'use strict';
/**
 * ============================================================
 * © 2025 Diploy — a brand of Bisht Technologies Private Limited
 * Original Author: BTPL Engineering Team
 * Website: https://diploy.in
 * Contact: cs@diploy.in
 *
 * Distributed under the Envato / CodeCanyon License Agreement.
 * Licensed to the purchaser for use as defined by the
 * Envato Market (CodeCanyon) Regular or Extended License.
 *
 * You are NOT permitted to redistribute, resell, sublicense,
 * or share this source code, in whole or in part.
 * Respect the author's rights and Envato licensing terms.
 * ============================================================
 */

import { Router, Request, Response } from "express";
import { RouteContext, AuthRequest } from "./common";
import { eq, and } from "drizzle-orm";
import { llmModels, flows, FlowNode, FlowEdge, knowledgeBase } from "@shared/schema";
import { ElevenLabsService, isAgentOnSipPhoneNumber, getSipTrunkOutboundAddress } from "../services/elevenlabs";
import { ElevenLabsPoolService } from "../services/elevenlabs-pool";
import { OpenAIPoolService } from "../engines/plivo/services/openai-pool.service";
import { IncomingAgentService } from "../services/incoming-agent";
import { FlowAgentService } from "../services/flow-agent";
import { setupRAGToolForAgent, isRAGEnabled } from "../services/rag-elevenlabs-tool";

async function fetchWhatsappTemplateNames(userId: string): Promise<string[]> {
  try {
    const { importPlugin } = await import('../utils/plugin-import');
    const { metaWhatsAppService, whatswayService } = await importPlugin('plugins/messaging/index.ts');

    try {
      const metaSettings = await metaWhatsAppService.getSettings(userId);
      if (metaSettings && metaSettings.isActive) {
        const templates = await metaWhatsAppService.getTemplates(userId);
        const names = templates.map((t: any) => t.name);
        console.log(`📋 [WhatsApp Templates] Fetched ${names.length} Meta template(s) for user ${userId}`);
        return names;
      }
    } catch (metaErr: any) {
      console.log(`⚠️  [WhatsApp Templates] Meta fetch failed: ${metaErr.message}`);
    }

    try {
      const wwSettings = await whatswayService.getSettings(userId);
      if (wwSettings && wwSettings.isActive) {
        const templates = await whatswayService.getTemplates(userId);
        const names = templates.map((t: any) => t.name);
        console.log(`📋 [WhatsApp Templates] Fetched ${names.length} WhatsWay template(s) for user ${userId}`);
        return names;
      }
    } catch (wwErr: any) {
      console.log(`⚠️  [WhatsApp Templates] WhatsWay fetch failed: ${wwErr.message}`);
    }

    return [];
  } catch (err: any) {
    console.log(`⚠️  [WhatsApp Templates] Messaging plugin not available: ${err.message}`);
    return [];
  }
}

export function createAgentRoutes(ctx: RouteContext): Router {
  const router = Router();
  const { db, storage, authenticateToken, authenticateHybrid, elevenLabsService, upload } = ctx;

  // ========================================
  // Agent CRUD Routes
  // ========================================

  router.get("/api/agents", authenticateHybrid, async (req: AuthRequest, res: Response) => {
    try {
      let agents = await storage.getUserAgents(req.userId!);

      const typeFilter = req.query.type as string | undefined;
      if (typeFilter && (typeFilter === 'incoming' || typeFilter === 'flow')) {
        agents = agents.filter(agent => agent.type === typeFilter);
      }

      res.json(agents);
    } catch (error: any) {
      console.error("Get agents error:", error);
      res.status(500).json({ error: "Failed to get agents" });
    }
  });

  router.post("/api/agents", authenticateHybrid, async (req: AuthRequest, res: Response) => {
    try {
      const {
        type,
        name,
        voiceTone,
        personality,
        systemPrompt,
        config,
        elevenLabsVoiceId,
        firstMessage,
        language,
        llmModel,
        temperature,
        knowledgeBaseIds,
        transferEnabled,
        transferPhoneNumber,
        transferMessage,
        detectLanguageEnabled,
        endConversationEnabled,
        appointmentBookingEnabled,
        messagingEmailEnabled,
        messagingWhatsappEnabled,
        messagingEmailTemplate,
        messagingWhatsappTemplate,
        messagingWhatsappVariables,
        expressiveMode,
        voiceStability,
        voiceSimilarityBoost,
        voiceSpeed,
        turnTimeout,
        telephonyProvider,
        openaiVoice
      } = req.body;

      if (!type || (type !== 'incoming' && type !== 'flow')) {
        return res.status(400).json({ error: "Valid agent type is required (incoming or flow)" });
      }

      if (!name) {
        return res.status(400).json({ error: "Agent name is required" });
      }

      if (type === 'incoming' && !systemPrompt) {
        return res.status(400).json({ error: "System prompt is required for incoming agents" });
      }

      if (type === 'flow' && (!voiceTone || !personality)) {
        return res.status(400).json({ error: "Voice tone and personality are required for flow agents" });
      }

