From 06855f1cd823555f1b79f0bf8be1f96f91556739 Mon Sep 17 00:00:00 2001
From: Alexander Linder <34923333+SeineEloquenz@users.noreply.github.com>
Date: Thu, 22 Aug 2024 14:14:51 +0200
Subject: [PATCH] nixos/mautrix-whatsapp: automatic appservice registration
 option, pull login_shared_secret_map setting from env file (#311681)

Co-authored-by: Sandro <sandro.jaeckel@gmail.com>
---
 .../services/matrix/mautrix-whatsapp.nix      | 26 +++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/nixos/modules/services/matrix/mautrix-whatsapp.nix b/nixos/modules/services/matrix/mautrix-whatsapp.nix
index d124edc216dd..89bf7f9e9fac 100644
--- a/nixos/modules/services/matrix/mautrix-whatsapp.nix
+++ b/nixos/modules/services/matrix/mautrix-whatsapp.nix
@@ -108,6 +108,16 @@ in {
         List of Systemd services to require and wait for when starting the application service.
       '';
     };
+
+    registerToSynapse = lib.mkOption {
+      type = lib.types.bool;
+      default = config.services.matrix-synapse.enable;
+      defaultText = lib.literalExpression "config.services.matrix-synapse.enable";
+      description = ''
+        Whether to add the bridge's app service registration file to
+        `services.matrix-synapse.settings.app_service_config_files`.
+      '';
+    };
   };
 
   config = lib.mkIf cfg.enable {
@@ -121,6 +131,13 @@ in {
 
     users.groups.mautrix-whatsapp = {};
 
+    services.matrix-synapse = lib.mkIf cfg.registerToSynapse {
+      settings.app_service_config_files = [ registrationFile ];
+    };
+    systemd.services.matrix-synapse = lib.mkIf cfg.registerToSynapse {
+      serviceConfig.SupplementaryGroups = [ "mautrix-whatsapp" ];
+    };
+
     services.mautrix-whatsapp.settings = lib.mkMerge (map mkDefaults [
       defaultConfig
       # Note: this is defined here to avoid the docs depending on `config`
@@ -155,10 +172,15 @@ in {
         chmod 640 ${registrationFile}
 
         umask 0177
+        # 1. Overwrite registration tokens in config
+        # 2. If environment variable MAUTRIX_WHATSAPP_BRIDGE_LOGIN_SHARED_SECRET
+        #    is set, set it as the login shared secret value for the configured
+        #    homeserver domain.
         ${pkgs.yq}/bin/yq -s '.[0].appservice.as_token = .[1].as_token
           | .[0].appservice.hs_token = .[1].hs_token
-          | .[0]' '${settingsFile}' '${registrationFile}' \
-          > '${settingsFile}.tmp'
+          | .[0]
+          | if env.MAUTRIX_WHATSAPP_BRIDGE_LOGIN_SHARED_SECRET then .bridge.login_shared_secret_map.[.homeserver.domain] = env.MAUTRIX_WHATSAPP_BRIDGE_LOGIN_SHARED_SECRET else . end' \
+          '${settingsFile}' '${registrationFile}' > '${settingsFile}.tmp'
         mv '${settingsFile}.tmp' '${settingsFile}'
         umask $old_umask
       '';