Group storage and vmail user options at mailserver.storage

Create a nicer option structure that deals with the mail storage and its
owner, uid, group and gid. Also includes the directory layout as a
property of how mails are stored..

mail-server/dovecot.nix

@@ -50,7 +50,7 @@ let
       }) attrs
     );
 
-  maildirLayoutAppendix = lib.optionalString cfg.useFsLayout ":LAYOUT=fs";
+  maildirLayoutAppendix = lib.optionalString (cfg.storage.directoryLayout == "fs") ":LAYOUT=fs";
   maildirUTF8FolderNames = lib.optionalString cfg.useUTF8FolderNames ":UTF-8";
 
   # https://doc.dovecot.org/2.3/configuration_manual/home_directories_for_virtual_users/#ways-to-set-up-home-directory
@@ -79,7 +79,7 @@ let
       scope = ${mkLdapSearchScope cfg.ldap.scope}
       user_attrs = \
         ${ldapUuidAttribute}=${ldapUuidAttribute}, \
-        =home=${cfg.mailDirectory}/ldap/%{ldap:${ldapUuidAttribute}}, \
+        =home=${cfg.storage.path}/ldap/%{ldap:${ldapUuidAttribute}}, \
         =mail=maildir:~/mail${maildirLayoutAppendix}${maildirUTF8FolderNames}${
           lib.optionalString (cfg.indexDir != null) ":INDEX=${cfg.indexDir}/ldap/%{ldap:${ldapUuidAttribute}}"
         }
@@ -228,8 +228,8 @@ in
       enablePop3 = cfg.enablePop3 || cfg.enablePop3Ssl;
       enablePAM = false;
       enableQuota = true;
-      mailGroup = cfg.vmailGroupName;
-      mailUser = cfg.vmailUserName;
+      mailGroup = cfg.storage.group;
+      mailUser = cfg.storage.owner;
       mailLocation = dovecotMaildir;
       sslServerCert = x509CertificateFile;
       sslServerKey = x509PrivateKeyFile;
@@ -371,7 +371,7 @@ in
           mail_max_userip_connections = ${toString cfg.maxConnectionsPerUser}
         }
 
-        mail_access_groups = ${cfg.vmailGroupName}
+        mail_access_groups = ${cfg.storage.group}
 
         # https://ssl-config.mozilla.org/#server=dovecot&version=2.3.21&config=intermediate&openssl=3.4.1&guideline=5.7
         ssl = required
@@ -431,9 +431,9 @@ in
           driver = passwd-file
           args = ${userdbFile}
           default_fields = \
-            home=${cfg.mailDirectory}/%{domain}/%{username} \
-            uid=${builtins.toString cfg.vmailUID} \
-            gid=${builtins.toString cfg.vmailUID}
+            home=${cfg.storage.path}/%{domain}/%{username} \
+            uid=${builtins.toString cfg.storage.uid} \
+            gid=${builtins.toString cfg.storage.uid}
         }
 
         ${lib.optionalString cfg.ldap.enable ''
@@ -446,8 +446,8 @@ in
             driver = ldap
             args = ${ldapConfFile}
             override_fields = \
-              uid=${toString cfg.vmailUID} \
-              gid=${toString cfg.vmailUID}
+              uid=${toString cfg.storage.uid} \
+              gid=${toString cfg.storage.uid}
           }
         ''}