      // Voice validation depends on telephony provider
      // OpenAI-based providers (plivo, twilio_openai, openai-sip) use OpenAI voices, not ElevenLabs
      // SIP providers (elevenlabs-sip, openai-sip) need special handling
      const isOpenAIProvider = telephonyProvider === 'plivo' || telephonyProvider === 'twilio_openai' || telephonyProvider === 'openai-sip';
      const isSipProvider = telephonyProvider === 'elevenlabs-sip' || telephonyProvider === 'openai-sip';

      if (type === 'incoming') {
        if (isOpenAIProvider) {
          // OpenAI-based agents use OpenAI voices - openaiVoice has a default in schema ('alloy')
          // No validation needed as schema provides default
          console.log(`📞 Creating ${telephonyProvider} agent with OpenAI voice: ${openaiVoice || 'alloy'}`);
        } else {
          // Twilio/ElevenLabs agents require elevenLabsVoiceId
          if (!elevenLabsVoiceId) {
            return res.status(400).json({ error: "Voice ID is required for incoming agents" });
          }
        }
      }

      if (type === 'incoming' && transferEnabled && !transferPhoneNumber?.trim()) {
        return res.status(400).json({ error: "Transfer phone number is required when call transfer is enabled" });
      }

      // Sanitize sipPhoneNumberId: convert empty string to null to avoid foreign key constraint violation
      if ('sipPhoneNumberId' in req.body && req.body.sipPhoneNumberId === '') {
        req.body.sipPhoneNumberId = null;
      }

      const user = await storage.getUser(req.userId!);
      if (!user) {
        return res.status(404).json({ error: "User not found" });
      }

      const plan = await storage.getPlanByName(user.planType || 'free');
      if (!plan) {
        return res.status(500).json({ error: "Plan configuration not found" });
      }

      const existingAgents = await storage.getUserAgents(req.userId!);
      // Skip limit check if explicitly unlimited (-1 or 999)
      if (plan.maxAgents !== -1 && plan.maxAgents !== 999 && existingAgents.length >= plan.maxAgents) {
        return res.status(403).json({
          error: `Agent limit reached. Your ${plan.displayName} allows maximum ${plan.maxAgents} agent(s).`,
          upgradeRequired: true
        });
      }

      if (llmModel) {
        const { getUserPlanCapabilities } = await import('../services/membership-service');
        const capabilities = await getUserPlanCapabilities(req.userId!);

        if (!capabilities.canChooseLlm) {
          const { or } = await import('drizzle-orm');
          const requestedModel = await db
            .select({ tier: llmModels.tier })
            .from(llmModels)
            .where(or(eq(llmModels.name, llmModel), eq(llmModels.modelId, llmModel)))
            .limit(1);

          const modelTier = requestedModel.length > 0 ? requestedModel[0].tier : null;

          if (modelTier && modelTier !== 'free') {
            return res.status(403).json({
              error: "Plan upgrade required",
              message: `Your ${capabilities.planDisplayName} plan only allows free-tier LLM models. Please upgrade to Pro to use premium models.`,
              upgradeRequired: true
            });
          }
        }
      }

      let elevenLabsAgentId = null;
      let effectiveLlmModelId: string | null = "gpt-4o-mini";

      if (llmModel) {
        const modelRecord = await db
          .select({ modelId: llmModels.modelId })
          .from(llmModels)
          .where(eq(llmModels.name, llmModel))
          .limit(1);

        if (modelRecord.length > 0) {
          effectiveLlmModelId = modelRecord[0].modelId;
          console.log(`📝 Using user-selected LLM model: ${llmModel} → ${effectiveLlmModelId}`);
        } else {
          effectiveLlmModelId = llmModel;
          console.log(`📝 Using user-provided LLM model ID: ${effectiveLlmModelId}`);
        }

        // Sanitize the model ID for ElevenLabs compatibility
        effectiveLlmModelId = ElevenLabsService.sanitizeLlmModel(effectiveLlmModelId!);
      } else {
        const defaultSetting = await storage.getGlobalSetting('default_llm_free');
        if (defaultSetting?.value) {
          const displayName = String(defaultSetting.value).replace(/^"|"$/g, '');
          console.log(`📝 Admin default LLM display name: ${displayName}`);

          const modelRecord = await db
            .select({ modelId: llmModels.modelId })
            .from(llmModels)
            .where(eq(llmModels.name, displayName))
            .limit(1);

          if (modelRecord.length > 0) {
            effectiveLlmModelId = modelRecord[0].modelId;
            console.log(`📝 Resolved to model ID: ${effectiveLlmModelId}`);
          } else {
            console.log(`⚠️  Could not find model for "${displayName}", using default: ${effectiveLlmModelId}`);
          }
        }
      }

