Centralize formatter target policy

formatter_target.py

@@ -0,0 +1,57 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+from typing import Any
+
+
+FORMATTER_TARGETS = ("auto", "single", "softcore", "hardcore")
+PAIR_SIDE_TARGETS = ("softcore", "hardcore")
+DEFAULT_FORMATTER_TARGET = "auto"
+DEFAULT_PAIR_SELECTED_SIDE = "softcore"
+
+_TARGET_ALIASES = {
+    "soft": "softcore",
+    "soft_core": "softcore",
+    "hard": "hardcore",
+    "hard_core": "hardcore",
+}
+
+
+@dataclass(frozen=True)
+class PairTargetPolicy:
+    target: str
+    pair_target: str
+    selected_side: str
+    include_softcore: bool
+    include_hardcore: bool
+
+
+def normalize_target(value: Any) -> str:
+    target = str(value or "").strip().lower().replace("-", "_").replace(" ", "_")
+    target = _TARGET_ALIASES.get(target, target)
+    return target if target in FORMATTER_TARGETS else DEFAULT_FORMATTER_TARGET
+
+
+def pair_target(value: Any) -> str:
+    target = normalize_target(value)
+    return target if target in PAIR_SIDE_TARGETS else DEFAULT_FORMATTER_TARGET
+
+
+def pair_selected_side(value: Any, default: str = DEFAULT_PAIR_SELECTED_SIDE) -> str:
+    side = pair_target(value)
+    if side in PAIR_SIDE_TARGETS:
+        return side
+    return default if default in PAIR_SIDE_TARGETS else DEFAULT_PAIR_SELECTED_SIDE
+
+
+def pair_policy(value: Any, *, selected_default: str = DEFAULT_PAIR_SELECTED_SIDE) -> PairTargetPolicy:
+    target = normalize_target(value)
+    side_target = pair_target(target)
+    selected_side = pair_selected_side(side_target, selected_default)
+    return PairTargetPolicy(
+        target=target,
+        pair_target=side_target,
+        selected_side=selected_side,
+        include_softcore=side_target in ("auto", "softcore"),
+        include_hardcore=side_target in ("auto", "hardcore"),
+    )