From 5b5930e4425a6602e994d432fb99e40201c7e106 Mon Sep 17 00:00:00 2001
From: youzini <an48934293@gmail.com>
Date: Sun, 31 May 2026 20:14:32 +0000
Subject: [PATCH] feat(recall): resolve reroll parent user floor

---
 retrieval/recall-persistence.js | 22 ++----------
 runtime/generation-context.js   | 60 +++++++++++++++++++++++++++++++++
 tests/generation-context.mjs    | 46 +++++++++++++++++++++++++
 3 files changed, 109 insertions(+), 19 deletions(-)

diff --git a/retrieval/recall-persistence.js b/retrieval/recall-persistence.js
index 69b5cfe..f1fa370 100644
--- a/retrieval/recall-persistence.js
+++ b/retrieval/recall-persistence.js
@@ -1,5 +1,7 @@
 // ST-BME: 持久化召回记录纯函数
 
+import { resolveGenerationParentUserFloor } from "../runtime/generation-context.js";
+
 export const BME_RECALL_EXTRA_KEY = "bme_recall";
 export const BME_RECALL_VERSION = 1;
 
@@ -135,25 +137,7 @@ export function resolveGenerationTargetUserMessageIndex(
   { generationType = "normal" } = {},
 ) {
   if (!Array.isArray(chat) || chat.length === 0) return null;
-
-  const normalizedType = String(generationType || "normal").trim() || "normal";
-
-  // normal：取「最后一条非系统用户楼层」。若直接 return 末条非 user（常见为刚追加的助手回合），
-  // 会得到 null，导致持久化无法回绑到本轮 user，`hasRecordForLatest` 长期为 false。
-  if (normalizedType === "normal") {
-    for (let index = chat.length - 1; index >= 0; index--) {
-      const message = chat[index];
-      if (message?.is_system) continue;
-      if (message?.is_user) return index;
-    }
-    return null;
-  }
-
-  for (let index = chat.length - 1; index >= 0; index--) {
-    if (chat[index]?.is_user) return index;
-  }
-
-  return null;
+  return resolveGenerationParentUserFloor(chat, { type: generationType });
 }
 
 export function resolveFinalRecallInjectionSource({
diff --git a/runtime/generation-context.js b/runtime/generation-context.js
index d55eaa3..350f9df 100644
--- a/runtime/generation-context.js
+++ b/runtime/generation-context.js
@@ -23,6 +23,66 @@ export function classifyGenerationKind(type = "normal", params = {}) {
   return "fresh";
 }
 
+export function isVisibleUserGenerationMessage(message, { index = null, chat = null, isSystemMessage = null } = {}) {
+  if (!message?.is_user) return false;
+  if (message?.extra?.isSmallSys) return false;
+  if (typeof isSystemMessage === "function" && isSystemMessage(message, { index, chat })) {
+    return false;
+  }
+  if (message?.is_system) return false;
+  return true;
+}
+
+export function resolveGenerationParentUserFloor(
+  chat,
+  context = {},
+  { phase = "", isSystemMessage = null } = {},
+) {
+  if (!Array.isArray(chat) || chat.length === 0) return null;
+  const generationType = normalizeGenerationType(context?.type || context?.generationType || "normal");
+  const findVisibleUserBefore = (startIndex) => {
+    for (let index = Math.min(chat.length - 1, Math.floor(Number(startIndex))); index >= 0; index--) {
+      if (isVisibleUserGenerationMessage(chat[index], { index, chat, isSystemMessage })) return index;
+    }
+    return null;
+  };
+  const findLastVisibleNonSystemIndex = () => {
+    for (let index = chat.length - 1; index >= 0; index--) {
+      const message = chat[index];
+      if (!message) continue;
+      if (message?.extra?.isSmallSys) continue;
+      if (typeof isSystemMessage === "function" && isSystemMessage(message, { index, chat })) continue;
+      if (message?.is_system) continue;
+      return index;
+    }
+    return null;
+  };
+
+  if (generationType === "swipe") {
+    const swipedFloor = Number(context?.swipedAssistantFloor);
+    if (Number.isFinite(swipedFloor)) return findVisibleUserBefore(swipedFloor - 1);
+    const lastVisible = findLastVisibleNonSystemIndex();
+    return Number.isFinite(lastVisible) ? findVisibleUserBefore(lastVisible - 1) : null;
+  }
+
+  if (generationType === "regenerate") {
+    const lastVisible = findLastVisibleNonSystemIndex();
+    if (!Number.isFinite(lastVisible)) return null;
+    if (isVisibleUserGenerationMessage(chat[lastVisible], { index: lastVisible, chat, isSystemMessage })) {
+      return lastVisible;
+    }
+    return findVisibleUserBefore(lastVisible - 1);
+  }
+
+  if (generationType === "continue") {
+    const lastVisible = findLastVisibleNonSystemIndex();
+    if (!Number.isFinite(lastVisible)) return null;
+    return findVisibleUserBefore(lastVisible - (chat[lastVisible]?.is_user ? 0 : 1));
+  }
+
+  return findVisibleUserBefore(chat.length - 1);
+}
+
 function clonePlain(value, fallback = null) {
   if (!value || typeof value !== "object") return fallback;
   try {
diff --git a/tests/generation-context.mjs b/tests/generation-context.mjs
index 7f1d3ad..7bedfe9 100644
--- a/tests/generation-context.mjs
+++ b/tests/generation-context.mjs
@@ -2,6 +2,7 @@ import assert from "node:assert/strict";
 import {
   classifyGenerationKind,
   createGenerationContextTracker,
+  resolveGenerationParentUserFloor,
 } from "../runtime/generation-context.js";
 
 assert.equal(classifyGenerationKind("normal"), "fresh");
@@ -100,3 +101,48 @@ assert.equal(classifyGenerationKind("normal", { quiet_prompt: true }), "skip");
   chatId = "chat-original";
   assert.equal(tracker.get(), null);
 }
+
+{
+  const chat = [
+    { is_system: true, mes: "greeting" },
+    { is_user: true, mes: "first" },
+    { is_user: false, mes: "assistant first" },
+    { is_user: true, mes: "parent" },
+    { is_user: false, mes: "assistant active" },
+  ];
+
+  assert.equal(
+    resolveGenerationParentUserFloor(chat, {
+      type: "swipe",
+      swipedAssistantFloor: 4,
+    }),
+    3,
+  );
+  assert.equal(resolveGenerationParentUserFloor(chat, { type: "regenerate" }), 3);
+}
+
+{
+  const chatAfterRegenerateDelete = [
+    { is_system: true, mes: "greeting" },
+    { is_user: true, mes: "parent" },
+  ];
+  assert.equal(
+    resolveGenerationParentUserFloor(chatAfterRegenerateDelete, {
+      type: "regenerate",
+    }),
+    1,
+  );
+}
+
+{
+  const chat = [
+    { is_system: true, mes: "greeting" },
+    { is_user: true, mes: "hidden", is_system: true },
+    { is_user: true, mes: "visible" },
+    { is_user: false, mes: "assistant" },
+  ];
+  assert.equal(
+    resolveGenerationParentUserFloor(chat, { type: "swipe", swipedAssistantFloor: 3 }),
+    2,
+  );
+}