chatbot : init

src/modules/chatbot/providers/chatbot.service.ts

@@ -0,0 +1,495 @@
+import { EntityManager } from "@mikro-orm/postgresql";
+import { BadRequestException, Injectable, Logger, NotFoundException } from "@nestjs/common";
+import { ConfigService } from "@nestjs/config";
+
+import { LangChainService } from "./langchain.service";
+import { LLMService } from "./llm.service";
+import { User } from "../../users/entities/user.entity";
+// import { UsersService } from "../../users/services/users.service";
+import { CreateChatSessionDto } from "../DTO/create-chat-session.dto";
+import { SendMessageDto } from "../DTO/send-message.dto";
+import { ChatMessage, MessageStatus, MessageType } from "../entities/chat-message.entity";
+import { ChatSession, ChatSessionStatus } from "../entities/chat-session.entity";
+import { IChatContext } from "../interfaces/chatbot.interface";
+import { ChatMessageRepository } from "../repositories/chat-message.repository";
+import { ChatSessionRepository } from "../repositories/chat-session.repository";
+
+export enum LLMProvider {
+  LANGCHAIN = "langchain",
+  GEMINI = "gemini",
+}
+
+@Injectable()
+export class ChatbotService {
+  private readonly logger = new Logger(ChatbotService.name);
+  private defaultProvider: LLMProvider;
+
+  constructor(
+    private em: EntityManager,
+    private llmService: LLMService,
+    private langChainService: LangChainService,
+    private chatSessionRepo: ChatSessionRepository,
+    private chatMessageRepo: ChatMessageRepository,
+    private configService: ConfigService,
+    // private usersService: UsersService,
+  ) {
+    // Configure default provider - LangChain for enhanced responses
+    this.defaultProvider = this.configService.get("DEFAULT_LLM_PROVIDER") === "gemini" ? LLMProvider.GEMINI : LLMProvider.LANGCHAIN;
+
+    this.logger.log(`Using ${this.defaultProvider} as default LLM provider`);
+  }
+
+  async createChatSession(userId: string, createDto: CreateChatSessionDto) {
+    const em = this.em.fork();
+    const user = await em.findOne(User, { id: userId });
+    if (!user) {
+      throw new NotFoundException("User not found");
+    }
+
+    const session = new ChatSession();
+    session.title = createDto.title;
+    session.user = user;
+    session.context = createDto.context || {};
+    session.lastMessageAt = new Date();
+
+    await em.persistAndFlush(session);
+
+    return this.mapSessionToDto(session);
+  }
+  //************************************ */
+  async getUserChatSessions(userId: string, limit = 10) {
+    const em = this.em.fork();
+    const sessions = await this.chatSessionRepo.findByUserWithMessages(userId, limit, em);
+    return sessions.map((session) => this.mapSessionToDto(session));
+  }
+  //************************************ */
+
+  async getChatSession(sessionId: string, userId: string) {
+    const em = this.em.fork();
+    const session = await em.findOne(ChatSession, { id: sessionId, user: userId }, { populate: ["messages", "messages.sender"] });
+
+    if (!session) {
+      throw new NotFoundException("Chat session not found");
+    }
+
+    return this.mapSessionToDto(session);
+  }
+  //************************************ */
+
+  async sendMessage(userId: string, sendDto: SendMessageDto, provider?: LLMProvider) {
+    const selectedProvider = provider || this.defaultProvider;
+
+    // Use LangChain by default for enhanced responses
+    if (selectedProvider === LLMProvider.LANGCHAIN) {
+      try {
+        return await this.sendMessageWithLangChain(userId, sendDto);
+      } catch (error) {
+        this.logger.error("LangChain failed, falling back to Gemini", error);
+        // Fallback to Gemini service
+        return await this.sendMessageWithGemini(userId, sendDto);
+      }
+    } else {
+      return await this.sendMessageWithGemini(userId, sendDto);
+    }
+  }
+
+  //************************************ */
+
+  private async sendMessageWithGemini(userId: string, sendDto: SendMessageDto) {
+    const em = this.em.fork();
+    const session = await em.findOne(ChatSession, { id: sendDto.sessionId, user: userId }, { populate: ["messages"] });
+
+    if (!session) {
+      throw new NotFoundException("Chat session not found");
+    }
+
+    if (session.status !== ChatSessionStatus.ACTIVE) {
+      throw new BadRequestException("Cannot send message to inactive session");
+    }
+
+    const user = await em.findOne(User, { id: userId });
+    if (!user) {
+      throw new NotFoundException("User not found");
+    }
+
+    // Create user message
+    const userMessage = new ChatMessage();
+    userMessage.content = sendDto.content;
+    userMessage.type = MessageType.USER;
+    userMessage.session = session;
+    userMessage.sender = user;
+    userMessage.responseToId = sendDto.responseToId;
+    userMessage.metadata = sendDto.metadata;
+
+    await em.persistAndFlush(userMessage);
+
+    // Update session last message time
+    await this.chatSessionRepo.updateLastMessageTime(session.id, em);
+
+    // Generate bot response asynchronously using original Gemini service
+    this.generateBotResponse(session, userMessage, userId);
+
+    return this.mapMessageToDto(userMessage);
+  }
+
+  //************************************ */
+
+  async sendMessageStream(userId: string, sendDto: SendMessageDto, provider?: LLMProvider) {
+    const selectedProvider = provider || this.defaultProvider;
+
+    // Use LangChain by default for enhanced streaming responses
+    if (selectedProvider === LLMProvider.LANGCHAIN) {
+      try {
+        return await this.sendMessageStreamWithLangChain(userId, sendDto);
+      } catch (error) {
+        this.logger.error("LangChain streaming failed, falling back to Gemini", error);
+        // Fallback to Gemini service
+        return await this.sendMessageStreamWithGemini(userId, sendDto);
+      }
+    } else {
+      return await this.sendMessageStreamWithGemini(userId, sendDto);
+    }
+  }
+
+  //************************************ */
+
+  private async sendMessageStreamWithGemini(userId: string, sendDto: SendMessageDto) {
+    const em = this.em.fork();
+    const session = await em.findOne(ChatSession, { id: sendDto.sessionId, user: userId }, { populate: ["messages"] });
+
+    if (!session) {
+      throw new NotFoundException("Chat session not found");
+    }
+
+    if (session.status !== ChatSessionStatus.ACTIVE) {
+      throw new BadRequestException("Cannot send message to inactive session");
+    }
+
+    const user = await em.findOne(User, { id: userId });
+    if (!user) {
+      throw new NotFoundException("User not found");
+    }
+
+    // Create user message
+    const userMessage = new ChatMessage();
+    userMessage.content = sendDto.content;
+    userMessage.type = MessageType.USER;
+    userMessage.session = session;
+    userMessage.sender = user;
+    userMessage.responseToId = sendDto.responseToId;
+    userMessage.metadata = sendDto.metadata;
+
+    await em.persistAndFlush(userMessage);
+
+    // Update session last message time
+    await this.chatSessionRepo.updateLastMessageTime(session.id, em);
+
+    // Get conversation history for context
+    const history = await this.chatMessageRepo.getConversationHistory(session.id, 20, em);