      // Validate that the model is a conversational model, not a transcription model
      // Transcription models like "scribe_v2_realtime" are not valid for ElevenLabs Conversational AI
      const INVALID_TRANSCRIPTION_MODELS = ['scribe_v2_realtime', 'scribe_v2', 'scribe'];
      if (effectiveLlmModelId && INVALID_TRANSCRIPTION_MODELS.some(m => effectiveLlmModelId!.toLowerCase().includes(m))) {
        return res.status(400).json({
          error: "Invalid LLM model for conversational agents",
          message: "Scribe models are designed for transcription, not conversational AI. Please select a different LLM model such as GPT-4o Mini, Claude 3, or Gemini."
        });
      }

      let usedCredentialId: string | null = null;

      // Only create ElevenLabs agent for Twilio-based incoming agents (not OpenAI providers)
      if (type === 'incoming' && !isOpenAIProvider) {
        const credential = await ElevenLabsPoolService.getUserCredential(req.userId!);
        if (!credential) {
          return res.status(500).json({ error: "No available ElevenLabs API keys" });
        }
        usedCredentialId = credential.id;

        try {
          const knowledgeBases: Array<{ type: string; title: string; elevenLabsDocId: string }> = [];
          if (knowledgeBaseIds && Array.isArray(knowledgeBaseIds) && knowledgeBaseIds.length > 0) {
            console.log(`📚 Preparing ${knowledgeBaseIds.length} knowledge base(s) for agent creation`);

            for (const kbId of knowledgeBaseIds) {
              try {
                const kbItem = await storage.getKnowledgeBaseItem(kbId);

                if (!kbItem) {
                  console.warn(`⚠️  Knowledge base item ${kbId} not found, skipping`);
                  continue;
                }

                if (!kbItem.elevenLabsDocId) {
                  console.warn(`⚠️  Knowledge base item ${kbId} has no ElevenLabs doc ID, skipping`);
                  continue;
                }

                console.log(`   Adding KB "${kbItem.title}" (${kbItem.elevenLabsDocId})`);
                knowledgeBases.push({
                  type: kbItem.type,
                  title: kbItem.title,
                  elevenLabsDocId: kbItem.elevenLabsDocId
                });
              } catch (error: any) {
                console.error(`   ❌ Failed to fetch KB ${kbId}:`, error.message);
              }
            }
          }

          const incomingElevenLabsService = new ElevenLabsService(credential.apiKey);

          const agentResponse = await incomingElevenLabsService.createAgent({
            name,
            voice_id: elevenLabsVoiceId,
            prompt: systemPrompt,
            first_message: firstMessage || "Hello! How can I help you today?",
            language: language || "en",
            model: effectiveLlmModelId!,
            temperature: temperature || 0.5,
            personality: personality || "helpful",
            voice_tone: voiceTone || "professional",
            knowledge_bases: knowledgeBases.length > 0 ? knowledgeBases : undefined,
            transferEnabled: transferEnabled || false,
            transferPhoneNumber: transferPhoneNumber || undefined,
            detectLanguageEnabled: detectLanguageEnabled || false,
            endConversationEnabled: endConversationEnabled || false,
            suggestedAudioTags: expressiveMode || false,
            voiceStability: voiceStability ?? 0.65,
            voiceSimilarityBoost: voiceSimilarityBoost ?? 0.85,
            voiceSpeed: voiceSpeed ?? 0.92,
            turnTimeout: turnTimeout ?? 1.5,
            skipWorkflow: true,
          });

          elevenLabsAgentId = agentResponse.agent_id;
        } catch (error) {
          console.error("Error creating ElevenLabs agent:", error);
          return res.status(500).json({ error: "Failed to create ElevenLabs agent" });
        }
      }

      // Log OpenAI-based agent creation
      if (type === 'incoming' && isOpenAIProvider) {
        console.log(`📞 [${telephonyProvider} Agent Create] Creating ${telephonyProvider} agent "${name}" with OpenAI voice: ${openaiVoice || 'alloy'}`);
      }

      if (type === 'flow') {
        const { flowId, maxDurationSeconds } = req.body;

        if (!flowId) {
          return res.status(400).json({ error: "Flow ID is required for flow agents" });
        }

        // Voice validation depends on telephony provider for flow agents
        if (isOpenAIProvider) {
          // OpenAI-based flow agents use OpenAI voices - openaiVoice has a default in schema ('alloy')
          console.log(`📞 [Flow Agent Create] Creating ${telephonyProvider} flow agent with OpenAI voice: ${openaiVoice || 'alloy'}`);
        } else {
          // ElevenLabs/Twilio flow agents require elevenLabsVoiceId
          if (!elevenLabsVoiceId) {
            return res.status(400).json({ error: "Voice ID is required for flow agents" });
          }
        }

        const [flow] = await db
          .select()
          .from(flows)
          .where(eq(flows.id, flowId));

        if (!flow) {
          return res.status(404).json({ error: "Selected flow not found" });
        }

