refactor: Code cleanup and deduplication

app/api/rag/summary/route.ts

@@ -1,6 +1,7 @@
 import { NextRequest, NextResponse } from 'next/server';
 import { createClient } from '@supabase/supabase-js';
 import OpenAI from 'openai';
+import { SUMMARY_MODEL, SUMMARY_MAX_TOKENS, MAX_SUMMARY_CONTEXT_LENGTH, TOP_K_CHUNKS } from '@/lib/constants';
 
 const supabase = createClient(
   process.env.NEXT_PUBLIC_SUPABASE_URL!,
@@ -72,18 +73,18 @@ export async function POST(request: NextRequest) {
       .select('content')
       .eq('paper_id', paper_id)
       .order('page_no', { ascending: true })
-      .limit(5);
+      .limit(TOP_K_CHUNKS);
 
     // If we have chunks, use them. Otherwise, try to use raw PDF content
     let contextForSummary = '';
 
     if (chunks && chunks.length > 0) {
-      contextForSummary = chunks.map(c => c.content).join('\n\n').slice(0, 4000);
+      contextForSummary = chunks.map(c => c.content).join('\n\n').slice(0, MAX_SUMMARY_CONTEXT_LENGTH);
     } else if (pdfContent) {
       // Extract readable text from the PDF content (it might be garbled but often contains some text)
       const textMatch = pdfContent.match(/[\x20-\x7E\n\r]+/g);
       if (textMatch) {
-        contextForSummary = textMatch.join(' ').slice(0, 4000);
+        contextForSummary = textMatch.join(' ').slice(0, MAX_SUMMARY_CONTEXT_LENGTH);
       }
     }
 
@@ -104,7 +105,7 @@ You can inquire about complex concepts, request explanations of technical detail
 
     // Generate summary using OpenAI with whatever content we have
     const completion = await openai.chat.completions.create({
-      model: 'gpt-3.5-turbo',
+      model: SUMMARY_MODEL,
       messages: [
         {
           role: 'system',
@@ -115,7 +116,7 @@ You can inquire about complex concepts, request explanations of technical detail
           content: `Extract the title and summarize this research paper content:\n\n${contextForSummary}`
         }
       ],
-      max_tokens: 400,
+      max_tokens: SUMMARY_MAX_TOKENS,
       temperature: 0.3,
     });
 

app/chat-new/page.tsx

@@ -22,27 +22,18 @@ import { useConfirm } from "@/lib/contexts/ConfirmContext";
 import { useBreakpoint } from "@/lib/hooks/useMediaQuery";
 import { MobileChatLayout } from "@/frontend/components/chat/MobileChatLayout";
 import { PdfViewer } from "@/frontend/components/PdfViewer";
+import { ChatMessage, ChatSession } from "@/lib/types/chat";
+import {
+  CHAT_PANEL_DEFAULT_WIDTH,
+  CHAT_PANEL_MIN_WIDTH,
+  CHAT_PANEL_MAX_WIDTH,
+  SIDEBAR_EXPANDED_WIDTH,
+  SIDEBAR_COLLAPSED_WIDTH,
+  MESSAGE_TITLE_TRUNCATE_LENGTH,
+  SIGNED_URL_EXPIRY_SECONDS,
+} from "@/lib/constants";
 
-interface ChatSession {
-  id: string;
-  paper_id: string | null;
-  title: string;
-  created_at: string;
-  updated_at: string;
-  user_id: string;
-  paper?: {
-    title: string;
-  };
-}
-
-interface Message {
-  id: string;
-  content: string;
-  role: 'user' | 'assistant';
-  created_at: string;
-  session_id: string;
-  metadata?: any;
-}
+type Message = ChatMessage;
 
 function ChatNewPageContent() {
   const supabase = useSupabase();
@@ -64,7 +55,7 @@ function ChatNewPageContent() {
   const [previewLoading, setPreviewLoading] = useState(false);
   const [chatOpen, setChatOpen] = useState(false);
   const [chatEverOpened, setChatEverOpened] = useState(false);
-  const [chatWidth, setChatWidth] = useState(550);
+  const [chatWidth, setChatWidth] = useState(CHAT_PANEL_DEFAULT_WIDTH);
   const [isResizing, setIsResizing] = useState(false);
   const [pdfBaseUrl, setPdfBaseUrl] = useState<string | null>(null);
   const [processingStatus, setProcessingStatus] = useState<'pending' | 'processing' | 'completed' | 'failed' | null>(null);
@@ -258,13 +249,13 @@ function ChatNewPageContent() {
 
       if (messagesError) throw messagesError;
 
