Show trade open/close times and hold period by target exit.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/app/api/hold_timing.py

@@ -0,0 +1,76 @@
+"""交易组持仓周期：目标出场以策略平仓时刻为准；永续先平则以永续平仓为准。"""
+
+from __future__ import annotations
+
+from typing import Any, Mapping, Sequence
+
+# 目标平仓（含 15U / 权利金倍数 / 只平永续）
+_TARGET_REASONS = frozenset({"fixed_usdt", "premium_multiple", "target_perp_only"})
+
+
+def _ts(v: Any) -> int | None:
+    if v is None:
+        return None
+    try:
+        n = int(v)
+    except (TypeError, ValueError):
+        return None
+    return n if n > 0 else None
+
+
+def first_perp_close_ts_ms(fills: Sequence[Mapping[str, Any]]) -> int | None:
+    """永续平仓成交时间（目标只平永续时作为持仓结束时刻）。"""
+    best: int | None = None
+    for f in fills:
+        if str(f.get("leg") or "") != "perp":
+            continue
+        if str(f.get("action") or "") != "close":
+            continue
+        ts = _ts(f.get("ts_ms"))
+        if ts is None:
+            continue
+        if best is None or ts < best:
+            best = ts
+    return best
+
+
+def hold_timing(
+    group: Mapping[str, Any], fills: Sequence[Mapping[str, Any]]
+) -> dict[str, Any]:
+    """
+    返回展示用开仓/平仓/持仓时长。
+
+    - 开仓：groups.open_at_ms
+    - 平仓（策略持仓周期）：
+      - `target_perp_only` / `option_residual`：永续平仓 fill 时间
+      - 其它已平：groups.close_at_ms（缺则回退成交）
+    """
+    open_ms = _ts(group.get("open_at_ms"))
+    status = str(group.get("status") or "")
+    reason = str(group.get("close_reason") or "")
+    group_close = _ts(group.get("close_at_ms"))
+    perp_close = first_perp_close_ts_ms(fills)
+
+    use_perp = reason == "target_perp_only" or status == "option_residual"
+    if use_perp:
+        close_ms = perp_close or group_close
+        basis = "perp"
+    elif status == "open":
+        close_ms = None
+        basis = "open"
+    else:
+        close_ms = group_close
+        if close_ms is None and reason in _TARGET_REASONS:
+            close_ms = perp_close
+        basis = "group"
+
+    hold_ms: int | None = None
+    if open_ms is not None and close_ms is not None and close_ms >= open_ms:
+        hold_ms = close_ms - open_ms
+
+    return {
+        "hold_open_at_ms": open_ms,
+        "hold_close_at_ms": close_ms,
+        "hold_ms": hold_ms,
+        "hold_basis": basis,
+    }