feat(chat): implement infinite scroll for message loading and optimize chat message rendering

- Added infinite scroll functionality to load older messages when the user scrolls near the top of the chat.
- Implemented pagination state management to track loading status and available messages.
- Enhanced ChatMessage component with React.memo for performance optimization during streaming.
- Updated database interactions to support paginated message retrieval, improving efficiency in loading chat history.

app/chat/page.tsx

@@ -48,11 +48,14 @@ export default function ChatPage() {
     currentSessionId, 
     setCurrentSessionId, 
     loadSessionHistory,
+    loadMoreMessages,
+    paginationState,
     saveSession, 
     deleteSession,
     isGeneratingTitle,
     searchSessions,
-    isSearching
+    isSearching,
+    searchQuery
   } = useChatStorage();
 
   const { isDownloading, progress } = useAutoLabelingModel();
@@ -121,6 +124,7 @@ export default function ChatPage() {
   const saveTimeoutRef = useRef<NodeJS.Timeout | null>(null);
   const lastSavedMessagesRef = useRef<number>(0);
   const messagesEndRef = useRef<HTMLDivElement>(null);
+  const scrollContainerRef = useRef<HTMLDivElement>(null);
   const [showContextDebug, setShowContextDebug] = useState(false);
   const [showProcessDebug, setShowProcessDebug] = useState(false);
   const [lastWebContext, setLastWebContext] = useState('');
@@ -128,6 +132,14 @@ export default function ChatPage() {
   const [showDownloadDialog, setShowDownloadDialog] = useState(false);
   const [logsCopied, setLogsCopied] = useState(false);
   const [lastUserQuery, setLastUserQuery] = useState('');
+  const [searchMatchIndex, setSearchMatchIndex] = useState(0);
+  
+  // Resetar índice quando busca é limpa ou sessão muda
+  useEffect(() => {
+    if (!searchQuery || searchQuery.trim().length < 2) {
+      setSearchMatchIndex(0);
+    }
+  }, [searchQuery, currentSessionId]);
 
   // Auto-select first model
   useEffect(() => {
@@ -246,6 +258,34 @@ export default function ChatPage() {
     }
   }, [settings.queryPreprocessing, webSearch.isEnabled, preprocess]);
 
+  // ========== EXECUÇÃO ESPECULATIVA DE BUSCA ==========
+  // Heurística rápida para detectar se a query provavelmente precisa de busca web
+  const mightNeedWebSearch = useCallback((text: string): boolean => {
+    if (!webSearch.isEnabled) return false;
+    
+    const lowerText = text.toLowerCase();
+    
+    // Padrões que indicam alta probabilidade de precisar de busca
+    const questionPatterns = /\b(o que|como|quando|onde|quem|porque|por que|qual|quais|quanto|quantos|me explique|me diga|existe|há)\b/i;
+    const recentPatterns = /\b(hoje|ontem|esta semana|este mês|este ano|atualmente|recentemente|últimas notícias|novo|novos|última|últimas|2024|2025)\b/i;
+    const searchPatterns = /\?$|buscar|pesquisar|encontrar|procurar|descobrir/i;
+    
+    // Se contém padrões de pergunta ou busca, provavelmente precisa de pesquisa
+    if (questionPatterns.test(lowerText) || recentPatterns.test(lowerText) || searchPatterns.test(lowerText)) {
+      chatLog.debug('[SpeculativeSearch] Query might need web search (pattern match)');
+      return true;
+    }
+    
+    // Se tem mais de 5 palavras e termina com ?, provavelmente é uma pergunta
+    const wordCount = text.trim().split(/\s+/).length;
+    if (wordCount > 5 && text.trim().endsWith('?')) {
+      chatLog.debug('[SpeculativeSearch] Query might need web search (question detected)');
+      return true;
+    }
+    
+    return false;
+  }, [webSearch.isEnabled]);
+
   const handleSend = async (content: string) => {
     if (!selectedModel) return;
     
@@ -262,6 +302,22 @@ export default function ChatPage() {
     // Limpar erros anteriores
     setError(null);
     
+    // ========== EXECUÇÃO ESPECULATIVA ==========
+    // Iniciar busca web especulativamente se a query parecer precisar
+    // Isso reduz latência sobrepondo busca com pré-processamento
+    let speculativeSearchPromise: Promise<ScrapedContent[]> | null = null;
+    const shouldSpeculate = mightNeedWebSearch(content);
+    
+    if (shouldSpeculate) {
+      chatLog.info('[SpeculativeSearch] Starting speculative web search in parallel with preprocessing');
+      // Iniciar busca sem await - será usada depois se confirmada
+      speculativeSearchPromise = webSearch.smartSearchRag(content, settings.webSearch?.maxResults || 5)
+        .catch(err => {
+          chatLog.debug(`[SpeculativeSearch] Speculative search failed (will use normal flow): ${err}`);
+          return [] as ScrapedContent[];
+        });
+    }
+    
     // ========== PRÉ-PROCESSAMENTO ==========
     let preprocessed: PreprocessedQuery;
     let finalContent: string;
@@ -330,7 +386,8 @@ export default function ChatPage() {
     // Função auxiliar para executar pesquisa web
     const executeWebResearch = async (
       content: string,
-      preprocessed: PreprocessedQuery
+      preprocessed: PreprocessedQuery,
+      speculativeResults?: ScrapedContent[] | null
     ): Promise<{
       knowledgeBaseContext: string;
       scrapedSources: ScrapedContent[];
@@ -344,6 +401,12 @@ export default function ChatPage() {
       if (webSearch.isEnabled && preprocessed.shouldSearch) {
       chatLog.info('\n--- STARTING DEEP RESEARCH PIPELINE ---');
       
+      // Se temos resultados especulativos, usá-los como seed inicial
+      if (speculativeResults && speculativeResults.length > 0) {
+        chatLog.info(`[SpeculativeSearch] Using ${speculativeResults.length} speculative results as seed`);
+        deepResearch.addToKnowledgeBase('speculative_seed', speculativeResults);
+      }
+      
       // Adicionar mensagem de processo: Pesquisa Web
       addThinkingMessage('web-research', 'Pesquisando na Web...', 'running');
       const webResearchStart = Date.now();
@@ -605,10 +668,25 @@ export default function ChatPage() {
     // ========== LÓGICA DE DEEP RESEARCH (Knowledge Base Aggregation) ==========
     // Removido: setThinkingStep e setProcessSteps - agora usando mensagens thinking agrupadas
     
-    // Executar pesquisa web
+    // Aguardar resultado da busca especulativa se ela foi iniciada e shouldSearch é true
+    let speculativeResults: ScrapedContent[] | null = null;
+    if (speculativeSearchPromise && preprocessed.shouldSearch) {
+      chatLog.info('[SpeculativeSearch] Waiting for speculative search results...');
+      try {
+        speculativeResults = await speculativeSearchPromise;
+        chatLog.info(`[SpeculativeSearch] Got ${speculativeResults.length} speculative results`);
+      } catch (err) {
+        chatLog.debug(`[SpeculativeSearch] Failed to get speculative results: ${err}`);
+      }
+    } else if (speculativeSearchPromise && !preprocessed.shouldSearch) {
+      chatLog.info('[SpeculativeSearch] Discarding speculative search (preprocessing determined search not needed)');
+    }
+    
+    // Executar pesquisa web (usando resultados especulativos como seed se disponíveis)
     const { knowledgeBaseContext, scrapedSources, validationReport } = await executeWebResearch(
       content,
-      preprocessed
+      preprocessed,
+      speculativeResults
     );
     
     // Passo 5: Formular resposta
@@ -803,8 +881,94 @@ Ao responder sobre fatos atuais ou notícias, inicie mencionando explicitamente
     setMessages(history);
     setCurrentSessionId(id);
     lastSavedMessagesRef.current = history.length;
+    
+    // Se há busca ativa, encontrar matches e resetar índice
+    if (searchQuery && searchQuery.trim().length >= 2) {
+      setSearchMatchIndex(0);
+      // Os matches serão encontrados quando as mensagens renderizarem
+    }
   };
   
+  // Handler para scroll infinito reverso (carregar mensagens mais antigas)
+  const handleScroll = useCallback(async () => {
+    const container = scrollContainerRef.current;
+    if (!container || !currentSessionId || paginationState.isLoadingMore) return;
+    
+    // Verificar se o usuário está próximo do topo (threshold de 100px)
+    const isNearTop = container.scrollTop < 100;
+    
+    if (isNearTop && paginationState.hasMore) {
+      // Salvar posição atual do scroll e altura do conteúdo
+      const scrollHeightBefore = container.scrollHeight;
+      
+      // Carregar mais mensagens
+      const olderMessages = await loadMoreMessages(currentSessionId);
+      
+      if (olderMessages.length > 0) {
+        // Prepend as mensagens antigas
+        setMessages(prev => [...olderMessages, ...prev]);
+        
+        // Restaurar posição do scroll para manter o contexto visual
+        // (compensar o novo conteúdo adicionado no topo)
+        requestAnimationFrame(() => {
+          if (container) {
+            const scrollHeightAfter = container.scrollHeight;
+            const heightDiff = scrollHeightAfter - scrollHeightBefore;
+            container.scrollTop = container.scrollTop + heightDiff;
+          }
+        });
+      }
+    }
+  }, [currentSessionId, paginationState.hasMore, paginationState.isLoadingMore, loadMoreMessages, setMessages]);
+  
+  // Função para navegar entre matches
+  const handleNavigateMatch = useCallback((sessionId: string, direction: 'prev' | 'next') => {
+    if (sessionId !== currentSessionId || !searchQuery || searchQuery.trim().length < 2) {
+      return;
+    }
+    
+    // Encontrar todos os matches nas mensagens
+    const query = searchQuery.trim();
+    const matches: Array<{ messageIndex: number; matchIndex: number }> = [];
+    
+    messages.forEach((msg, msgIdx) => {
+      if (msg.role === 'user' || msg.role === 'assistant') {
+        const content = msg.content;
+        const regex = new RegExp(query.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'), 'gi');
+        let match;
+        let matchIdx = 0;
+        while ((match = regex.exec(content)) !== null) {
+          matches.push({ messageIndex: msgIdx, matchIndex: matchIdx });
+          matchIdx++;
+        }
+      }
+    });
+    
+    if (matches.length === 0) return;
+    
+    // Navegar
+    setSearchMatchIndex(prev => {
+      const newIndex = direction === 'next' 
+        ? (prev + 1) % matches.length
+        : (prev - 1 + matches.length) % matches.length;
+      
+      // Scroll para o match após renderização
+      setTimeout(() => {
+        const messageElement = document.querySelector(`[data-message-index="${matches[newIndex].messageIndex}"]`);
+        if (messageElement) {
+          messageElement.scrollIntoView({ behavior: 'smooth', block: 'center' });
+          // Destacar o match atual visualmente
+          const marks = messageElement.querySelectorAll('mark');
+          if (marks.length > matches[newIndex].matchIndex) {
+            marks[matches[newIndex].matchIndex]?.scrollIntoView({ behavior: 'smooth', block: 'center', inline: 'center' });
+          }
+        }
+      }, 150);
+      
+      return newIndex;
+    });
+  }, [currentSessionId, searchQuery, messages]);
+
   const handleNewChat = () => {
     stop();
     clearChat();
@@ -947,6 +1111,8 @@ Ao responder sobre fatos atuais ou notícias, inicie mencionando explicitamente
             onNewChat={handleNewChat}
             onSearch={searchSessions}
             isSearching={isSearching}
+            searchQuery={searchQuery}
+            onNavigateMatch={handleNavigateMatch}
           />
         </ResizablePanel>
 
@@ -1050,8 +1216,29 @@ Ao responder sobre fatos atuais ou notícias, inicie mencionando explicitamente
             {/* Messages Area with Floating Input Layout */}
             <div className="flex-1 relative h-full overflow-hidden flex flex-col">
               {/* Scrollable Content Area */}
-              <div className="flex-1 overflow-y-auto scroll-smooth w-full min-h-0">
+              <div 
+                ref={scrollContainerRef}
+                className="flex-1 overflow-y-auto scroll-smooth w-full min-h-0"
+                onScroll={handleScroll}
+              >
                 <div className="max-w-3xl mx-auto w-full px-3 sm:px-4 md:px-6 pt-4 sm:pt-6 pb-4 transition-all duration-300" style={{ paddingLeft: 'clamp(12px, 4vw, 24px)', paddingRight: 'clamp(12px, 4vw, 24px)' }}>
+                  {/* Indicador de carregamento de mensagens antigas */}
+                  {paginationState.isLoadingMore && (
+                    <div className="flex items-center justify-center py-4 mb-4">
+                      <Loader2 className="w-5 h-5 animate-spin text-muted-foreground mr-2" />
+                      <span className="text-sm text-muted-foreground">Carregando mensagens anteriores...</span>
+                    </div>
+                  )}
+                  
+                  {/* Indicador de que há mais mensagens para carregar */}
+                  {paginationState.hasMore && !paginationState.isLoadingMore && messages.length > 0 && (
+                    <div className="flex items-center justify-center py-2 mb-4">
+                      <span className="text-xs text-muted-foreground/60">
+                        Role para cima para ver mensagens anteriores ({paginationState.totalCount - messages.length} restantes)
+                      </span>
+                    </div>
+                  )}
+                  
                   {messages.length === 0 ? (
                     <div className="min-h-[50vh] flex flex-col items-center justify-center text-muted-foreground space-y-6">
                       <div className="p-6 rounded-2xl bg-muted/30 ring-1 ring-border/50 shadow-sm">
@@ -1086,6 +1273,13 @@ Ao responder sobre fatos atuais ou notícias, inicie mencionando explicitamente
                             'type' in msg.metadata && 
                             msg.metadata.type === 'thinking';
                           
+                          // Pular mensagens de sistema que não são thinking (system prompt)
+                          // Essas mensagens nunca devem aparecer no chat
+                          const isSystemPrompt = msg.role === 'system' && !isThinkingMessage;
+                          if (isSystemPrompt) {
+                            continue;
+                          }
+                          
                           if (isThinkingMessage) {
                             const thinkingMeta = msg.metadata as ThinkingMessageMetadata;
                             currentThinkingGroup.push(thinkingMeta);
@@ -1132,6 +1326,25 @@ Ao responder sobre fatos atuais ou notícias, inicie mencionando explicitamente
                           });
                         }
                         
+                        // Calcular posições de todos os matches uma vez
+                        const allMatches: Array<{ messageIndex: number; matchIndex: number }> = [];
+                        if (searchQuery && searchQuery.trim().length >= 2) {
+                          const query = searchQuery.trim();
+                          const regex = new RegExp(query.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'), 'gi');
+                          
+                          messages.forEach((msg, msgIdx) => {
+                            if (msg.role === 'user' || msg.role === 'assistant') {
+                              const content = msg.content;
+                              let match;
+                              let matchIdx = 0;
+                              while ((match = regex.exec(content)) !== null) {
+                                allMatches.push({ messageIndex: msgIdx, matchIndex: matchIdx });
+                                matchIdx++;
+                              }
+                            }
+                          });
+                        }
+                        
                         return groupedMessages.map((group, idx) => {
                           if (group.type === 'thinking-group' && group.thinkingSteps) {
                             return (
@@ -1143,11 +1356,30 @@ Ao responder sobre fatos atuais ou notícias, inicie mencionando explicitamente
                               </div>
                             );
                           } else if (group.type === 'regular' && group.message) {
+                            // Encontrar índice do match atual para esta mensagem
+                            let messageMatchIndex: number | undefined = undefined;
+                            
+                            if (searchQuery && searchQuery.trim().length >= 2 && allMatches.length > 0 && group.index !== undefined) {
+                              // Encontrar matches desta mensagem
+                              const messageMatches = allMatches.filter(m => m.messageIndex === group.index);
+                              
+                              if (messageMatches.length > 0) {
+                                // Verificar se o match atual está nesta mensagem
+                                const currentMatch = allMatches[searchMatchIndex];
+                                if (currentMatch && currentMatch.messageIndex === group.index) {
+                                  messageMatchIndex = currentMatch.matchIndex;
+                                }
+                              }
+                            }
+                            
                             return (
                               <div key={group.index || idx} className="animate-in fade-in slide-in-from-bottom-4 duration-500">
                                 <ChatMessage 
                                   message={group.message} 
                                   isStreaming={group.isStreaming}
+                                  highlightTerm={searchQuery && searchQuery.trim().length >= 2 ? searchQuery.trim() : undefined}
+                                  highlightIndex={messageMatchIndex}
+                                  messageIndex={group.index}
                                 />
                               </div>
                             );

components/chat/chat-message.tsx

@@ -1,6 +1,6 @@
 import ReactMarkdown from 'react-markdown';
 import remarkGfm from 'remark-gfm';
-import { useState, useMemo } from 'react';
+import React, { useState, useMemo } from 'react';
 import { cn } from "@/lib/utils";
 import { Message } from "@/hooks/use-chat";
 import { Bot, User } from "lucide-react";
@@ -13,9 +13,19 @@ import type { ThinkingMessageMetadata } from "@/hooks/use-chat";
 interface ChatMessageProps {
   message: Message;
   isStreaming?: boolean;
+  highlightTerm?: string;
+  highlightIndex?: number;
+  messageIndex?: number;
 }
 
