add more matrix bridges through flake input

hosts/profiles/matrix/default.nix

@@ -3,6 +3,7 @@
 {
   imports = [
     ./mautrix-telegram.nix
+    ./mautrix-services.nix
     # ./mautrix-discord.nix
     # ./mautrix-whatsapp.nix
     # ./mautrix-slack.nix

hosts/profiles/matrix/mautrix-services.nix

@@ -0,0 +1,49 @@
+{ config, lib, pkgs, ... }:
+
+{
+  # Mautrix-signal settings
+  services.signald.enable = true;
+  systemd.services.matrix-as-signal = {
+    requires = [ "signald.service" ];
+    after = [ "signald.service" ];
+    unitConfig = {
+      JoinsNamespaceOf = "signald.service";
+    };
+    path = [
+      pkgs.ffmpeg # voice messages need `ffmpeg`
+    ];
+  };
+
+  services.matrix-appservices = {
+    addRegistrationFiles = false;
+    homeserverURL = "https://sealight.xyz/";
+    homeserverDomain = "sealight.xyz";
+    services = {
+      whatsapp = {
+        port = 29183;
+        format = "mautrix-go";
+        package = pkgs.mautrix-whatsapp;
+      };
+
+      discord = {
+        port = 29188;
+        format = "mautrix-go";
+        package = pkgs.mautrix-discord;
+      };
+
+      signal = {
+        port = 29184;
+        format = "mautrix-python";
+        package = pkgs.mautrix-signal;
+        serviceConfig = {
+          StateDirectory = [ "matrix-as-signal" "signald" ];
+          SupplementaryGroups = [ "signald" ];
+        };
+        settings.signal = {
+          socket_path = config.services.signald.socketPath;
+          outgoing_attachment_dir = "/var/lib/signald/tmp";
+        };
+      };
+    };
+  };
+}