From e3cbec30dedd349a84def7e5ea282bfe82c5a407 Mon Sep 17 00:00:00 2001
From: Kadxy <2230318258@qq.com>
Date: Sat, 5 Apr 2025 12:56:52 +0800
Subject: [PATCH] refactor: clean up chat and markdown components, improve
 markdown rendering with lazy loading and streaming support

---
 app/components/chat.tsx     |  12 +--
 app/components/markdown.tsx | 166 ++++++++++++++++++++++++++++++++++++
 app/styles/markdown.scss    | 115 +++++++++++++++++++++++--
 3 files changed, 281 insertions(+), 12 deletions(-)

diff --git a/app/components/chat.tsx b/app/components/chat.tsx
index 6691403e6..14a1f9659 100644
--- a/app/components/chat.tsx
+++ b/app/components/chat.tsx
@@ -18,7 +18,6 @@ import ReturnIcon from "../icons/return.svg";
 import CopyIcon from "../icons/copy.svg";
 import SpeakIcon from "../icons/speak.svg";
 import SpeakStopIcon from "../icons/speak-stop.svg";
-import LoadingIcon from "../icons/three-dots.svg";
 import LoadingButtonIcon from "../icons/loading.svg";
 import PromptIcon from "../icons/prompt.svg";
 import MaskIcon from "../icons/mask.svg";
@@ -79,8 +78,6 @@ import {
 
 import { uploadImage as uploadImageRemote } from "@/app/utils/chat";
 
-import dynamic from "next/dynamic";
-
 import { ChatControllerPool } from "../client/controller";
 import { DalleQuality, DalleStyle, ModelSize } from "../typing";
 import { Prompt, usePromptStore } from "../store/prompt";
@@ -125,14 +122,15 @@ import { getModelProvider } from "../utils/model";
 import { RealtimeChat } from "@/app/components/realtime-chat";
 import clsx from "clsx";
 import { getAvailableClientsCount, isMcpEnabled } from "../mcp/actions";
+import { Markdown } from "./markdown";
 
 const localStorage = safeLocalStorage();
 
 const ttsPlayer = createTTSPlayer();
 
-const Markdown = dynamic(async () => (await import("./markdown")).Markdown, {
-  loading: () => <LoadingIcon />,
-});
+// const Markdown = dynamic(async () => (await import("./markdown")).Markdown, {
+//   loading: () => <LoadingIcon />,
+// });
 
 const MCPAction = () => {
   const navigate = useNavigate();
@@ -1984,6 +1982,8 @@ function _Chat() {
                               fontFamily={fontFamily}
                               parentRef={scrollRef}
                               defaultShow={i >= messages.length - 6}
+                              immediatelyRender={i >= messages.length - 3}
+                              streaming={message.streaming}
                             />
                             {getMessageImages(message).length == 1 && (
                               <img
diff --git a/app/components/markdown.tsx b/app/components/markdown.tsx
index ba85f0970..934f186cb 100644
--- a/app/components/markdown.tsx
+++ b/app/components/markdown.tsx
@@ -267,6 +267,136 @@ function tryWrapHtmlCode(text: string) {
     );
 }
 