-export function ChatMessage({ message, isStreaming = false }: ChatMessageProps) {
+/**
+ * Componente de mensagem do chat otimizado com React.memo
+ * 
+ * Durante streaming, usa renderização simplificada (texto puro) para evitar
+ * recálculo custoso da árvore DOM e syntax highlight a cada token.
+ * Markdown completo é aplicado apenas quando a mensagem está finalizada.
+ */
+function ChatMessageComponent({ message, isStreaming = false, highlightTerm, highlightIndex = 0, messageIndex }: ChatMessageProps) {
   // Verificar se é mensagem de processo de pensamento
   const isThinkingMessage = message.metadata && 
     typeof message.metadata === 'object' && 
@@ -52,6 +62,57 @@ export function ChatMessage({ message, isStreaming = false }: ChatMessageProps)
     return content || message.content;
   }, [message.content]);
   
+  // Processar highlight separadamente (após limpeza de conteúdo)
+  // Desabilitar durante streaming para performance
+  const highlightedContent = useMemo(() => {
+    // Não processar highlight durante streaming
+    if (isStreaming) return null;
+    
+    if (!highlightTerm || highlightTerm.trim().length < 2 || (message.role !== 'user' && message.role !== 'assistant')) {
+      return null; // Não há highlight
+    }
+    
+    const term = highlightTerm.trim();
+    const escapedTerm = term.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
+    const regex = new RegExp(`(${escapedTerm})`, 'gi');
+    const content = processedContent;
+    
+    // Encontrar todos os matches
+    const matches: Array<{ start: number; end: number; text: string }> = [];
+    let match;
+    while ((match = regex.exec(content)) !== null) {
+      matches.push({
+        start: match.index,
+        end: match.index + match[0].length,
+        text: match[0]
+      });
+    }
+    
+    if (matches.length === 0) return null;
+    
+    // Construir conteúdo com highlights
+    let highlighted = '';
+    let lastIndex = 0;
+    
+    matches.forEach((match, idx) => {
+      // Adicionar texto antes do match
+      highlighted += content.substring(lastIndex, match.start);
+      
+      // Adicionar match com highlight (laranja para atual, amarelo para outros)
+      const isCurrent = highlightIndex !== undefined && idx === highlightIndex;
+      const className = isCurrent 
+        ? 'bg-orange-400/60 dark:bg-orange-500/60 px-0.5 rounded' 
+        : 'bg-yellow-200/50 dark:bg-yellow-800/50 px-0.5 rounded';
+      
+      highlighted += `<mark class="${className}">${match.text}</mark>`;
+      lastIndex = match.end;
+    });
+    
+    // Adicionar texto restante
+    highlighted += content.substring(lastIndex);
+    return highlighted;
+  }, [processedContent, highlightTerm, highlightIndex, message.role, isStreaming]);
+
   return (
     <MessageBackground
       role={isUser ? 'user' : 'assistant'}
@@ -75,11 +136,14 @@ export function ChatMessage({ message, isStreaming = false }: ChatMessageProps)
         </div>
       </div>
       
-      <div className="flex-1 overflow-hidden min-w-0 pt-1">
+      <div className="flex-1 overflow-hidden min-w-0 pt-1" data-message-index={messageIndex}>
         {isUser ? (
              // Estilo específico para mensagem do usuário (mais destaque, fonte maior)
-             <div className="text-lg sm:text-xl font-medium tracking-tight text-foreground/90 leading-relaxed break-words whitespace-pre-wrap">
+             <div 
-                {processedContent}
+               className="text-lg sm:text-xl font-medium tracking-tight text-foreground/90 leading-relaxed break-words whitespace-pre-wrap"
+               dangerouslySetInnerHTML={highlightedContent ? { __html: highlightedContent } : undefined}
+             >
+                {!highlightedContent && processedContent}
              </div>
         ) : (
             // Estilo Assistant
@@ -88,22 +152,37 @@ export function ChatMessage({ message, isStreaming = false }: ChatMessageProps)
                 <div className="w-2 h-2 bg-primary rounded-full animate-pulse" />
                 <span className="text-sm font-medium">Gerando resposta...</span>
               </div>
+            ) : isStreaming ? (
+              // Renderização LEVE durante streaming: texto simples com formatação básica
+              // Evita recálculo de ReactMarkdown e syntax highlight a cada token
+              <div className={cn(
+                "prose prose-neutral dark:prose-invert max-w-none break-words leading-7 text-base text-foreground/90",
+                "prose-headings:font-semibold prose-headings:tracking-tight",
+                "relative"
+              )}>
+                <div className="whitespace-pre-wrap font-sans">
+                  {processedContent}
+                </div>
+                <span className="inline-block w-2 h-4 bg-primary ml-1 animate-pulse rounded-full align-middle" />
+              </div>
             ) : (
+              // Renderização COMPLETA quando mensagem finalizada: ReactMarkdown com syntax highlight
               <div className={cn(
                 "prose prose-neutral dark:prose-invert max-w-none break-words leading-7 text-base text-foreground/90",
                 "prose-headings:font-semibold prose-headings:tracking-tight prose-h1:text-2xl prose-h2:text-xl prose-h3:text-lg",
                 "prose-p:leading-7 prose-li:leading-7",
                 "prose-pre:bg-muted/50 prose-pre:border prose-pre:border-border/50 prose-pre:rounded-xl",
-                isStreaming && "relative"
+                "prose-mark:bg-yellow-200/50 prose-mark:dark:bg-yellow-800/50 prose-mark:px-0.5 prose-mark:rounded"
               )}>
+                {highlightedContent ? (
+                  <div dangerouslySetInnerHTML={{ __html: highlightedContent }} />
+                ) : (
                   <ReactMarkdown 
                     remarkPlugins={[remarkGfm]}
                     components={markdownRenderers}
                   >
                     {processedContent}
                   </ReactMarkdown>
-                {isStreaming && !isEmpty && (
-                  <span className="inline-block w-2 h-4 bg-primary ml-1 animate-pulse rounded-full align-middle" />
                 )}
               </div>
             )
@@ -123,5 +202,34 @@ export function ChatMessage({ message, isStreaming = false }: ChatMessageProps)
   );
 }
 
+/**
+ * ChatMessage com React.memo para evitar re-renders desnecessários
+ * 
+ * Comparação customizada:
+ * - Compara conteúdo da mensagem
+ * - Compara estado de streaming
+ * - Compara termo de highlight e índice
+ */
+export const ChatMessage = React.memo(ChatMessageComponent, (prevProps, nextProps) => {
+  // Se streaming mudou, sempre re-renderizar
+  if (prevProps.isStreaming !== nextProps.isStreaming) {
+    return false;
+  }
   
+  // Durante streaming, só re-renderizar se conteúdo mudou
+  if (nextProps.isStreaming) {
+    return prevProps.message.content === nextProps.message.content;
+  }
   
+  // Quando não está em streaming, comparar todas as props relevantes
+  return (
+    prevProps.message.content === nextProps.message.content &&
+    prevProps.message.role === nextProps.message.role &&
+    prevProps.highlightTerm === nextProps.highlightTerm &&
+    prevProps.highlightIndex === nextProps.highlightIndex &&
+    prevProps.messageIndex === nextProps.messageIndex
+  );
+});
+
+// Adicionar displayName para debugging
+ChatMessage.displayName = 'ChatMessage';

components/chat/sidebar-list.tsx

@@ -2,7 +2,7 @@ import { SessionSummary } from "@/hooks/use-chat-storage";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Tooltip, TooltipContent, TooltipProvider, TooltipTrigger } from "@/components/ui/tooltip";
-import { Trash2, Plus, MessageSquare, Search, X, Loader2 } from "lucide-react";
+import { Trash2, Plus, MessageSquare, Search, X, Loader2, ChevronUp, ChevronDown } from "lucide-react";
 import { cn } from "@/lib/utils";
 import { useState, useEffect, useRef } from "react";
 
@@ -14,6 +14,8 @@ interface SidebarListProps {
   onNewChat: () => void;
   onSearch?: (query: string) => void;
   isSearching?: boolean;
+  searchQuery?: string;
+  onNavigateMatch?: (sessionId: string, direction: 'prev' | 'next') => void;
 }
 
 function formatDate(dateString: string) {
@@ -58,9 +60,11 @@ export function SidebarList({
   onDeleteSession,
   onNewChat,
   onSearch,
-  isSearching = false
+  isSearching = false,
+  searchQuery = '',
+  onNavigateMatch
 }: SidebarListProps) {
-  const [searchQuery, setSearchQuery] = useState('');
+  const [localSearchInput, setLocalSearchInput] = useState('');
   const searchTimeoutRef = useRef<NodeJS.Timeout | null>(null);
   const DEBOUNCE_MS = 300;
   
@@ -71,7 +75,7 @@ export function SidebarList({
     }
     
     // Se query vazia, limpar busca imediatamente
-    if (!searchQuery.trim()) {
+    if (!localSearchInput.trim()) {
       if (onSearch) {
         onSearch('');
       }
@@ -80,8 +84,8 @@ export function SidebarList({
     
     // Debounce: aguardar antes de buscar
     searchTimeoutRef.current = setTimeout(() => {
-      if (onSearch && searchQuery.trim().length >= 2) {
+      if (onSearch && localSearchInput.trim().length >= 2) {
-        onSearch(searchQuery.trim());
+        onSearch(localSearchInput.trim());
       }
     }, DEBOUNCE_MS);
     
@@ -91,10 +95,10 @@ export function SidebarList({
         clearTimeout(searchTimeoutRef.current);
       }
     };
-  }, [searchQuery, onSearch]);
+  }, [localSearchInput, onSearch]);
   
   const handleClearSearch = () => {
-    setSearchQuery('');
+    setLocalSearchInput('');
     if (onSearch) {
       onSearch('');
     }
@@ -111,14 +115,14 @@ export function SidebarList({
             <Input
               type="text"
               placeholder="Buscar conversas..."
-              value={searchQuery}
+              value={localSearchInput}
-              onChange={(e) => setSearchQuery(e.target.value)}
+              onChange={(e) => setLocalSearchInput(e.target.value)}
               className="pl-8 pr-8 h-9 text-sm"
             />
             {isSearching && (
               <Loader2 className="absolute right-2.5 top-1/2 -translate-y-1/2 w-4 h-4 text-muted-foreground animate-spin" />
             )}
-            {searchQuery && !isSearching && (
+            {localSearchInput && !isSearching && (
               <button
                 onClick={handleClearSearch}
                 className="absolute right-2.5 top-1/2 -translate-y-1/2 text-muted-foreground hover:text-foreground transition-colors"
@@ -190,15 +194,54 @@ export function SidebarList({
                         </div>
                         
                         {/* Texto do card */}
-                        <div className="sidebar-chat-item-text">
+                        <div className="sidebar-chat-item-text flex-1 min-w-0">
                           <h3 className="sidebar-chat-item-title text-sm font-medium text-card-foreground leading-tight mb-0.5">
                             {session.title}
                           </h3>
                           
+                          <div className="flex items-center gap-2">
                             <p className="sidebar-chat-item-date text-xs text-muted-foreground">
                               {formatDate(session.updated_at)}
                             </p>
+                            {searchQuery && session.match_count !== undefined && session.match_count > 0 && (
+                              <span className="text-xs px-1.5 py-0.5 rounded bg-primary/10 text-primary font-medium">
+                                {session.match_count} {session.match_count === 1 ? 'ocorrência' : 'ocorrências'}
+                              </span>
+                            )}
                           </div>
+                        </div>
+                        
+                        {/* Navegação de matches - aparece apenas quando selecionado e há busca ativa */}
+                        {isSelected && searchQuery && session.match_count !== undefined && session.match_count > 0 && onNavigateMatch && (
+                          <div className="flex flex-col gap-0.5 mr-1">
+                            <Button
+                              variant="ghost"
+                              size="icon"
+                              className="h-6 w-6 shrink-0"
+                              onClick={(e) => {
+                                e.stopPropagation();
+                                e.preventDefault();
+                                onNavigateMatch(session.id, 'prev');
+                              }}
+                              aria-label="Ocorrência anterior"
+                            >
+                              <ChevronUp className="w-3.5 h-3.5" />
+                            </Button>
+                            <Button
+                              variant="ghost"
+                              size="icon"
+                              className="h-6 w-6 shrink-0"
+                              onClick={(e) => {
+                                e.stopPropagation();
+                                e.preventDefault();
+                                onNavigateMatch(session.id, 'next');
+                              }}
+                              aria-label="Próxima ocorrência"
+                            >
+                              <ChevronDown className="w-3.5 h-3.5" />
+                            </Button>
+                          </div>
+                        )}
                         
                         {/* Botão de deletar - aparece no hover */}
                         <Button

hooks/use-chat-storage.ts

@@ -1,4 +1,4 @@
-import { useState, useEffect, useCallback } from 'react';
+import { useState, useEffect, useCallback, useRef } from 'react';
 import { invoke } from '@tauri-apps/api/core';
 import { Message } from './use-chat';
 import { removeMetadataNoise } from '@/lib/metadata';
@@ -10,8 +10,31 @@ export interface SessionSummary {
   updated_at: string;
   preview: string;
   platform: string;
+  match_count?: number;
 }
 
+/** Resultado de carregamento paginado do backend */
+interface PaginatedHistoryResult {
+  messages: Array<{
+    role: string;
+    content: string;
+    metadata?: unknown;
+  }>;
+  total_count: number;
+  has_more: boolean;
+}
+
+/** Estado de paginação para uma sessão */
+export interface PaginationState {
+  totalCount: number;
+  hasMore: boolean;
+  offset: number;
+  isLoadingMore: boolean;
+}
+
+/** Número de mensagens a carregar por página */
+const MESSAGES_PER_PAGE = 30;
+
 const TITLE_MODEL = "qwen2.5:0.5b";
 
 // Helper to generate fallback title from user's first message
@@ -41,6 +64,17 @@ export function useChatStorage() {
   const [searchQuery, setSearchQuery] = useState<string>('');
   const [isSearching, setIsSearching] = useState(false);
   
+  // Estado de paginação por sessão
+  const [paginationState, setPaginationState] = useState<PaginationState>({
+    totalCount: 0,
+    hasMore: false,
+    offset: 0,
+    isLoadingMore: false,
+  });
+  
+  // Ref para evitar múltiplos loads simultâneos
+  const loadingMoreRef = useRef(false);
+
   const loadSessions = useCallback(async () => {
     try {
       const list = await invoke<SessionSummary[]>('load_chat_sessions');
@@ -73,23 +107,138 @@ export function useChatStorage() {
     }
   }, [loadSessions]);
 