+
+    // Build context for LLM
+    const context: IChatContext = {
+      userId,
+      sessionId: session.id,
+      conversationHistory: history.reverse().map((msg) => ({
+        content: msg.content,
+        type: msg.type as "user" | "bot" | "system",
+        timestamp: msg.createdAt,
+        metadata: msg.metadata,
+      })),
+      userPreferences: session.context,
+    };
+
+    // Return a function that generates the stream using original LLM service
+    const streamGenerator = () => this.llmService.generateStreamResponse(sendDto.content, context);
+
+    return {
+      userMessage: this.mapMessageToDto(userMessage),
+      streamGenerator,
+    };
+  }
+
+  //************************************ */
+
+  private async generateBotResponse(session: ChatSession, userMessage: ChatMessage, userId: string): Promise<void> {
+    const em = this.em.fork();
+    try {
+      // Get conversation history
+      const history = await this.chatMessageRepo.getConversationHistory(session.id, 20, em);
+
+      // Build context for LLM
+      const context: IChatContext = {
+        userId,
+        sessionId: session.id,
+        conversationHistory: history.reverse().map((msg) => ({
+          content: msg.content,
+          type: msg.type as "user" | "bot" | "system",
+          timestamp: msg.createdAt,
+          metadata: msg.metadata,
+        })),
+        userPreferences: session.context,
+      };
+
+      // Generate response using LLM
+      const llmResponse = await this.llmService.generateResponse(userMessage.content, context);
+
+      // Create bot message
+      const botMessage = new ChatMessage();
+      botMessage.content = llmResponse.message;
+      botMessage.type = MessageType.BOT;
+      botMessage.session = session;
+      botMessage.responseToId = userMessage.id;
+      botMessage.tokensUsed = llmResponse.tokensUsed;
+      botMessage.metadata = {
+        confidence: llmResponse.confidence,
+        sources: llmResponse.sources,
+        llmContext: llmResponse.context,
+      };
+
+      await em.persistAndFlush(botMessage);
+
+      // Update session last message time
+      await this.chatSessionRepo.updateLastMessageTime(session.id, em);
+
+      this.logger.log(`Generated bot response for session ${session.id}`);
+    } catch (error) {
+      this.logger.error(`Failed to generate bot response for session ${session.id}`, error);
+
+      // Create error message
+      const errorMessage = new ChatMessage();
+      errorMessage.content = "متأسفم، در حال حاضر مشکلی در پاسخگویی دارم. لطفاً دوباره تلاش کنید. 🙏";
+      errorMessage.type = MessageType.BOT;
+      errorMessage.session = session;
+      errorMessage.responseToId = userMessage.id;
+      errorMessage.status = MessageStatus.FAILED;
+
+      await em.persistAndFlush(errorMessage);
+    }
+  }
+
+  //************************************ */
+
+  async closeChatSession(sessionId: string, userId: string) {
+    const em = this.em.fork();
+    const session = await em.findOne(ChatSession, { id: sessionId, user: userId });
+
+    if (!session) {
+      throw new NotFoundException("Chat session not found");
+    }
+
+    session.status = ChatSessionStatus.CLOSED;
+    await em.persistAndFlush(session);
+
+    return { message: "Chat session closed successfully" };
+  }
+
+  //************************************ */
+
+  async markMessagesAsRead(sessionId: string, userId: string, messageIds: string[]) {
+    const em = this.em.fork();
+    const session = await em.findOne(ChatSession, { id: sessionId, user: userId });
+
+    if (!session) {
+      throw new NotFoundException("Chat session not found");
+    }
+
+    await this.chatMessageRepo.markAsRead(messageIds, em);
+
+    return { message: "Messages marked as read successfully" };
+  }
+
+  //************************************ */
+
+  private mapSessionToDto(session: ChatSession) {
+    return {
+      id: session.id,
+      title: session.title,
+      status: session.status,
+      createdAt: session.createdAt,
+      lastMessageAt: session.lastMessageAt,
+      context: session.context,
+      messages: session.messages ? session.messages.getItems().map((msg) => this.mapMessageToDto(msg)) : [],
+    };
+  }
+
+  //************************************ */
+
+  private mapMessageToDto(message: ChatMessage) {
+    return {
+      id: message.id,
+      content: message.content,
+      type: message.type,
+      status: message.status,
+      createdAt: message.createdAt,
+      responseToId: message.responseToId,
+      metadata: message.metadata,
+      tokensUsed: message.tokensUsed,
+    };
+  }
+
+  //************************************ */
+
+  async sendMessageWithLangChain(userId: string, sendDto: SendMessageDto) {
+    const em = this.em.fork();
+    const session = await em.findOne(ChatSession, { id: sendDto.sessionId, user: userId }, { populate: ["messages"] });
+
+    if (!session) {
+      throw new NotFoundException("Chat session not found");
+    }
+
+    if (session.status !== ChatSessionStatus.ACTIVE) {
+      throw new BadRequestException("Cannot send message to inactive session");
+    }
+
+    const user = await em.findOne(User, { id: userId });
+    if (!user) {
+      throw new NotFoundException("User not found");
+    }
+
+    // Create user message
+    const userMessage = new ChatMessage();
+    userMessage.content = sendDto.content;
+    userMessage.type = MessageType.USER;
+    userMessage.session = session;
+    userMessage.sender = user;
+    userMessage.responseToId = sendDto.responseToId;
+    userMessage.metadata = sendDto.metadata;
+
+    await em.persistAndFlush(userMessage);
+
+    // Update session last message time
+    await this.chatSessionRepo.updateLastMessageTime(session.id, em);
+
+    // Generate bot response using LangChain
+    this.generateBotResponseWithLangChain(session, userMessage, userId);
+
+    return this.mapMessageToDto(userMessage);
+  }
+
+  //************************************ */
+
+  async sendMessageStreamWithLangChain(userId: string, sendDto: SendMessageDto) {
+    const em = this.em.fork();
+    const session = await em.findOne(ChatSession, { id: sendDto.sessionId, user: userId }, { populate: ["messages"] });
+
+    if (!session) {
+      throw new NotFoundException("Chat session not found");
+    }
+
+    if (session.status !== ChatSessionStatus.ACTIVE) {
+      throw new BadRequestException("Cannot send message to inactive session");
+    }
+
+    const user = await em.findOne(User, { id: userId });
+    if (!user) {
+      throw new NotFoundException("User not found");
+    }
+
+    // Create user message
+    const userMessage = new ChatMessage();
+    userMessage.content = sendDto.content;
+    userMessage.type = MessageType.USER;
+    userMessage.session = session;
+    userMessage.sender = user;
+    userMessage.responseToId = sendDto.responseToId;
+    userMessage.metadata = sendDto.metadata;
+
+    await em.persistAndFlush(userMessage);
+
+    // Update session last message time
+    await this.chatSessionRepo.updateLastMessageTime(session.id, em);
+
+    // Get conversation history for context
+    const history = await this.chatMessageRepo.getConversationHistory(session.id, 20, em);