+// Split content into paragraphs while preserving code blocks
+function splitContentIntoParagraphs(content: string) {
+  // Check for unclosed code blocks
+  const codeBlockStartCount = (content.match(/```/g) || []).length;
+  let processedContent = content;
+
+  // Add closing tag if there's an odd number of code block markers
+  if (codeBlockStartCount % 2 !== 0) {
+    processedContent = content + "\n```";
+  }
+
+  // Extract code blocks
+  const codeBlockRegex = /```[\s\S]*?```/g;
+  const codeBlocks: string[] = [];
+  let codeBlockCounter = 0;
+
+  // Replace code blocks with placeholders
+  const contentWithPlaceholders = processedContent.replace(
+    codeBlockRegex,
+    (match) => {
+      codeBlocks.push(match);
+      const placeholder = `__CODE_BLOCK_${codeBlockCounter++}__`;
+      return placeholder;
+    },
+  );
+
+  // Split by double newlines
+  const paragraphs = contentWithPlaceholders
+    .split(/\n\n+/)
+    .filter((p) => p.trim());
+
+  // Restore code blocks
+  return paragraphs.map((p) => {
+    if (p.match(/__CODE_BLOCK_\d+__/)) {
+      return p.replace(/__CODE_BLOCK_\d+__/g, (match) => {
+        const index = parseInt(match.match(/\d+/)?.[0] || "0");
+        return codeBlocks[index] || match;
+      });
+    }
+    return p;
+  });
+}
+
+// Lazy-loaded paragraph component
+function MarkdownParagraph({
+  content,
+  onLoad,
+}: {
+  content: string;
+  onLoad?: () => void;
+}) {
+  const [isLoaded, setIsLoaded] = useState(false);
+  const placeholderRef = useRef<HTMLDivElement>(null);
+  const [isVisible, setIsVisible] = useState(false);
+
+  useEffect(() => {
+    let observer: IntersectionObserver;
+    if (placeholderRef.current) {
+      observer = new IntersectionObserver(
+        (entries) => {
+          if (entries[0].isIntersecting) {
+            setIsVisible(true);
+          }
+        },
+        { threshold: 0.1, rootMargin: "200px 0px" },
+      );
+      observer.observe(placeholderRef.current);
+    }
+    return () => observer?.disconnect();
+  }, []);
+
+  useEffect(() => {
+    if (isVisible && !isLoaded) {
+      setIsLoaded(true);
+      onLoad?.();
+    }
+  }, [isVisible, isLoaded, onLoad]);
+
+  // Generate preview content
+  const previewContent = useMemo(() => {
+    if (content.startsWith("```")) {
+      return "```" + (content.split("\n")[0] || "").slice(3) + "...```";
+    }
+    return content.length > 60 ? content.slice(0, 60) + "..." : content;
+  }, [content]);
+
+  return (
+    <div className="markdown-paragraph" ref={placeholderRef}>
+      {!isLoaded ? (
+        <div className="markdown-paragraph-placeholder">{previewContent}</div>
+      ) : (
+        <_MarkDownContent content={content} />
+      )}
+    </div>
+  );
+}
+
+// Memoized paragraph component to prevent unnecessary re-renders
+const MemoizedMarkdownParagraph = React.memo(
+  ({ content }: { content: string }) => {
+    return <_MarkDownContent content={content} />;
+  },
+  (prevProps, nextProps) => prevProps.content === nextProps.content,
+);
+
+MemoizedMarkdownParagraph.displayName = "MemoizedMarkdownParagraph";
+
+// Specialized component for streaming content
+function StreamingMarkdownContent({ content }: { content: string }) {
+  const paragraphs = useMemo(
+    () => splitContentIntoParagraphs(content),
+    [content],
+  );
+  const lastParagraphRef = useRef<HTMLDivElement>(null);
+
+  return (
+    <div className="markdown-streaming-content">
+      {paragraphs.map((paragraph, index) => (
+        <div
+          key={`p-${index}-${paragraph.substring(0, 20)}`}
+          className="markdown-paragraph markdown-streaming-paragraph"
+          ref={index === paragraphs.length - 1 ? lastParagraphRef : null}
+        >
+          <MemoizedMarkdownParagraph content={paragraph} />
+        </div>
+      ))}
+    </div>
+  );
+}
+
 function _MarkDownContent(props: { content: string }) {
   const escapedContent = useMemo(() => {
     return tryWrapHtmlCode(escapeBrackets(props.content));
@@ -326,9 +456,27 @@ export function Markdown(
     fontFamily?: string;
     parentRef?: RefObject<HTMLDivElement>;
     defaultShow?: boolean;
+    immediatelyRender?: boolean;
+    streaming?: boolean; // Whether this is a streaming response
   } & React.DOMAttributes<HTMLDivElement>,
 ) {
   const mdRef = useRef<HTMLDivElement>(null);
+  const paragraphs = useMemo(
+    () => splitContentIntoParagraphs(props.content),
+    [props.content],
+  );
+  const [loadedCount, setLoadedCount] = useState(0);
+
+  // Determine rendering strategy based on props
+  const shouldAsyncRender =
+    !props.immediatelyRender && !props.streaming && paragraphs.length > 1;
+
+  useEffect(() => {
+    // Immediately render all paragraphs if specified
+    if (props.immediatelyRender) {
+      setLoadedCount(paragraphs.length);
+    }
+  }, [props.immediatelyRender, paragraphs.length]);
 
