to restart after the script has been run.";
  };
  runAlwaysOption = lib.mkOption {
    type = lib.types.bool;
    default = false;
    example = true;
    description = ''
      When enabled the script will run even if no changes have been made
      since last successful run.
    '';
  };

  startupScriptType = lib.types.submodule {
    options = {
      text = textOption;
      priority = priorityOption;
      restartServices = restartServicesOption;
      runAlways = runAlwaysOption;
    };
  };
  desktopScriptType = lib.types.submodule {
    options = {
      text = textOption;
      priority = priorityOption;
      restartServices = restartServicesOption;
      runAlways = runAlwaysOption;
      preCommands = lib.mkOption {
        type = lib.types.str;
        description = "Commands to run before the desktop script lines.";
        default = "";
      };
      postCommands = lib.mkOption {
        type = lib.types.str;
        description = "Commands to run after the desktop script lines.";
        default = "";
      };
    };
  };

  createScriptContentRunOnce = name: sha256sumFile: script: text: ''
    last_update="$(sha256sum ${sha256sumFile})"
    last_update_file=${config.xdg.dataHome}/plasma-manager/last_run_${name}
    if [ -f "$last_update_file" ]; then
      stored_last_update=$(cat "$last_update_file")
    fi

    if ! [ "$last_update" = "$stored_last_update" ]; then
      echo "Running script: ${name}"
      success=1
      trap 'success=0' ERR
      ${text}
      if [ $success -eq 1 ]; then
        echo "$last_update" > "$last_update_file"
        ${
          builtins.concatStringsSep "\n" (
            map (
              s: "echo ${s} >> ${config.xdg.dataHome}/plasma-manager/services_to_restart"
            ) script.restartServices
          )
        }
      fi
    fi
  '';

  createScriptContentRunAlways = name: text: ''
    echo "Running script: ${name}"
    ${text}
  '';

  createScriptContent = name: sha256sumFile: script: text: {
    "plasma-manager/${cfg.startup.scriptsDir}/${builtins.toString script.priority}_${name}.sh" = {
      text = ''
        #!/bin/sh
        ${
          if script.runAlways then
            (createScriptContentRunAlways name text)
          else
            (createScriptContentRunOnce name sha256sumFile script text)
        }
      '';
      executable = true;
    };
  };
in
{
  options.programs.plasma.startup = {
    startupScript = lib.mkOption {
      type = lib.types.attrsOf startupScriptType;
      default = { };
      description = "Commands/scripts to be run at startup.";
    };
    desktopScript = lib.mkOption {
      type = lib.types.attrsOf desktopScriptType;
      default = { };
      description = ''
        Plasma desktop scripts to be run exactly once at startup. See
        https://develop.kde.org/docs/plasma/scripting/ for details on plasma
        desktop scripts.
      '';
    };
    dataFile = lib.mkOption {
      type = with lib.types; attrsOf str;
      default = { };
      description = "Datafiles, typically for use in autostart scripts.";
    };
    scriptsDir = lib.mkOption {
      type = lib.types.str;
      default = "scripts";
      description = "The name of the subdirectory where the scripts should be.";
    };
    dataDir = lib.mkOption {
      type = lib.types.str;
      default = "data";
      description = "The name of the subdirectory where the datafiles should be.";
    };
  };

  config.xdg =
    lib.mkIf
      (
        cfg.enable
        && (
          builtins.length (builtins.attrNames cfg.startup.startupScript) != 0
          || (builtins.length (builtins.attrNames cfg.startup.desktopScript)) != 0
        )
      )
      {
        dataFile = lib.mkMerge [
          # Autostart scripts
          (lib.mkMerge (
            lib.mapAttrsToList (
              name: script: createScriptContent "script_${name}" "$0" script script.text
            ) cfg.startup.startupScript
          ))
          # Desktop scripts
          (lib.mkMerge (
            (lib.mapAttrsToList (
              name: script:
              let
                layoutScriptPath = "${config.xdg.dataHome}/plasma-manager/${cfg.startup.dataDir}/desktop_script_${name}.js";
              in
              createScriptContent "desktop_script_${name}" layoutScriptPath script ''
                ${script.preCommands}
                qdbus org.kde.plasmashell /PlasmaShell org.kde.PlasmaShell.evaluateScript "$(cat ${layoutScriptPath})"
                ${script.postCommands}
              ''
            ) cfg.startup.desktopScript)
            ++ (lib.mapAttrsToList (name: content: {
              "plasma-manager/${cfg.startup.dataDir}/desktop_script_${name}.js" = {
                text = content.text;
              };
            }) cfg.startup.desktopScript)
          ))
          # Datafiles
          (lib.mkMerge (
            lib.mapAttrsToList (name: content: {
              "plasma-manager/${cfg.startup.dataDir}/${name}" = {
                text = content;
              };
            }) cfg.startup.dataFile
          ))
          # Autostart script runner
          {
            "plasma-manager/${topScriptName}" = {
              text = ''
                #!/bin/sh

                services_restart_file="${config.xdg.dataHome}/plasma-manager/services_to_restart"

                # Reset the file keeping track of which scripts to restart.
                # Technically can be put at the end as well (maybe better, at
                # least assuming the file hasn't been tampered with of some sort).
                if [ -f $services_restart_file ]; then rm $services_restart_file; fi

                for script in ${config.xdg.dataHome}/plasma-manager/${cfg.startup.scriptsDir}/*.sh; do
                  [ -x "$script" ] && $script
                done

                # Restart the services
                if [ -f $services_restart_file ]; then
                  for service in $(sort $services_restart_file | uniq); do
                    systemctl --user restart $service
                  done
                fi
              '';
              executable = true;
            };
          }
        ];

        configFile."autostart/plasma-manager-autostart.desktop".text = ''
          [Desktop Entry]
          Type=Application
          Name=Plasma Manager theme application
          Exec=${config.xdg.dataHome}/plasma-manager/${topScriptName}
          X-KDE-autostart-condition=ksmserver
        '';
      };

  # Due to the fact that running certain desktop-scripts can reset what has
  # been applied by other desktop-script (for example running the panel
  # desktop-script will reset the wallpaper), we make it so that if any of the
  # desktop-scripts have been modified, that we must re-run all the
  # desktop-scripts, not just the ones who have been changed.
  config.programs.plasma.startup.startupScript."reset_lastrun_desktopscripts" =
    lib.mkIf (cfg.startup.desktopScript != { })
      {
        text = ''
          should_reset=0
          for ds in ${config.xdg.dataHome}/plasma-manager/data/desktop_script_*.js; do
            ds_name="$(basename $ds)"
            ds_name="''${ds_name%.js}"
            ds_shafile="${config.xdg.dataHome}/plasma-manager/last_run_"$ds_name

            if ! [ -f "$ds_shafile" ]; then
              echo "Resetting desktop-script last_run-files since $ds_name is a new desktop-script"
              should_reset=1
            elif ! [ "$(cat $ds_shafile)" = "$(sha256sum $ds)" ]; then
              echo "Resetting desktop-script last_run-files since $ds_name has changed content"
              should_reset=1
            fi
          done

          [ $should_reset = 1 ] && rm ${config.xdg.dataHome}/plasma-manager/last_run_desktop_script_*
        '';
        runAlways = true;
      };
}