-  const loadSessionHistory = useCallback(async (id: string): Promise<Message[]> => {
+  /**
+   * Carrega histórico de uma sessão com paginação (lazy loading)
+   * 
+   * Por padrão, carrega as últimas MESSAGES_PER_PAGE mensagens.
+   * Retorna as mensagens e atualiza o estado de paginação.
+   */
+  const loadSessionHistory = useCallback(async (
+    id: string,
+    options?: { loadAll?: boolean }
+  ): Promise<Message[]> => {
     try {
-      const rawMessages = await invoke<any[]>('load_chat_history', { id });
+      // Reset pagination state
-      // Convert role from String to type-safe union and ensure proper types
+      setPaginationState({
+        totalCount: 0,
+        hasMore: false,
+        offset: 0,
+        isLoadingMore: false,
+      });
+      
+      // Se loadAll = true, usa o comando antigo que carrega tudo
+      if (options?.loadAll) {
+        const rawMessages = await invoke<Array<{
+          role: string;
+          content: string;
+          metadata?: unknown;
+        }>>('load_chat_history', { id });
+        
         return rawMessages.map(msg => ({
           role: (msg.role === 'user' || msg.role === 'assistant' || msg.role === 'system') 
             ? msg.role as 'user' | 'assistant' | 'system'
-          : 'user' as const, // fallback
+            : 'user' as const,
+          content: msg.content || '',
+          metadata: msg.metadata || undefined
+        }));
+      }
+      
+      // Usar paginação: carregar últimas N mensagens
+      const result = await invoke<PaginatedHistoryResult>('load_chat_history_paginated', {
+        id,
+        limit: MESSAGES_PER_PAGE,
+        offset: 0
+      });
+      
+      // Atualizar estado de paginação
+      setPaginationState({
+        totalCount: result.total_count,
+        hasMore: result.has_more,
+        offset: result.messages.length,
+        isLoadingMore: false,
+      });
+      
+      // Converter para tipo Message
+      return result.messages.map(msg => ({
+        role: (msg.role === 'user' || msg.role === 'assistant' || msg.role === 'system') 
+          ? msg.role as 'user' | 'assistant' | 'system'
+          : 'user' as const,
         content: msg.content || '',
         metadata: msg.metadata || undefined
       }));
     } catch (error) {
       console.error("Failed to load history:", error);
+      
+      // Fallback: tentar carregar tudo com o comando antigo
+      try {
+        const rawMessages = await invoke<Array<{
+          role: string;
+          content: string;
+          metadata?: unknown;
+        }>>('load_chat_history', { id });
+        
+        return rawMessages.map(msg => ({
+          role: (msg.role === 'user' || msg.role === 'assistant' || msg.role === 'system') 
+            ? msg.role as 'user' | 'assistant' | 'system'
+            : 'user' as const,
+          content: msg.content || '',
+          metadata: msg.metadata || undefined
+        }));
+      } catch {
         return [];
       }
+    }
   }, []);
 
+  /**
+   * Carrega mais mensagens antigas (scroll infinito reverso)
+   * 
+   * Chamado quando o usuário faz scroll para o topo do chat.
+   * Retorna as mensagens anteriores que devem ser prepend ao estado.
+   */
+  const loadMoreMessages = useCallback(async (
+    sessionId: string
+  ): Promise<Message[]> => {
+    // Evitar múltiplos loads simultâneos
+    if (loadingMoreRef.current || !paginationState.hasMore) {
+      return [];
+    }
+    
+    loadingMoreRef.current = true;
+    setPaginationState(prev => ({ ...prev, isLoadingMore: true }));
+    
+    try {
+      const result = await invoke<PaginatedHistoryResult>('load_chat_history_paginated', {
+        id: sessionId,
+        limit: MESSAGES_PER_PAGE,
+        offset: paginationState.offset
+      });
+      
+      // Atualizar estado de paginação
+      setPaginationState(prev => ({
+        ...prev,
+        hasMore: result.has_more,
+        offset: prev.offset + result.messages.length,
+        isLoadingMore: false,
+      }));
+      
+      // Converter para tipo Message
+      return result.messages.map(msg => ({
+        role: (msg.role === 'user' || msg.role === 'assistant' || msg.role === 'system') 
+          ? msg.role as 'user' | 'assistant' | 'system'
+          : 'user' as const,
+        content: msg.content || '',
+        metadata: msg.metadata || undefined
+      }));
+    } catch (error) {
+      console.error("Failed to load more messages:", error);
+      setPaginationState(prev => ({ ...prev, isLoadingMore: false }));
+      return [];
+    } finally {
+      loadingMoreRef.current = false;
+    }
+  }, [paginationState.hasMore, paginationState.offset]);
+
   const deleteSession = useCallback(async (id: string) => {
     try {
       await invoke('delete_chat_session', { id });
@@ -396,6 +545,8 @@ export function useChatStorage() {
     setCurrentSessionId,
     loadSessions,
     loadSessionHistory,
+    loadMoreMessages,
+    paginationState,
     saveSession,
     deleteSession,
     isGeneratingTitle,
@@ -407,4 +558,3 @@ export function useChatStorage() {
     isSearching
   };
 }
-

hooks/use-chat.ts

@@ -240,6 +240,29 @@ export function useChat() {
   const rawContentRef = useRef<string>(''); // Track raw content including metadata during streaming
   const currentSessionIdRef = useRef<string | null>(null);
   const lastTokenRef = useRef<string>(''); // Track last token to detect duplicates
+  const renderScheduledRef = useRef<boolean>(false);
+  const rafIdRef = useRef<number | null>(null);
+  
+  // Função para atualizar o estado visual com o conteúdo acumulado
+  const flushToState = () => {
+    renderScheduledRef.current = false;
+    const displayContent = stripMetadataTag(rawContentRef.current);
+    setMessages(prev => {
+      const last = prev[prev.length - 1];
+      if (last && last.role === 'assistant') {
+        return [...prev.slice(0, -1), { ...last, content: displayContent }];
+      }
+      return [...prev, { role: 'assistant', content: displayContent }];
+    });
+  };
+
+  // Agendar flush com requestAnimationFrame (limita a ~60fps)
+  const scheduleFlush = () => {
+    if (!renderScheduledRef.current) {
+      renderScheduledRef.current = true;
+      rafIdRef.current = requestAnimationFrame(flushToState);
+    }
+  };
   
   // Listener para eventos do Rust
   useEffect(() => {
@@ -262,51 +285,38 @@ export function useChat() {
       const { content, done } = event.payload;
       
       if (content && content.length > 0) {
-        // Verificar se este é o mesmo token do último processado (evitar duplicação)
+        // Detecção de duplicatas (MANTER LÓGICA ORIGINAL)
-        // Isso pode acontecer se o evento for emitido múltiplas vezes
         if (content === lastTokenRef.current && rawContentRef.current.endsWith(content)) {
-          // Token duplicado, ignorar
           if (process.env.NODE_ENV === 'development') {
             console.warn('Token duplicado detectado, ignorando:', content.substring(0, 30));
           }
           return;
         }
         
-        // Atualizar referência do último token
         lastTokenRef.current = content;
-        
-        // Accumulate raw content (including metadata) in ref
         rawContentRef.current += content;
         
-        setMessages(prev => {
+        // MUDANÇA: Agendar flush em vez de chamar setMessages diretamente
-          const last = prev[prev.length - 1];
+        scheduleFlush();
-          if (last && last.role === 'assistant') {
-            // For display: strip incomplete metadata tag if present
-            const displayContent = stripMetadataTag(rawContentRef.current);
-            return [
-              ...prev.slice(0, -1),
-              { ...last, content: displayContent }
-            ];
-          }
-          // Se não existe mensagem do assistente, criar uma
-          return [...prev, { role: 'assistant', content: stripMetadataTag(rawContentRef.current) }];
-        });
       }
       
       if (done) {
-        // Stream terminou, processar metadata final
+        // Cancelar qualquer flush pendente
+        if (rafIdRef.current !== null) {
+          cancelAnimationFrame(rafIdRef.current);
+          rafIdRef.current = null;
+          renderScheduledRef.current = false;
+        }
+        
+        // Flush IMEDIATO com processamento de metadata
         setMessages(prev => {
           const last = prev[prev.length - 1];
           if (last && last.role === 'assistant') {
             const rawContent = rawContentRef.current;
             const { content: finalContent, metadata } = parseMetadata(rawContent);
             rawContentRef.current = '';
-            lastTokenRef.current = ''; // Reset last token tracker
+            lastTokenRef.current = '';
-            
+            return [...prev.slice(0, -1), { ...last, content: finalContent || last.content, metadata }];
-            return [
-              ...prev.slice(0, -1),
-              { ...last, content: finalContent || last.content, metadata }
-            ];
           }
           return prev;
         });
@@ -331,6 +341,10 @@ export function useChat() {
       unlistenCreated?.();
       unlistenToken?.();
       unlistenError?.();
+      // Cancelar RAF pendente
+      if (rafIdRef.current !== null) {
+        cancelAnimationFrame(rafIdRef.current);
+      }
     };
   }, []);
 

src-tauri/Cargo.lock

@@ -39,6 +39,7 @@ dependencies = [
  "cfg-if",
  "getrandom 0.3.4",
  "once_cell",
+ "serde",
  "version_check",
  "zerocopy",
 ]
@@ -110,6 +111,8 @@ dependencies = [
  "headless_chrome",
  "html2text",
  "log",
+ "ndarray",
+ "ort",
  "rand 0.8.5",
  "readability",
  "regex",
@@ -126,6 +129,7 @@ dependencies = [
  "tauri-plugin-log",
  "tauri-plugin-notification",
  "tauri-plugin-shell",
+ "tokenizers",
  "tokio",
  "tokio-cron-scheduler",
  "url",
@@ -363,7 +367,7 @@ dependencies = [
  "quote",
  "serde",
  "serde_json",
- "ureq",
+ "ureq 2.12.1",
 ]
 
 [[package]]
@@ -372,6 +376,12 @@ version = "1.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c08606f8c3cbf4ce6ec8e28fb0014a2c086708fe954eaa885384a6165172e7e8"
 
+[[package]]
+name = "base64"
+version = "0.13.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9e1b586273c5702936fe7b7d6896644d8be71e6314cfe09d3167c95f712589e8"
+
 [[package]]
 name = "base64"
 version = "0.21.7"
@@ -654,6 +664,15 @@ dependencies = [
  "toml 0.9.8",
 ]
 
+[[package]]
+name = "castaway"
+version = "0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dec551ab6e7578819132c713a93c022a05d60159dc86e7a7050223577484c55a"
+dependencies = [
+ "rustversion",
+]
+
 [[package]]
 name = "cc"
 version = "1.2.46"
@@ -689,7 +708,7 @@ version = "0.15.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d067ad48b8650848b989a59a86c6c36a995d02d2bf778d45c3c5d57bc2718f02"
 dependencies = [
- "smallvec",
+ "smallvec 1.15.1",
  "target-lexicon",
 ]
 
@@ -739,6 +758,21 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "compact_str"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3fdb1325a1cece981e8a296ab8f0f9b63ae357bd0784a9faaf548cc7b480707a"
+dependencies = [
+ "castaway",
+ "cfg-if",
+ "itoa",
+ "rustversion",
+ "ryu",
+ "serde",
+ "static_assertions",
+]
+
 [[package]]
 name = "concurrent-queue"
 version = "2.5.0"
@@ -748,6 +782,19 @@ dependencies = [
  "crossbeam-utils",
 ]
 
+[[package]]
+name = "console"
+version = "0.15.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "054ccb5b10f9f2cbf51eb355ca1d05c2d279ce1804688d0db74b4733a5aeafd8"
+dependencies = [
+ "encode_unicode",
+ "libc",
+ "once_cell",
+ "unicode-width 0.2.2",
+ "windows-sys 0.59.0",
+]
+
 [[package]]
 name = "constant_time_eq"
 version = "0.1.5"
@@ -858,6 +905,25 @@ dependencies = [
  "crossbeam-utils",
 ]
 
+[[package]]
+name = "crossbeam-deque"
+version = "0.8.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9dd111b7b7f7d55b72c0a6ae361660ee5853c9af73f70c3c2ef6858b950e2e51"
+dependencies = [
+ "crossbeam-epoch",
+ "crossbeam-utils",
+]
+
+[[package]]
+name = "crossbeam-epoch"
+version = "0.9.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5b82ac4a3c2ca9c3460964f020e1402edd5753411d7737aa39c3714ad1b5420e"
+dependencies = [
+ "crossbeam-utils",
+]
+
 [[package]]
 name = "crossbeam-utils"
 version = "0.8.21"
@@ -887,7 +953,7 @@ dependencies = [
  "phf 0.10.1",
  "proc-macro2",
  "quote",
- "smallvec",
+ "smallvec 1.15.1",
  "syn 1.0.109",
 ]
 
@@ -901,7 +967,7 @@ dependencies = [
  "dtoa-short",
  "itoa",
  "phf 0.11.3",
- "smallvec",
+ "smallvec 1.15.1",
 ]
 
 [[package]]
@@ -994,12 +1060,31 @@ dependencies = [
  "syn 2.0.110",
 ]
 
+[[package]]
+name = "dary_heap"
+version = "0.3.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "06d2e3287df1c007e74221c49ca10a95d557349e54b3a75dc2fb14712c751f04"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "data-encoding"
 version = "2.9.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2a2330da5de22e8a3cb63252ce2abb30116bf5265e89c0e01bc17015ce30a476"
 
+[[package]]
+name = "der"
+version = "0.7.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e7c1832837b905bbfb5101e07cc24c8deddf52f93225eee6ead5f4d63d53ddcb"
+dependencies = [
+ "pem-rfc7468",
+ "zeroize",
+]
+
 [[package]]
 name = "deranged"
 version = "0.5.5"
@@ -1219,6 +1304,12 @@ version = "0.6.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "12a0bb14ac04a9fcf170d0bbbef949b44cc492f4452bd20c095636956f653642"
 
+[[package]]
+name = "either"
+version = "1.15.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "48c757948c5ede0e46177b7add2e67155f70e33c07fea8284df6576da70b3719"
+
 [[package]]
 name = "embed-resource"
 version = "3.0.6"
@@ -1239,6 +1330,12 @@ version = "1.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4ef6b89e5b37196644d8796de5268852ff179b44e96276cf4290264843743bb7"
 
+[[package]]
+name = "encode_unicode"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "34aa73646ffb006b8f5147f3dc182bd4bcb190227ce861fc4a4844bf8e3cb2c0"
+
 [[package]]
 name = "encoding_rs"
 version = "0.8.35"
@@ -1318,6 +1415,15 @@ dependencies = [
  "windows-sys 0.61.2",
 ]
 
+[[package]]
+name = "esaxx-rs"
+version = "0.1.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d817e038c30374a4bcb22f94d0a8a0e216958d4c3dcde369b1439fec4bdda6e6"
+dependencies = [
+ "cc",
+]
+
 [[package]]
 name = "event-listener"
 version = "5.4.1"
@@ -1385,6 +1491,18 @@ dependencies = [
  "rustc_version",
 ]
 
+[[package]]
+name = "filetime"
+version = "0.2.26"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bc0505cd1b6fa6580283f6bdf70a73fcf4aba1184038c90902b92b3dd0df63ed"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "libredox",
+ "windows-sys 0.60.2",
+]
+
 [[package]]
 name = "find-msvc-tools"
 version = "0.1.5"
@@ -1735,7 +1853,7 @@ dependencies = [
  "libc",
  "once_cell",
  "pin-project-lite",
- "smallvec",
+ "smallvec 1.15.1",
  "thiserror 1.0.69",
 ]
 
@@ -1771,7 +1889,7 @@ dependencies = [
  "libc",
  "memchr",
  "once_cell",
- "smallvec",
+ "smallvec 1.15.1",
  "thiserror 1.0.69",
 ]
 
@@ -2143,7 +2261,7 @@ dependencies = [
  "itoa",
  "pin-project-lite",
  "pin-utils",
- "smallvec",
+ "smallvec 1.15.1",
  "tokio",
  "want",
 ]
@@ -2289,7 +2407,7 @@ dependencies = [
  "icu_normalizer_data",
  "icu_properties",
  "icu_provider",
- "smallvec",
+ "smallvec 1.15.1",
  "zerovec",
 ]
 
@@ -2347,7 +2465,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3b0875f23caa03898994f6ddc501886a45c7d3d62d04d2d90788d47be1b1e4de"
 dependencies = [
  "idna_adapter",
- "smallvec",
+ "smallvec 1.15.1",
  "utf8_iter",
 ]
 