        // For OpenAI-based flow agents (Plivo or Twilio+OpenAI), skip ElevenLabs agent creation
        // These flow agents will use OpenAI Realtime API directly during calls
        if (isOpenAIProvider) {
          console.log(`📞 [Flow Agent Create] Skipping ElevenLabs agent creation for ${telephonyProvider} flow agent`);
          // elevenLabsAgentId remains null for OpenAI-based flow agents
        } else {
          // ElevenLabs/Twilio flow agents - delegate to FlowAgentService for proper two-phase creation
          // This handles play audio nodes, appointment nodes, form nodes, and webhook tools correctly
          try {
            const result = await FlowAgentService.createInElevenLabs({
              userId: req.userId!,
              name,
              flowId,
              elevenLabsVoiceId: elevenLabsVoiceId!,
              systemPrompt: systemPrompt || undefined,
              firstMessage: firstMessage || undefined,
              language: language || 'en',
              llmModel: effectiveLlmModelId || undefined,
              temperature: temperature ?? 0.3,
              maxDurationSeconds: maxDurationSeconds || 600,
              voiceStability: voiceStability ?? 0.65,
              voiceSimilarityBoost: voiceSimilarityBoost ?? 0.85,
              voiceSpeed: voiceSpeed ?? 0.92,
              turnTimeout: turnTimeout ?? 1.5,
              detectLanguageEnabled: detectLanguageEnabled || false,
              expressiveMode: expressiveMode || false,
              knowledgeBaseIds: knowledgeBaseIds || undefined,
            });

            elevenLabsAgentId = result.elevenLabsAgentId;
            usedCredentialId = result.credentialId;
            console.log(`✅ [Flow Agent Create] ElevenLabs agent created via FlowAgentService: ${elevenLabsAgentId}`);
          } catch (error: any) {
            console.error("Error creating ElevenLabs Flow agent:", error);
            const statusCode = error.status || 500;
            return res.status(statusCode).json({
              error: "Failed to create ElevenLabs Flow agent",
              code: error.code || 'INTERNAL_ERROR'
            });
          }
        } // End of else block for non-OpenAI providers
      }

      const { flowId, maxDurationSeconds } = req.body;

      const agent = await storage.createAgent({
        userId: req.userId!,
        type,
        name,
        voiceTone: voiceTone || null,
        personality: personality || null,
        systemPrompt,
        config: config || null,
        elevenLabsAgentId,
        elevenLabsCredentialId: usedCredentialId,
        elevenLabsVoiceId: (type === 'incoming' || type === 'flow') ? elevenLabsVoiceId : null,
        firstMessage: (type === 'incoming' || type === 'flow') ? (firstMessage || null) : null,
        language: (type === 'incoming' || type === 'flow') ? (language || null) : null,
        llmModel: (type === 'incoming' || type === 'flow') ? effectiveLlmModelId : null,
        temperature: (type === 'incoming' || type === 'flow') ? (temperature ?? null) : null,
        knowledgeBaseIds: (type === 'incoming' || type === 'flow') ? (knowledgeBaseIds || null) : null,
        transferEnabled: type === 'incoming' ? (transferEnabled || false) : false,
        transferPhoneNumber: type === 'incoming' ? (transferPhoneNumber || null) : null,
        detectLanguageEnabled: (type === 'incoming' || type === 'flow') ? (detectLanguageEnabled || false) : false,
        endConversationEnabled: type === 'incoming' ? (endConversationEnabled || false) : false,
        appointmentBookingEnabled: type === 'incoming' ? (appointmentBookingEnabled || false) : false,
        messagingEmailEnabled: (type === 'incoming' || type === 'flow') ? (messagingEmailEnabled || false) : false,
        messagingWhatsappEnabled: (type === 'incoming' || type === 'flow') ? (messagingWhatsappEnabled || false) : false,
        messagingEmailTemplate: (type === 'incoming' || type === 'flow') ? (messagingEmailTemplate || null) : null,
        messagingWhatsappTemplate: (type === 'incoming' || type === 'flow') ? (messagingWhatsappTemplate || null) : null,
        messagingWhatsappVariables: (type === 'incoming' || type === 'flow') ? (messagingWhatsappVariables || null) : null,
        expressiveMode: (type === 'incoming' || type === 'flow') ? (expressiveMode || false) : false,
        flowId: type === 'flow' ? flowId : null,
        maxDurationSeconds: type === 'flow' ? (maxDurationSeconds || 600) : null,
        voiceStability: (type === 'incoming' || type === 'flow') ? (voiceStability ?? 0.65) : null,
        voiceSimilarityBoost: (type === 'incoming' || type === 'flow') ? (voiceSimilarityBoost ?? 0.85) : null,
        voiceSpeed: (type === 'incoming' || type === 'flow') ? (voiceSpeed ?? 0.92) : null,
        turnTimeout: (type === 'incoming' || type === 'flow') ? (turnTimeout ?? 1.5) : null,
        // Telephony provider: preserve SIP providers, OpenAI providers, otherwise default to twilio
        telephonyProvider: isSipProvider ? telephonyProvider : (isOpenAIProvider ? telephonyProvider : 'twilio'),
        openaiVoice: isOpenAIProvider ? (openaiVoice || 'alloy') : null,
      });

