#  nixos-mailserver: a simple mail server
#  Copyright (C) 2016-2018  Robin Raymond
#
#  This program is free software: you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation, either version 3 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program. If not, see <http://www.gnu.org/licenses/>

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

let
  cfg = config.mailserver;

  postfixCfg = config.services.postfix;
  rspamdCfg = config.services.rspamd;
  rspamdSocket = "rspamd.service";
in
{
  config = with cfg; lib.mkIf enable {
    services.rspamd = {
      enable = true;
      inherit debug;
      locals = {
          "milter_headers.conf" = { text = ''
              extended_spam_headers = yes;
          ''; };
          "redis.conf" = { text = ''
              servers = "${cfg.redis.address}:${toString cfg.redis.port}";
          '' + (lib.optionalString (cfg.redis.password != null) ''
              password = "${cfg.redis.password}";
          ''); };
          "classifier-bayes.conf" = { text = ''
              cache {
                backend = "redis";
              }
          ''; };
          "antivirus.conf" = lib.mkIf cfg.virusScanning { text = ''
              clamav {
                action = "reject";
                symbol = "CLAM_VIRUS";
                type = "clamav";
                log_clean = true;
                servers = "/run/clamav/clamd.ctl";
                scan_mime_parts = false; # scan mail as a whole unit, not parts. seems to be needed to work at all
              }
          ''; };
          "dkim_signing.conf" = { text = ''
              # Disable outbound email signing, we use opendkim for this
              enabled = false;
          ''; };
      };

      overrides = {
        "milter_headers.conf" = {
          text = ''
            extended_spam_headers = true;
          '';
        };
      };

      workers.rspamd_proxy = {
        type = "rspamd_proxy";
        bindSockets = [{
          socket = "/run/rspamd/rspamd-milter.sock";
          mode = "0664";
        }];
        count = 1; # Do not spawn too many processes of this type
        extraConfig = ''
          milter = yes; # Enable milter mode
          timeout = 120s; # Needed for Milter usually

          upstream "local" {
            default = yes; # Self-scan upstreams are always default
            self_scan = yes; # Enable self-scan
          }
        '';
      };
      workers.controller = {
        type = "controller";
        count = 1;
        bindSockets = [{
          socket = "/run/rspamd/worker-controller.sock";
          mode = "0666";
        }];
        includes = [];
        extraConfig = ''
          static_dir = "''${WWWDIR}"; # Serve the web UI static assets
        '';
      };

    };

    services.redis.enable = true;
    assertions = [
      { 
        assertion = isNull config.services.redis.unixSocket;
        message = "nixos-mailserver doesn't support redis over UNIX socket";
      }
    ];

    systemd.services.rspamd = {
      requires = [ "redis.service" ] ++ (lib.optional cfg.virusScanning "clamav-daemon.service");
      after = [ "redis.service" ] ++ (lib.optional cfg.virusScanning "clamav-daemon.service");
    };

    systemd.services.postfix = {
      after = [ rspamdSocket ];
      requires = [ rspamdSocket ];
    };

    users.extraUsers.${postfixCfg.user}.extraGroups = [ rspamdCfg.group ];
  };
}