{ nglib, nixpkgs }:
{
  postgresql = nglib.makeSystem {
    system = "x86_64-linux";
    name = "nixng-synapse-postgresql";
    inherit nixpkgs;
    config = { pkgs, config, ... }:
      {
        config = {
          dumb-init = {
            enable = true;
            type.services = {};
          };
          services.postgresql = {
            enable = true;
            package = pkgs.postgresql_12;

            initialScript = "/secrets/init.sql";
            enableTCPIP = true;

            authentication = "host  all all all          md5";

            ensureDatabases = { "synapse" = { ENCODING = "UTF8"; TEMPLATE = "template0"; }; };
            ensureExtensions = {};
            ensureUsers = [
              { name = "synapse"; ensurePermissions = {
                  "DATABASE \"synapse\"" = "ALL PRIVILEGES";
                };
              }
            ];
          };
        };
      };
  };

  synapse = nglib.makeSystem {
    system = "x86_64-linux";
    name = "synapse";
    inherit nixpkgs;
    config = ({ pkgs, ... }:
      {
        dumb-init = {
          enable = true;
          type.services = { };
        };

        init.services.synapse = {
          enabled = true;
          shutdownOnExit = true;
          script =
            let
              logConfig = (pkgs.formats.yaml {}).generate "log.yaml"
                {
                  # Log configuration for Synapse.
                  #
                  # This is a YAML file containing a standard Python logging configuration
                  # dictionary. See [1] for details on the valid settings.
                  #
                  # Synapse also supports structured logging for machine readable logs which can
                  # be ingested by ELK stacks. See [2] for details.
                  #
                  # [1]: https://docs.python.org/3.7/library/logging.config.html#configuration-dictionary-schema
                  # [2]: https://matrix-org.github.io/synapse/latest/structured_logging.html

                  version = 1;

                  formatters.precise.format = "%(asctime)s - %(name)s - %(lineno)d - %(levelname)s - %(request)s - %(message)s";
                  handlers.console =
                    {
                      class = "logging.StreamHandler";
                      formatter = "precise";
                    };
                  loggers."synapse.storage.SQL" =
                    {
                      level = "INFO";
                    };
                  root =
                    {
                      level = "INFO";
                      handlers = [ "console" ];
                    };

                  disable_existing_loggers = false;
                };
              synapseConfig = (pkgs.formats.yaml {}).generate "synapse.yaml"
                {
                  server_name = "matrix.redalder.org";
                  report_stats = "yes";
                  pid_file = "/homeserver.pid";

                  enable_registration = false;
                  enable_registration_without_verification = false;

                  listeners =
                    [
                      {
                        port = 6167;
                        tls = false;
                        type = "http";
                        x_forwarded = true;
                        bind_adrresses = [ "127.0.0.1" ];
                        resources =
                          [
                            {
                              names = [ "client" "federation" ];
                              compress = false;
                            }
                          ];
                      }
                    ];
                  log_config = logConfig;
                  trusted_key_servers =
                    [
                      {
                        server_name = "matrix.org";
                      }
                    ];
                  media_store_path = "/var/lib/synapse/media_store";
                  signing_key_path = "/var/lib/synapse/signing.key";
                };
            in
              pkgs.writeShellScript "synapse"
                ''
                  if [ -f "/var/lib/synapse/sqlite.db" ] && ! [ -f "/var/lib/synapse/migration_done" ]
                  then
                    echo "Beginning migration from SQLite to PostgeSQL!"

                    cat > /tmp/synapse_postgres.yaml <<EOF
                  database:
                    name: psycopg2
                    args:
                      user: synapse
                      password: ''${PSQL_PASSWORD}
                      database: synapse
                      host: 127.0.0.1
                      cp_min: 5
                      cp_max: 10
                  $(cat ${synapseConfig})
                  EOF

                    for ((i=0; i<5; i++))
                    do
                      ${pkgs.matrix-synapse.python.withPackages (_: [ (pkgs.python3.pkgs.toPythonModule pkgs.matrix-synapse) ] ++ pkgs.matrix-synapse.propagatedBuildInputs)}/bin/python ${pkgs.matrix-synapse}/lib/python*/site-packages/synapse/_scripts/synapse_port_db.py \
                        --sqlite-database "/var/lib/synapse/sqlite.db" \
                        --postgres-config "/tmp/synapse_postgres.yaml"
                      [ $? -eq 0 ] && touch /var/lib/synapse/migration_done && break

                      echo "Migration attempt ''${i}/5 failed! Retrying in 30 seconds..."
                      sleep 30

                      if ((5 == i))
                      then
                        echo "Migration failed!"
                        exit 1
                      fi
                    done
                  fi

                  [ -e /var/lib/synapse/signing.key ] || \
                    ${pkgs.matrix-synapse}/bin/synapse_homeserver \
                      --config-path ${synapseConfig} \
                      --config-path /secrets/extra.yaml \
                      --config-path /var/lib/registrations/extra.yaml \
                      --keys-directory /var/lib/synapse/keys \
                      --generate-keys
                  ${pkgs.matrix-synapse}/bin/synapse_homeserver \
                    --config-path ${synapseConfig} \
                    --config-path /secrets/extra.yaml \
                    --config-path /var/lib/registrations/extra.yaml \
                    --keys-directory /var/lib/synapse/keys
                '';
        };
      });
  };
}