+
+    // Build context for LangChain
+    const context: IChatContext = {
+      userId,
+      sessionId: session.id,
+      conversationHistory: history.reverse().map((msg) => ({
+        content: msg.content,
+        type: msg.type as "user" | "bot" | "system",
+        timestamp: msg.createdAt,
+        metadata: msg.metadata,
+      })),
+      userPreferences: session.context,
+    };
+
+    // Return a function that generates the stream using LangChain
+    const streamGenerator = () => this.langChainService.generateStreamResponse(sendDto.content, context);
+
+    return {
+      userMessage: this.mapMessageToDto(userMessage),
+      streamGenerator,
+    };
+  }
+
+  //************************************ */
+
+  private async generateBotResponseWithLangChain(session: ChatSession, userMessage: ChatMessage, userId: string): Promise<void> {
+    const em = this.em.fork();
+    try {
+      // Get conversation history
+      const history = await this.chatMessageRepo.getConversationHistory(session.id, 20, em);
+
+      // Build context for LangChain
+      const context: IChatContext = {
+        userId,
+        sessionId: session.id,
+        conversationHistory: history.reverse().map((msg) => ({
+          content: msg.content,
+          type: msg.type as "user" | "bot" | "system",
+          timestamp: msg.createdAt,
+          metadata: msg.metadata,
+        })),
+        userPreferences: session.context,
+      };
+
+      // Generate response using LangChain
+      const langChainResponse = await this.langChainService.generateResponse(userMessage.content, context);
+
+      // Create bot message
+      const botMessage = new ChatMessage();
+      botMessage.content = langChainResponse.message;
+      botMessage.type = MessageType.BOT;
+      botMessage.session = session;
+      botMessage.responseToId = userMessage.id;
+      botMessage.tokensUsed = langChainResponse.tokensUsed;
+      botMessage.metadata = {
+        confidence: langChainResponse.confidence,
+        sources: langChainResponse.sources,
+        llmContext: langChainResponse.context,
+        provider: "langchain",
+        documentsRetrieved: langChainResponse.context?.documentsRetrieved || 0,
+      };
+
+      await em.persistAndFlush(botMessage);
+
+      // Update session last message time
+      await this.chatSessionRepo.updateLastMessageTime(session.id, em);
+
+      this.logger.log(`Generated LangChain bot response for session ${session.id}`);
+    } catch (error) {
+      this.logger.error(`Failed to generate LangChain bot response for session ${session.id}`, error);
+
+      // Fallback to regular LLM service
+      this.logger.log(`Falling back to regular LLM service for session ${session.id}`);
+      await this.generateBotResponse(session, userMessage, userId);
+    }
+  }
+
+  //************************************ */
+
+  async refreshLangChainData() {
+    try {
+      await this.langChainService.refreshVectorStore();
+      this.logger.log("LangChain vector store refreshed successfully");
+      return { message: "LangChain vector store refreshed successfully" };
+    } catch (error) {
+      this.logger.error("Failed to refresh LangChain vector store", error);
+      throw new Error("Failed to refresh training data");
+    }
+  }
+
+  //************************************ */
+}

src/modules/chatbot/providers/data-context.service.ts

@@ -0,0 +1,226 @@
+import { EntityManager } from "@mikro-orm/core";
+import { Injectable, Logger } from "@nestjs/common";
+
+import { Business } from "../../businesses/entities/business.entity";
+import { Company } from "../../companies/entities/company.entity";
+import { Industry } from "../../industries/entities/industry.entity";
+import { Invoice } from "../../invoices/entities/invoice.entity";
+import { InvoiceStatus } from "../../invoices/enums/invoice-status.enum";
+import { Payment } from "../../payments/entities/payment.entity";
+import { PaymentStatus } from "../../payments/enums/payment-status.enum";
+import { Ticket } from "../../tickets/entities/ticket.entity";
+import { TicketStatus } from "../../tickets/enums/ticket-status.enum";
+import { IChatContext } from "../interfaces/chatbot.interface";
+
+@Injectable()
+export class DataContextService {
+  private readonly logger = new Logger(DataContextService.name);
+
+  constructor(private em: EntityManager) {}
+
+  async getRelevantContext(message: string, context: IChatContext): Promise<{ data: string[]; sources: string[] }> {
+    const relevantData: string[] = [];
+    const sources: string[] = [];
+
+    try {
+      // Analyze message to determine what data to fetch
+      const keywords = this.extractKeywords(message);
+
+      // Fetch relevant data based on keywords and user context
+      await Promise.all([
+        this.getBusinessData(keywords, context.userId, relevantData, sources),
+        this.getInvoiceData(keywords, context.userId, relevantData, sources),
+        this.getPaymentData(keywords, context.userId, relevantData, sources),
+        this.getCompanyData(keywords, context.userId, relevantData, sources),
+        this.getTicketData(keywords, context.userId, relevantData, sources),
+        this.getIndustryData(keywords, relevantData, sources),
+      ]);
+
+      return { data: relevantData, sources };
+    } catch (error) {
+      this.logger.error("Failed to get relevant context", error);
+      return { data: [], sources: [] };
+    }
+  }
+
+  private extractKeywords(message: string): string[] {
+    const commonWords = ["the", "is", "at", "which", "on", "a", "an", "and", "or", "but", "in", "with", "to", "for", "of", "as", "by"];
+
+    return message
+      .toLowerCase()
+      .replace(/[^\w\s]/g, "")
+      .split(/\s+/)
+      .filter((word) => word.length > 2 && !commonWords.includes(word));
+  }
+
+  private async getBusinessData(keywords: string[], userId: string, relevantData: string[], sources: string[]): Promise<void> {
+    if (this.hasBusinessKeywords(keywords)) {
+      try {
+        const businesses = await this.em.find(Business, { danakSubscriptionId: userId }, { limit: 5, populate: ["users"] });
+
+        businesses.forEach((business) => {
+          relevantData.push(
+            `Business: ${business.name} - Domain: ${business.domain || "No domain"} - Verified: ${business.isDomainVerified ? "Yes" : "No"}`,
+          );
+          sources.push("Businesses Database");
+        });
+      } catch (error) {
+        this.logger.warn("Failed to fetch business data", error);
+      }
+    }
+  }
+
+  private async getInvoiceData(keywords: string[], userId: string, relevantData: string[], sources: string[]): Promise<void> {
+    if (this.hasInvoiceKeywords(keywords)) {
+      try {
+        // Find user's businesses first
+        const userBusinesses = await this.em.find(Business, { danakSubscriptionId: userId });
+
+        if (userBusinesses.length > 0) {
+          const businessIds = userBusinesses.map((b) => b.id);
+          const invoices = await this.em.find(Invoice, { business: { $in: businessIds } }, { limit: 10, orderBy: { createdAt: "DESC" } });
+
+          const summary = {
+            total: invoices.length,
