build-inventory: move inventory and inventoryClass into explizitly different folders

lib/modules/inventoryClass/builder/roles.nix

@@ -0,0 +1,65 @@
+{
+  lib,
+  config,
+  resolveTags,
+  inventory,
+  clanLib,
+  machineName,
+  serviceConfigs,
+  ...
+}:
+let
+  serviceName = config.serviceName;
+in
+{
+  # Roles resolution
+  # : List String
+  supportedRoles = clanLib.modules.getRoles "inventory.modules" inventory.modules serviceName;
+  matchedRoles = builtins.attrNames (
+    lib.filterAttrs (_: ms: builtins.elem machineName ms) config.machinesRoles
+  );
+  resolvedRolesPerInstance = lib.mapAttrs (
+    instanceName: instanceConfig:
+    let
+      resolvedRoles = lib.genAttrs config.supportedRoles (
+        roleName:
+        resolveTags {
+          members = instanceConfig.roles.${roleName} or { };
+          inherit
+            instanceName
+            serviceName
+            roleName
+            inventory
+            ;
+        }
+      );
+      usedRoles = builtins.attrNames instanceConfig.roles;
+      unmatchedRoles = builtins.filter (role: !builtins.elem role config.supportedRoles) usedRoles;
+    in
+    if unmatchedRoles != [ ] then
+      throw ''
+        Roles ${builtins.toJSON unmatchedRoles} are not defined in the service ${serviceName}.
+        Instance: '${instanceName}'
+        Please use one of available roles: ${builtins.toJSON config.supportedRoles}
+      ''
+    else
+      resolvedRoles
+  ) serviceConfigs;
+
+  machinesRoles = builtins.zipAttrsWith (
+    _n: vs:
+    let
+      flat = builtins.foldl' (acc: s: acc ++ s.machines) [ ] vs;
+    in
+    lib.unique flat
+  ) (builtins.attrValues config.resolvedRolesPerInstance);
+
+  assertions = lib.concatMapAttrs (
+    instanceName: resolvedRoles:
+    clanLib.modules.checkConstraints {
+      moduleName = serviceName;
+      allModules = inventory.modules;
+      inherit resolvedRoles instanceName;
+    }
+  ) config.resolvedRolesPerInstance;
+}