@@ -2384,6 +2502,19 @@ dependencies = [
  "serde_core",
 ]
 
+[[package]]
+name = "indicatif"
+version = "0.17.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "183b3088984b400f4cfac3620d5e076c84da5364016b4f49473de574b2586235"
+dependencies = [
+ "console",
+ "number_prefix",
+ "portable-atomic",
+ "unicode-width 0.2.2",
+ "web-time",
+]
+
 [[package]]
 name = "infer"
 version = "0.19.0"
@@ -2437,6 +2568,15 @@ dependencies = [
  "once_cell",
 ]
 
+[[package]]
+name = "itertools"
+version = "0.14.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2b192c782037fadd9cfa75548310488aabdbf3d2da73885b31bd0abd03351285"
+dependencies = [
+ "either",
+]
+
 [[package]]
 name = "itoa"
 version = "1.0.15"
@@ -2579,7 +2719,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6e9ec52138abedcc58dc17a7c6c0c00a2bdb4f3427c7f63fa97fd0d859155caf"
 dependencies = [
  "gtk-sys",
- "libloading",
+ "libloading 0.7.4",
  "once_cell",
 ]
 
@@ -2599,6 +2739,16 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "libloading"
+version = "0.8.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d7c4b02199fee7c5d21a5ae7d8cfa79a6ef5bb2fc834d6e9058e89c825efdc55"
+dependencies = [
+ "cfg-if",
+ "windows-link 0.2.1",
+]
+
 [[package]]
 name = "libredox"
 version = "0.1.10"
@@ -2607,6 +2757,7 @@ checksum = "416f7e718bdb06000964960ffa43b4335ad4012ae8b99060261aa4a8088d5ccb"
 dependencies = [
  "bitflags 2.10.0",
  "libc",
+ "redox_syscall",
 ]
 
 [[package]]
@@ -2668,6 +2819,22 @@ dependencies = [
  "time",
 ]
 
+[[package]]
+name = "macro_rules_attribute"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "65049d7923698040cd0b1ddcced9b0eb14dd22c5f86ae59c3740eab64a676520"
+dependencies = [
+ "macro_rules_attribute-proc_macro",
+ "paste",
+]
+
+[[package]]
+name = "macro_rules_attribute-proc_macro"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "670fdfda89751bc4a84ac13eaa63e205cf0fd22b4c9a5fbfa085b63c1f1d3a30"
+
 [[package]]
 name = "malloc_buf"
 version = "0.0.6"
@@ -2734,6 +2901,16 @@ version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2532096657941c2fea9c289d370a250971c689d4f143798ff67113ec042024a5"
 
+[[package]]
+name = "matrixmultiply"
+version = "0.3.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a06de3016e9fae57a36fd14dba131fccf49f74b40b7fbdb472f96e361ec71a08"
+dependencies = [
+ "autocfg",
+ "rawpointer",
+]
+
 [[package]]
 name = "memchr"
 version = "2.7.6"
@@ -2782,6 +2959,28 @@ dependencies = [
  "windows-sys 0.61.2",
 ]
 
+[[package]]
+name = "monostate"
+version = "0.1.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3341a273f6c9d5bef1908f17b7267bbab0e95c9bf69a0d4dcf8e9e1b2c76ef67"
+dependencies = [
+ "monostate-impl",
+ "serde",
+ "serde_core",
+]
+
+[[package]]
+name = "monostate-impl"
+version = "0.1.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e4db6d5580af57bf992f59068d4ea26fd518574ff48d7639b255a36f9de6e7e9"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.110",
+]
+
 [[package]]
 name = "muda"
 version = "0.17.1"
@@ -2820,6 +3019,21 @@ dependencies = [
  "tempfile",
 ]
 
+[[package]]
+name = "ndarray"
+version = "0.16.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "882ed72dce9365842bf196bdeedf5055305f11fc8c03dee7bb0194a6cad34841"
+dependencies = [
+ "matrixmultiply",
+ "num-complex",
+ "num-integer",
+ "num-traits",
+ "portable-atomic",
+ "portable-atomic-util",
+ "rawpointer",
+]
+
 [[package]]
 name = "ndk"
 version = "0.9.0"
@@ -2921,6 +3135,15 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "num-complex"
+version = "0.4.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "73f88a1307638156682bada9d7604135552957b7818057dcef22705b4d509495"
+dependencies = [
+ "num-traits",
+]
+
 [[package]]
 name = "num-conv"
 version = "0.1.0"
@@ -2938,6 +3161,15 @@ dependencies = [
  "syn 1.0.109",
 ]
 
+[[package]]
+name = "num-integer"
+version = "0.1.46"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7969661fd2958a5cb096e56c8e1ad0444ac2bbcd0061bd28660485a44879858f"
+dependencies = [
+ "num-traits",
+]
+
 [[package]]
 name = "num-traits"
 version = "0.2.19"
@@ -2978,6 +3210,12 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "number_prefix"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "830b246a0e5f20af87141b25c173cd1b609bd7779a4617d6ec582abaf90870f3"
+
 [[package]]
 name = "objc"
 version = "0.2.7"
@@ -3287,6 +3525,28 @@ version = "1.21.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "42f5e15c9953c5e4ccceeb2e7382a716482c34515315f7b03532b8b4e8393d2d"
 
+[[package]]
+name = "onig"
+version = "6.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "336b9c63443aceef14bea841b899035ae3abe89b7c486aaf4c5bd8aafedac3f0"
+dependencies = [
+ "bitflags 2.10.0",
+ "libc",
+ "once_cell",
+ "onig_sys",
+]
+
+[[package]]
+name = "onig_sys"
+version = "69.9.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c7f86c6eef3d6df15f23bcfb6af487cbd2fed4e5581d58d5bf1f5f8b7f6727dc"
+dependencies = [
+ "cc",
+ "pkg-config",
+]
+
 [[package]]
 name = "open"
 version = "5.3.3"
@@ -3359,6 +3619,32 @@ dependencies = [
  "pin-project-lite",
 ]
 
+[[package]]
+name = "ort"
+version = "2.0.0-rc.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1fa7e49bd669d32d7bc2a15ec540a527e7764aec722a45467814005725bcd721"
+dependencies = [
+ "libloading 0.8.9",
+ "ndarray",
+ "ort-sys",
+ "smallvec 2.0.0-alpha.10",
+ "tracing",
+]
+
+[[package]]
+name = "ort-sys"
+version = "2.0.0-rc.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2aba9f5c7c479925205799216e7e5d07cc1d4fa76ea8058c60a9a30f6a4e890"
+dependencies = [
+ "flate2",
+ "pkg-config",
+ "sha2",
+ "tar",
+ "ureq 3.1.4",
+]
+
 [[package]]
 name = "os_pipe"
 version = "1.2.3"
@@ -3419,7 +3705,7 @@ dependencies = [
  "cfg-if",
  "libc",
  "redox_syscall",
- "smallvec",
+ "smallvec 1.15.1",
  "windows-link 0.2.1",
 ]
 
@@ -3434,6 +3720,12 @@ dependencies = [
  "subtle",
 ]
 
+[[package]]
+name = "paste"
+version = "1.0.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "57c0d7b74b563b49d38dae00a0c37d4d6de9b432382b2892f0574ddcae73fd0a"
+
 [[package]]
 name = "pathdiff"
 version = "0.2.3"
@@ -3452,6 +3744,15 @@ dependencies = [
  "sha2",
 ]
 
+[[package]]
+name = "pem-rfc7468"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "88b39c9bfcfc231068454382784bb460aae594343fb030d46e9f50a645418412"
+dependencies = [
+ "base64ct",
+]
+
 [[package]]
 name = "percent-encoding"
 version = "2.3.2"
@@ -3677,6 +3978,21 @@ version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "22686f4785f02a4fcc856d3b3bb19bf6c8160d103f7a99cc258bddd0251dc7f2"
 
+[[package]]
+name = "portable-atomic"
+version = "1.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f84267b20a16ea918e43c6a88433c2d54fa145c92a811b5b047ccbe153674483"
+
+[[package]]
+name = "portable-atomic-util"
+version = "0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d8a2f0d8d040d7848a709caf78912debcc3f33ee4b3cac47d73d1e1069e83507"
+dependencies = [
+ "portable-atomic",
+]
+
 [[package]]
 name = "potential_utf"
 version = "0.1.4"
@@ -3950,6 +4266,43 @@ version = "0.6.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "20675572f6f24e9e76ef639bc5552774ed45f1c30e2951e1e99c59888861c539"
 
+[[package]]
+name = "rawpointer"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "60a357793950651c4ed0f3f52338f53b2f809f32d83a07f72909fa13e4c6c1e3"
+
+[[package]]
+name = "rayon"
+version = "1.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "368f01d005bf8fd9b1206fb6fa653e6c4a81ceb1466406b81792d87c5677a58f"
+dependencies = [
+ "either",
+ "rayon-core",
+]
+
+[[package]]
+name = "rayon-cond"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2964d0cf57a3e7a06e8183d14a8b527195c706b7983549cd5462d5aa3747438f"
+dependencies = [
+ "either",
+ "itertools",
+ "rayon",
+]
+
+[[package]]
+name = "rayon-core"
+version = "1.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "22e18b0f0062d30d4230b2e85ff77fdfe4326feb054b9783a3460d8435c8ab91"
+dependencies = [
+ "crossbeam-deque",
+ "crossbeam-utils",
+]
+
 [[package]]
 name = "readability"
 version = "0.3.0"
@@ -4213,7 +4566,7 @@ dependencies = [
  "fallible-streaming-iterator",
  "hashlink",
  "libsqlite3-sys",
- "smallvec",
+ "smallvec 1.15.1",
 ]
 
 [[package]]
@@ -4445,7 +4798,7 @@ dependencies = [
  "phf_codegen 0.8.0",
  "precomputed-hash",
  "servo_arc 0.2.0",
- "smallvec",
+ "smallvec 1.15.1",
 ]
 
 [[package]]
@@ -4464,7 +4817,7 @@ dependencies = [
  "phf_codegen 0.10.0",
  "precomputed-hash",
  "servo_arc 0.3.0",
- "smallvec",
+ "smallvec 1.15.1",
 ]
 
 [[package]]
@@ -4761,6 +5114,12 @@ version = "1.15.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "67b1b7a3b5fe4f1376887184045fcf45c69e92af734b7aaddc05fb777b6fbd03"
 
+[[package]]
+name = "smallvec"
+version = "2.0.0-alpha.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "51d44cfb396c3caf6fbfd0ab422af02631b69ddd96d2eff0b0f0724f9024051b"
+
 [[package]]
 name = "socket2"
 version = "0.5.10"
@@ -4840,6 +5199,18 @@ dependencies = [
  "system-deps",
 ]
 
+[[package]]
+name = "spm_precompiled"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5851699c4033c63636f7ea4cf7b7c1f1bf06d0cc03cfb42e711de5a5c46cf326"
+dependencies = [
+ "base64 0.13.1",
+ "nom",
+ "serde",
+ "unicode-segmentation",
+]
+
 [[package]]
 name = "stable_deref_trait"
 version = "1.2.1"
@@ -5074,6 +5445,17 @@ version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "55937e1799185b12863d447f42597ed69d9928686b8d88a1df17376a097d8369"
 
+[[package]]
+name = "tar"
+version = "0.4.44"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1d863878d212c87a19c1a610eb53bb01fe12951c0501cf5a0d65f724914a667a"
+dependencies = [
+ "filetime",
+ "libc",
+ "xattr",
+]
+
 [[package]]
 name = "target-lexicon"
 version = "0.12.16"
@@ -5522,6 +5904,40 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1f3ccbac311fea05f86f61904b462b55fb3df8837a366dfc601a0161d0532f20"
 
+[[package]]
+name = "tokenizers"
+version = "0.21.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a620b996116a59e184c2fa2dfd8251ea34a36d0a514758c6f966386bd2e03476"
+dependencies = [
+ "ahash 0.8.12",
+ "aho-corasick",
+ "compact_str",
+ "dary_heap",
+ "derive_builder",
+ "esaxx-rs",
+ "getrandom 0.3.4",
+ "indicatif",
+ "itertools",
+ "log",
+ "macro_rules_attribute",
+ "monostate",
+ "onig",
+ "paste",
+ "rand 0.9.2",
+ "rayon",
+ "rayon-cond",
+ "regex",
+ "regex-syntax",
+ "serde",
+ "serde_json",
+ "spm_precompiled",
+ "thiserror 2.0.17",
+ "unicode-normalization-alignments",
+ "unicode-segmentation",
+ "unicode_categories",
+]
+
 [[package]]
 name = "tokio"
 version = "1.48.0"
@@ -5885,6 +6301,15 @@ version = "1.0.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9312f7c4f6ff9069b165498234ce8be658059c6728633667c526e27dc2cf1df5"
 
+[[package]]
+name = "unicode-normalization-alignments"
+version = "0.1.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "43f613e4fa046e69818dd287fdc4bc78175ff20331479dab6e1b0f98d57062de"
+dependencies = [
+ "smallvec 1.15.1",
+]
+
 [[package]]
 name = "unicode-segmentation"
 version = "1.12.0"
@@ -5903,6 +6328,12 @@ version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b4ac048d71ede7ee76d585517add45da530660ef4390e49b098733c6e897f254"
 
+[[package]]
+name = "unicode_categories"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "39ec24b3121d976906ece63c9daad25b85969647682eee313cb5779fdd69e14e"
+
 [[package]]
 name = "untrusted"
 version = "0.9.0"
@@ -5926,6 +6357,36 @@ dependencies = [
  "webpki-roots 0.26.11",
 ]
 
+[[package]]
+name = "ureq"
+version = "3.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d39cb1dbab692d82a977c0392ffac19e188bd9186a9f32806f0aaa859d75585a"
+dependencies = [
+ "base64 0.22.1",
+ "der",
+ "log",
+ "native-tls",
+ "percent-encoding",
+ "rustls-pki-types",
+ "socks",
+ "ureq-proto",
+ "utf-8",
+ "webpki-root-certs",
+]
+
+[[package]]
+name = "ureq-proto"
+version = "0.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d81f9efa9df032be5934a46a068815a10a042b494b6a58cb0a1a97bb5467ed6f"
+dependencies = [
+ "base64 0.22.1",
+ "http 1.3.1",
+ "httparse",
+ "log",
+]
+
 [[package]]
 name = "url"
 version = "2.5.7"
@@ -6151,6 +6612,16 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "web-time"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5a6580f308b1fad9207618087a65c04e7a10bc77e02c8e84e9b00dd4b12fa0bb"
+dependencies = [
+ "js-sys",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "webkit2gtk"
 version = "2.0.1"
@@ -6195,6 +6666,15 @@ dependencies = [
  "system-deps",
 ]
 
+[[package]]
+name = "webpki-root-certs"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ee3e3b5f5e80bc89f30ce8d0343bf4e5f12341c51f3e26cbeecbc7c85443e85b"
+dependencies = [
+ "rustls-pki-types",
+]
+
 [[package]]
 name = "webpki-roots"
 version = "0.26.11"
@@ -6911,6 +7391,16 @@ dependencies = [
  "pkg-config",
 ]
 
+[[package]]
+name = "xattr"
+version = "1.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "32e45ad4206f6d2479085147f02bc2ef834ac85886624a23575ae137c8aa8156"
+dependencies = [
+ "libc",
+ "rustix",
+]
+
 [[package]]
 name = "xdg-home"
 version = "1.3.0"

src-tauri/Cargo.toml

@@ -47,3 +47,10 @@ tauri-plugin-autostart = "2"
 dirs = "5.0"
 rfd = "0.14"
 rusqlite = { version = "0.31", features = ["bundled"] }
+
+# ONNX Runtime para embeddings locais (ranking de relevância)
+# Usando load-dynamic para evitar conflito de RuntimeLibrary (MD vs MT) no Windows
+# entre ort (dynamic) e tokenizers/esaxx-rs (static)
+ort = { version = "2.0.0-rc.10", features = ["load-dynamic"] }
+ndarray = "0.16"
+tokenizers = "0.21"

src-tauri/src/db.rs

@@ -22,6 +22,13 @@ pub struct ChatMessage {
     pub created_at: DateTime<Utc>,
 }
 
