{ config, lib, ... }:

let
  cfg = config.services.matrix-synapse;
  dbGroup = "medium";
  workers = lib.range 0 (cfg.federationReaders - 1);
  workerName = "federation_reader";
  workerRoutes = {
    client = [ ];
    federation = [
      "~ ^/_matrix/federation/(v1|v2)/event/"
      "~ ^/_matrix/federation/(v1|v2)/state/"
      "~ ^/_matrix/federation/(v1|v2)/state_ids/"
      "~ ^/_matrix/federation/(v1|v2)/backfill/"
      "~ ^/_matrix/federation/(v1|v2)/get_missing_events/"
      "~ ^/_matrix/federation/(v1|v2)/publicRooms"
      "~ ^/_matrix/federation/(v1|v2)/query/"
      "~ ^/_matrix/federation/(v1|v2)/make_join/"
      "~ ^/_matrix/federation/(v1|v2)/make_leave/"
      "~ ^/_matrix/federation/(v1|v2)/send_join/"
      "~ ^/_matrix/federation/(v1|v2)/send_leave/"
      "~ ^/_matrix/federation/v1/make_knock/"
      "~ ^/_matrix/federation/v1/send_knock/"
      "~ ^/_matrix/federation/(v1|v2)/invite/"
      "~ ^/_matrix/federation/(v1|v2)/query_auth/"
      "~ ^/_matrix/federation/(v1|v2)/event_auth/"
      "~ ^/_matrix/federation/v1/timestamp_to_event/"
      "~ ^/_matrix/federation/(v1|v2)/exchange_third_party_invite/"
      "~ ^/_matrix/federation/(v1|v2)/user/devices/"
      "~ ^/_matrix/federation/(v1|v2)/get_groups_publicised$"
      "~ ^/_matrix/key/v2/query"
      # extra
      "~ ^/_matrix/key/v2/server$"
    ];
    media = [ ];
  };
in
{
  config = lib.mkIf (cfg.federationReaders > 0) {
    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
        );
      };

      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;
                  }
                ];
              }
              {
                type = "http";
                path = "/run/matrix-synapse/${workerName}-federation-${toString index}.sock";
                mode = "666";
                resources = [
                  {
                    names = [ "federation" ];
                    compress = false;
                  }
                ];
              }
            ];
            database = (
              import ../db.nix {
                inherit dbGroup;
                workerName = "${workerName}-${toString index}";
              }
            );
          };
        }) workers
      );
    };

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

    services.nginx = {
      virtualHosts."${cfg.nginxVirtualHostName}".locations = lib.listToAttrs (
        lib.flatten (
          lib.forEach
            [
              "client"
              "federation"
              "media"
            ]
            (
              type:
              lib.map (route: {
                name = route;
                value = {
                  proxyPass = "http://unix:/run/matrix-synapse/${workerName}-${type}.sock";
                };
              }) workerRoutes.${type}
            )
        )
      );
    };
  };
}