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

let
  inherit (lib) generators literalExpression mkEnableOption mkIf mkOption recursiveUpdate types;
  cfg = config.services.zeronet;
  dataDir = "/var/lib/zeronet";
  configFile = pkgs.writeText "zeronet.conf" (generators.toINI {} (recursiveUpdate defaultSettings cfg.settings));

  defaultSettings = {
    global = {
      data_dir = dataDir;
      log_dir = dataDir;
      ui_port = cfg.port;
      fileserver_port = cfg.fileserverPort;
      tor = if !cfg.tor then "disable" else if cfg.torAlways then "always" else "enable";
    };
  };
in with lib; {
  options.services.zeronet = {
    enable = mkEnableOption "zeronet";

    package = mkOption {
      type = types.package;
      default = pkgs.zeronet;
      defaultText = literalExpression "pkgs.zeronet";
      description = "ZeroNet package to use";
    };

    settings = mkOption {
      type = with types; attrsOf (oneOf [ str int bool (listOf str) ]);
      default = {};
      example = literalExpression "{ global.tor = enable; }";

      description = ''
        <filename>zeronet.conf</filename> configuration. Refer to
        <link xlink:href="https://zeronet.readthedocs.io/en/latest/faq/#is-it-possible-to-use-a-configuration-file"/>
        for details on supported values;
      '';
    };

    port = mkOption {
      type = types.port;
      default = 43110;
      description = "Optional zeronet web UI port.";
    };

    fileserverPort = mkOption {
      # Not optional: when absent zeronet tries to write one to the
      # read-only config file and crashes
      type = types.port;
      default = 12261;
      description = "Zeronet fileserver port.";
    };

    tor = mkOption {
      type = types.bool;
      default = false;
      description = "Use TOR for zeronet traffic where possible.";
    };

    torAlways = mkOption {
      type = types.bool;
      default = false;
      description = "Use TOR for all zeronet traffic.";
    };
  };

  config = mkIf cfg.enable {
    services.tor = mkIf cfg.tor {
      enable = true;
      controlPort = 9051;

      extraConfig = ''
        CacheDirectoryGroupReadable 1
        CookieAuthentication 1
        CookieAuthFileGroupReadable 1
      '';
    };

    systemd.services.zeronet = {
      description = "zeronet";
      after = [ "network.target" ] ++ optional cfg.tor "tor.service";
      wantedBy = [ "multi-user.target" ];

      serviceConfig = {
        User = "zeronet";
        DynamicUser = true;
        StateDirectory = "zeronet";
        SupplementaryGroups = mkIf cfg.tor [ "tor" ];
        ExecStart = "${cfg.package}/bin/zeronet --config_file ${configFile}";
      };
    };
  };

  imports = [
    (mkRemovedOptionModule [ "services" "zeronet" "dataDir" ] "Zeronet will store data by default in /var/lib/zeronet")
    (mkRemovedOptionModule [ "services" "zeronet" "logDir" ] "Zeronet will log by default in /var/lib/zeronet")
  ];

  meta.maintainers = with maintainers; [ Madouura ];
}