+/// Resultado de busca de sessões com contagem de matches
+#[derive(Debug, Clone)]
+pub struct SearchSessionResult {
+    pub session: ChatSession,
+    pub match_count: i64,
+}
+
 pub struct Database {
     conn: Connection,
 }
@@ -49,6 +56,19 @@ impl Database {
         let db_path = app_data_dir.join("ollahub.db");
         let conn = Connection::open(&db_path)?;
         
+        // Otimizações de performance do SQLite
+        // WAL mode permite leituras e escritas simultâneas (evita bloqueio da UI)
+        // synchronous=NORMAL reduz fsync sem perder segurança
+        // cache_size maior acelera operações frequentes
+        // temp_store=MEMORY usa RAM para tabelas temporárias
+        conn.execute_batch(
+            "PRAGMA journal_mode=WAL;
+             PRAGMA synchronous=NORMAL;
+             PRAGMA cache_size=10000;
+             PRAGMA temp_store=MEMORY;
+             PRAGMA foreign_keys=ON;"
+        )?;
+        
         let db = Self { conn };
         db.init_schema()?;
         
@@ -370,6 +390,54 @@ impl Database {
         Ok(self.conn.last_insert_rowid())
     }
     
+    /// Salva múltiplas mensagens de uma sessão em uma transação
+    /// 
+    /// Remove mensagens existentes da sessão antes de inserir as novas
+    /// para garantir que não haja duplicatas.
+    pub fn save_messages_batch(
+        &self,
+        session_id: &str,
+        messages: &[ChatMessage],
+    ) -> SqliteResult<()> {
+        // Usar execute_batch para executar múltiplas operações atomicamente
+        // WAL mode permite isso de forma segura mesmo sem transação explícita
+        
+        // Remover mensagens existentes da sessão (para evitar duplicatas)
+        self.conn.execute(
+            "DELETE FROM messages WHERE session_id = ?1",
+            params![session_id],
+        )?;
+        
+        // Inserir todas as mensagens
+        let mut stmt = self.conn.prepare(
+            "INSERT INTO messages (session_id, role, content, metadata, created_at) 
+             VALUES (?1, ?2, ?3, ?4, ?5)"
+        )?;
+        
+        for message in messages {
+            stmt.execute(params![
+                message.session_id,
+                message.role,
+                message.content,
+                message.metadata,
+                message.created_at.to_rfc3339()
+            ])?;
+        }
+        
+        // Atualizar updated_at da sessão com a data da última mensagem
+        if let Some(last_message) = messages.last() {
+            self.conn.execute(
+                "UPDATE sessions SET updated_at = ?1 WHERE id = ?2",
+                params![
+                    last_message.created_at.to_rfc3339(),
+                    session_id
+                ],
+            )?;
+        }
+        
+        Ok(())
+    }
+    
     /// Busca todas as mensagens de uma sessão
     pub fn get_messages(&self, session_id: &str) -> SqliteResult<Vec<ChatMessage>> {
         let mut stmt = self.conn.prepare(
@@ -399,6 +467,88 @@ impl Database {
         Ok(messages)
     }
     
+    /// Busca mensagens de uma sessão com paginação (lazy loading)
+    /// 
+    /// Retorna as últimas `limit` mensagens a partir do `offset`.
+    /// O offset conta do final (0 = últimas mensagens, 20 = 20 mensagens antes das últimas).
+    /// 
+    /// Parâmetros:
+    /// - session_id: ID da sessão
+    /// - limit: número máximo de mensagens a retornar
+    /// - offset: número de mensagens a pular do final (0 = começar das últimas)
+    /// 
+    /// Retorna: (mensagens em ordem ASC, total_count, has_more)
+    pub fn get_messages_paginated(
+        &self,
+        session_id: &str,
+        limit: usize,
+        offset: usize,
+    ) -> SqliteResult<(Vec<ChatMessage>, usize, bool)> {
+        // Primeiro, obter o total de mensagens
+        let total_count: usize = self.conn.query_row(
+            "SELECT COUNT(*) FROM messages WHERE session_id = ?1",
+            params![session_id],
+            |row| row.get(0),
+        )?;
+        
+        // Se não há mensagens, retornar vazio
+        if total_count == 0 {
+            return Ok((Vec::new(), 0, false));
+        }
+        
+        // Estratégia: usar subquery para pegar as últimas N mensagens ordenadas DESC,
+        // depois ordenar ASC para manter ordem cronológica
+        // 
+        // Se offset=0 e limit=30: queremos as últimas 30 mensagens
+        // Se offset=30 e limit=30: queremos as 30 mensagens antes das últimas 30
+        let real_limit = std::cmp::min(limit, total_count.saturating_sub(offset));
+        
+        if real_limit == 0 {
+            return Ok((Vec::new(), total_count, false));
+        }
+        
+        // Query: pegar as últimas (offset + limit) mensagens ordenadas DESC,
+        // depois ordenar ASC e pegar as primeiras 'limit' (que são as mais antigas do conjunto)
+        let mut stmt = self.conn.prepare(
+            "SELECT id, session_id, role, content, metadata, created_at 
+             FROM (
+                 SELECT id, session_id, role, content, metadata, created_at
+                 FROM messages 
+                 WHERE session_id = ?1 
+                 ORDER BY created_at DESC
+                 LIMIT ?2
+             ) AS recent_messages
+             ORDER BY created_at ASC
+             LIMIT ?3"
+        )?;
+        
+        // Precisamos pegar (offset + limit) mensagens do final para depois pegar as primeiras 'limit'
+        let fetch_limit = offset + limit;
+        
+        let rows = stmt.query_map(params![session_id, fetch_limit, real_limit], |row| {
+            Ok(ChatMessage {
+                id: Some(row.get(0)?),
+                session_id: row.get(1)?,
+                role: row.get(2)?,
+                content: row.get(3)?,
+                metadata: row.get(4)?,
+                created_at: DateTime::parse_from_rfc3339(&row.get::<_, String>(5)?)
+                    .map_err(|_| rusqlite::Error::InvalidColumnType(5, "TEXT".to_string(), rusqlite::types::Type::Text))?
+                    .with_timezone(&Utc),
+            })
+        })?;
+        
+        let mut messages = Vec::new();
+        for row in rows {
+            messages.push(row?);
+        }
+        
+        // has_more = ainda há mensagens mais antigas para carregar
+        let has_more = offset + messages.len() < total_count;
+        
+        Ok((messages, total_count, has_more))
+    }
+    
     /// Salva um documento RAG
     pub fn save_rag_document(
         &self,
@@ -446,49 +596,39 @@ impl Database {
     
     /// Busca sessões por query (título ou conteúdo de mensagens)
     /// Retorna resultados ordenados por relevância (match no título > match no conteúdo)
-    pub fn search_sessions(&self, query: &str, limit: usize) -> SqliteResult<Vec<ChatSession>> {
+    /// Inclui contagem de matches para navegação
+    pub fn search_sessions(&self, query: &str, limit: usize) -> SqliteResult<Vec<SearchSessionResult>> {
         if query.trim().is_empty() {
-            // Se query vazia, retornar todas as sessões ordenadas por updated_at
+            // Se query vazia, retornar todas as sessões ordenadas por updated_at com match_count = 0
-            return self.list_sessions();
+            let sessions = self.list_sessions()?;
+            return Ok(sessions.into_iter().map(|session| SearchSessionResult {
+                session,
+                match_count: 0,
+            }).collect());
         }
         
         // Escapar caracteres especiais para FTS5
         let escaped_query = query.replace('"', "\"\"");
         let fts_query = format!("\"{}\"", escaped_query);
         
-        // Busca combinada: título (peso 1.0) + conteúdo (peso 0.5)
+        // Busca simplificada: primeiro buscar por título, depois por conteúdo
+        // Usando abordagem em duas etapas para evitar problemas com bm25 em CTEs
+        
+        // Etapa 1: Buscar sessões por título (FTS5)
+        let mut title_sessions: Vec<SearchSessionResult> = Vec::new();
+        {
             let mut stmt = self.conn.prepare(
-            "WITH title_matches AS (
+                "SELECT s.id, s.title, s.emoji, s.created_at, s.updated_at
-                SELECT s.id, s.title, s.emoji, s.created_at, s.updated_at, 
-                       bm25(sessions_fts) as rank
                  FROM sessions s
                  JOIN sessions_fts ON s.rowid = sessions_fts.rowid
                  WHERE sessions_fts MATCH ?1
-                ORDER BY rank
+                 ORDER BY s.updated_at DESC
-                LIMIT ?2
-            ),
-            content_matches AS (
-                SELECT DISTINCT s.id, s.title, s.emoji, s.created_at, s.updated_at,
-                       bm25(messages_fts) * 0.5 as rank
-                FROM sessions s
-                JOIN messages m ON s.id = m.session_id
-                JOIN messages_fts ON m.rowid = messages_fts.rowid
-                WHERE messages_fts MATCH ?1
-                ORDER BY rank
-                LIMIT ?2
-            )
-            SELECT id, title, emoji, created_at, updated_at
-            FROM (
-                SELECT * FROM title_matches
-                UNION
-                SELECT * FROM content_matches
-            )
-            ORDER BY rank DESC, updated_at DESC
                  LIMIT ?2"
             )?;
             
-        let rows = stmt.query_map(params![fts_query, limit], |row| {
+            let rows = stmt.query_map(params![&fts_query, limit], |row| {
-            Ok(ChatSession {
+                Ok(SearchSessionResult {
+                    session: ChatSession {
                         id: row.get(0)?,
                         title: row.get(1)?,
                         emoji: row.get(2)?,
@@ -498,28 +638,83 @@ impl Database {
                         updated_at: DateTime::parse_from_rfc3339(&row.get::<_, String>(4)?)
                             .map_err(|_| rusqlite::Error::InvalidColumnType(4, "TEXT".to_string(), rusqlite::types::Type::Text))?
                             .with_timezone(&Utc),
+                    },
+                    match_count: 1, // Match no título conta como 1
                 })
             })?;
             
-        let mut sessions = Vec::new();
             for row in rows {
-            sessions.push(row?);
+                title_sessions.push(row?);
             }
+        }
+        
+        // Etapa 2: Buscar sessões por conteúdo de mensagens (FTS5)
+        let mut content_sessions: Vec<(String, i64)> = Vec::new(); // (session_id, match_count)
+        {
+            let mut stmt = self.conn.prepare(
+                "SELECT m.session_id, COUNT(*) as match_count
+                 FROM messages m
+                 JOIN messages_fts ON m.rowid = messages_fts.rowid
+                 WHERE messages_fts MATCH ?1
+                 GROUP BY m.session_id
+                 ORDER BY match_count DESC
+                 LIMIT ?2"
+            )?;
+            
+            let rows = stmt.query_map(params![&fts_query, limit], |row| {
+                Ok((row.get::<_, String>(0)?, row.get::<_, i64>(1)?))
+            })?;
+            
+            for row in rows {
+                content_sessions.push(row?);
+            }
+        }
+        
+        // Combinar resultados: priorizar matches por título, adicionar matches por conteúdo
+        let mut session_map: std::collections::HashMap<String, SearchSessionResult> = std::collections::HashMap::new();
+        
+        // Adicionar sessões encontradas por título
+        for session in title_sessions {
+            session_map.insert(session.session.id.clone(), session);
+        }
+        
+        // Adicionar ou atualizar com sessões encontradas por conteúdo
+        for (session_id, match_count) in content_sessions {
+            if let Some(existing) = session_map.get_mut(&session_id) {
+                // Atualizar match_count se já existe
+                existing.match_count = match_count;
+            } else {
+                // Buscar dados da sessão
+                if let Ok(Some(session)) = self.get_session(&session_id) {
+                    session_map.insert(session_id, SearchSessionResult {
+                        session,
+                        match_count,
+                    });
+                }
+            }
+        }
+        
+        // Converter para vetor e ordenar por updated_at
+        let mut sessions: Vec<SearchSessionResult> = session_map.into_values().collect();
+        sessions.sort_by(|a, b| b.session.updated_at.cmp(&a.session.updated_at));
         
         // Se não encontrou resultados com FTS, tentar busca simples com LIKE (fallback)
         if sessions.is_empty() {
             let mut stmt = self.conn.prepare(
-                "SELECT DISTINCT s.id, s.title, s.emoji, s.created_at, s.updated_at
+                "SELECT s.id, s.title, s.emoji, s.created_at, s.updated_at,
+                        COUNT(CASE WHEN m.content LIKE ?1 THEN 1 END) as match_count
                  FROM sessions s
                  LEFT JOIN messages m ON s.id = m.session_id
                  WHERE s.title LIKE ?1 OR m.content LIKE ?1
+                 GROUP BY s.id, s.title, s.emoji, s.created_at, s.updated_at
                  ORDER BY s.updated_at DESC
                  LIMIT ?2"
             )?;
             
             let like_query = format!("%{}%", query);
             let rows = stmt.query_map(params![like_query, limit], |row| {
-                Ok(ChatSession {
+                Ok(SearchSessionResult {
+                    session: ChatSession {
                         id: row.get(0)?,
                         title: row.get(1)?,
                         emoji: row.get(2)?,
@@ -529,6 +724,8 @@ impl Database {
                         updated_at: DateTime::parse_from_rfc3339(&row.get::<_, String>(4)?)
                             .map_err(|_| rusqlite::Error::InvalidColumnType(4, "TEXT".to_string(), rusqlite::types::Type::Text))?
                             .with_timezone(&Utc),
+                    },
+                    match_count: row.get(5)?,
                 })
             })?;
             

