feat(package): add langgraph

closes #889

package.json

@@ -20,6 +20,7 @@
     "@langchain/core": "^0.3.66",
     "@langchain/google-genai": "^0.2.15",
     "@langchain/groq": "^0.2.3",
+    "@langchain/langgraph": "^0.4.9",
     "@langchain/ollama": "^0.2.3",
     "@langchain/openai": "^0.6.2",
     "@langchain/textsplitters": "^0.1.0",

src/app/api/chat/route.ts

@@ -17,35 +17,71 @@ import {
   getCustomOpenaiModelName,
 } from '@/lib/config';
 import { searchHandlers } from '@/lib/search';
+import { z } from 'zod';
 
 export const runtime = 'nodejs';
 export const dynamic = 'force-dynamic';
 
-type Message = {
-  messageId: string;
-  chatId: string;
-  content: string;
-};
+const messageSchema = z.object({
+  messageId: z.string().min(1, 'Message ID is required'),
+  chatId: z.string().min(1, 'Chat ID is required'),
+  content: z.string().min(1, 'Message content is required'),
+});
 
-type ChatModel = {
-  provider: string;
-  name: string;
-};
+const chatModelSchema = z.object({
+  provider: z.string().optional(),
+  name: z.string().optional(),
+});
 
-type EmbeddingModel = {
-  provider: string;
-  name: string;
-};
+const embeddingModelSchema = z.object({
+  provider: z.string().optional(),
+  name: z.string().optional(),
+});
 
-type Body = {
-  message: Message;
-  optimizationMode: 'speed' | 'balanced' | 'quality';
-  focusMode: string;
-  history: Array<[string, string]>;
-  files: Array<string>;
-  chatModel: ChatModel;
-  embeddingModel: EmbeddingModel;
-  systemInstructions: string;
+const bodySchema = z.object({
+  message: messageSchema,
+  optimizationMode: z.enum(['speed', 'balanced', 'quality'], {
+    errorMap: () => ({
+      message: 'Optimization mode must be one of: speed, balanced, quality',
+    }),
+  }),
+  focusMode: z.string().min(1, 'Focus mode is required'),
+  history: z
+    .array(
+      z.tuple([z.string(), z.string()], {
+        errorMap: () => ({
+          message: 'History items must be tuples of two strings',
+        }),
+      }),
+    )
+    .optional()
+    .default([]),
+  files: z.array(z.string()).optional().default([]),
+  chatModel: chatModelSchema.optional().default({}),
+  embeddingModel: embeddingModelSchema.optional().default({}),
+  systemInstructions: z.string().nullable().optional().default(''),
+});
+
+type Message = z.infer<typeof messageSchema>;
+type Body = z.infer<typeof bodySchema>;
+
+const safeValidateBody = (data: unknown) => {
+  const result = bodySchema.safeParse(data);
+
+  if (!result.success) {
+    return {
+      success: false,
+      error: result.error.errors.map((e) => ({
+        path: e.path.join('.'),
+        message: e.message,
+      })),
+    };
+  }
+
+  return {
+    success: true,
+    data: result.data,
+  };
 };
 
 const handleEmitterEvents = async (
@@ -190,7 +226,17 @@ const handleHistorySave = async (
 
 export const POST = async (req: Request) => {
   try {
-    const body = (await req.json()) as Body;
+    const reqBody = (await req.json()) as Body;
+
+    const parseBody = safeValidateBody(reqBody);
+    if (!parseBody.success) {
+      return Response.json(
+        { message: 'Invalid request body', error: parseBody.error },
+        { status: 400 },
+      );
+    }
+
+    const body = parseBody.data as Body;
     const { message } = body;
 
     if (message.content === '') {
@@ -285,7 +331,7 @@ export const POST = async (req: Request) => {
       embedding,
       body.optimizationMode,
       body.files,
-      body.systemInstructions,
+      body.systemInstructions as string,
     );
 
     const responseStream = new TransformStream();

src/app/globals.css

@@ -20,6 +20,15 @@
   }
 }
 
+@layer utilities {
+  .line-clamp-2 {
+    display: -webkit-box;
+    -webkit-box-orient: vertical;
+    -webkit-line-clamp: 2;
+    overflow: hidden;
+  }
+}
+
 @media screen and (-webkit-min-device-pixel-ratio: 0) {
   select,
   textarea,

src/components/MessageBox.tsx

@@ -69,9 +69,7 @@ const MessageBox = ({
 
   return (
     <div className="space-y-6">
-      <div
-        className={'w-full pt-8 break-words'}
-      >
+      <div className={'w-full pt-8 break-words'}>
         <h2 className="text-black dark:text-white font-medium text-3xl lg:w-9/12">
           {section.userMessage.content}
         </h2>

