global refactoring; add support for Assets without the computed hash

app/database/helpers/projection.py

@@ -0,0 +1,64 @@
+from decimal import Decimal
+
+
+def is_scalar(v):
+    if v is None:
+        return True
+    if isinstance(v, bool):
+        return True
+    if isinstance(v, (int, float, Decimal, str)):
+        return True
+    return False
+
+
+def project_kv(key: str, value):
+    """
+    Turn a metadata key/value into typed projection rows.
+    Returns list[dict] with keys:
+      key, ordinal, and one of val_str / val_num / val_bool / val_json (others None)
+    """
+    rows: list[dict] = []
+
+    def _null_row(ordinal: int) -> dict:
+        return {
+            "key": key, "ordinal": ordinal,
+            "val_str": None, "val_num": None, "val_bool": None, "val_json": None
+        }
+
+    if value is None:
+        rows.append(_null_row(0))
+        return rows
+
+    if is_scalar(value):
+        if isinstance(value, bool):
+            rows.append({"key": key, "ordinal": 0, "val_bool": bool(value)})
+        elif isinstance(value, (int, float, Decimal)):
+            num = value if isinstance(value, Decimal) else Decimal(str(value))
+            rows.append({"key": key, "ordinal": 0, "val_num": num})
+        elif isinstance(value, str):
+            rows.append({"key": key, "ordinal": 0, "val_str": value})
+        else:
+            rows.append({"key": key, "ordinal": 0, "val_json": value})
+        return rows
+
+    if isinstance(value, list):
+        if all(is_scalar(x) for x in value):
+            for i, x in enumerate(value):
+                if x is None:
+                    rows.append(_null_row(i))
+                elif isinstance(x, bool):
+                    rows.append({"key": key, "ordinal": i, "val_bool": bool(x)})
+                elif isinstance(x, (int, float, Decimal)):
+                    num = x if isinstance(x, Decimal) else Decimal(str(x))
+                    rows.append({"key": key, "ordinal": i, "val_num": num})
+                elif isinstance(x, str):
+                    rows.append({"key": key, "ordinal": i, "val_str": x})
+                else:
+                    rows.append({"key": key, "ordinal": i, "val_json": x})
+            return rows
+        for i, x in enumerate(value):
+            rows.append({"key": key, "ordinal": i, "val_json": x})
+        return rows
+
+    rows.append({"key": key, "ordinal": 0, "val_json": value})
+    return rows