+            paid: invoices.filter((inv) => inv.status === InvoiceStatus.PAID).length,
+            pending: invoices.filter((inv) => inv.status === InvoiceStatus.PENDING).length,
+            totalAmount: invoices.reduce((sum, inv) => sum + Number(inv.totalPrice), 0),
+          };
+
+          relevantData.push(
+            `Invoice Summary: Total invoices: ${summary.total}, Paid: ${summary.paid}, Pending: ${summary.pending}, Total amount: $${summary.totalAmount}`,
+          );
+          sources.push("Invoices Database");
+        }
+      } catch (error) {
+        this.logger.warn("Failed to fetch invoice data", error);
+      }
+    }
+  }
+
+  private async getPaymentData(keywords: string[], userId: string, relevantData: string[], sources: string[]): Promise<void> {
+    if (this.hasPaymentKeywords(keywords)) {
+      try {
+        // Find user's businesses first
+        const userBusinesses = await this.em.find(Business, { danakSubscriptionId: userId });
+
+        if (userBusinesses.length > 0) {
+          const businessIds = userBusinesses.map((b) => b.id);
+          const payments = await this.em.find(Payment, { business: { $in: businessIds } }, { limit: 10, orderBy: { createdAt: "DESC" } });
+
+          const summary = {
+            total: payments.length,
+            successful: payments.filter((pay) => pay.status === PaymentStatus.COMPLETED).length,
+            failed: payments.filter((pay) => pay.status === PaymentStatus.FAILED).length,
+            totalAmount: payments.reduce((sum, pay) => sum + Number(pay.amount), 0),
+          };
+
+          relevantData.push(
+            `Payment Summary: Total payments: ${summary.total}, Successful: ${summary.successful}, Failed: ${summary.failed}, Total amount: $${summary.totalAmount}`,
+          );
+          sources.push("Payments Database");
+        }
+      } catch (error) {
+        this.logger.warn("Failed to fetch payment data", error);
+      }
+    }
+  }
+
+  private async getCompanyData(keywords: string[], userId: string, relevantData: string[], sources: string[]): Promise<void> {
+    if (this.hasCompanyKeywords(keywords)) {
+      try {
+        // Find user's businesses first
+        const userBusinesses = await this.em.find(Business, { danakSubscriptionId: userId });
+
+        if (userBusinesses.length > 0) {
+          const businessIds = userBusinesses.map((b) => b.id);
+          const companies = await this.em.find(Company, { business: { $in: businessIds } }, { limit: 5, populate: ["industry"] });
+
+          companies.forEach((company) => {
+            relevantData.push(`Company: ${company.name} - Industry: ${company.industry?.title || "N/A"} - Status: ${company.status}`);
+            sources.push("Companies Database");
+          });
+        }
+      } catch (error) {
+        this.logger.warn("Failed to fetch company data", error);
+      }
+    }
+  }
+
+  private async getTicketData(keywords: string[], userId: string, relevantData: string[], sources: string[]): Promise<void> {
+    if (this.hasTicketKeywords(keywords)) {
+      try {
+        // Find user's businesses first
+        const userBusinesses = await this.em.find(Business, { danakSubscriptionId: userId });
+
+        if (userBusinesses.length > 0) {
+          const businessIds = userBusinesses.map((b) => b.id);
+          const tickets = await this.em.find(
+            Ticket,
+            { business: { $in: businessIds } },
+            { limit: 10, orderBy: { createdAt: "DESC" }, populate: ["category"] },
+          );
+
+          const summary = {
+            total: tickets.length,
+            pending: tickets.filter((t) => t.status === TicketStatus.PENDING).length,
+            answered: tickets.filter((t) => t.status === TicketStatus.ANSWERED).length,
+            closed: tickets.filter((t) => t.status === TicketStatus.CLOSED).length,
+            categories: [...new Set(tickets.map((t) => t.category?.title || "Uncategorized"))],
+          };
+
+          relevantData.push(
+            `Support Tickets: Total: ${summary.total}, Pending: ${summary.pending}, Answered: ${summary.answered}, Closed: ${summary.closed}, Categories: ${summary.categories.join(", ")}`,
+          );
+          sources.push("Support Tickets Database");
+        }
+      } catch (error) {
+        this.logger.warn("Failed to fetch ticket data", error);
+      }
+    }
+  }
+
+  private async getIndustryData(keywords: string[], relevantData: string[], sources: string[]): Promise<void> {
+    if (this.hasIndustryKeywords(keywords)) {
+      try {
+        const industries = await this.em.find(Industry, {}, { limit: 10 });
+
+        const industryInfo = industries.map((ind) => `${ind.title}: ${ind.isActive ? "Active" : "Inactive"}`);
+        relevantData.push(`Available Industries: ${industryInfo.join("; ")}`);
+        sources.push("Industries Database");
+      } catch (error) {
+        this.logger.warn("Failed to fetch industry data", error);
+      }
+    }
+  }
+
+  private hasBusinessKeywords(keywords: string[]): boolean {
+    const businessTerms = ["business", "company", "startup", "enterprise", "organization", "firm"];
+    return keywords.some((keyword) => businessTerms.includes(keyword));
+  }
+
+  private hasInvoiceKeywords(keywords: string[]): boolean {
+    const invoiceTerms = ["invoice", "bill", "billing", "payment", "charge", "fee", "cost", "price"];
+    return keywords.some((keyword) => invoiceTerms.includes(keyword));
+  }
+
+  private hasPaymentKeywords(keywords: string[]): boolean {
+    const paymentTerms = ["payment", "pay", "transaction", "money", "refund", "charge", "card", "bank"];
+    return keywords.some((keyword) => paymentTerms.includes(keyword));
+  }
+
+  private hasCompanyKeywords(keywords: string[]): boolean {
+    const companyTerms = ["company", "corporation", "business", "organization", "enterprise"];
+    return keywords.some((keyword) => companyTerms.includes(keyword));
+  }
+
+  private hasTicketKeywords(keywords: string[]): boolean {
+    const ticketTerms = ["ticket", "support", "help", "issue", "problem", "bug", "error"];
+    return keywords.some((keyword) => ticketTerms.includes(keyword));
+  }
+
+  private hasIndustryKeywords(keywords: string[]): boolean {
+    const industryTerms = ["industry", "sector", "field", "domain", "market"];
+    return keywords.some((keyword) => industryTerms.includes(keyword));
+  }
+}

src/modules/chatbot/providers/langchain.service.ts

@@ -0,0 +1,389 @@
+import { Document } from "@langchain/core/documents";
+import { StringOutputParser } from "@langchain/core/output_parsers";
+import { PromptTemplate } from "@langchain/core/prompts";
+import { RunnableSequence } from "@langchain/core/runnables";
+import { ChatGoogleGenerativeAI, GoogleGenerativeAIEmbeddings } from "@langchain/google-genai";
+import { EntityManager } from "@mikro-orm/core";
+import { Injectable, Logger, OnModuleInit } from "@nestjs/common";
+import { ConfigService } from "@nestjs/config";
+import { RecursiveCharacterTextSplitter } from "langchain/text_splitter";
+import { MemoryVectorStore } from "langchain/vectorstores/memory";
+
+import { Company } from "../../companies/entities/company.entity";