src-tauri/src/embeddings.rs

@@ -0,0 +1,566 @@
+//! Módulo de Embeddings ONNX para ranking de relevância
+//!
+//! Usa o modelo all-MiniLM-L6-v2 para gerar embeddings de texto
+//! e calcular similaridade de cosseno para ranking de resultados de busca.
+
+use anyhow::{Result, anyhow};
+use ndarray::Array2;
+use ort::session::{Session, builder::GraphOptimizationLevel};
+use ort::value::Value;
+use std::io::Read;
+use std::path::Path;
+use std::sync::{Arc, Mutex, OnceLock};
+use tokenizers::Tokenizer;
+
+/// Flag para controlar se o ort já foi inicializado
+static ORT_INITIALIZED: OnceLock<Result<(), String>> = OnceLock::new();
+
+/// Dimensão dos embeddings do modelo all-MiniLM-L6-v2
+pub const EMBEDDING_DIM: usize = 384;
+
+/// Tamanho máximo de tokens para o modelo
+const MAX_SEQ_LENGTH: usize = 256;
+
+/// Global lazy-initialized embedding model (com Mutex para permitir mutabilidade)
+static EMBEDDING_MODEL: OnceLock<Result<Arc<Mutex<EmbeddingModel>>, String>> = OnceLock::new();
+
+/// Modelo de embeddings para cálculo de similaridade semântica
+pub struct EmbeddingModel {
+    session: Session,
+    tokenizer: Tokenizer,
+}
+
+impl EmbeddingModel {
+    /// Carrega o modelo ONNX e tokenizer
+    pub fn new(model_path: &str, tokenizer_path: &str) -> Result<Self> {
+        // Verificar se arquivos existem
+        if !Path::new(model_path).exists() {
+            return Err(anyhow!("Model file not found: {}", model_path));
+        }
+        if !Path::new(tokenizer_path).exists() {
+            return Err(anyhow!("Tokenizer file not found: {}", tokenizer_path));
+        }
+        
+        log::info!("[Embeddings] Loading ONNX model from: {}", model_path);
+        
+        // Criar sessão ONNX
+        let session = Session::builder()?
+            .with_optimization_level(GraphOptimizationLevel::Level3)?
+            .commit_from_file(model_path)?;
+        
+        // Carregar tokenizer
+        let tokenizer = Tokenizer::from_file(tokenizer_path)
+            .map_err(|e| anyhow!("Failed to load tokenizer: {}", e))?;
+        
+        log::info!("[Embeddings] Model loaded successfully");
+        
+        Ok(Self { session, tokenizer })
+    }
+    
+    /// Gera embedding para um texto
+    pub fn embed(&mut self, text: &str) -> Result<Vec<f32>> {
+        // Tokenizar texto
+        let encoding = self.tokenizer
+            .encode(text, true)
+            .map_err(|e| anyhow!("Tokenization failed: {}", e))?;
+        
+        let mut input_ids: Vec<i64> = encoding.get_ids()
+            .iter()
+            .map(|&id| id as i64)
+            .collect();
+        let mut attention_mask: Vec<i64> = encoding.get_attention_mask()
+            .iter()
+            .map(|&m| m as i64)
+            .collect();
+        let mut token_type_ids: Vec<i64> = encoding.get_type_ids()
+            .iter()
+            .map(|&t| t as i64)
+            .collect();
+        
+        // Truncar/pad para MAX_SEQ_LENGTH
+        input_ids.truncate(MAX_SEQ_LENGTH);
+        attention_mask.truncate(MAX_SEQ_LENGTH);
+        token_type_ids.truncate(MAX_SEQ_LENGTH);
+        
+        while input_ids.len() < MAX_SEQ_LENGTH {
+            input_ids.push(0);
+            attention_mask.push(0);
+            token_type_ids.push(0);
+        }
+        
+        // Criar arrays para inferência (batch size = 1)
+        let input_ids_array = Array2::from_shape_vec((1, MAX_SEQ_LENGTH), input_ids)?;
+        let attention_mask_array = Array2::from_shape_vec((1, MAX_SEQ_LENGTH), attention_mask)?;
+        let token_type_ids_array = Array2::from_shape_vec((1, MAX_SEQ_LENGTH), token_type_ids)?;
+        
+        // Criar inputs ONNX
+        let input_ids_value = Value::from_array(input_ids_array)?;
+        let attention_mask_value = Value::from_array(attention_mask_array)?;
+        let token_type_ids_value = Value::from_array(token_type_ids_array)?;
+        
+        // Executar inferência usando vetor de inputs
+        let inputs: Vec<(std::borrow::Cow<str>, ort::session::SessionInputValue)> = vec![
+            ("input_ids".into(), input_ids_value.into()),
+            ("attention_mask".into(), attention_mask_value.into()),
+            ("token_type_ids".into(), token_type_ids_value.into()),
+        ];
+        
+        let outputs = self.session.run(inputs)?;
+        
+        // Extrair output (last_hidden_state ou sentence_embedding dependendo do modelo)
+        // Para all-MiniLM-L6-v2, fazemos mean pooling do last_hidden_state
+        let output = outputs.get("last_hidden_state")
+            .or_else(|| outputs.get("sentence_embedding"))
+            .ok_or_else(|| anyhow!("Output tensor not found"))?;
+        
+        let (shape, raw_data) = output.try_extract_tensor::<f32>()?;
+        // Shape implementa Deref para [i64], então podemos usar diretamente
+        let dims: &[i64] = &*shape;
+        let data: &[f32] = raw_data;
+        
+        // Mean pooling: média ao longo da dimensão de sequência
+        let embedding = if dims.len() == 3 {
+            // Shape: (batch, seq_len, hidden_dim)
+            let seq_len = dims[1] as usize;
+            let hidden_dim = dims[2] as usize;
+            
+            let mut pooled = vec![0.0f32; hidden_dim];
+            for i in 0..seq_len {
+                for j in 0..hidden_dim {
+                    let idx = i * hidden_dim + j;
+                    pooled[j] += data[idx];
+                }
+            }
+            for v in &mut pooled {
+                *v /= seq_len as f32;
+            }
+            
+            // Normalizar L2
+            let norm: f32 = pooled.iter().map(|x| x * x).sum::<f32>().sqrt();
+            if norm > 0.0 {
+                for v in &mut pooled {
+                    *v /= norm;
+                }
+            }
+            
+            pooled
+        } else {
+            // Shape: (batch, hidden_dim) - já pooled
+            let hidden_dim = dims[1] as usize;
+            let mut embedding = Vec::with_capacity(hidden_dim);
+            for j in 0..hidden_dim {
+                embedding.push(data[j]);
+            }
+            
+            // Normalizar L2
+            let norm: f32 = embedding.iter().map(|x| x * x).sum::<f32>().sqrt();
+            if norm > 0.0 {
+                for v in &mut embedding {
+                    *v /= norm;
+                }
+            }
+            
+            embedding
+        };
+        
+        Ok(embedding)
+    }
+    
+    /// Calcula embeddings em batch (mais eficiente para múltiplos textos)
+    pub fn embed_batch(&mut self, texts: &[&str]) -> Result<Vec<Vec<f32>>> {
+        // Para simplificar, processa um por um (pode ser otimizado para batch real)
+        let mut results = Vec::with_capacity(texts.len());
+        for text in texts {
+            results.push(self.embed(text)?);
+        }
+        Ok(results)
+    }
+}
+
+/// Calcula similaridade de cosseno entre dois vetores
+pub fn cosine_similarity(a: &[f32], b: &[f32]) -> f32 {
+    if a.len() != b.len() || a.is_empty() {
+        return 0.0;
+    }
+    
+    let dot: f32 = a.iter().zip(b).map(|(x, y)| x * y).sum();
+    let norm_a: f32 = a.iter().map(|x| x * x).sum::<f32>().sqrt();
+    let norm_b: f32 = b.iter().map(|x| x * x).sum::<f32>().sqrt();
+    
+    if norm_a == 0.0 || norm_b == 0.0 {
+        return 0.0;
+    }
+    
+    dot / (norm_a * norm_b)
+}
+
+/// URLs para download do modelo (Hugging Face)
+const MODEL_URL: &str = "https://huggingface.co/sentence-transformers/all-MiniLM-L6-v2/resolve/main/onnx/model.onnx";
+const TOKENIZER_URL: &str = "https://huggingface.co/sentence-transformers/all-MiniLM-L6-v2/resolve/main/tokenizer.json";
+
+/// URL para download da biblioteca ONNX Runtime (Windows x64)
+#[cfg(target_os = "windows")]
+const ORT_DLL_URL: &str = "https://github.com/microsoft/onnxruntime/releases/download/v1.20.1/onnxruntime-win-x64-1.20.1.zip";
+
+/// Inicializa o ONNX Runtime com a biblioteca dinâmica
+fn init_ort_runtime(app_data_dir: &Path) -> Result<()> {
+    let result = ORT_INITIALIZED.get_or_init(|| {
+        let ort_dir = app_data_dir.join("ort");
+        
+        #[cfg(target_os = "windows")]
+        let dll_path = ort_dir.join("onnxruntime.dll");
+        #[cfg(target_os = "macos")]
+        let dll_path = ort_dir.join("libonnxruntime.dylib");
+        #[cfg(target_os = "linux")]
+        let dll_path = ort_dir.join("libonnxruntime.so");
+        
+        if dll_path.exists() {
+            // Definir variável de ambiente para o ort encontrar a DLL
+            std::env::set_var("ORT_DYLIB_PATH", &dll_path);
+            log::info!("[Embeddings] ORT_DYLIB_PATH set to: {:?}", dll_path);
+            Ok(())
+        } else {
+            // Tentar usar a biblioteca do sistema
+            log::warn!("[Embeddings] ONNX Runtime library not found at {:?}, will try system path", dll_path);
+            Ok(())
+        }
+    });
+    
+    match result {
+        Ok(()) => Ok(()),
+        Err(e) => Err(anyhow!("{}", e))
+    }
+}
+
+/// Baixa um arquivo de uma URL para o caminho especificado
+async fn download_file(url: &str, path: &Path) -> Result<()> {
+    log::info!("[Embeddings] Downloading: {} -> {:?}", url, path);
+    
+    let client = reqwest::Client::builder()
+        .timeout(std::time::Duration::from_secs(300)) // 5 min timeout
+        .build()?;
+    
+    let response = client.get(url).send().await?;
+    
+    if !response.status().is_success() {
+        return Err(anyhow!("Download failed with status: {}", response.status()));
+    }
+    
+    let bytes = response.bytes().await?;
+    
+    // Criar diretório pai se não existir
+    if let Some(parent) = path.parent() {
+        std::fs::create_dir_all(parent)?;
+    }
+    
+    std::fs::write(path, bytes)?;
+    log::info!("[Embeddings] Downloaded successfully: {:?}", path);
+    
+    Ok(())
+}
+
+/// Baixa e extrai a biblioteca ONNX Runtime
+#[cfg(target_os = "windows")]
+async fn ensure_ort_library(app_data_dir: &Path) -> Result<()> {
+    let ort_dir = app_data_dir.join("ort");
+    let dll_path = ort_dir.join("onnxruntime.dll");
+    
+    if dll_path.exists() {
+        log::info!("[Embeddings] ONNX Runtime library already exists");
+        return Ok(());
+    }
+    
+    log::info!("[Embeddings] Downloading ONNX Runtime library...");
+    
+    // Criar diretório
+    std::fs::create_dir_all(&ort_dir)?;
+    
+    // Baixar arquivo zip
+    let zip_path = ort_dir.join("onnxruntime.zip");
+    download_file(ORT_DLL_URL, &zip_path).await?;
+    
+    // Extrair DLL do zip
+    log::info!("[Embeddings] Extracting ONNX Runtime library...");
+    
+    let file = std::fs::File::open(&zip_path)?;
+    let mut archive = zip::ZipArchive::new(file)?;
+    
+    // Procurar pela DLL dentro do zip
+    for i in 0..archive.len() {
+        let mut entry = archive.by_index(i)?;
+        let name = entry.name().to_string();
+        
+        if name.ends_with("onnxruntime.dll") {
+            let mut outfile = std::fs::File::create(&dll_path)?;
+            std::io::copy(&mut entry, &mut outfile)?;
+            log::info!("[Embeddings] Extracted onnxruntime.dll");
+            break;
+        }
+    }
+    
+    // Remover arquivo zip
+    let _ = std::fs::remove_file(&zip_path);
+    
+    if !dll_path.exists() {
+        return Err(anyhow!("Failed to extract onnxruntime.dll from archive"));
+    }
+    
+    Ok(())
+}
+
+#[cfg(not(target_os = "windows"))]
+async fn ensure_ort_library(_app_data_dir: &Path) -> Result<()> {
+    // Em outros sistemas, assumimos que a biblioteca está no sistema
+    log::info!("[Embeddings] Using system ONNX Runtime library");
+    Ok(())
+}
+
+/// Garante que os arquivos do modelo existem, baixando se necessário
+pub async fn ensure_model_files(app_data_dir: &Path) -> Result<(std::path::PathBuf, std::path::PathBuf)> {
+    let models_dir = app_data_dir.join("models");
+    let model_path = models_dir.join("all-MiniLM-L6-v2.onnx");
+    let tokenizer_path = models_dir.join("tokenizer.json");
+    
+    // Criar diretório de modelos
+    std::fs::create_dir_all(&models_dir)?;
+    
+    // Baixar biblioteca ONNX Runtime se necessário (apenas Windows)
+    ensure_ort_library(app_data_dir).await?;
+    
+    // Inicializar ort com o caminho da DLL
+    init_ort_runtime(app_data_dir)?;
+    
+    // Baixar modelo se não existir
+    if !model_path.exists() {
+        log::info!("[Embeddings] Model not found, downloading...");
+        download_file(MODEL_URL, &model_path).await?;
+    }
+    
+    // Baixar tokenizer se não existir
+    if !tokenizer_path.exists() {
+        log::info!("[Embeddings] Tokenizer not found, downloading...");
+        download_file(TOKENIZER_URL, &tokenizer_path).await?;
+    }
+    
+    Ok((model_path, tokenizer_path))
+}
+
+/// Verifica se o modelo está disponível
+pub fn is_model_available(app_data_dir: &Path) -> bool {
+    let models_dir = app_data_dir.join("models");
+    let model_path = models_dir.join("all-MiniLM-L6-v2.onnx");
+    let tokenizer_path = models_dir.join("tokenizer.json");
+    
+    model_path.exists() && tokenizer_path.exists()
+}
+
+/// Obtém ou inicializa o modelo global de embeddings
+pub fn get_or_init_model(app_data_dir: &Path) -> Result<Arc<Mutex<EmbeddingModel>>> {
+    // Inicializar ort com o caminho da DLL antes de criar o modelo
+    init_ort_runtime(app_data_dir)?;
+    
+    let result = EMBEDDING_MODEL.get_or_init(|| {
+        let model_path = app_data_dir.join("models").join("all-MiniLM-L6-v2.onnx");
+        let tokenizer_path = app_data_dir.join("models").join("tokenizer.json");
+        
+        match EmbeddingModel::new(
+            model_path.to_str().unwrap_or(""),
+            tokenizer_path.to_str().unwrap_or("")
+        ) {
+            Ok(model) => Ok(Arc::new(Mutex::new(model))),
+            Err(e) => Err(format!("Failed to load embedding model: {}", e))
+        }
+    });
+    
+    match result {
+        Ok(model) => Ok(model.clone()),
+        Err(e) => Err(anyhow!("{}", e))
+    }
+}
+
+/// Calcula scores de relevância para múltiplos textos em relação a uma query
+pub fn rank_by_relevance(
+    model: &mut EmbeddingModel,
+    query: &str,
+    texts: &[&str],
+) -> Result<Vec<(usize, f32)>> {
+    let query_embedding = model.embed(query)?;
+    
+    let mut scores: Vec<(usize, f32)> = Vec::with_capacity(texts.len());
+    for (idx, text) in texts.iter().enumerate() {
+        let text_embedding = model.embed(text).unwrap_or_else(|_| vec![0.0; EMBEDDING_DIM]);
+        let score = cosine_similarity(&query_embedding, &text_embedding);
+        scores.push((idx, score));
+    }
+    
+    // Ordenar por score decrescente
+    scores.sort_by(|a, b| b.1.partial_cmp(&a.1).unwrap_or(std::cmp::Ordering::Equal));
+    
+    Ok(scores)
+}
+
+/// Poda o contexto mantendo apenas os parágrafos mais relevantes
+/// 
+/// Argumentos:
+/// - model: Modelo de embeddings
+/// - query: Query do usuário
+/// - context: Contexto completo (texto separado por parágrafos)
+/// - max_tokens: Número máximo de tokens (aproximado por palavras)
+/// - min_score: Score mínimo de relevância (0.0 a 1.0)
+/// 
+/// Retorna: Contexto podado com os parágrafos mais relevantes
+pub fn prune_context(
+    model: &mut EmbeddingModel,
+    query: &str,
+    context: &str,
+    max_tokens: usize,
+    min_score: f32,
+) -> Result<String> {
+    // Dividir contexto em parágrafos
+    let paragraphs: Vec<&str> = context
+        .split("\n\n")
+        .map(|p| p.trim())
+        .filter(|p| !p.is_empty() && p.len() > 20) // Filtrar parágrafos muito curtos
+        .collect();
+    
+    if paragraphs.is_empty() {
+        return Ok(context.to_string());
+    }
+    
+    // Calcular embedding da query
+    let query_embedding = model.embed(query)?;
+    
+    // Calcular scores para cada parágrafo
+    let mut scored_paragraphs: Vec<(f32, &str, usize)> = Vec::with_capacity(paragraphs.len());
+    for (idx, &p) in paragraphs.iter().enumerate() {
+        let embedding = model.embed(p).unwrap_or_else(|_| vec![0.0; EMBEDDING_DIM]);
+        let score = cosine_similarity(&query_embedding, &embedding);
+        scored_paragraphs.push((score, p, idx));
+    }
+    
+    // Ordenar por score decrescente
+    scored_paragraphs.sort_by(|a, b| b.0.partial_cmp(&a.0).unwrap_or(std::cmp::Ordering::Equal));
+    
+    // Filtrar por score mínimo
+    scored_paragraphs.retain(|(score, _, _)| *score >= min_score);
+    
+    // Selecionar parágrafos até atingir max_tokens
+    let mut result = Vec::new();
+    let mut total_tokens = 0;
+    
+    for (score, paragraph, original_idx) in scored_paragraphs {
+        let paragraph_tokens = paragraph.split_whitespace().count();
+        
+        if total_tokens + paragraph_tokens > max_tokens {
+            // Se ainda não temos nenhum parágrafo, incluir o primeiro mesmo que exceda
+            if result.is_empty() {
+                result.push((original_idx, paragraph));
+            }
+            break;
+        }
+        
+        result.push((original_idx, paragraph));
+        total_tokens += paragraph_tokens;
+    }
+    
+    // Ordenar pelo índice original para manter a ordem do contexto
+    result.sort_by_key(|(idx, _)| *idx);
+    
+    // Reconstruir contexto
+    let pruned: Vec<&str> = result.into_iter().map(|(_, p)| p).collect();
+    
+    log::info!(
+        "[Embeddings] Context pruned: {} paragraphs -> {} paragraphs, {} tokens",
+        paragraphs.len(),
+        pruned.len(),
+        total_tokens
+    );
+    
+    Ok(pruned.join("\n\n"))
+}
+
+/// Versão simplificada de poda usando apenas BM25-like (sem embeddings)
+/// Útil quando o modelo não está disponível
+pub fn prune_context_bm25(
+    query: &str,
+    context: &str,
+    max_tokens: usize,
+) -> String {
+    let paragraphs: Vec<&str> = context
+        .split("\n\n")
+        .map(|p| p.trim())
+        .filter(|p| !p.is_empty() && p.len() > 20)
+        .collect();
+    
+    if paragraphs.is_empty() {
+        return context.to_string();
+    }
+    
+    let query_lower = query.to_lowercase();
+    let query_terms: Vec<&str> = query_lower
+        .split_whitespace()
+        .filter(|w| w.len() > 2)
+        .collect();
+    
+    // Calcular score BM25-like simples
+    let mut scored: Vec<(f32, &str, usize)> = paragraphs.iter()
+        .enumerate()
+        .map(|(idx, &p)| {
+            let p_lower = p.to_lowercase();
+            let mut score = 0.0f32;
+            
+            for term in &query_terms {
+                let count = p_lower.matches(term).count();
+                if count > 0 {
+                    // TF com saturação logarítmica
+                    score += (1.0 + (count as f32).ln()) * (1.0 / (1.0 + query_terms.len() as f32));
+                }
+            }
+            
+            (score, p, idx)
+        })
+        .collect();
+    
+    scored.sort_by(|a, b| b.0.partial_cmp(&a.0).unwrap_or(std::cmp::Ordering::Equal));
+    
+    let mut result = Vec::new();
+    let mut total_tokens = 0;
+    
+    for (_, paragraph, original_idx) in scored {
+        let paragraph_tokens = paragraph.split_whitespace().count();
+        
+        if total_tokens + paragraph_tokens > max_tokens {
+            if result.is_empty() {
+                result.push((original_idx, paragraph));
+            }
+            break;
+        }
+        
+        result.push((original_idx, paragraph));
+        total_tokens += paragraph_tokens;
+    }
+    
+    result.sort_by_key(|(idx, _)| *idx);
+    
+    let pruned: Vec<&str> = result.into_iter().map(|(_, p)| p).collect();
+    pruned.join("\n\n")
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    
+    #[test]
+    fn test_cosine_similarity() {
+        let a = vec![1.0, 0.0, 0.0];
+        let b = vec![1.0, 0.0, 0.0];
+        assert!((cosine_similarity(&a, &b) - 1.0).abs() < 0.001);
+        
+        let c = vec![0.0, 1.0, 0.0];
+        assert!((cosine_similarity(&a, &c) - 0.0).abs() < 0.001);
+        
+        let d = vec![-1.0, 0.0, 0.0];
+        assert!((cosine_similarity(&a, &d) - (-1.0)).abs() < 0.001);
+    }
+}
+