-      const transformedMessages = (messagesData || []).map((msg, index) => ({
+      const transformedMessages: ChatMessage[] = (messagesData || []).map((msg, index) => ({
         id: `${msg.id}-${index}`,
         content: msg.content,
         role: msg.role as 'user' | 'assistant',
         created_at: msg.created_at,
         session_id: msg.session_id,
-        metadata: msg.metadata
+        metadata: msg.metadata as ChatMessage['metadata']
       }));
 
       // Cache the messages
@@ -318,7 +309,7 @@ function ChatNewPageContent() {
 
     try {
       if (messages.length === 0) {
-        const newTitle = messageContent.slice(0, 50) + (messageContent.length > 50 ? '...' : '');
+        const newTitle = messageContent.slice(0, MESSAGE_TITLE_TRUNCATE_LENGTH) + (messageContent.length > MESSAGE_TITLE_TRUNCATE_LENGTH ? '...' : '');
         await supabase
           .from('chat_sessions')
           .update({
@@ -516,7 +507,7 @@ function ChatNewPageContent() {
                 if (updatedPaper.storage_path) {
                   const { data: signed } = await supabase.storage
                     .from('papers')
-                    .createSignedUrl(updatedPaper.storage_path, 60 * 60);
+                    .createSignedUrl(updatedPaper.storage_path, SIGNED_URL_EXPIRY_SECONDS);
                   if (signed?.signedUrl) {
                     setPdfBaseUrl(signed.signedUrl);
                   }
@@ -556,7 +547,7 @@ function ChatNewPageContent() {
 
         const { data: signed, error: signedError } = await supabase.storage
           .from('papers')
-          .createSignedUrl(paper.storage_path, 60 * 60);
+          .createSignedUrl(paper.storage_path, SIGNED_URL_EXPIRY_SECONDS);
 
         if (signedError || !signed?.signedUrl) {
           console.error('Signed URL error:', signedError);
@@ -661,10 +652,10 @@ function ChatNewPageContent() {
     const handleMouseMove = (e: MouseEvent) => {
       if (!isResizing) return;
       e.preventDefault();
-      const sidebarWidth = sidebarOpen ? 256 : 56;
+      const sidebarWidth = sidebarOpen ? SIDEBAR_EXPANDED_WIDTH : SIDEBAR_COLLAPSED_WIDTH;
       const newWidth = e.clientX - sidebarWidth;
       requestAnimationFrame(() => {
-        setChatWidth(Math.min(Math.max(280, newWidth), 800));
+        setChatWidth(Math.min(Math.max(CHAT_PANEL_MIN_WIDTH, newWidth), CHAT_PANEL_MAX_WIDTH));
       });
     };
 

app/globals.css

@@ -46,15 +46,6 @@ body {
   -webkit-overflow-scrolling: touch;
 }
 
-/* Hide scrollbar on mobile for cleaner UI */
-.scrollbar-hide::-webkit-scrollbar {
-  display: none;
-}
-.scrollbar-hide {
-  -ms-overflow-style: none;
-  scrollbar-width: none;
-}
-
 /* Hide scrollbar utility */
 .scrollbar-hide {
   -ms-overflow-style: none;

app/papers/page.tsx

@@ -18,6 +18,7 @@ import {
 import { CollectionsSidebar, AddToCollectionModal, CollectionBadges } from "@/frontend/components/collections";
 import { useCollections, useCollectionPapers, invalidateCollectionCaches } from "@/lib/hooks/useCollections";
 import { CollectionWithCount } from "@/lib/types/database";
+import { SIGNED_URL_EXPIRY_SECONDS } from "@/lib/constants";
 import { formatDate } from "@/lib/utils/dateFormat";
 import { renderPdfFirstPage } from "@/lib/utils/pdfPreview";
 
@@ -155,7 +156,7 @@ function PapersPageContent() {
         if (paper.storage_path) {
           const { data, error } = await supabase.storage
             .from('papers')
-            .createSignedUrl(paper.storage_path, 60 * 60);
+            .createSignedUrl(paper.storage_path, SIGNED_URL_EXPIRY_SECONDS);
           if (!error && data?.signedUrl) {
             const img = await renderPdfFirstPage(data.signedUrl, 560);
             if (img) {

frontend/components/ExportChatButton.tsx

@@ -4,24 +4,14 @@ import { useState } from "react";
 import { Download, Loader2, FileText, File } from "lucide-react";
 import { exportChatAsPDF, exportChatAsTXT } from "@/lib/utils/export-chat";
 import { useAlert } from "@/lib/contexts/AlertContext";
+import { ChatMessage } from "@/lib/types/chat";
 