+import { Industry } from "../../industries/entities/industry.entity";
+import { CHATBOT_CONSTANTS } from "../constants/chatbot.constants";
+import { IChatContext, IChatbotResponse } from "../interfaces/chatbot.interface";
+
+@Injectable()
+export class LangChainService implements OnModuleInit {
+  private readonly logger = new Logger(LangChainService.name);
+  private embeddings: GoogleGenerativeAIEmbeddings;
+  private llm: ChatGoogleGenerativeAI;
+  private vectorStore: MemoryVectorStore;
+  private textSplitter: RecursiveCharacterTextSplitter;
+  private isInitialized = false;
+
+  constructor(
+    private em: EntityManager,
+    private configService: ConfigService,
+  ) {
+    // Initialize Google Gemini components
+    this.embeddings = new GoogleGenerativeAIEmbeddings({
+      apiKey: this.configService.getOrThrow("GEMINI_API_KEY"),
+      modelName: "embedding-001", // Google's embedding model
+    });
+
+    this.llm = new ChatGoogleGenerativeAI({
+      apiKey: this.configService.getOrThrow("GEMINI_API_KEY"),
+      model: CHATBOT_CONSTANTS.DEFAULT_MODEL,
+      temperature: CHATBOT_CONSTANTS.DEFAULT_TEMPERATURE,
+      maxOutputTokens: CHATBOT_CONSTANTS.DEFAULT_MAX_TOKENS,
+    });
+
+    this.textSplitter = new RecursiveCharacterTextSplitter({
+      chunkSize: 1000,
+      chunkOverlap: 200,
+      separators: ["\n\n", "\n", ".", "!", "?", "؟", "!", ".", " ", ""],
+    });
+  }
+
+  async onModuleInit() {
+    await this.initializeVectorStore();
+  }
+
+  private async initializeVectorStore() {
+    try {
+      this.logger.log(CHATBOT_CONSTANTS.LANGCHAIN_MESSAGES.LOADING_DATA);
+
+      // Load company and industry data for training
+      const documents = await this.loadCompanyAndIndustryDocuments();
+
+      if (documents.length === 0) {
+        this.logger.warn(CHATBOT_CONSTANTS.LANGCHAIN_MESSAGES.NO_DATA_FOUND);
+        this.vectorStore = new MemoryVectorStore(this.embeddings);
+        this.isInitialized = true;
+        return;
+      }
+
+      // Split documents into chunks
+      const splitDocs = await this.textSplitter.splitDocuments(documents);
+
+      this.logger.log(
+        CHATBOT_CONSTANTS.LANGCHAIN_MESSAGES.DOCUMENTS_SPLIT.replace("{totalDocs}", documents.length.toString()).replace(
+          "{chunks}",
+          splitDocs.length.toString(),
+        ),
+      );
+
+      // Create vector store from documents
+      this.vectorStore = await MemoryVectorStore.fromDocuments(splitDocs, this.embeddings);
+
+      this.isInitialized = true;
+      this.logger.log(CHATBOT_CONSTANTS.LANGCHAIN_MESSAGES.VECTOR_STORE_READY);
+    } catch (error) {
+      this.logger.error(CHATBOT_CONSTANTS.LANGCHAIN_MESSAGES.VECTOR_STORE_ERROR, error);
+      // Fallback to empty vector store
+      this.vectorStore = new MemoryVectorStore(this.embeddings);
+      this.isInitialized = true;
+    }
+  }
+
+  private async loadCompanyAndIndustryDocuments(): Promise<Document[]> {
+    const documents: Document[] = [];
+    const em = this.em.fork();
+
+    try {
+      // Load companies data with their products and services
+      const companies = await em.find(Company, { isActive: true, deletedAt: null }, { populate: ["industry", "business", "products", "services"] });
+
+      companies.forEach((company) => {
+        // Company basic information using template
+        const companyContent = this.replaceTemplate(CHATBOT_CONSTANTS.COMPANY_DATA_TEMPLATES.COMPANY_INFO, {
+          name: company.name,
+          ceo: company.chiefExecutiveOfficer,
+          email: company.email,
+          phone: company.phone,
+          registrationNumber: company.identificationNumber,
+          establishmentDate: new Date(company.dateOfEstablishment).toLocaleDateString("fa-IR"),
+          address: company.address,
+          website: company.websiteUrl || CHATBOT_CONSTANTS.DEFAULT_VALUES.NO_WEBSITE,
+          description: company.description,
+          industry: company.industry?.title || CHATBOT_CONSTANTS.DEFAULT_VALUES.UNSPECIFIED,
+          status: company.status,
+          business: company.business?.name || CHATBOT_CONSTANTS.DEFAULT_VALUES.UNSPECIFIED,
+        });
+
+        documents.push(
+          new Document({
+            pageContent: companyContent,
+            metadata: {
+              type: "company",
+              id: company.id,
+              name: company.name,
+              industry: company.industry?.title,
+              businessId: company.business?.id,
+              status: company.status,
+            },
+          }),
+        );
+
+        // Company products using template
+        if (company.products && company.products.getItems().length > 0) {
+          company.products.getItems().forEach((product) => {
+            const productContent = this.replaceTemplate(CHATBOT_CONSTANTS.COMPANY_DATA_TEMPLATES.COMPANY_PRODUCT, {
+              companyName: company.name,
+              productTitle: product.title,
+              industry: company.industry?.title || CHATBOT_CONSTANTS.DEFAULT_VALUES.UNSPECIFIED,
+              companyDescription: company.description,
+              companyAddress: company.address,
+              companyPhone: company.phone,
+              companyEmail: company.email,
+            });
+
+            documents.push(
+              new Document({
+                pageContent: productContent,
+                metadata: {
+                  type: "product",
+                  id: product.id,
+                  title: product.title,
+                  companyId: company.id,
+                  companyName: company.name,
+                  industry: company.industry?.title,
+                },
+              }),
+            );
+          });
+        }
+
+        // Company services using template
+        if (company.services && company.services.getItems().length > 0) {
+          company.services.getItems().forEach((service) => {
+            const serviceContent = this.replaceTemplate(CHATBOT_CONSTANTS.COMPANY_DATA_TEMPLATES.COMPANY_SERVICE, {
+              companyName: company.name,
+              serviceTitle: service.title,
+              industry: company.industry?.title || CHATBOT_CONSTANTS.DEFAULT_VALUES.UNSPECIFIED,
+              companyDescription: company.description,
+              companyAddress: company.address,
+              companyPhone: company.phone,
+              companyEmail: company.email,
+            });
+
+            documents.push(
+              new Document({
+                pageContent: serviceContent,
+                metadata: {
+                  type: "service",
+                  id: service.id,
+                  title: service.title,
+                  companyId: company.id,
+                  companyName: company.name,
+                  industry: company.industry?.title,
+                },
+              }),
+            );
+          });
+        }
+      });
+
+      // Load industries data using template
+      const industries = await em.find(Industry, { isActive: true, deletedAt: null }, { populate: ["companies", "business"] });
+      industries.forEach((industry) => {
+        const companiesInIndustry = industry.companies?.getItems().filter((c) => c.isActive && !c.deletedAt) || [];
