feat(migrate): template migrations

src/lib/utils/template-diff.ts

@@ -0,0 +1,51 @@
+import type { Template } from '../types';
+
+export interface TemplateDiff {
+	addedFields: string[];
+	removedFields: string[];
+	renamedFields: { from: string; to: string }[];
+	addedRecords: string[];
+	removedRecords: string[];
+}
+
+export function diffTemplates(old: Template, current: Template): TemplateDiff {
+	const oldRecordTypes = new Set(old.records.map((r) => r.type));
+	const newRecordTypes = new Set(current.records.map((r) => r.type));
+
+	const oldFields = new Set(old.records.flatMap((r) => r.fields.map((f) => f.label)));
+	const newFields = new Set(current.records.flatMap((r) => r.fields.map((f) => f.label)));
+
+	// Detect renames via `from` attribute
+	const renamedFields: { from: string; to: string }[] = [];
+	const renamedOld = new Set<string>();
+	const renamedNew = new Set<string>();
+
+	for (const record of current.records) {
+		for (const field of record.fields) {
+			if (!field.from) continue;
+			const fromNames = field.from.split(',').map((s) => s.trim());
+			const match = fromNames.find((f) => oldFields.has(f));
+			if (match && !newFields.has(match)) {
+				renamedFields.push({ from: match, to: field.label });
+				renamedOld.add(match);
+				renamedNew.add(field.label);
+			}
+		}
+	}
+
+	return {
+		addedFields: [...newFields].filter((f) => !oldFields.has(f) && !renamedNew.has(f)),
+		removedFields: [...oldFields].filter((f) => !newFields.has(f) && !renamedOld.has(f)),
+		renamedFields,
+		addedRecords: [...newRecordTypes].filter((r) => !oldRecordTypes.has(r)),
+		removedRecords: [...oldRecordTypes].filter((r) => !newRecordTypes.has(r))
+	};
+}
+
+export function hasChanges(diff: TemplateDiff): boolean {
+	return diff.addedFields.length > 0
+		|| diff.removedFields.length > 0
+		|| diff.renamedFields.length > 0
+		|| diff.addedRecords.length > 0
+		|| diff.removedRecords.length > 0;
+}