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

  sonoffSwitches = {
    "pal01" = {
      label = "Schlafzimmer Lampe Links";
      icon = "mdi:lightbulb-on";
      room = "bed_room_lights";
      type = "light";
    };
    "pal02" = {
      label = "Wohnzimmer Lampe";
      icon = "mdi:lightbulb-on";
      room = "living_room_lights";
      type = "light";
    };
    "pal03" = {
      label = "Wohnzimmer Lampe";
      icon = "mdi:lightbulb-on";
      room = "living_room_lights";
      type = "light";
    };
    "pal04" = {
      label = "Schlafzimmer Lampe Rechts";
      icon = "mdi:lightbulb-on";
      room = "bed_room_lights";
      type = "light";
    };
    "pal05" = {
      label = "TV";
      icon = "mdi:television";
      room = "living_room_lights";
      type = "device";
      device = "tv";
    };
    "pal06" = {
      label = "Küchen Lampe";
      icon = "mdi:lightbulb-on";
      room = "kitchen_room_lights";
      type = "light";
    };
    "pal07" = {
      label = "Nummer 7";
      icon = "mdi:power-plug-off";
    };
    "pal08" = {
      label = "Nummer 8";
      icon = "mdi:power-plug-off";
    };
  };

  toSwitch = name: "switch.${name}";

in {

  imports = [ ./mqtt.nix ];

  services.homeAssistantConfig = {

    # nicer names
    # -----------
    homeassistant.customize = lib.mapAttrs' (entity:
      { label, icon, ... }: {
        name = toSwitch entity;
        value = {
          friendly_name = label;
          icon = icon;
        };
      }) sonoffSwitches;

    # define switches
    # ---------------
    switch = builtins.map (name: {
      name = name;
      platform = "mqtt";
      command_topic = "cmnd/${lib.toUpper name}/POWER";
      state_topic = "stat/${lib.toUpper name}/POWER";
      payload_on = "ON";
      payload_off = "OFF";
      state_on = "ON";
      state_off = "OFF";
    }) (builtins.attrNames sonoffSwitches);

    # discover state on init
    # ----------------------
    automation = [{
      alias = "Sonoff initial Power state";
      trigger = {
        platform = "homeassistant";
        event = "start";
      };
      action = builtins.map (name: {
        service = "mqtt.publish";
        data = {
          topic = "cmnd/${lib.toUpper name}/power";
          payload = "";
        };
      }) (builtins.attrNames sonoffSwitches);
    }];

    # append to scripts
    # -----------------
    script.turn_all_off.sequence = [
      {
        alias = "turn off sonoff lights";
        service = "switch.turn_off";
        data.entity_id = "group.all_lights";
      }
      {
        alias = "turn off tv";
        service = "switch.turn_off";
        data.entity_id = "group.tv";
      }
    ];
    script.turn_all_lights_off.sequence = [{
      alias = "turn off sonoff lights";
      service = "switch.turn_off";
      data.entity_id = "group.all_lights";
    }];

    # append to groups
    # ----------------

    group = let
      flatSonoffSwitches =
        lib.mapAttrsToList (name: values: { name = name; } // values)
        sonoffSwitches;
      allLights' = lib.filter ({ type ? "unknown", ... }: type == "light")
        flatSonoffSwitches;
      allLights = {
        all_lights.entities = map ({ name, ... }: "switch.${name}") allLights';
      };
      allRooms' = lib.groupBy ({ room ? "unknown", ... }: room) allLights';
      allRooms = lib.mapAttrs (_: devices: {
        entities = map ({ name, ... }: "switch.${name}") devices;
      }) allRooms';
    in allRooms // allLights // {
      # this is a quick hack. it should not be the norm to define this stuff down here
      tv = { entities = builtins.map toSwitch [ "pal05" ]; };
    };

  };

}