refactor(chat): 抽象化跨群聊上下文构建逻辑

将 `build_cross_context` 方法的实现委托给 `cross_context_api`。
这简化了 `prompt_utils` 中的代码，将复杂的上下文构建逻辑（包括获取其他群聊、根据模式获取和格式化消息）封装到专用的API中，提高了代码的模块化和可维护性。

src/chat/utils/prompt_utils.py

@@ -9,13 +9,9 @@ from typing import Dict, Any, Optional, Tuple
 
 from src.common.logger import get_logger
 from src.config.config import global_config
-from src.chat.utils.chat_message_builder import (
-    get_raw_msg_before_timestamp_with_chat,
-    build_readable_messages_with_id,
-)
 from src.chat.message_receive.chat_stream import get_chat_manager
 from src.person_info.person_info import get_person_info_manager
-
+from src.plugin_system.apis import cross_context_api
 logger = get_logger("prompt_utils")
 
 
@@ -84,113 +80,29 @@ class PromptUtils:
 
     @staticmethod
     async def build_cross_context(
-        chat_id: str, target_user_info: Optional[Dict[str, Any]], current_prompt_mode: str
+            chat_id: str, target_user_info: Optional[Dict[str, Any]], current_prompt_mode: str
-    ) -> str:
+        ) -> str:
-        """
+            """
-        构建跨群聊上下文 - 统一实现，完全继承DefaultReplyer功能
+            构建跨群聊上下文 - 统一实现，完全继承DefaultReplyer功能
+            """
+            if not global_config.cross_context.enable:
+                return ""
 
-        Args:
+            other_chat_raw_ids = cross_context_api.get_context_groups(chat_id)
-            chat_id: 当前聊天ID
+            if not other_chat_raw_ids:
-            target_user_info: 目标用户信息
+                return ""
-            current_prompt_mode: 当前提示模式
+
+            chat_stream = get_chat_manager().get_stream(chat_id)
+            if not chat_stream:
+                return ""
+
+            if current_prompt_mode == "normal":
+                return await cross_context_api.build_cross_context_normal(chat_stream, other_chat_raw_ids)
+            elif current_prompt_mode == "s4u":
+                return await cross_context_api.build_cross_context_s4u(chat_stream, other_chat_raw_ids, target_user_info)
 
-        Returns:
-            str: 跨群上下文块
-        """
-        if not global_config.cross_context.enable:
             return ""
 
-        # 找到当前群聊所在的共享组
-        target_group = None
-        current_stream = get_chat_manager().get_stream(chat_id)
-        if not current_stream or not current_stream.group_info:
-            return ""
-
-        try:
-            current_chat_raw_id = current_stream.group_info.group_id
-        except Exception as e:
-            logger.error(f"获取群聊ID失败: {e}")
-            return ""
-
-        for group in global_config.cross_context.groups:
-            if str(current_chat_raw_id) in group.chat_ids:
-                target_group = group
-                break
-
-        if not target_group:
-            return ""
-
-        # 根据prompt_mode选择策略
-        other_chat_raw_ids = [chat_id for chat_id in target_group.chat_ids if chat_id != str(current_chat_raw_id)]
-
-        cross_context_messages = []
-
-        if current_prompt_mode == "normal":
-            # normal模式：获取其他群聊的最近N条消息
-            for chat_raw_id in other_chat_raw_ids:
-                stream_id = get_chat_manager().get_stream_id(current_stream.platform, chat_raw_id, is_group=True)
-                if not stream_id:
-                    continue
-
-                try:
-                    messages = get_raw_msg_before_timestamp_with_chat(
-                        chat_id=stream_id,
-                        timestamp=time.time(),
-                        limit=5,  # 可配置
-                    )
-                    if messages:
-                        chat_name = get_chat_manager().get_stream_name(stream_id) or stream_id
-                        formatted_messages, _ = build_readable_messages_with_id(messages, timestamp_mode="relative")
-                        cross_context_messages.append(f'[以下是来自"{chat_name}"的近期消息]\n{formatted_messages}')
-                except Exception as e:
-                    logger.error(f"获取群聊{chat_raw_id}的消息失败: {e}")
-                    continue
-
-        elif current_prompt_mode == "s4u":
-            # s4u模式：获取当前发言用户在其他群聊的消息
-            if target_user_info:
-                user_id = target_user_info.get("user_id")
-
-                if user_id:
-                    for chat_raw_id in other_chat_raw_ids:
-                        stream_id = get_chat_manager().get_stream_id(
-                            current_stream.platform, chat_raw_id, is_group=True
-                        )
-                        if not stream_id:
-                            continue
-
-                        try:
-                            messages = get_raw_msg_before_timestamp_with_chat(
-                                chat_id=stream_id,
-                                timestamp=time.time(),
-                                limit=20,  # 获取更多消息以供筛选
-                            )
-                            user_messages = [msg for msg in messages if msg.get("user_id") == user_id][
-                                -5:
-                            ]  # 筛选并取最近5条
-
-                            if user_messages:
-                                chat_name = get_chat_manager().get_stream_name(stream_id) or stream_id
-                                user_name = (
-                                    target_user_info.get("person_name")
-                                    or target_user_info.get("user_nickname")
-                                    or user_id
-                                )
-                                formatted_messages, _ = build_readable_messages_with_id(
-                                    user_messages, timestamp_mode="relative"
-                                )
-                                cross_context_messages.append(
-                                    f'[以下是"{user_name}"在"{chat_name}"的近期发言]\n{formatted_messages}'
-                                )
-                        except Exception as e:
-                            logger.error(f"获取用户{user_id}在群聊{chat_raw_id}的消息失败: {e}")
-                            continue
-
-        if not cross_context_messages:
-            return ""
-
-        return "# 跨群上下文参考\n" + "\n\n".join(cross_context_messages) + "\n"
-
     @staticmethod
     def parse_reply_target_id(reply_to: str) -> str:
         """