      if (usedCredentialId) {
        try {
          await ElevenLabsPoolService.updateAssignmentCount(usedCredentialId, true);
          console.log(`📊 [Agent Create] Incremented agent count for credential ${usedCredentialId}`);
        } catch (countError) {
          console.warn("Failed to update credential agent count:", countError);
        }
      }

      if (type === 'flow' && flowId) {
        try {
          await db
            .update(flows)
            .set({ agentId: agent.id })
            .where(eq(flows.id, flowId));
          console.log(`✅ [Flow Agent Create] Flow ${flowId} now references agent ${agent.id}`);

          await ElevenLabsPoolService.syncExistingAgents();
        } catch (poolError) {
          console.warn("Failed to update flow or sync agent to pool:", poolError);
        }
      }

      if (type === 'incoming') {
        try {
          await ElevenLabsPoolService.syncExistingAgents();
        } catch (poolError) {
          console.warn("Failed to sync incoming agent to pool:", poolError);
        }
      }

      let updatedAgent = agent;

      // If appointment booking is enabled for incoming agents, update ElevenLabs with the tool
      // The webhook URL uses the ElevenLabs agent ID which is available at this point
      if (type === 'incoming' && appointmentBookingEnabled && elevenLabsAgentId && usedCredentialId) {
        try {
          console.log(`📅 [Agent Create] Adding appointment booking tool for ElevenLabs agent ${elevenLabsAgentId}`);
          const credential = await ElevenLabsPoolService.getCredentialForAgent(agent.id);
          if (credential) {
            const appointmentElevenLabsService = new ElevenLabsService(credential.apiKey);
            await appointmentElevenLabsService.updateAgent(elevenLabsAgentId, {
              appointmentBookingEnabled: true,
              transferEnabled: transferEnabled || false,
              transferPhoneNumber: transferPhoneNumber || undefined,
              detectLanguageEnabled: detectLanguageEnabled || false,
              endConversationEnabled: endConversationEnabled || false,
              databaseAgentId: agent.id,
              skipWorkflowRebuild: true,
            });
            console.log(`✅ [Agent Create] Appointment booking tool added (with system tools preserved)`);
          }
        } catch (appointmentError) {
          console.warn("Failed to add appointment booking tool (non-fatal):", appointmentError);
        }
      }

      if (type === 'incoming' && (messagingEmailEnabled || messagingWhatsappEnabled) && elevenLabsAgentId && usedCredentialId) {
        try {
          console.log(`📨 [Agent Create] Adding messaging tools for ElevenLabs agent ${elevenLabsAgentId}`);

          let whatsappTemplateNames: string[] = [];
          if (messagingWhatsappEnabled) {
            whatsappTemplateNames = await fetchWhatsappTemplateNames(req.userId!);
          }

          const credential = await ElevenLabsPoolService.getCredentialForAgent(agent.id);
          if (credential) {
            const messagingElevenLabsService = new ElevenLabsService(credential.apiKey);
            await messagingElevenLabsService.updateAgent(elevenLabsAgentId, {
              messagingEmailEnabled: messagingEmailEnabled || false,
              messagingWhatsappEnabled: messagingWhatsappEnabled || false,
              messagingWhatsappTemplates: whatsappTemplateNames,
              messagingEmailSelectedTemplate: messagingEmailTemplate || undefined,
              messagingWhatsappSelectedTemplate: messagingWhatsappTemplate || undefined,
              messagingWhatsappVariables: messagingWhatsappVariables || undefined,
              transferEnabled: transferEnabled || false,
              transferPhoneNumber: transferPhoneNumber || undefined,
              detectLanguageEnabled: detectLanguageEnabled || false,
              endConversationEnabled: endConversationEnabled || false,
              appointmentBookingEnabled: appointmentBookingEnabled || false,
              databaseAgentId: agent.id,
              skipWorkflowRebuild: true,
            });
            console.log(`✅ [Agent Create] Messaging tools added`);
          }
        } catch (messagingError) {
          console.warn("Failed to add messaging tools (non-fatal):", messagingError);
        }
      }

      if (elevenLabsAgentId && isRAGEnabled() && knowledgeBaseIds && knowledgeBaseIds.length > 0) {
        try {
          console.log(`📚 [Agent Create] Setting up RAG workspace tool for agent ${agent.id}`);