src/components/NewsArticleWidget.tsx

@@ -29,15 +29,13 @@ const NewsArticleWidget = () => {
   return (
     <div className="bg-light-secondary dark:bg-dark-secondary rounded-2xl border border-light-200 dark:border-dark-200 shadow-sm shadow-light-200/10 dark:shadow-black/25 flex flex-row items-stretch w-full h-24 min-h-[96px] max-h-[96px] p-0 overflow-hidden">
       {loading ? (
-        <>
-          <div className="animate-pulse flex flex-row items-center w-full h-full">
-            <div className="rounded-lg w-16 min-w-16 max-w-16 h-16 min-h-16 max-h-16 bg-light-200 dark:bg-dark-200 mr-3" />
-            <div className="flex flex-col justify-center flex-1 h-full w-0 gap-2">
-              <div className="h-4 w-3/4 rounded bg-light-200 dark:bg-dark-200" />
-              <div className="h-3 w-1/2 rounded bg-light-200 dark:bg-dark-200" />
-            </div>
+        <div className="animate-pulse flex flex-row items-stretch w-full h-full">
+          <div className="w-24 min-w-24 max-w-24 h-full bg-light-200 dark:bg-dark-200" />
+          <div className="flex flex-col justify-center flex-1 px-3 py-2 gap-2">
+            <div className="h-4 w-3/4 rounded bg-light-200 dark:bg-dark-200" />
+            <div className="h-3 w-1/2 rounded bg-light-200 dark:bg-dark-200" />
           </div>
-        </>
+        </div>
       ) : error ? (
         <div className="w-full text-xs text-red-400">Could not load news.</div>
       ) : article ? (

src/lib/hooks/useChat.tsx

@@ -399,6 +399,7 @@ export const ChatProvider = ({
           (m, j) =>
             j > i &&
             m.role === 'source' &&
+            m.sources &&
             (nextUserMessageIndex === -1 || j < nextUserMessageIndex),
         ) as SourceMessage | undefined;
 
@@ -417,7 +418,7 @@ export const ChatProvider = ({
             const closeThinkTag =
               processedMessage.match(/<\/think>/g)?.length || 0;
 
-            if (openThinkTag > closeThinkTag) {
+            if (openThinkTag && !closeThinkTag) {
               processedMessage += '</think> <a> </a>';
             }
           }
@@ -426,7 +427,11 @@ export const ChatProvider = ({
             thinkingEnded = true;
           }
 
-          if (sourceMessage && sourceMessage.sources.length > 0) {
+          if (
+            sourceMessage &&
+            sourceMessage.sources &&
+            sourceMessage.sources.length > 0
+          ) {
             processedMessage = processedMessage.replace(
               citationRegex,
               (_, capturedContent: string) => {
@@ -635,23 +640,22 @@ export const ChatProvider = ({
             },
           ]);
           added = true;
+          setMessageAppeared(true);
+        } else {
+          setMessages((prev) =>
+            prev.map((message) => {
+              if (
+                message.messageId === data.messageId &&
+                message.role === 'assistant'
+              ) {
+                return { ...message, content: message.content + data.data };
+              }
+
+              return message;
+            }),
+          );
         }
-
-        setMessages((prev) =>
-          prev.map((message) => {
-            if (
-              message.messageId === data.messageId &&
-              message.role === 'assistant'
-            ) {
-              return { ...message, content: message.content + data.data };
-            }
-
-            return message;
-          }),
-        );
-
         recievedMessage += data.data;
-        setMessageAppeared(true);
       }
 
       if (data.type === 'messageEnd') {

src/lib/outputParsers/lineOutputParser.ts

@@ -4,7 +4,7 @@ interface LineOutputParserArgs {
   key?: string;
 }
 
-class LineOutputParser extends BaseOutputParser<string> {
+class LineOutputParser extends BaseOutputParser<string | undefined> {
   private key = 'questions';
 
   constructor(args?: LineOutputParserArgs) {
@@ -18,7 +18,7 @@ class LineOutputParser extends BaseOutputParser<string> {
 
   lc_namespace = ['langchain', 'output_parsers', 'line_output_parser'];
 
-  async parse(text: string): Promise<string> {
+  async parse(text: string): Promise<string | undefined> {
     text = text.trim() || '';
 
     const regex = /^(\s*(-|\*|\d+\.\s|\d+\)\s|\u2022)\s*)+/;
@@ -26,7 +26,7 @@ class LineOutputParser extends BaseOutputParser<string> {
     const endKeyIndex = text.indexOf(`</${this.key}>`);
 
     if (startKeyIndex === -1 || endKeyIndex === -1) {
-      return '';
+      return undefined;
     }
 
     const questionsStartIndex =

src/lib/search/metaSearchAgent.ts

@@ -453,7 +453,6 @@ class MetaSearchAgent implements MetaSearchAgentType {
         event.event === 'on_chain_end' &&
         event.name === 'FinalSourceRetriever'
       ) {
-        ``;
         emitter.emit(
           'data',
           JSON.stringify({ type: 'sources', data: event.data.output }),

yarn.lock

@@ -661,6 +661,33 @@
     groq-sdk "^0.19.0"
     zod "^3.22.4"
 