+
+        const industryContent = this.replaceTemplate(CHATBOT_CONSTANTS.COMPANY_DATA_TEMPLATES.INDUSTRY_INFO, {
+          title: industry.title,
+          status: industry.isActive ? CHATBOT_CONSTANTS.DEFAULT_VALUES.ACTIVE : CHATBOT_CONSTANTS.DEFAULT_VALUES.INACTIVE,
+          companiesCount: companiesInIndustry.length.toString(),
+          business: industry.business?.name || CHATBOT_CONSTANTS.DEFAULT_VALUES.UNSPECIFIED,
+          companiesList: companiesInIndustry.map((company) => `- ${company.name}`).join("\n"),
+        });
+
+        documents.push(
+          new Document({
+            pageContent: industryContent,
+            metadata: {
+              type: "industry",
+              id: industry.id,
+              title: industry.title,
+              isActive: industry.isActive,
+              companiesCount: companiesInIndustry.length,
+              businessId: industry.business?.id,
+            },
+          }),
+        );
+      });
+
+      // Add comprehensive Farsi guidance documents from constants
+      const companyGuidanceDocuments = [
+        new Document({
+          pageContent: CHATBOT_CONSTANTS.COMPANY_GUIDANCE_DOCUMENTS.COMPANY_GUIDE,
+          metadata: {
+            type: "company_guide",
+            category: "guidance",
+            language: "فارسی",
+          },
+        }),
+        new Document({
+          pageContent: CHATBOT_CONSTANTS.COMPANY_GUIDANCE_DOCUMENTS.COMPANY_FAQ,
+          metadata: {
+            type: "company_faq",
+            category: "support",
+            language: "فارسی",
+          },
+        }),
+        new Document({
+          pageContent: CHATBOT_CONSTANTS.COMPANY_GUIDANCE_DOCUMENTS.SEARCH_GUIDE,
+          metadata: {
+            type: "search_guide",
+            category: "tutorial",
+            language: "فارسی",
+          },
+        }),
+        new Document({
+          pageContent: CHATBOT_CONSTANTS.COMPANY_GUIDANCE_DOCUMENTS.INDUSTRY_GUIDE,
+          metadata: {
+            type: "industry_guide",
+            category: "education",
+            language: "فارسی",
+          },
+        }),
+      ];
+
+      documents.push(...companyGuidanceDocuments);
+
+      this.logger.log(CHATBOT_CONSTANTS.LANGCHAIN_MESSAGES.DOCUMENTS_LOADED.replace("{count}", documents.length.toString()));
+      return documents;
+    } catch (error) {
+      this.logger.error(CHATBOT_CONSTANTS.LANGCHAIN_MESSAGES.LOADING_ERROR, error);
+      return [];
+    }
+  }
+
+  async generateResponse(message: string, context: IChatContext): Promise<IChatbotResponse> {
+    if (!this.isInitialized) {
+      throw new Error(CHATBOT_CONSTANTS.LANGCHAIN_MESSAGES.SERVICE_NOT_INITIALIZED);
+    }
+
+    try {
+      // Retrieve relevant documents based on the user's query
+      const relevantDocs = await this.vectorStore.similaritySearch(message, 5);
+
+      // Build context from retrieved documents
+      const retrievedContext = relevantDocs.map((doc, index) => `${index + 1}. ${doc.pageContent}`).join("\n\n");
+
+      // Build conversation history
+      const conversationHistory =
+        context.conversationHistory
+          ?.slice(-CHATBOT_CONSTANTS.MAX_CONVERSATION_HISTORY / 4)
+          ?.map((msg) => {
+            const roleLabel = msg.type === "user" ? "کاربر" : msg.type === "bot" ? "ربات" : "سیستم";
+            return `${roleLabel}: ${msg.content}`;
+          })
+          ?.join("\n") || "";
+
+      // Create the prompt template using constants
+      const promptTemplate = PromptTemplate.fromTemplate(CHATBOT_CONSTANTS.COMPANY_GUIDANCE_SYSTEM_PROMPT);
+
+      // Create the runnable sequence
+      const chain = RunnableSequence.from([promptTemplate, this.llm, new StringOutputParser()]);
+
+      // Execute the chain
+      const response = await chain.invoke({
+        context: retrievedContext,
+        conversation_history: conversationHistory,
+        question: message,
+      });
+
+      // Calculate approximate token usage
+      const tokensUsed = this.estimateTokens(retrievedContext) + this.estimateTokens(message) + this.estimateTokens(response);
+
+      return {
+        message: response,
+        confidence: 0.9, // Higher confidence for company guidance
+        sources: relevantDocs.map((doc) => {
+          const type = doc.metadata.type || "شرکت";
+          return CHATBOT_CONSTANTS.SOURCE_TYPE_LABELS[type as keyof typeof CHATBOT_CONSTANTS.SOURCE_TYPE_LABELS] || type;
+        }),
+        tokensUsed,
+        context: {
+          model: `${CHATBOT_CONSTANTS.DEFAULT_MODEL}-company-guide`,
+          relevantDataFound: relevantDocs.length > 0,
+          documentsRetrieved: relevantDocs.length,
+          vectorStoreInitialized: this.isInitialized,
+          language: "فارسی",
+          dataTypes: relevantDocs.map((doc) => doc.metadata.type).filter((type, index, arr) => arr.indexOf(type) === index),
+          focus: "company_and_industry_guidance",
+        },
+      };
+    } catch (error) {
+      this.logger.error(CHATBOT_CONSTANTS.LANGCHAIN_MESSAGES.RESPONSE_ERROR, error);
+      throw new Error(CHATBOT_CONSTANTS.ERROR_MESSAGES.LLM_SERVICE_ERROR);
+    }
+  }
+
+  async generateStreamResponse(message: string, context: IChatContext) {
+    if (!this.isInitialized) {
+      throw new Error(CHATBOT_CONSTANTS.LANGCHAIN_MESSAGES.SERVICE_NOT_INITIALIZED);
+    }
+
+    try {
+      // Retrieve relevant documents
+      const relevantDocs = await this.vectorStore.similaritySearch(message, 5);
+      const retrievedContext = relevantDocs.map((doc, index) => `${index + 1}. ${doc.pageContent}`).join("\n\n");
+
+      // Build conversation history
+      const conversationHistory =
+        context.conversationHistory
+          ?.slice(-CHATBOT_CONSTANTS.MAX_CONVERSATION_HISTORY / 4)
+          ?.map((msg) => {
+            const roleLabel = msg.type === "user" ? "کاربر" : msg.type === "bot" ? "ربات" : "سیستم";
+            return `${roleLabel}: ${msg.content}`;
+          })
+          ?.join("\n") || "";
+
+      // Create prompt template using constants
+      const promptTemplate = PromptTemplate.fromTemplate(CHATBOT_CONSTANTS.COMPANY_GUIDANCE_SYSTEM_PROMPT);
+
+      // Create streaming chain
+      const chain = RunnableSequence.from([promptTemplate, this.llm, new StringOutputParser()]);
+
+      // Return async iterable for streaming
+      const stream = await chain.stream({
+        context: retrievedContext,
+        conversation_history: conversationHistory,
+        question: message,
+      });
+
+      return stream;
+    } catch (error) {
+      this.logger.error(CHATBOT_CONSTANTS.LANGCHAIN_MESSAGES.STREAM_RESPONSE_ERROR, error);
+      throw new Error(CHATBOT_CONSTANTS.ERROR_MESSAGES.LLM_SERVICE_ERROR);
+    }
+  }
+
+  async refreshVectorStore(): Promise<void> {
+    this.logger.log(CHATBOT_CONSTANTS.LANGCHAIN_MESSAGES.REFRESHING_VECTOR_STORE);
+    await this.initializeVectorStore();
+  }
+
+  private estimateTokens(text: string): number {
+    // Rough estimation: 1 token ≈ 4 characters for most languages
+    return Math.ceil(text.length / 4);
+  }
+
+  /**
+   * Replace placeholders in template with actual values
+   */
+  private replaceTemplate(template: string, values: Record<string, string>): string {