          const systemTools: any[] = [];

          if (type === 'incoming') {
            if (transferEnabled && transferPhoneNumber) {
              let agentTransferType: "conference" | "sip_refer" = "conference";
              let sipTrunkAddress: string | null = null;
              try {
                if (await isAgentOnSipPhoneNumber(agent.id)) {
                  agentTransferType = "sip_refer";
                  sipTrunkAddress = await getSipTrunkOutboundAddress(agent.id);
                  console.log(`   📞 [Agent Create] SIP agent detected - using sip_refer transfer type (trunk: ${sipTrunkAddress})`);
                }
              } catch { }

              let transferDestination: any;
              if (agentTransferType === "sip_refer" && sipTrunkAddress) {
                const phoneNum = transferPhoneNumber.startsWith('+') ? transferPhoneNumber : `+${transferPhoneNumber}`;
                const sipUri = `sip:${phoneNum}@${sipTrunkAddress}`;
                transferDestination = { type: "sip_uri", sip_uri: sipUri };
                console.log(`   📞 [Agent Create] SIP REFER: ${phoneNum} → ${sipUri}`);
              } else {
                transferDestination = { type: "phone", phone_number: transferPhoneNumber };
              }

              systemTools.push({
                type: "system",
                name: "transfer_to_number",
                description: "Transfer the caller to a human agent when they request it or when you cannot handle their request.",
                params: {
                  system_tool_type: "transfer_to_number",
                  transfers: [
                    {
                      transfer_destination: transferDestination,
                      condition: "When the user asks to speak with a human or when the AI cannot handle the request.",
                      transfer_type: agentTransferType
                    }
                  ]
                }
              });
            }
            if (detectLanguageEnabled) {
              systemTools.push({
                type: "system",
                name: "language_detection",
                description: "Automatically detect and switch to the user's preferred language"
              });
            }
            if (endConversationEnabled) {
              systemTools.push({
                type: "system",
                name: "end_call",
                description: "End the call when the user is finished or says goodbye"
              });
            }
          }

          if (type === 'flow') {
            if (detectLanguageEnabled) {
              systemTools.push({
                type: "system",
                name: "language_detection",
                description: "Automatically detect and switch to the user's preferred language"
              });
            }
          }

          await setupRAGToolForAgent(
            elevenLabsAgentId,
            agent.id,
            knowledgeBaseIds && knowledgeBaseIds.length > 0,
            systemTools,
            type === 'incoming' ? (appointmentBookingEnabled || false) : false
          );
          console.log(`✅ [Agent Create] RAG tool setup complete`);

          updatedAgent = await storage.getAgent(agent.id) || agent;
        } catch (ragError) {
          console.warn("Failed to setup RAG tool (non-fatal):", ragError);
        }
      }

      if (elevenLabsVoiceId) {
        setImmediate(async () => {
          try {
            const { VoiceSyncService } = await import("../services/voice-sync");

            if (elevenLabsVoiceId.startsWith('21m00') || elevenLabsVoiceId.length < 20) {
              console.log(`🔊 Voice ${elevenLabsVoiceId} is a default voice, skipping sync`);
              return;
            }

            const agentCredential = usedCredentialId
              ? await ElevenLabsPoolService.getCredentialForAgent(agent.id)
              : null;
            const syncService = agentCredential
              ? new ElevenLabsService(agentCredential.apiKey)
              : elevenLabsService;

            const sharedVoices = await syncService.listSharedVoices({ search: '' });
            const matchingVoice = sharedVoices.voices.find(v => v.voice_id === elevenLabsVoiceId);

            if (matchingVoice?.public_owner_id) {
              console.log(`🔊 Starting async voice sync for ${elevenLabsVoiceId} (${matchingVoice.name})`);
              const result = await VoiceSyncService.syncVoiceToAllCredentials(
                elevenLabsVoiceId,
                matchingVoice.public_owner_id,
                matchingVoice.name
              );
              console.log(`🔊 Voice sync complete: ${result.synced} synced, ${result.failed} failed`);
            } else {
              console.log(`🔊 Voice ${elevenLabsVoiceId} not found in shared library, skipping pool sync`);
            }
          } catch (syncError) {
            console.warn(`⚠️ Async voice sync failed (non-fatal):`, syncError instanceof Error ? syncError.message : syncError);
          }
        });
      }

      res.json(updatedAgent);
    } catch (error: any) {
      console.error("Create agent error:", error);
      res.status(500).json({ error: "Failed to create agent" });
    }
  });

  router.get("/api/agents/:id", authenticateHybrid, async (req: AuthRequest, res: Response) => {
    try {
      const agent = await storage.getAgent(req.params.id);
      if (!agent || agent.userId !== req.userId) {
        return res.status(404).json({ error: "Agent not found" });
      }

      res.json(agent);
    } catch (error: any) {
      console.error("Get agent error:", error);
      res.status(500).json({ error: "Failed to get agent" });
    }
  });

  router.patch("/api/agents/:id", authenticateHybrid, async (req: AuthRequest, res: Response) => {
    try {
      const agent = await storage.getAgent(req.params.id);
      if (!agent || agent.userId !== req.userId) {
        return res.status(404).json({ error: "Agent not found" });
      }

      if (req.body.type && req.body.type !== agent.type) {
        return res.status(400).json({ error: "Cannot change agent type after creation" });
      }

      if (agent.type === 'incoming' && req.body.transferEnabled === true && !req.body.transferPhoneNumber?.trim()) {
        return res.status(400).json({ error: "Transfer phone number is required when call transfer is enabled" });
      }