+"@langchain/langgraph-checkpoint@^0.1.1":
+  version "0.1.1"
+  resolved "https://registry.yarnpkg.com/@langchain/langgraph-checkpoint/-/langgraph-checkpoint-0.1.1.tgz#500569a02af4b85172d775de63eeba06afa0c189"
+  integrity sha512-h2bP0RUikQZu0Um1ZUPErQLXyhzroJqKRbRcxYRTAh49oNlsfeq4A3K4YEDRbGGuyPZI/Jiqwhks1wZwY73AZw==
+  dependencies:
+    uuid "^10.0.0"
+
+"@langchain/langgraph-sdk@~0.1.0":
+  version "0.1.9"
+  resolved "https://registry.yarnpkg.com/@langchain/langgraph-sdk/-/langgraph-sdk-0.1.9.tgz#5442bd1a4257b5d94927af6e09b0aed341ae8a1d"
+  integrity sha512-7WEDHtbI3pYPUiiHq+dPaF92ZN2W7lqObdpK0X+roa8zPdHUjve/HiqYuKNWS12u1N+L5QIuQWqZvVNvUA7BfQ==
+  dependencies:
+    "@types/json-schema" "^7.0.15"
+    p-queue "^6.6.2"
+    p-retry "4"
+    uuid "^9.0.0"
+
+"@langchain/langgraph@^0.4.9":
+  version "0.4.9"
+  resolved "https://registry.yarnpkg.com/@langchain/langgraph/-/langgraph-0.4.9.tgz#470a238ea98662d6ec9dfc42859a00acad00fc81"
+  integrity sha512-+rcdTGi4Ium4X/VtIX3Zw4RhxEkYWpwUyz806V6rffjHOAMamg6/WZDxpJbrP33RV/wJG1GH12Z29oX3Pqq3Aw==
+  dependencies:
+    "@langchain/langgraph-checkpoint" "^0.1.1"
+    "@langchain/langgraph-sdk" "~0.1.0"
+    uuid "^10.0.0"
+    zod "^3.25.32"
+
 "@langchain/ollama@^0.2.3":
   version "0.2.3"
   resolved "https://registry.yarnpkg.com/@langchain/ollama/-/ollama-0.2.3.tgz#4868e66db4fc480f08c42fc652274abbab0416f0"
@@ -939,6 +966,11 @@
   resolved "https://registry.yarnpkg.com/@types/html-to-text/-/html-to-text-9.0.4.tgz#4a83dd8ae8bfa91457d0b1ffc26f4d0537eff58c"
   integrity sha512-pUY3cKH/Nm2yYrEmDlPR1mR7yszjGx4DrwPjQ702C4/D5CwHuZTgZdIdwPkRbcuhs7BAh2L5rg3CL5cbRiGTCQ==
 
+"@types/json-schema@^7.0.15":
+  version "7.0.15"
+  resolved "https://registry.yarnpkg.com/@types/json-schema/-/json-schema-7.0.15.tgz#596a1747233694d50f6ad8a7869fcb6f56cf5841"
+  integrity sha512-5+fP8P8MFNC+AyZCDxrB2pkZFPGzqQWUzpSeuuVLvm8VMcorNYavBqoFcxK8bQz4Qsbn4oUEEem4wDLfcysGHA==
+
 "@types/json5@^0.0.29":
   version "0.0.29"
   resolved "https://registry.yarnpkg.com/@types/json5/-/json5-0.0.29.tgz#ee28707ae94e11d2b827bcbe5270bcea7f3e71ee"
@@ -5133,7 +5165,7 @@ uuid@^11.1.0:
   resolved "https://registry.yarnpkg.com/uuid/-/uuid-11.1.0.tgz#9549028be1753bb934fc96e2bca09bb4105ae912"
   integrity sha512-0/A9rDy9P7cJ+8w1c9WD9V//9Wj15Ce2MPz8Ri6032usz+NfePxx5AcN3bN+r6ZL6jEo066/yNYB3tn4pQEx+A==
 
-uuid@^9.0.1:
+uuid@^9.0.0, uuid@^9.0.1:
   version "9.0.1"
   resolved "https://registry.yarnpkg.com/uuid/-/uuid-9.0.1.tgz#e188d4c8853cc722220392c424cd637f32293f30"
   integrity sha512-b+1eJOlsR9K8HJpow9Ok3fiWOWSIcIzXodvv0rQjVoOVNpWMpxf1wZNpt4y9h10odCNrqnYp1OBzRktckBe3sA==