+    let result = template;
+    Object.entries(values).forEach(([key, value]) => {
+      result = result.replace(new RegExp(`{${key}}`, "g"), value);
+    });
+    return result;
+  }
+
+  get initialized(): boolean {
+    return this.isInitialized;
+  }
+}

src/modules/chatbot/providers/llm.service.ts

@@ -0,0 +1,237 @@
+import { GoogleGenerativeAI, HarmBlockThreshold, HarmCategory } from "@google/generative-ai";
+import { Injectable, Logger } from "@nestjs/common";
+import { ConfigService } from "@nestjs/config";
+
+import { DataContextService } from "./data-context.service";
+import { CHATBOT_CONSTANTS } from "../constants/chatbot.constants";
+import { IChatContext, IChatbotResponse, ILLMConfig } from "../interfaces/chatbot.interface";
+
+@Injectable()
+export class LLMService {
+  private readonly logger = new Logger(LLMService.name);
+  private genAI: GoogleGenerativeAI;
+  private config: ILLMConfig;
+
+  constructor(
+    private configService: ConfigService,
+    private dataContextService: DataContextService,
+  ) {
+    this.config = {
+      model: this.configService.get("GEMINI_MODEL", CHATBOT_CONSTANTS.DEFAULT_MODEL),
+      temperature: Number(this.configService.get("GEMINI_TEMPERATURE", CHATBOT_CONSTANTS.DEFAULT_TEMPERATURE)),
+      maxTokens: Number(this.configService.get("GEMINI_MAX_TOKENS", CHATBOT_CONSTANTS.DEFAULT_MAX_TOKENS)),
+      topP: Number(this.configService.get("GEMINI_TOP_P", 0.95)),
+      apiKey: this.configService.getOrThrow("GEMINI_API_KEY"),
+    };
+
+    this.genAI = new GoogleGenerativeAI(this.config.apiKey);
+  }
+
+  async generateResponse(message: string, context: IChatContext): Promise<IChatbotResponse> {
+    try {
+      // Get relevant data from database
+      const relevantData = await this.dataContextService.getRelevantContext(message, context);
+
+      // Build system instruction with context
+      const systemInstruction = this.buildSystemInstruction(relevantData);
+
+      // Get the generative model with system instruction
+      const model = this.genAI.getGenerativeModel({
+        model: this.config.model,
+        systemInstruction,
+        generationConfig: {
+          temperature: this.config.temperature,
+          maxOutputTokens: this.config.maxTokens,
+          topP: this.config.topP,
+        },
+        safetySettings: [
+          {
+            category: HarmCategory.HARM_CATEGORY_HARASSMENT,
+            threshold: HarmBlockThreshold.BLOCK_MEDIUM_AND_ABOVE,
+          },
+          {
+            category: HarmCategory.HARM_CATEGORY_HATE_SPEECH,
+            threshold: HarmBlockThreshold.BLOCK_MEDIUM_AND_ABOVE,
+          },
+          {
+            category: HarmCategory.HARM_CATEGORY_SEXUALLY_EXPLICIT,
+            threshold: HarmBlockThreshold.BLOCK_MEDIUM_AND_ABOVE,
+          },
+          {
+            category: HarmCategory.HARM_CATEGORY_DANGEROUS_CONTENT,
+            threshold: HarmBlockThreshold.BLOCK_MEDIUM_AND_ABOVE,
+          },
+        ],
+      });
+
+      // Build conversation history
+      const conversationHistory = this.buildConversationHistory(context);
+
+      // Generate response using conversation history or direct message
+      let result;
+      if (conversationHistory.length > 0) {
+        // Use chat session for multi-turn conversation
+        const chat = model.startChat({
+          history: conversationHistory,
+        });
+        result = await chat.sendMessage(message);
+      } else {
+        // Single message generation
+        result = await model.generateContent(message);
+      }
+
+      const response = await result.response;
+      const botMessage = response.text() || "متأسفم، نمی‌توانم پاسخی تولید کنم. لطفاً سوال خود را دوباره مطرح کنید. 🤖";
+
+      // Calculate token usage (approximate)
+      const tokensUsed = this.estimateTokens(systemInstruction) + this.estimateTokens(message) + this.estimateTokens(botMessage);
+
+      return {
+        message: botMessage,
+        confidence: this.calculateConfidence(response),
+        sources: relevantData.sources,
+        tokensUsed,
+        context: {
+          model: this.config.model,
+          relevantDataFound: relevantData.data.length > 0,
+          finishReason: response.candidates?.[0]?.finishReason || "unknown",
+          safetyRatings: response.candidates?.[0]?.safetyRatings || [],
+        },
+      };
+    } catch (error) {
+      this.logger.error("Failed to generate Gemini response", error);
+      throw new Error("Failed to generate response from AI service");
+    }
+  }
+
+  async generateStreamResponse(message: string, context: IChatContext): Promise<AsyncIterable<string>> {
+    try {
+      // Get relevant data from database
+      const relevantData = await this.dataContextService.getRelevantContext(message, context);
+
+      // Build system instruction with context
+      const systemInstruction = this.buildSystemInstruction(relevantData);
+
+      // Get the generative model
+      const model = this.genAI.getGenerativeModel({
+        model: this.config.model,
+        systemInstruction,
+        generationConfig: {
+          temperature: this.config.temperature,
+          maxOutputTokens: this.config.maxTokens,
+          topP: this.config.topP,
+        },
+      });
+
+      // Build conversation history
+      const conversationHistory = this.buildConversationHistory(context);
+
+      let streamResult;
+      if (conversationHistory.length > 0) {
+        const chat = model.startChat({
+          history: conversationHistory,
+        });
+        streamResult = await chat.sendMessageStream(message);
+      } else {
+        streamResult = await model.generateContentStream(message);
+      }
+
+      return this.createAsyncIterableFromStream(streamResult);
+    } catch (error) {
+      this.logger.error("Failed to generate streaming Gemini response", error);
+      throw new Error("Failed to generate streaming response from AI service");
+    }
+  }
+
+  private buildSystemInstruction(relevantData: { data: string[]; sources: string[] }): string {
+    let instruction = CHATBOT_CONSTANTS.SYSTEM_PROMPT;
+
+    // Add relevant data context
+    if (relevantData.data.length > 0) {
+      instruction += "\n\nRelevant information from our database:\n";
+      instruction += relevantData.data.map((data, index) => `${index + 1}. ${data}`).join("\n");
+      instruction += "\n\nUse this information to provide accurate and specific answers.";
+    }
+
+    return instruction;
+  }
+
+  private buildConversationHistory(context: IChatContext): Array<{ role: string; parts: Array<{ text: string }> }> {
+    if (!context.conversationHistory || context.conversationHistory.length === 0) {
+      return [];
+    }
+
+    const history = [];
+    const recentHistory = context.conversationHistory.slice(-CHATBOT_CONSTANTS.MAX_CONVERSATION_HISTORY).filter((msg) => msg.type !== "system");
+
+    for (const msg of recentHistory) {
+      history.push({
+        role: msg.type === "user" ? "user" : "model",
+        parts: [{ text: msg.content }],
+      });
+    }
+
+    return history;
+  }
+
+  private async *createAsyncIterableFromStream(streamResult: any): AsyncIterable<string> {