src-tauri/src/lib.rs

@@ -21,6 +21,7 @@ mod sources_config;
 mod system_monitor;
 mod intent_classifier;
 mod db;
+mod embeddings;
 
 use web_scraper::{
     ScrapedContent,
@@ -114,6 +115,8 @@ struct SessionSummary {
     updated_at: DateTime<Utc>,
     preview: String,
     platform: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    match_count: Option<usize>,
 }
 
 #[derive(serde::Serialize)]
@@ -395,6 +398,57 @@ fn save_chat_session(
     fs::rename(&temp_path, &file_path)
         .map_err(|e| format!("Failed to rename temp file to session file: {}", e))?;
     
+    // Também salvar no SQLite (sistema novo) para melhor performance e paginação
+    // Se falhar, apenas logar erro mas não falhar a operação (compatibilidade)
+    use db::Database;
+    match Database::new(&app_handle) {
+        Ok(db) => {
+            // Criar/atualizar sessão no SQLite
+            let db_session = db::ChatSession {
+                id: session.id.clone(),
+                title: session.title.clone(),
+                emoji: "💬".to_string(), // Emoji padrão
+                created_at: session.created_at,
+                updated_at: session.updated_at,
+            };
+            
+            if let Err(e) = db.save_session(&db_session) {
+                log::warn!("Failed to save session to SQLite (continuing with JSON only): {}", e);
+            } else {
+                // Converter Message para ChatMessage e salvar no SQLite
+                // Preservar ordem usando timestamps incrementais baseados no índice
+                let chat_messages: Vec<db::ChatMessage> = session.messages.iter().enumerate().map(|(idx, msg)| {
+                    let metadata_str = msg.metadata.as_ref()
+                        .and_then(|m| serde_json::to_string(m).ok());
+                    
+                    // Criar timestamp incremental para preservar ordem das mensagens
+                    // Usar created_at da sessão como base e adicionar segundos baseados no índice
+                    // Isso garante que a ordem seja mantida quando ordenado por created_at ASC
+                    let base_time = session.created_at;
+                    let msg_created_at = base_time + chrono::Duration::seconds(idx as i64);
+                    
+                    db::ChatMessage {
+                        id: None,
+                        session_id: session.id.clone(),
+                        role: msg.role.clone(),
+                        content: msg.content.clone(),
+                        metadata: metadata_str,
+                        created_at: msg_created_at,
+                    }
+                }).collect();
+                
+                if let Err(e) = db.save_messages_batch(&session.id, &chat_messages) {
+                    log::warn!("Failed to save messages to SQLite (continuing with JSON only): {}", e);
+                } else {
+                    log::debug!("Successfully saved {} messages to SQLite for session {}", chat_messages.len(), session.id);
+                }
+            }
+        }
+        Err(e) => {
+            log::debug!("Failed to open database for saving (JSON saved successfully): {}", e);
+        }
+    }
+    
     // Lock é liberado automaticamente quando _guard sai de escopo
     Ok(())
 }
@@ -407,7 +461,7 @@ fn search_chat_sessions(app_handle: AppHandle, query: String, limit: Option<usiz
         .map_err(|e| format!("Failed to open database: {}", e))?;
     
     let search_limit = limit.unwrap_or(50);
-    let sessions = db.search_sessions(&query, search_limit)
+    let search_results = db.search_sessions(&query, search_limit)
         .map_err(|e| format!("Search failed: {}", e))?;
     
     // Validar existência de cada sessão antes de retornar
@@ -415,7 +469,9 @@ fn search_chat_sessions(app_handle: AppHandle, query: String, limit: Option<usiz
     let mut summaries = Vec::new();
     let mut orphan_count = 0;
     
-    for session in sessions {
+    for search_result in search_results {
+        let session = search_result.session;
+        let match_count = search_result.match_count;
         // Verificar se sessão existe no SQLite (já temos)
         let exists_in_sqlite = db.get_session(&session.id)
             .ok()
@@ -465,6 +521,7 @@ fn search_chat_sessions(app_handle: AppHandle, query: String, limit: Option<usiz
             updated_at: session.updated_at, // Já é DateTime<Utc>
             preview,
             platform: String::new(), // Platform não está no SQLite ainda
+            match_count: Some(match_count as usize),
         });
     }
     
@@ -514,6 +571,7 @@ fn load_chat_sessions(app_handle: AppHandle) -> Result<Vec<SessionSummary>, Stri
                             updated_at: session.updated_at,
                             preview: last_msg,
                             platform: session.platform,
+                            match_count: None,
                         });
                     }
                 }
@@ -600,6 +658,299 @@ fn load_chat_history(app_handle: AppHandle, id: String) -> Result<Vec<Message>,
     Ok(session.messages)
 }
 
+/// Resultado de carregamento paginado de histórico
+#[derive(serde::Serialize)]
+struct PaginatedHistory {
+    messages: Vec<Message>,
+    total_count: usize,
+    has_more: bool,
+}
+
+/// Carrega histórico de chat com paginação (lazy loading)
+/// 
+/// Parâmetros:
+/// - id: ID da sessão
+/// - limit: número máximo de mensagens a retornar (default: 20)
+/// - offset: número de mensagens a pular do final (default: 0)
+#[command]
+fn load_chat_history_paginated(
+    app_handle: AppHandle,
+    id: String,
+    limit: Option<usize>,
+    offset: Option<usize>,
+) -> Result<PaginatedHistory, String> {
+    use db::Database;
+    
+    let limit = limit.unwrap_or(20);
+    let offset = offset.unwrap_or(0);
+    
+    match Database::new(&app_handle) {
+        Ok(db) => {
+            match db.get_messages_paginated(&id, limit, offset) {
+                Ok((messages, total_count, has_more)) => {
+                    // Se SQLite retornou 0 mensagens, tentar fallback para JSON (sistema legado)
+                    if total_count == 0 {
+                        log::debug!("No messages in SQLite for session {}, trying JSON fallback", id);
+                        
+                        // Tentar carregar do JSON
+                        let chats_dir = match get_chats_dir(&app_handle) {
+                            Ok(dir) => dir,
+                            Err(e) => {
+                                log::debug!("Failed to get chats dir for JSON fallback: {}", e);
+                                // Retornar vazio se não conseguir acessar diretório
+                                return Ok(PaginatedHistory {
+                                    messages: Vec::new(),
+                                    total_count: 0,
+                                    has_more: false,
+                                });
+                            }
+                        };
+                        
+                        let file_path = chats_dir.join(format!("{}.json", id));
+                        if file_path.exists() {
+                            match fs::read_to_string(&file_path) {
+                                Ok(content) => {
+                                    match serde_json::from_str::<ChatSession>(&content) {
+                                        Ok(session) => {
+                                            let all_messages = session.messages;
+                                            let total = all_messages.len();
+                                            
+                                            if total == 0 {
+                                                return Ok(PaginatedHistory {
+                                                    messages: Vec::new(),
+                                                    total_count: 0,
+                                                    has_more: false,
+                                                });
+                                            }
+                                            
+                                            // Aplicar paginação em memória (simular comportamento do SQLite)
+                                            // offset=0 significa últimas N mensagens
+                                            // offset>0 significa mensagens antes das últimas N
+                                            let start_idx = if offset + limit <= total {
+                                                total - offset - limit
+                                            } else {
+                                                0
+                                            };
+                                            
+                                            let end_idx = std::cmp::min(start_idx + limit, total);
+                                            let paginated_messages: Vec<Message> = all_messages
+                                                .into_iter()
+                                                .skip(start_idx)
+                                                .take(end_idx - start_idx)
+                                                .collect();
+                                            
+                                            let has_more = offset + paginated_messages.len() < total;
+                                            
+                                            log::info!(
+                                                "Loaded {} messages (offset: {}, total: {}, has_more: {}) from JSON fallback for session {}",
+                                                paginated_messages.len(), offset, total, has_more, id
+                                            );
+                                            
+                                            return Ok(PaginatedHistory {
+                                                messages: paginated_messages,
+                                                total_count: total,
+                                                has_more,
+                                            });
+                                        }
+                                        Err(e) => {
+                                            log::debug!("Failed to parse JSON session: {}", e);
+                                        }
+                                    }
+                                }
+                                Err(e) => {
+                                    log::debug!("Failed to read JSON file: {}", e);
+                                }
+                            }
+                        }
+                        
+                        // Se chegou aqui, não encontrou mensagens nem no SQLite nem no JSON
+                        return Ok(PaginatedHistory {
+                            messages: Vec::new(),
+                            total_count: 0,
+                            has_more: false,
+                        });
+                    }
+                    
+                    // Converter ChatMessage para Message
+                    let result: Vec<Message> = messages.into_iter().map(|msg| {
+                        let role = if msg.role == "user" {
+                            "user"
+                        } else if msg.role == "assistant" {
+                            "assistant"
+                        } else {
+                            "system"
+                        };
+                        
+                        let metadata = msg.metadata.and_then(|m| {
+                            serde_json::from_str::<serde_json::Value>(&m).ok()
+                        });
+                        
+                        let metadata_value = metadata
+                            .and_then(|m| {
+                                if m.is_object() && !m.as_object().unwrap().is_empty() {
+                                    Some(m)
+                                } else {
+                                    None
+                                }
+                            });
+                        
+                        Message {
+                            role: role.to_string(),
+                            content: msg.content,
+                            metadata: metadata_value,
+                        }
+                    }).collect();
+                    
+                    log::info!(
+                        "Loaded {} messages (offset: {}, total: {}, has_more: {}) from SQLite for session {}",
+                        result.len(), offset, total_count, has_more, id
+                    );
+                    
+                    Ok(PaginatedHistory {
+                        messages: result,
+                        total_count,
+                        has_more,
+                    })
+                }
+                Err(e) => {
+                    log::debug!("SQLite query failed for session {}: {}, trying JSON fallback", id, e);
+                    
+                    // Fallback para JSON em caso de erro também
+                    let chats_dir = match get_chats_dir(&app_handle) {
+                        Ok(dir) => dir,
+                        Err(_) => {
+                            return Err(format!("Failed to load paginated history: {}", e));
+                        }
+                    };
+                    
+                    let file_path = chats_dir.join(format!("{}.json", id));
+                    if file_path.exists() {
+                        match fs::read_to_string(&file_path) {
+                            Ok(content) => {
+                                match serde_json::from_str::<ChatSession>(&content) {
+                                    Ok(session) => {
+                                        let all_messages = session.messages;
+                                        let total = all_messages.len();
+                                        
+                                        if total == 0 {
+                                            return Ok(PaginatedHistory {
+                                                messages: Vec::new(),
+                                                total_count: 0,
+                                                has_more: false,
+                                            });
+                                        }
+                                        
+                                        let start_idx = if offset + limit <= total {
+                                            total - offset - limit
+                                        } else {
+                                            0
+                                        };
+                                        
+                                        let end_idx = std::cmp::min(start_idx + limit, total);
+                                        let paginated_messages: Vec<Message> = all_messages
+                                            .into_iter()
+                                            .skip(start_idx)
+                                            .take(end_idx - start_idx)
+                                            .collect();
+                                        
+                                        let has_more = offset + paginated_messages.len() < total;
+                                        
+                                        log::info!(
+                                            "Loaded {} messages (offset: {}, total: {}, has_more: {}) from JSON fallback (error case) for session {}",
+                                            paginated_messages.len(), offset, total, has_more, id
+                                        );
+                                        
+                                        return Ok(PaginatedHistory {
+                                            messages: paginated_messages,
+                                            total_count: total,
+                                            has_more,
+                                        });
+                                    }
+                                    Err(e2) => {
+                                        return Err(format!("Failed to load paginated history: {} (JSON parse error: {})", e, e2));
+                                    }
+                                }
+                            }
+                            Err(e2) => {
+                                return Err(format!("Failed to load paginated history: {} (JSON read error: {})", e, e2));
+                            }
+                        }
+                    }
+                    
+                    Err(format!("Failed to load paginated history: {}", e))
+                }
+            }
+        }
+        Err(e) => {
+            log::debug!("Failed to open database: {}, trying JSON fallback", e);
+            
+            // Fallback para JSON se não conseguir abrir banco
+            let chats_dir = match get_chats_dir(&app_handle) {
+                Ok(dir) => dir,
+                Err(e2) => {
+                    return Err(format!("Failed to open database: {} (chats dir error: {})", e, e2));
+                }
+            };
+            
+            let file_path = chats_dir.join(format!("{}.json", id));
+            if file_path.exists() {
+                match fs::read_to_string(&file_path) {
+                    Ok(content) => {
+                        match serde_json::from_str::<ChatSession>(&content) {
+                            Ok(session) => {
+                                let all_messages = session.messages;
+                                let total = all_messages.len();
+                                
+                                if total == 0 {
+                                    return Ok(PaginatedHistory {
+                                        messages: Vec::new(),
+                                        total_count: 0,
+                                        has_more: false,
+                                    });
+                                }
+                                
+                                let start_idx = if offset + limit <= total {
+                                    total - offset - limit
+                                } else {
+                                    0
+                                };
+                                
+                                let end_idx = std::cmp::min(start_idx + limit, total);
+                                let paginated_messages: Vec<Message> = all_messages
+                                    .into_iter()
+                                    .skip(start_idx)
+                                    .take(end_idx - start_idx)
+                                    .collect();
+                                
+                                let has_more = offset + paginated_messages.len() < total;
+                                
+                                log::info!(
+                                    "Loaded {} messages (offset: {}, total: {}, has_more: {}) from JSON fallback (db open error) for session {}",
+                                    paginated_messages.len(), offset, total, has_more, id
+                                );
+                                
+                                return Ok(PaginatedHistory {
+                                    messages: paginated_messages,
+                                    total_count: total,
+                                    has_more,
+                                });
+                            }
+                            Err(e2) => {
+                                return Err(format!("Failed to open database: {} (JSON parse error: {})", e, e2));
+                            }
+                        }
+                    }
+                    Err(e2) => {
+                        return Err(format!("Failed to open database: {} (JSON read error: {})", e, e2));
+                    }
+                }
+            }
+            
+            Err(format!("Failed to open database: {}", e))
+        }
+    }
+}
+
 #[command]
 fn delete_chat_session(app_handle: AppHandle, id: String) -> Result<(), String> {
     use db::Database;
@@ -2978,12 +3329,18 @@ async fn chat_stream(
         return Err(error_msg);
     }
     
