refactor(dotfiles): split registry responsibilities

src/dotfiles/registry/validation.nix

@@ -0,0 +1,44 @@
+{
+  definitions,
+  lib,
+}:
+let
+  assertValid =
+    data:
+    let
+      assertions = validationAssertions data;
+      failures = lib.filter (assertion: !assertion.assertion) assertions;
+    in
+    assert lib.assertMsg (lib.all (assertion: assertion.assertion) assertions) (
+      lib.concatMapStringsSep "\n" (assertion: assertion.message) failures
+    );
+    data;
+
+  validationAssertions =
+    data:
+    lib.concatLists (
+      lib.mapAttrsToList (
+        registryName: registry:
+        let
+          entries = flattenRegistryEntries registryName data.${registryName};
+        in
+        map (check: {
+          assertion = check.assertion entries;
+          inherit (check) message;
+        }) registry.checks
+      ) definitions
+    );
+
+  flattenRegistryEntries =
+    registryName: data:
+    lib.concatLists (
+      lib.mapAttrsToList (
+        host: entries:
+        lib.mapAttrsToList (entry: value: {
+          path = "registry.${registryName}.${host}.${entry}";
+          inherit host entry value;
+        }) entries
+      ) data
+    );
+in
+assertValid