      // Sanitize sipPhoneNumberId: convert empty string to null to avoid foreign key constraint violation
      if ('sipPhoneNumberId' in req.body && req.body.sipPhoneNumberId === '') {
        req.body.sipPhoneNumberId = null;
      }

      try {
        console.log(`📝 [Version History] Agent update for ${agent.id} (${agent.type})`);
        console.log(`   Request body keys: ${Object.keys(req.body).join(', ')}`);

        const latestVersion = await storage.getLatestAgentVersion(agent.id);
        const nextVersionNumber = (latestVersion?.versionNumber || 0) + 1;

        const currentSnapshot = {
          name: agent.name,
          type: agent.type,
          voiceTone: agent.voiceTone,
          personality: agent.personality,
          systemPrompt: agent.systemPrompt,
          language: agent.language,
          firstMessage: agent.firstMessage,
          llmModel: agent.llmModel,
          temperature: agent.temperature,
          elevenLabsVoiceId: agent.elevenLabsVoiceId,
          voiceStability: agent.voiceStability,
          voiceSimilarityBoost: agent.voiceSimilarityBoost,
          voiceSpeed: agent.voiceSpeed,
          transferPhoneNumber: agent.transferPhoneNumber,
          transferEnabled: agent.transferEnabled,
          detectLanguageEnabled: agent.detectLanguageEnabled,
          endConversationEnabled: agent.endConversationEnabled,
          knowledgeBaseIds: agent.knowledgeBaseIds,
          maxDurationSeconds: agent.maxDurationSeconds,
          config: agent.config as Record<string, unknown> | null,
        };

        const changedFields: string[] = [];
        const changeDescriptions: string[] = [];

        const fieldsToCheck = [
          'name', 'voiceTone', 'personality', 'systemPrompt', 'language',
          'firstMessage', 'llmModel', 'temperature', 'elevenLabsVoiceId',
          'voiceStability', 'voiceSimilarityBoost', 'voiceSpeed', 'turnTimeout',
          'transferPhoneNumber', 'transferEnabled', 'detectLanguageEnabled',
          'endConversationEnabled', 'knowledgeBaseIds', 'maxDurationSeconds',
          'flowId', 'config'
        ];

        for (const field of fieldsToCheck) {
          const reqValue = req.body[field];
          const agentValue = (agent as any)[field];

          if (reqValue !== undefined) {
            let hasChanged = false;

            if (field === 'config' || field === 'knowledgeBaseIds') {
              hasChanged = JSON.stringify(reqValue) !== JSON.stringify(agentValue);
            } else {
              hasChanged = reqValue !== agentValue;
            }

            if (hasChanged) {
              changedFields.push(field);
              if (field === 'systemPrompt' || field === 'firstMessage') {
                changeDescriptions.push(`Updated ${field.replace(/([A-Z])/g, ' $1').toLowerCase()}`);
              } else if (field === 'config') {
                changeDescriptions.push('Updated agent configuration');
              } else if (field === 'flowId') {
                changeDescriptions.push('Changed conversation flow');
              } else {
                changeDescriptions.push(`Changed ${field.replace(/([A-Z])/g, ' $1').toLowerCase()}`);
              }
            }
          }
        }

        if (changedFields.length > 0) {
          console.log(`   ✅ Creating version ${nextVersionNumber}: ${changedFields.join(', ')}`);
          await storage.createAgentVersion({
            agentId: agent.id,
            versionNumber: nextVersionNumber,
            snapshot: currentSnapshot,
            changesSummary: changeDescriptions.join(', ') || 'Configuration updated',
            changedFields,
            editedBy: req.userId!,
            note: null,
          });
        } else {
          console.log(`   ⏭️ No changes detected, skipping version creation`);
        }
      } catch (versionError) {
        console.warn("Failed to create agent version:", versionError);
      }