src/plugin_system/apis/cross_context_api.py

@@ -0,0 +1,118 @@
+"""
+跨群聊上下文API
+"""
+
+import time
+from typing import Dict, Any, Optional, List
+
+from src.common.logger import get_logger
+from src.config.config import global_config
+from src.chat.utils.chat_message_builder import (
+    get_raw_msg_before_timestamp_with_chat,
+    build_readable_messages_with_id,
+)
+from src.chat.message_receive.chat_stream import get_chat_manager, ChatStream
+
+logger = get_logger("cross_context_api")
+
+
+def get_context_groups(chat_id: str) -> Optional[List[str]]:
+    """
+    获取当前群聊所在的共享组的其他群聊ID
+    """
+    current_stream = get_chat_manager().get_stream(chat_id)
+    if not current_stream or not current_stream.group_info:
+        return None
+
+    try:
+        current_chat_raw_id = current_stream.group_info.group_id
+    except Exception as e:
+        logger.error(f"获取群聊ID失败: {e}")
+        return None
+
+    for group in global_config.cross_context.groups:
+        if str(current_chat_raw_id) in group.chat_ids:
+            return [chat_id for chat_id in group.chat_ids if chat_id != str(current_chat_raw_id)]
+
+    return None
+
+
+async def build_cross_context_normal(chat_stream: ChatStream, other_chat_raw_ids: List[str]) -> str:
+    """
+    构建跨群聊上下文 (Normal模式)
+    """
+    cross_context_messages = []
+    for chat_raw_id in other_chat_raw_ids:
+        stream_id = get_chat_manager().get_stream_id(chat_stream.platform, chat_raw_id, is_group=True)
+        if not stream_id:
+            continue
+
+        try:
+            messages = get_raw_msg_before_timestamp_with_chat(
+                chat_id=stream_id,
+                timestamp=time.time(),
+                limit=5,  # 可配置
+            )
+            if messages:
+                chat_name = get_chat_manager().get_stream_name(stream_id) or stream_id
+                formatted_messages, _ = build_readable_messages_with_id(messages, timestamp_mode="relative")
+                cross_context_messages.append(f'[以下是来自"{chat_name}"的近期消息]\n{formatted_messages}')
+        except Exception as e:
+            logger.error(f"获取群聊{chat_raw_id}的消息失败: {e}")
+            continue
+
+    if not cross_context_messages:
+        return ""
+
+    return "# 跨群上下文参考\n" + "\n\n".join(cross_context_messages) + "\n"
+
+
+async def build_cross_context_s4u(
+    chat_stream: ChatStream, other_chat_raw_ids: List[str], target_user_info: Optional[Dict[str, Any]]
+) -> str:
+    """
+    构建跨群聊上下文 (S4U模式)
+    """
+    cross_context_messages = []
+    if target_user_info:
+        user_id = target_user_info.get("user_id")
+
+        if user_id:
+            for chat_raw_id in other_chat_raw_ids:
+                stream_id = get_chat_manager().get_stream_id(
+                    chat_stream.platform, chat_raw_id, is_group=True
+                )
+                if not stream_id:
+                    continue
+
+                try:
+                    messages = get_raw_msg_before_timestamp_with_chat(
+                        chat_id=stream_id,
+                        timestamp=time.time(),
+                        limit=20,  # 获取更多消息以供筛选
+                    )
+                    user_messages = [msg for msg in messages if msg.get("user_id") == user_id][
+                        -5:
+                    ]  # 筛选并取最近5条
+
+                    if user_messages:
+                        chat_name = get_chat_manager().get_stream_name(stream_id) or stream_id
+                        user_name = (
+                            target_user_info.get("person_name")
+                            or target_user_info.get("user_nickname")
+                            or user_id
+                        )
+                        formatted_messages, _ = build_readable_messages_with_id(
+                            user_messages, timestamp_mode="relative"
+                        )
+                        cross_context_messages.append(
+                            f'[以下是"{user_name}"在"{chat_name}"的近期发言]\n{formatted_messages}'
+                        )
+                except Exception as e:
+                    logger.error(f"获取用户{user_id}在群聊{chat_raw_id}的消息失败: {e}")
+                    continue
+
+    if not cross_context_messages:
+        return ""
+
+    return "# 跨群上下文参考\n" + "\n\n".join(cross_context_messages) + "\n"