fix: add nginx virtualHost for mastodon

We use pub.solar as our LOCAL_DOMAIN and mastodon.pub.solar as our
WEB_DOMAIN. The NixOS module does not support this special use case.
See: https://github.com/NixOS/nixpkgs/issues/202399

hosts/nachtigall/apps/mastodon.nix

@@ -36,7 +36,6 @@
     enable = true;
     # Different from WEB_DOMAIN in our case
     localDomain = "pub.solar";
-    configureNginx = true;
     enableUnixSocket = true;
     # Processes used by the mastodon-streaming service. Defaults to the number
     # of CPU cores minus one

hosts/nachtigall/apps/nginx-mastodon.nix

@@ -0,0 +1,30 @@
+{ config, lib, ... }:
+let
+  cfg = config.services.mastodon;
+in
+{
+  services.nginx.virtualHosts = {
+    "mastodon.pub.solar" = {
+      root = "${cfg.package}/public/";
+      # mastodon only supports https, but you can override this if you offload tls elsewhere.
+      forceSSL = lib.mkDefault true;
+      enableACME = lib.mkDefault true;
+
+      locations."/system/".alias = "/var/lib/mastodon/public-system/";
+
+      locations."/" = {
+        tryFiles = "$uri @proxy";
+      };
+
+      locations."@proxy" = {
+        proxyPass = (if cfg.enableUnixSocket then "http://unix:/run/mastodon-web/web.socket" else "http://127.0.0.1:${toString(cfg.webPort)}");
+        proxyWebsockets = true;
+      };
+
+      locations."/api/v1/streaming/" = {
+        proxyPass = (if cfg.enableUnixSocket then "http://unix:/run/mastodon-streaming/streaming.socket" else "http://127.0.0.1:${toString(cfg.streamingPort)}/");
+        proxyWebsockets = true;
+      };
+    };
+  };
+}

hosts/nachtigall/default.nix

@@ -10,6 +10,7 @@
       ./nix.nix
       ./apps/nginx.nix
 
+      ./apps/nginx-mastodon.nix
       ./apps/nginx-mastodon-files.nix
       ./apps/nginx-website.nix
       ./apps/mastodon.nix