first commit

backend/app/domain/editor_builder.py

@@ -0,0 +1,33 @@
+from __future__ import annotations
+
+from app.domain.editor import RuntimeOperation, VariantChange, VariantRuntimePayload
+
+
+def build_runtime_payload_from_changes(
+    variant_id: str,
+    changes: list[VariantChange],
+) -> VariantRuntimePayload:
+    """Convert editor-facing change records into runtime-facing operations.
+
+    The builder keeps the runtime contract stable even if the editor UI later
+    changes how it stores intermediate draft state.
+    """
+
+    operations: list[RuntimeOperation] = []
+
+    for change in sorted(changes, key=lambda item: item.sort_order):
+        action = change.payload.get("action") if isinstance(change.payload, dict) else None
+        operations.append(
+            RuntimeOperation(
+                selector_type=change.selector_type,
+                selector_value=change.selector_value,
+                action=action or change.change_type,
+                payload=change.payload,
+            )
+        )
+
+    return VariantRuntimePayload(
+        variant_id=variant_id,
+        operations=operations,
+    )
+