set a system role as a persistent role

#130
ztjhz · ztjhz · May 6, 2023 · Mar 26, 2023 · Mar 26, 2023 · Mar 26, 2023
commit bd8e72e7bb7f1a80bc79ab82c784b2197cdc3530
diff --git a/src/utils/messageUtils.ts b/src/utils/messageUtils.ts
@@ -49,13 +49,29 @@ export const limitMessageTokens = (
   const limitedMessages: MessageInterface[] = [];
   let tokenCount = 0;
 
+  if (messages[0]?.role === 'system') {
+    const count = countTokens([messages[0]], model);
+    tokenCount += count;
+  }
+
   for (let i = messages.length - 1; i >= 0; i--) {
     const count = countTokens([messages[i]], model);
     if (count + tokenCount > limit) break;
     tokenCount += count;
     limitedMessages.unshift({ ...messages[i] });
   }
 
+  if (messages[0]?.role === 'system' && limitedMessages[0]?.role !== 'system') {
+    limitedMessages.unshift({ ...messages[0] });
+  }
+
+  if (limitedMessages.length > 4 && limitedMessages[0].role === 'system'){
+    const firstElement = limitedMessages.shift(); // 取出第一个元素并移除
+    if (firstElement !== undefined) { // 确保 firstElement 不为 undefined
+      limitedMessages.splice(-3, 0, firstElement); // 将第一个元素插入到倒数第四个位置
+    }
+  }
+
   return limitedMessages;
 };