+    try {
+      // For Google Generative AI, the streamResult itself is the async iterable
+      for await (const chunk of streamResult.stream) {
+        const chunkText = chunk.text();
+        if (chunkText) {
+          yield chunkText;
+        }
+      }
+    } catch (error) {
+      this.logger.error("Error in streaming response", error);
+
+      // If the above doesn't work, try alternative approach for older SDK versions
+      try {
+        const response = await streamResult.response;
+        const text = response.text();
+        if (text) {
+          yield text;
+        }
+      } catch (fallbackError) {
+        this.logger.error("Fallback streaming approach also failed", fallbackError);
+        throw new Error("Failed to process streaming response");
+      }
+    }
+  }
+
+  private calculateConfidence(response: any): number {
+    const text = response.text() || "";
+
+    // Check safety ratings - lower confidence if blocked
+    const safetyRatings = response.candidates?.[0]?.safetyRatings || [];
+    const hasHighRiskRatings = safetyRatings.some((rating: any) => rating.probability === "HIGH" || rating.probability === "MEDIUM");
+
+    if (hasHighRiskRatings) {
+      return 0.4;
+    }
+
+    // Check for uncertainty indicators
+    if (text.includes("I don't know") || text.includes("I'm not sure") || text.includes("uncertain")) {
+      return 0.3;
+    }
+
+    // Check response length and quality
+    if (text.length < 50) {
+      return 0.6;
+    }
+
+    // Check if response uses provided data
+    if (text.includes("based on") || text.includes("according to")) {
+      return 0.95;
+    }
+
+    return 0.8;
+  }
+
+  private estimateTokens(text: string): number {
+    // Rough estimation: 1 token ≈ 4 characters for English text
+    // Gemini uses similar tokenization to other models
+    return Math.ceil(text.length / 4);
+  }
+}

src/modules/chatbot/providers/websocket-auth.service.ts

@@ -0,0 +1,178 @@
+import { Injectable, Logger } from "@nestjs/common";
+import { JwtService } from "@nestjs/jwt";
+import { Socket } from "socket.io";
+
+import { WebSocketMessage } from "../../../common/enums/message.enum";
+import { ITokenPayload } from "../../auth/interfaces/IToken-payload";
+import { extractTokenFromClient } from "../../utils/providers/extract-token.utils";
+import { WEBSOCKET_EVENTS } from "../constants/chatbot.constants";
+import { AuthenticationResult, WebSocketErrorContext } from "../interfaces/websocket.interface";
+
+/**
+ * Service responsible for WebSocket authentication logic
+ * Follows single responsibility principle and provides reusable authentication methods
+ */
+@Injectable()
+export class WebSocketAuthService {
+  private readonly logger = new Logger(WebSocketAuthService.name);
+
+  constructor(private readonly jwtService: JwtService) {}
+
+  /**
+   * Authenticates a WebSocket client and returns the result
+   *
+   * @param client - Socket.IO client to authenticate
+   * @returns Promise with authentication result
+   */
+  async authenticateClient(client: Socket): Promise<AuthenticationResult> {
+    try {
+      const token = extractTokenFromClient(client);
+
+      if (!token) {
+        this.logAuthenticationAttempt(client, false, "No token provided");
+        return {
+          success: false,
+          error: WebSocketMessage.AUTHENTICATION_REQUIRED,
+        };
+      }
+
+      const payload = await this.jwtService.verifyAsync<ITokenPayload>(token);
+
+      if (!payload?.id) {
+        this.logAuthenticationAttempt(client, false, "Invalid token payload");
+        return {
+          success: false,
+          error: WebSocketMessage.INVALID_TOKEN,
+        };
+      }
+
+      // Store user data in client
+      client.data.user = payload;
+
+      this.logAuthenticationAttempt(client, true, undefined, payload.id);
+
+      return {
+        success: true,
+        user: payload,
+      };
+    } catch (error) {
+      const errorMessage = this.getAuthErrorMessage(error);
+      this.logAuthenticationAttempt(client, false, errorMessage);
+
+      return {
+        success: false,
+        error: errorMessage,
+      };
+    }
+  }
+
+  /**
+   * Emits authentication failure event to client and disconnects
+   *
+   * @param client - Socket.IO client
+   * @param error - Error message to send
+   */
+  handleAuthenticationFailure(client: Socket, error: string): void {
+    client.emit(WEBSOCKET_EVENTS.UNAUTHORIZED, {
+      message: error,
+      timestamp: new Date().toISOString(),
+    });
+
+    // Graceful disconnect with delay to ensure message is received
+    setTimeout(() => {
+      client.disconnect(true);
+    }, 100);
+  }
+
+  /**
+   * Emits successful authentication event to client
+   *
+   * @param client - Socket.IO client
+   * @param user - Authenticated user payload
+   */
+  emitAuthenticationSuccess(client: Socket, user: ITokenPayload): void {
+    client.emit(WEBSOCKET_EVENTS.AUTHENTICATED, {
+      message: WebSocketMessage.AUTHENTICATED,
+      userId: user.id,
+      timestamp: new Date().toISOString(),
+    });
+  }
+
+  /**
+   * Creates error context object for logging and monitoring
+   *
+   * @param client - Socket.IO client
+   * @param event - Event name (optional)
+   * @param data - Event data (optional)
+   * @returns WebSocket error context
+   */
+  createErrorContext(client: Socket, event?: WEBSOCKET_EVENTS, data?: any): WebSocketErrorContext {
+    return {
+      clientId: client.id,
+      userId: client.data?.user?.id,
+      sessionId: client.data?.sessionId,
+      event,
+      data,
+      timestamp: new Date(),
+    };
+  }
+
+  /**
+   * Validates if client is authenticated
+   *
+   * @param client - Socket.IO client to validate
+   * @returns True if client has valid user data
+   */
+  isClientAuthenticated(client: Socket): boolean {
+    return !!client.data?.user?.id;
+  }
+
+  /**
+   * Gets user ID from authenticated client
+   *
+   * @param client - Socket.IO client
+   * @returns User ID or undefined if not authenticated
+   */
+  getUserId(client: Socket): string | undefined {
+    return client.data?.user?.id;
+  }
+
+  /**
+   * Logs authentication attempts with structured data
+   */
+  private logAuthenticationAttempt(client: Socket, success: boolean, error?: string, userId?: string): void {
+    const logData = {
+      clientId: client.id,
+      clientIP: client.handshake.address,
+      success,
+      userId,
+      error,
+      timestamp: new Date().toISOString(),
+    };
+
+    if (success) {
+      this.logger.log(`WebSocket authentication successful`, logData);
+    } else {
+      this.logger.warn(`WebSocket authentication failed`, logData);
+    }
+  }
+
+  /**
+   * Maps JWT errors to user-friendly messages
+   */
+  private getAuthErrorMessage(error: any): string {
+    if (error?.name === "TokenExpiredError") {
+      return WebSocketMessage.TOKEN_EXPIRED;
+    }
+
+    if (error?.name === "JsonWebTokenError") {
+      return WebSocketMessage.INVALID_TOKEN;
+    }
+
+    if (error?.name === "NotBeforeError") {
+      return WebSocketMessage.INVALID_TOKEN;
+    }
+
+    return WebSocketMessage.INVALID_TOKEN;
+  }
+}