{
  workerName,
  tasks,
  dbOverrides ? { },
  count ? 1,
}:
{ config, lib, ... }:

#let
#  dbGroup = "medium";
#  workerName = "account_data_stream_writer";
#  tasks = [ "stream_account_data" ];
##  workerRoutes = workerLib.workerRoutes.accountData;
#  count = 1;
#in
let
  workerLib = import ./lib.nix;
  cfg = config.services.matrix-synapse;
  enabledResources = lib.attrNames workerRoutes;
  workers = lib.range 0 count;
  streamTypes =
    [ ]
    ++ lib.optional (lib.elem "stream_account_data" tasks) "account_data"
    ++ lib.optional (lib.elem "stream_presence" tasks) "presence"
    ++ lib.optional (lib.elem "stream_push_rules" tasks) "push_rules"
    ++ lib.optional (lib.elem "stream_to_device" tasks) "to_device"
    ++ lib.optional (lib.elem "stream_typing" tasks) "typing"
    ++ lib.optional (lib.elem "stream_receipts" tasks) "receipts"
    ++ lib.optional (lib.elem "stream_events" tasks) "events";

  # recursive update list of attrs
#  recursiveMerge = list: lib.foldl (a: b: lib.recursiveUpdate a b) (lib.head list) (lib.tail list);
#  workerRoutes = recursiveMerge (lib.map (type: workerLib.workerRoutes.${type}) streamTypes);
in
{
  config = lib.mkIf (cfg.accountDataStreamWriters > 0) {
    monitoring.synapse.workerNames = if (count == 1) then [ workerName ] else lib.map (index: "${workerName}-${toString index}") workers;
    services.matrix-synapse = {
      settings = {
        instance_map = lib.listToAttrs (
          lib.map (index: {
            name = "${workerName}-${toString index}";
            value = {
              path = "/run/matrix-synapse/${workerName}-${toString index}.sock";
            };
          }) workers
        );

        stream_writers = lib.listToAttrs (
          lib.map (stream: {
            name = stream;
            value = lib.map (index: "${workerName}-${toString index}") workers;
          }) streamTypes
        );
      };

      workers = lib.listToAttrs (
        lib.map (index: {
          name = "${workerName}-${toString index}";
          value = {
            worker_app = "synapse.app.generic_worker";
            worker_listeners =
              [
                {
                  type = "http";
                  path = "/run/matrix-synapse/${workerName}-${toString index}.sock";
                  resources = [
                    {
                      names = [ "replication" ];
                      compress = false;
                    }
                  ];
                }
              ]
              ++ lib.map (type: {
                type = "http";
                path = "/run/matrix-synapse/${workerName}-${type}-${toString index}.sock";
                mode = "666";
                resources = [
                  {
                    names = [ type ];
                    compress = false;
                  }
                ];
              }) enabledResources;
            database = lib.recursiveUpdate (lib.recursiveUpdate config.services.matrix-synapse.settings.database {
              application_name = "matrix-synapse (${config.services.matrix-synapse.settings.server_name}) - ${if workerName == null then throw "synapse/db.nix: workerName unspecified" else workerName}";
            }) dbOverrides;

            #region Media
            max_upload_size = lib.mkIf (lib.elem "media_repo" tasks) "512M";
            max_avatar_size = lib.mkIf (lib.elem "media_repo" tasks) "512M";
            max_image_pixels = lib.mkIf (lib.elem "media_repo" tasks) "250M";

            max_pending_media_uploads = lib.mkIf (lib.elem "media_repo" tasks) 512;
            dynamic_thumbnails = lib.mkIf (lib.elem "media_repo" tasks) true;

            prevent_media_downloads_from = lib.mkIf (lib.elem "media_repo" tasks) [
              # none, give me all the media
            ];
            enable_authenticated_media = lib.mkIf (lib.elem "media_repo" tasks) false;

            url_preview_enabled = lib.mkIf (lib.elem "media_repo" tasks) true;
            max_spider_size = lib.mkIf (lib.elem "media_repo" tasks) "50M";
            #endregion
          };
        }) workers
      );
    };

    services.nginx = {
      upstreams = lib.listToAttrs (
        lib.map (type: {
          name = "${workerName}-${type}";
          value = {
            extraConfig = ''
              keepalive 32;
              least_conn;
            '';
            servers = lib.listToAttrs (
              lib.map (index: {
                name = "unix:/run/matrix-synapse/${workerName}-${type}-${toString index}.sock";
                value = {
                  max_fails = 0;
                  fail_timeout = "0s";
                };
              }) workers
            );
          };
        }) enabledResources
      );

      virtualHosts."${cfg.nginxVirtualHostName}".locations = lib.listToAttrs (
        lib.flatten (
          lib.forEach enabledResources (
            type:
            lib.map (route: {
              name = route;
              value = {
                proxyPass = "http://${workerName}-${type}";
                extraConfig = ''
                  proxy_http_version 1.1;
                  proxy_set_header Connection "";
                '';
              };
            }) workerRoutes.${type}
          )
        )
      );
    };
  };
}