   return (
     <div
@@ -344,6 +492,24 @@ export function Markdown(
     >
       {props.loading ? (
         <LoadingIcon />
+      ) : props.streaming ? (
+        // Use specialized component for streaming content
+        <StreamingMarkdownContent content={props.content} />
+      ) : shouldAsyncRender ? (
+        <div className="markdown-content">
+          {paragraphs.map((paragraph, index) => (
+            <MarkdownParagraph
+              key={index}
+              content={paragraph}
+              onLoad={() => setLoadedCount((prev) => prev + 1)}
+            />
+          ))}
+          {loadedCount < paragraphs.length && loadedCount > 0 && (
+            <div className="markdown-paragraph-loading">
+              <LoadingIcon />
+            </div>
+          )}
+        </div>
       ) : (
         <MarkdownContent content={props.content} />
       )}
diff --git a/app/styles/markdown.scss b/app/styles/markdown.scss
index 672167d4d..c0ca8d34d 100644
--- a/app/styles/markdown.scss
+++ b/app/styles/markdown.scss
@@ -99,6 +99,7 @@
   font-size: 14px;
   line-height: 1.5;
   word-wrap: break-word;
+  margin-bottom: 0;
 }
 
 .light {
@@ -358,8 +359,14 @@
 .markdown-body kbd {
   display: inline-block;
   padding: 3px 5px;
-  font: 11px ui-monospace, SFMono-Regular, SF Mono, Menlo, Consolas,
-    Liberation Mono, monospace;
+  font:
+    11px ui-monospace,
+    SFMono-Regular,
+    SF Mono,
+    Menlo,
+    Consolas,
+    Liberation Mono,
+    monospace;
   line-height: 10px;
   color: var(--color-fg-default);
   vertical-align: middle;
@@ -448,16 +455,28 @@
 .markdown-body tt,
 .markdown-body code,
 .markdown-body samp {
-  font-family: ui-monospace, SFMono-Regular, SF Mono, Menlo, Consolas,
-    Liberation Mono, monospace;
+  font-family:
+    ui-monospace,
+    SFMono-Regular,
+    SF Mono,
+    Menlo,
+    Consolas,
+    Liberation Mono,
+    monospace;
   font-size: 12px;
 }
 
 .markdown-body pre {
   margin-top: 0;
   margin-bottom: 0;
-  font-family: ui-monospace, SFMono-Regular, SF Mono, Menlo, Consolas,
-    Liberation Mono, monospace;
+  font-family:
+    ui-monospace,
+    SFMono-Regular,
+    SF Mono,
+    Menlo,
+    Consolas,
+    Liberation Mono,
+    monospace;
   font-size: 12px;
   word-wrap: normal;
 }
@@ -1130,3 +1149,87 @@
 #dmermaid {
   display: none;
 }
+
+.markdown-content {
+  width: 100%;
+}
+
+.markdown-paragraph {
+  transition: opacity 0.3s ease;
+  margin-bottom: 0.5em;
+
+  &.markdown-paragraph-visible {
+    opacity: 1;
+  }
+
+  &.markdown-paragraph-hidden {
+    opacity: 0.7;
+  }
+}
+
+.markdown-paragraph-placeholder {
+  padding: 8px;
+  color: var(--color-fg-subtle);
+  background-color: var(--color-canvas-subtle);
+  border-radius: 6px;
+  border-left: 3px solid var(--color-border-muted);
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  font-family: var(--font-family-sans);
+  font-size: 14px;
+  min-height: 1.2em;
+}
+
+.markdown-paragraph-loading {
+  height: 20px;
+  background-color: var(--color-canvas-subtle);
+  border-radius: 6px;
+  margin-bottom: 8px;
+  position: relative;
+  overflow: hidden;
+
+  &::after {
+    content: "";
+    position: absolute;
+    top: 0;
+    left: 0;
+    width: 30%;
+    height: 100%;
+    background: linear-gradient(
+      90deg,
+      transparent,
+      rgba(255, 255, 255, 0.1),
+      transparent
+    );
+    animation: shimmer 1.5s infinite;
+  }
+}
+
+@keyframes shimmer {
+  0% {
+    transform: translateX(-100%);
+  }
+  100% {
+    transform: translateX(200%);
+  }
+}
+
+.markdown-streaming-content {
+  width: 100%;
+}
+
+.markdown-streaming-paragraph {
+  opacity: 1;
+  animation: fadeIn 0.3s ease-in-out;
+  margin-bottom: 0.5em;
+}
+
+@keyframes fadeIn {
+  from {
+    opacity: 0.5;
+  }
+  to {
+    opacity: 1;
+  }
+}