 interface ExportChatButtonProps {
   sessionId: string;
   sessionTitle: string;
   paperTitle?: string;
   sessionDate: string;
-  messages: Array<{
-    id: string;
-    content: string;
-    role: 'user' | 'assistant';
-    created_at: string;
-    metadata?: {
-      citations?: Array<{
-        page_no: number;
-        score: number;
-      }>;
-    };
-  }>;
+  messages: ChatMessage[];
 }
 
 export function ExportChatButton({

frontend/components/NextReadList.tsx

@@ -14,7 +14,7 @@ import {
   hasPreview
 } from "@/lib/utils/previewCache";
 import { useCollections, useCollectionPapers, invalidateCollectionCaches } from "@/lib/hooks/useCollections";
-import { NEXT_READ_COLLECTION_NAME } from "@/lib/constants";
+import { NEXT_READ_COLLECTION_NAME, SIGNED_URL_EXPIRY_SECONDS } from "@/lib/constants";
 
 export function NextReadList() {
   const supabase = useSupabase();
@@ -91,7 +91,7 @@ export function NextReadList() {
         if (paper.storage_path) {
           const signed = await supabase.storage
             .from('papers')
-            .createSignedUrl(paper.storage_path, 60 * 60);
+            .createSignedUrl(paper.storage_path, SIGNED_URL_EXPIRY_SECONDS);
 
           const pdfUrl = signed.data?.signedUrl;
           if (pdfUrl) {

frontend/components/RecentPapers.tsx

@@ -15,7 +15,7 @@ import {
   clearPreview
 } from "@/lib/utils/previewCache";
 import { useCollections, useCollectionPapers } from "@/lib/hooks/useCollections";
-import { SYSTEM_COLLECTION_NAME } from "@/lib/constants";
+import { SYSTEM_COLLECTION_NAME, SIGNED_URL_EXPIRY_SECONDS } from "@/lib/constants";
 import { formatDate } from "@/lib/utils/dateFormat";
 import { renderPdfFirstPage } from "@/lib/utils/pdfPreview";
 
@@ -110,7 +110,7 @@ export function RecentPapers() {
         if (paper.storage_path) {
           const signed = await supabase.storage
             .from('papers')
-            .createSignedUrl(paper.storage_path, 60 * 60);
+            .createSignedUrl(paper.storage_path, SIGNED_URL_EXPIRY_SECONDS);
 
           const pdfUrl = signed.data?.signedUrl;
 

frontend/components/chat/MobileChatLayout.tsx

@@ -4,36 +4,13 @@ import { useState, useCallback, useRef, useEffect } from "react";
 import { MobileChatView } from "./MobileChatView";
 import { MobilePdfView } from "./MobilePdfView";
 import { MessageSquare, X, ChevronDown, Trash2, Plus, Search } from "lucide-react";
-
-interface Message {
-  id: string;
-  content: string;
-  role: "user" | "assistant";
-  created_at: string;
-  session_id: string;
-  metadata?: {
-    is_loading?: boolean;
-    is_system_summary?: boolean;
-  };
-}
-
-interface ChatSession {
-  id: string;
-  paper_id: string | null;
-  title: string;
-  created_at: string;
-  updated_at: string;
-  user_id: string;
-  paper?: {
-    title: string;
-  };
-}
+import { ChatMessage, ChatSession } from "@/lib/types/chat";
 
 interface MobileChatLayoutProps {
   sessions: ChatSession[];
   currentSession: ChatSession | null;
   filterPaperId: string | null;
-  messages: Message[];
+  messages: ChatMessage[];
   input: string;
   onInputChange: (value: string) => void;
   onSendMessage: () => void;

frontend/components/chat/MobileChatView.tsx

@@ -2,21 +2,10 @@
 
 import { useRef, useEffect } from "react";
 import { Send, Loader2 } from "lucide-react";
-
-interface Message {
-  id: string;
-  content: string;
-  role: "user" | "assistant";
-  created_at: string;
-  session_id: string;
-  metadata?: {
-    is_loading?: boolean;
-    is_system_summary?: boolean;
-  };
-}
+import { ChatMessage } from "@/lib/types/chat";
 
 interface MobileChatViewProps {
-  messages: Message[];
+  messages: ChatMessage[];
   input: string;
   onInputChange: (value: string) => void;
   onSendMessage: () => void;