Add atomic device row updates

src/domain/services/project-device-overrides.ts

@@ -0,0 +1,57 @@
+import {
+  projectDeviceSyncFields,
+  type ProjectDeviceSyncField,
+} from "../../shared/constants/project-device-sync-fields.js";
+
+export function parseOverriddenFields(
+  value: string | null | undefined
+): ProjectDeviceSyncField[] {
+  if (!value) {
+    return [];
+  }
+  try {
+    const parsed: unknown = JSON.parse(value);
+    if (!Array.isArray(parsed)) {
+      return [];
+    }
+    return parsed.filter((field): field is ProjectDeviceSyncField =>
+      projectDeviceSyncFields.includes(field as ProjectDeviceSyncField)
+    );
+  } catch {
+    return [];
+  }
+}
+
+export function serializeOverriddenFields(
+  fields: Iterable<ProjectDeviceSyncField>
+): string | undefined {
+  const fieldSet = new Set(fields);
+  const unique = projectDeviceSyncFields.filter((field) => fieldSet.has(field));
+  return unique.length > 0 ? JSON.stringify(unique) : undefined;
+}
+
+export function deriveOverriddenFieldsForLocalEdit(
+  current: {
+    linkedProjectDeviceId: string | null | undefined;
+    overriddenFields: string | null | undefined;
+  } & Partial<Record<ProjectDeviceSyncField, unknown>>,
+  patch: Partial<Record<ProjectDeviceSyncField | "overriddenFields", unknown>>
+): string | null | undefined {
+  if (
+    !current.linkedProjectDeviceId ||
+    Object.prototype.hasOwnProperty.call(patch, "overriddenFields")
+  ) {
+    return patch.overriddenFields as string | null | undefined;
+  }
+
+  const overrides = new Set(parseOverriddenFields(current.overriddenFields));
+  for (const field of projectDeviceSyncFields) {
+    if (
+      Object.prototype.hasOwnProperty.call(patch, field) &&
+      (patch[field] ?? null) !== (current[field] ?? null)
+    ) {
+      overrides.add(field);
+    }
+  }
+  return serializeOverriddenFields(overrides);
+}