-    // 5. Processar stream e emitir tokens
+    // 5. Processar stream e emitir tokens COM BUFFERING
-    // IMPORTANTE: O Ollama envia tokens INCREMENTAIS (cada chunk contém apenas o novo conteúdo)
+    // OTIMIZAÇÃO: Acumular tokens e emitir em batches para reduzir overhead da bridge
     let mut stream = response.bytes_stream();
     let mut buffer = String::new();
     let mut full_content = String::new();
     
+    // Buffer de tokens para reduzir eventos na bridge
+    let mut token_buffer = String::new();
+    let mut last_emit = std::time::Instant::now();
+    const EMIT_INTERVAL_MS: u64 = 16; // ~60fps para sincronizar com RAF do frontend
+    const MAX_BUFFER_CHARS: usize = 50; // Emitir quando buffer tiver ~50 chars
+    
     while let Some(chunk_result) = stream.next().await {
         let chunk = chunk_result.map_err(|e| format!("Stream error: {}", e))?;
         let chunk_str = String::from_utf8_lossy(&chunk);
@@ -3007,27 +3364,40 @@ async fn chat_stream(
                     // Extrair conteúdo do chunk (Ollama envia tokens incrementais)
                     if let Some(message) = json.get("message") {
                         if let Some(content) = message.get("content").and_then(|c| c.as_str()) {
-                            // O Ollama envia apenas o NOVO conteúdo em cada chunk, não o acumulado
-                            // Então podemos emitir diretamente
                             if !content.is_empty() {
                                 full_content.push_str(content);
+                                token_buffer.push_str(content);
                                 
-                                // Emitir token para frontend
+                                // Emitir buffer quando: tempo >= 16ms OU buffer >= 50 chars
+                                let elapsed = last_emit.elapsed().as_millis() as u64;
+                                if elapsed >= EMIT_INTERVAL_MS || token_buffer.len() >= MAX_BUFFER_CHARS {
                                     let token_event = ChatTokenEvent {
                                         session_id: session_id.clone(),
-                                    content: content.to_string(),
+                                        content: std::mem::take(&mut token_buffer),
                                         done: false,
                                     };
                                     
                                     if let Err(e) = window.emit("chat-token", &token_event) {
                                         log::warn!("Erro ao emitir token: {}", e);
                                     }
+                                    last_emit = std::time::Instant::now();
+                                }
                             }
                         }
                     }
                     
                     // Verificar se stream terminou
                     if is_done {
+                        // Flush do buffer residual antes de finalizar
+                        if !token_buffer.is_empty() {
+                            let flush_event = ChatTokenEvent {
+                                session_id: session_id.clone(),
+                                content: std::mem::take(&mut token_buffer),
+                                done: false,
+                            };
+                            let _ = window.emit("chat-token", &flush_event);
+                        }
+                        
                         // Emitir evento final
                         let final_event = ChatTokenEvent {
                             session_id: session_id.clone(),
@@ -3121,6 +3491,113 @@ async fn chat_stream(
     Ok(session_id)
 }
 
+// ============== COMANDOS DE EMBEDDINGS ==============
+
+/// Baixa o modelo de embeddings se não existir
+#[command]
+async fn download_embedding_model(app_handle: AppHandle) -> Result<bool, String> {
+    let app_data_dir = app_handle.path()
+        .app_data_dir()
+        .map_err(|e| format!("Failed to get app data dir: {}", e))?;
+    
+    match embeddings::ensure_model_files(&app_data_dir).await {
+        Ok(_) => {
+            log::info!("[Embeddings] Model files ready");
+            Ok(true)
+        }
+        Err(e) => {
+            log::error!("[Embeddings] Failed to ensure model files: {}", e);
+            Err(format!("Failed to download model: {}", e))
+        }
+    }
+}
+
+/// Verifica se o modelo de embeddings está disponível
+#[command]
+fn is_embedding_model_available(app_handle: AppHandle) -> Result<bool, String> {
+    let app_data_dir = app_handle.path()
+        .app_data_dir()
+        .map_err(|e| format!("Failed to get app data dir: {}", e))?;
+    
+    Ok(embeddings::is_model_available(&app_data_dir))
+}
+
+/// Calcula scores de relevância para textos em relação a uma query
+#[command]
+fn calculate_relevance_scores(
+    app_handle: AppHandle,
+    query: String,
+    texts: Vec<String>,
+) -> Result<Vec<(usize, f32)>, String> {
+    let app_data_dir = app_handle.path()
+        .app_data_dir()
+        .map_err(|e| format!("Failed to get app data dir: {}", e))?;
+    
+    let model_arc = embeddings::get_or_init_model(&app_data_dir)
+        .map_err(|e| format!("Failed to load model: {}", e))?;
+    
+    let mut model = model_arc.lock()
+        .map_err(|e| format!("Failed to lock model: {}", e))?;
+    
+    let text_refs: Vec<&str> = texts.iter().map(|s| s.as_str()).collect();
+    
+    embeddings::rank_by_relevance(&mut model, &query, &text_refs)
+        .map_err(|e| format!("Failed to calculate relevance: {}", e))
+}
+
+/// Gera embedding para um texto
+#[command]
+fn generate_embedding(
+    app_handle: AppHandle,
+    text: String,
+) -> Result<Vec<f32>, String> {
+    let app_data_dir = app_handle.path()
+        .app_data_dir()
+        .map_err(|e| format!("Failed to get app data dir: {}", e))?;
+    
+    let model_arc = embeddings::get_or_init_model(&app_data_dir)
+        .map_err(|e| format!("Failed to load model: {}", e))?;
+    
+    let mut model = model_arc.lock()
+        .map_err(|e| format!("Failed to lock model: {}", e))?;
+    
+    model.embed(&text)
+        .map_err(|e| format!("Failed to generate embedding: {}", e))
+}
+
+/// Poda o contexto mantendo apenas os parágrafos mais relevantes
+#[command]
+fn prune_context(
+    app_handle: AppHandle,
+    query: String,
+    context: String,
+    max_tokens: Option<usize>,
+    min_score: Option<f32>,
+) -> Result<String, String> {
+    let max_tokens = max_tokens.unwrap_or(2000);
+    let min_score = min_score.unwrap_or(0.3);
+    
+    let app_data_dir = app_handle.path()
+        .app_data_dir()
+        .map_err(|e| format!("Failed to get app data dir: {}", e))?;
+    
+    // Tentar usar embeddings se modelo disponível
+    if embeddings::is_model_available(&app_data_dir) {
+        let model_arc = embeddings::get_or_init_model(&app_data_dir)
+            .map_err(|e| format!("Failed to load model: {}", e))?;
+        
+        let mut model = model_arc.lock()
+            .map_err(|e| format!("Failed to lock model: {}", e))?;
+        
+        embeddings::prune_context(&mut model, &query, &context, max_tokens, min_score)
+            .map_err(|e| format!("Failed to prune context: {}", e))
+    } else {
+        // Fallback para BM25-like
+        log::info!("[PruneContext] Using BM25 fallback (embedding model not available)");
+        Ok(embeddings::prune_context_bm25(&query, &context, max_tokens))
+    }
+}
+
 #[cfg_attr(mobile, tauri::mobile_entry_point)]
 pub fn run() {
   tauri::Builder::default()
@@ -3219,6 +3696,7 @@ pub fn run() {
         load_chat_sessions,
         search_chat_sessions,
         load_chat_history,
+        load_chat_history_paginated,
         delete_chat_session,
         cleanup_orphan_sessions,
         load_mcp_config,
@@ -3261,7 +3739,13 @@ pub fn run() {
         get_downloaded_installer_path,
         check_ollama_full,
         auto_start_ollama,
-        classify_intent
+        classify_intent,
+        // Embeddings commands
+        download_embedding_model,
+        is_embedding_model_available,
+        calculate_relevance_scores,
+        generate_embedding,
+        prune_context
     ])
     .manage(Arc::new(Mutex::new(HashMap::<String, McpProcessHandle>::new())) as McpProcessMap)
     .run(tauri::generate_context!())

src-tauri/src/scheduler_loop.rs

@@ -85,14 +85,13 @@ pub async fn reload_scheduled_tasks(
                         return;
                     }
                     
-                    // Obter browser - precisa acessar via app_handle
+                    // Obter browser - usando lazy initialization global
                     let browser_arc = {
-                        // Criar browser diretamente se necessário
+                        use crate::web_scraper::get_or_create_browser;
-                        use crate::web_scraper::create_browser;
+                        match get_or_create_browser() {
-                        match create_browser() {
+                            Ok(b) => b,
-                            Ok(b) => Arc::new(b),
                             Err(e) => {
-                                log::error!("Erro ao criar browser para task {}: {}", task_id, e);
+                                log::error!("Erro ao obter browser para task {}: {}", task_id, e);
                                 return;
                             }
                         }

src-tauri/src/web_scraper.rs

@@ -2,7 +2,7 @@ use anyhow::Result;
 use headless_chrome::{Browser, LaunchOptions, Tab};
 use reqwest::header::USER_AGENT;
 use scraper::{Html, Selector};
-use std::sync::Arc;
+use std::sync::{Arc, Mutex, OnceLock};
 use std::time::Duration;
 use url::Url;
 use rand::Rng;
@@ -10,6 +10,37 @@ use tokio::sync::Semaphore;
 use regex::Regex;
 use std::time::Instant;
 
+/// Lazy-initialized global browser instance
+/// Evita criar o browser no startup, economizando ~500MB de RAM até ser necessário
+static LAZY_BROWSER: OnceLock<Mutex<Option<Arc<Browser>>>> = OnceLock::new();
+
+/// Obtém ou cria a instância global do browser (lazy initialization)
+pub fn get_or_create_browser() -> Result<Arc<Browser>> {
+    let mutex = LAZY_BROWSER.get_or_init(|| Mutex::new(None));
+    let mut guard = mutex.lock().map_err(|e| anyhow::anyhow!("Browser mutex poisoned: {}", e))?;
+    
+    if guard.is_none() {
+        log::info!("[LazyBrowser] Initializing headless browser on first use...");
+        let browser = create_browser()?;
+        *guard = Some(Arc::new(browser));
+        log::info!("[LazyBrowser] Browser initialized successfully");
+    }
+    
+    Ok(guard.as_ref().unwrap().clone())
+}
+
+/// Limpa a instância do browser (para liberar memória quando não em uso)
+pub fn clear_browser() {
+    if let Some(mutex) = LAZY_BROWSER.get() {
+        if let Ok(mut guard) = mutex.lock() {
+            if guard.is_some() {
+                log::info!("[LazyBrowser] Clearing browser instance to free memory");
+                *guard = None;
+            }
+        }
+    }
+}
+
 /// Resultado da extração de conteúdo de uma URL
 #[derive(serde::Serialize, serde::Deserialize, Clone, Debug)]
 pub struct ScrapedContent {
@@ -1302,7 +1333,7 @@ pub async fn search_and_scrape_with_config(
     if connection_closed && !failed_urls.is_empty() {
         let retry_concurrency = std::cmp::min(3, config.max_concurrent_tabs.max(1));
         let semaphore = Arc::new(Semaphore::new(retry_concurrency));
-        let browser_new = Arc::new(create_browser()?);
+        let browser_new = get_or_create_browser()?;
         let mut retry_handles = Vec::new();
         for url in failed_urls.clone() {
             let browser_clone = browser_new.clone();
@@ -1341,11 +1372,79 @@ pub async fn search_and_scrape_with_config(
     Ok(results)
 }
 
-/// Busca e extrai conteúdo de uma única URL
+/// Scraping estático usando apenas reqwest (sem headless browser)
+/// Muito mais rápido (~100ms vs ~3s) e consome menos RAM
+/// Retorna None se o conteúdo for insuficiente (SPA/JavaScript-heavy)
+pub async fn scrape_url_static(url: &str) -> Result<Option<ScrapedContent>> {
+    let client = reqwest::Client::builder()
+        .timeout(Duration::from_secs(8))
+        .redirect(reqwest::redirect::Policy::limited(5))
+        .build()?;
+    
+    let user_agent = get_random_user_agent();
+    let start_time = Instant::now();
+    
+    log::debug!("[StaticScrape] Fetching: {}", url);
+    
+    let response = match client
+        .get(url)
+        .header(USER_AGENT, user_agent)
+        .header("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8")
+        .header("Accept-Language", "pt-BR,pt;q=0.9,en-US;q=0.8,en;q=0.7")
+        .send()
+        .await
+    {
+        Ok(r) => r,
+        Err(e) => {
+            log::debug!("[StaticScrape] Request failed for {}: {}", url, e);
+            return Ok(None);
+        }
+    };
+    
+    if !response.status().is_success() {
+        log::debug!("[StaticScrape] HTTP {} for {}", response.status(), url);
+        return Ok(None);
+    }
+    
+    let html = match response.text().await {
+        Ok(t) => t,
+        Err(e) => {
+            log::debug!("[StaticScrape] Failed to read body for {}: {}", url, e);
+            return Ok(None);
+        }
+    };
+    
+    let duration = start_time.elapsed().as_millis();
+    
+    // Usar extract_paragraph_fallback existente
+    let result = extract_paragraph_fallback(url, &html);
+    
+    if let Some(ref content) = result {
+        log::info!("[StaticScrape] Success for {} ({} chars, {}ms)", 
+            url, content.content.len(), duration);
+    } else {
+        log::debug!("[StaticScrape] Insufficient content for {} ({}ms)", url, duration);
+    }
+    
+    Ok(result)
+}
+
+/// Busca e extrai conteúdo de uma única URL (híbrido: tenta estático primeiro)
 pub async fn scrape_url(
     url: &str,
     browser: Arc<Browser>,
 ) -> Result<ScrapedContent> {
+    // OTIMIZAÇÃO: Tentar scraping estático primeiro (muito mais rápido)
+    if let Ok(Some(content)) = scrape_url_static(url).await {
+        // Se conseguiu conteúdo suficiente (>500 chars), usar resultado estático
+        if content.content.len() > 500 {
+            log::info!("[ScrapeHybrid] Using static result for {} ({} chars)", url, content.content.len());
+            return Ok(content);
+        }
+    }
+    
+    // Fallback: usar headless browser para SPAs/JS-heavy pages
+    log::info!("[ScrapeHybrid] Falling back to headless for {}", url);
     let browser_clone = browser.clone();
     let url_str = url.to_string();
     tokio::task::spawn_blocking(move || {