Rework Curator into a Jellyfin-first library manager

src/core/transforms.py

@@ -0,0 +1,41 @@
+"""Tag-schema value transforms for miniDLNA folder names.
+
+Applied when building a folder name from a tag value — the tag keeps its exact
+value (e.g. rating 87 → tag "Hodnocení/87"), while the folder groups it
+(→ "…/80–89 %"). Config-driven and extensible via ``TAG_TRANSFORMS``.
+"""
+import re
+from typing import Optional
+
+
+def rating_band(rating: int) -> str:
+    """Bucket a 0–100 rating into a ten-point band label (e.g. "80–89 %").
+
+    The top bucket spans 90–100 % so a perfect 100 still lands in a band.
+    """
+    low = min((rating // 10) * 10, 90)
+    high = 100 if low == 90 else low + 9
+    return f"{low}–{high} %"
+
+
+def _decade_band(value) -> str:
+    """``decade_band`` transform: pull the leading integer and bucket it."""
+    match = re.search(r"\d+", str(value))
+    return rating_band(int(match.group())) if match else str(value)
+
+
+# Named value transforms usable from the tag schema (config-driven, extensible).
+TAG_TRANSFORMS = {
+    None: str,
+    "identity": str,
+    "decade_band": _decade_band,
+}
+
+
+def apply_transform(value: str, transform: Optional[str]) -> str:
+    """Apply a named tag-schema transform to a value, returning a string."""
+    fn = TAG_TRANSFORMS.get(transform, str)
+    try:
+        return str(fn(value))
+    except (ValueError, TypeError, AttributeError):
+        return str(value)