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

let
  tracktrain-config = ''
    dbstring: "dbname=tracktrain"
    gtfs: /persist/gtfs.zip
    assets: ${pkgs.tracktrain}/assets

    warp:
      port: 4000

    login:
      enable: true
      url: https://login.infra4future.de
      clientname: tracktrain
      # clientsecret defined in env file
  '';
in
{
  sops.secrets = {
    "tracktrain/env" = {};
  };

  services.nginx.virtualHosts."tracktrain.ilztalbahn.eu" = {
    enableACME = true;
    forceSSL = true;
    locations."/" = {
      proxyPass = "http://192.168.42.41:4000";
      proxyWebsockets = true;
    };
    # note: this shadows the /metrics endpoint of tracktrain
    # in case you remove this, please consider putting something
    # else here to keep it from being publicly scrapable
    locations."/metrics/" = {
      proxyPass = "http://192.168.42.41:2342";
      proxyWebsockets = true;
      extraConfig = ''
        rewrite  ^/metrics/(.*)  /$1 break;
      '';
    };
  };

  containers.tracktrain = {
    privateNetwork = true;
    hostAddress = "192.168.42.40";
    localAddress = "192.168.42.41";
    autoStart = true;
    ephemeral = true;
    bindMounts = {
      "/persist" = {
        hostPath = "/persist/containers/tracktrain";
        isReadOnly = false;
      };
      "/secrets".hostPath = "/run/secrets/tracktrain";
    };

    path = evalConfig ({ config, lib, pkgs, ... }: {
      system.stateVersion = "21.11";

      users.users.tracktrain = {
        group = "tracktrain";
        isSystemUser = true;
      };
      users.groups.tracktrain = {};

      systemd.services.tracktrain = {
        enable = true;

        description = "tracks trains, hopefully";
        wantedBy = [ "multi-user.target" ];
        requires = [ "network.target" ];
        after = [ "network.target" ];
        serviceConfig = {
          Type = "simple";
          EnvironmentFile = "/secrets/env";
          User = "tracktrain";
          Group = "tracktrain";
        };
        path = [ pkgs.wget ];
        script = ''
          mkdir -p /persist/tracktrain
          cd /persist/tracktrain
          ln -sf ${pkgs.writeText "tracktrain-config.yaml" tracktrain-config} config.yaml
          wget "https://ilztalbahn.eu/wp-content/uploads/2020/07/gtfs.zip" || sleep 4; wget "https://ilztalbahn.eu/wp-content/uploads/2020/07/gtfs.zip"
          ${pkgs.tracktrain}/bin/tracktrain +RTS -T
        '';
      };

      services.postgresql = {
        enable = true;

        package = pkgs.postgresql_15;
        ensureDatabases = [ "tracktrain" ];
        ensureUsers = [ {
          name = "tracktrain";
          ensureDBOwnership = true;
        } ];
        authentication = ''
          local   all   all                              trust
          host    all   all        127.0.0.1/32          trust
        '';
      };

      services.prometheus = {
        enable = true;
        port = 9001;
        scrapeConfigs = [ {
          job_name = "tracktrain";
          static_configs = [{
            targets = [  "0.0.0.0:4000" ];
          }];
        } ];
      };

      services.grafana = {
        enable = true;
        settings.server = {
          serve_from_sub_path = true;
          domain = "tracktrain.ilztalbahn.eu";
          root_url = "https://%(domain)s/metrics/";
          http_port = 2342;
          http_addr = "0.0.0.0";
        };

        settings."auth.generic_oauth" = {
          name = "uffd";
          enabled = true;
          allow_sign_up = true;
          empty_scopes = true;
          client_id = "ilztalbahn-grafana";
          client_secret = "\${GRAFANA_CLIENT_SECRET}";
          auth_url = "https://login.infra4future.de/oauth2/authorize";
          token_url = "https://login.infra4future.de/oauth2/token";
          api_url = "https://login.infra4future.de/oauth2/userinfo";
        };
        # disables the default login screen. comment out if for some
        # reason you do need it
        settings.auth.oauth_auto_login = true;
        settings.users.auto_assign_org_role = "Admin";

        provision = {
          enable = true;
          datasources.settings.datasources = [ {
            url = "http://localhost:9001";
            type = "prometheus";
            name = "prometheus";
          } ];
        };
      };

      systemd.services.grafana.serviceConfig.EnvironmentFile =
        "/secrets/env";
      hacc.bindToPersist = [ "/var/lib/grafana" ];
    });
  };

}