fix: @提及弹窗跟随光标位置

src/pages/chat/components/ChatInput.tsx

@@ -52,6 +52,50 @@ export default function ChatInput(props: {
   const [mentionPos, setMentionPos] = useState<{ top: number; left: number } | null>(null);
   const inputRef = useRef<TextAreaRef>(null);
 
+  const getCaretPos = (textarea: HTMLTextAreaElement, caretIndex: number) => {
+    const rect = textarea.getBoundingClientRect();
+    const cs = window.getComputedStyle(textarea);
+    const div = document.createElement('div');
+
+    div.style.position = 'absolute';
+    div.style.visibility = 'hidden';
+    div.style.top = '0';
+    div.style.left = '-9999px';
+    div.style.whiteSpace = 'pre-wrap';
+    div.style.wordWrap = 'break-word';
+    div.style.overflow = 'hidden';
+    div.style.boxSizing = cs.boxSizing;
+    div.style.width = rect.width + 'px';
+    div.style.fontFamily = cs.fontFamily;
+    div.style.fontSize = cs.fontSize;
+    div.style.fontWeight = cs.fontWeight;
+    div.style.fontStyle = cs.fontStyle;
+    div.style.letterSpacing = cs.letterSpacing;
+    div.style.textTransform = cs.textTransform;
+    div.style.lineHeight = cs.lineHeight;
+    div.style.padding = cs.padding;
+    div.style.border = cs.border;
+    div.style.tabSize = (cs as any).tabSize || '8';
+
+    const before = textarea.value.slice(0, caretIndex).replace(/ /g, '\u00a0');
+    div.textContent = before;
+    const span = document.createElement('span');
+    span.textContent = '\u200b';
+    div.appendChild(span);
+
+    document.body.appendChild(div);
+    const divRect = div.getBoundingClientRect();
+    const spanRect = span.getBoundingClientRect();
+    document.body.removeChild(div);
+
+    const lineHeight = Number.parseFloat(cs.lineHeight) || Number.parseFloat(cs.fontSize) * 1.2;
+    return {
+      top: rect.top + (spanRect.top - divRect.top) - textarea.scrollTop,
+      left: rect.left + (spanRect.left - divRect.left) - textarea.scrollLeft,
+      lineHeight
+    };
+  };
+
   // 检测 @ 触发提及选择
   const handleInputChange = (e: React.ChangeEvent<HTMLTextAreaElement>) => {
     const value = e.target.value;
@@ -82,10 +126,11 @@ export default function ChatInput(props: {
             console.log('[@mention] cannot get textarea DOM from inputRef:', inputRef.current);
             return;
           }
-          const rect = textarea.getBoundingClientRect();
-          console.log('[@mention] textarea rect:', rect);
-          setMentionPos({ top: rect.bottom, left: rect.left + 10 });
-          console.log('[@mention] show popover:', { top: rect.bottom, left: rect.left + 10, query });
+          const caret = getCaretPos(textarea, cursorPos);
+          const top = Math.min(window.innerHeight - 8, caret.top + caret.lineHeight + 8);
+          const left = Math.min(window.innerWidth - 160, Math.max(8, caret.left));
+          setMentionPos({ top, left });
+          console.log('[@mention] show popover:', { top, left, query });
           setShowMentionPopover(true);
         });
         return;