      const {
        name,
        systemPrompt,
        elevenLabsVoiceId,
        language,
        llmModel,
        knowledgeBaseIds,
        transferEnabled,
        transferPhoneNumber,
        detectLanguageEnabled,
        endConversationEnabled,
        appointmentBookingEnabled,
        messagingEmailEnabled,
        messagingWhatsappEnabled,
        messagingEmailTemplate,
        messagingWhatsappTemplate,
        messagingWhatsappVariables,
        expressiveMode,
        flowId: newFlowId,
        maxDurationSeconds: newMaxDuration,
        voiceStability,
        voiceSimilarityBoost,
        voiceSpeed,
        turnTimeout
      } = req.body;

      if (llmModel && llmModel !== agent.llmModel) {
        const { getUserPlanCapabilities } = await import('../services/membership-service');
        const capabilities = await getUserPlanCapabilities(req.userId!);

        if (!capabilities.canChooseLlm) {
          const { or } = await import('drizzle-orm');
          const requestedModel = await db
            .select({ tier: llmModels.tier })
            .from(llmModels)
            .where(or(eq(llmModels.name, llmModel), eq(llmModels.modelId, llmModel)))
            .limit(1);

          const modelTier = requestedModel.length > 0 ? requestedModel[0].tier : null;

          if (modelTier && modelTier !== 'free') {
            return res.status(403).json({
              error: "Plan upgrade required",
              message: `Your ${capabilities.planDisplayName} plan only allows free-tier LLM models. Please upgrade to Pro to use premium models.`,
              upgradeRequired: true
            });
          }
        }
      }

      if (agent.type === 'flow') {
        if (agent.elevenLabsAgentId) {
          try {
            await FlowAgentService.updateInElevenLabs(
              agent.id,
              agent.elevenLabsAgentId,
              agent,
              {
                name,
                flowId: newFlowId,
                elevenLabsVoiceId,
                systemPrompt,
                firstMessage: req.body.firstMessage,
                language,
                llmModel,
                temperature: req.body.temperature,
                maxDurationSeconds: newMaxDuration,
                detectLanguageEnabled,
                knowledgeBaseIds,
                voiceStability,
                voiceSimilarityBoost,
                voiceSpeed,
                turnTimeout,
                expressiveMode,
                messagingEmailEnabled: req.body.messagingEmailEnabled,
                messagingWhatsappEnabled: req.body.messagingWhatsappEnabled,
                messagingEmailTemplate: req.body.messagingEmailTemplate,
                messagingWhatsappTemplate: req.body.messagingWhatsappTemplate,
                messagingWhatsappVariables: req.body.messagingWhatsappVariables,
              }
            );
          } catch (syncError: any) {
            console.error(`❌ Flow agent ElevenLabs sync failed:`);
            console.error(`   Agent ID: ${agent.id}`);
            console.error(`   ElevenLabs Agent ID: ${agent.elevenLabsAgentId}`);
            console.error(`   Flow ID: ${newFlowId || agent.flowId || 'none'}`);
            console.error(`   Error: ${syncError.message}`);
            if (syncError.details) {
              console.error(`   Details:`, JSON.stringify(syncError.details, null, 2));
            }
            if (syncError.stack) {
              console.error(`   Stack:`, syncError.stack.split('\n').slice(0, 5).join('\n'));
            }
            return res.status(500).json({
              error: "Failed to sync changes to ElevenLabs",
              details: syncError.message
            });
          }
        }

        let resolvedLlmModel: string | null = agent.llmModel;
        if (llmModel) {
          const modelRecord = await db
            .select({ modelId: llmModels.modelId })
            .from(llmModels)
            .where(eq(llmModels.name, llmModel))
            .limit(1);
          resolvedLlmModel = modelRecord.length > 0 ? modelRecord[0].modelId : llmModel;

          // Sanitize the model ID for ElevenLabs compatibility
          resolvedLlmModel = ElevenLabsService.sanitizeLlmModel(resolvedLlmModel || undefined);
        }

        const flowAgentUpdateBody = {
          ...req.body,
          llmModel: resolvedLlmModel || agent.llmModel,
          temperature: req.body.temperature !== undefined ? req.body.temperature : agent.temperature,
          knowledgeBaseIds: knowledgeBaseIds !== undefined ? knowledgeBaseIds : agent.knowledgeBaseIds,
        };
        await storage.updateAgent(req.params.id, flowAgentUpdateBody);
        const updatedAgent = await storage.getAgent(req.params.id);
        return res.json(updatedAgent);
      }

      if (agent.type === 'incoming') {
        await storage.updateAgent(req.params.id, req.body);

        const updatedAgent = await storage.getAgent(req.params.id);
        if (!updatedAgent) {
          return res.status(500).json({ error: "Failed to retrieve updated agent" });
        }

        if (updatedAgent.elevenLabsAgentId) {
          try {
            let whatsappTemplateNames: string[] = [];
            const effectiveWhatsappEnabled = messagingWhatsappEnabled !== undefined
              ? messagingWhatsappEnabled
              : agent.messagingWhatsappEnabled;
            if (effectiveWhatsappEnabled) {
              whatsappTemplateNames = await fetchWhatsappTemplateNames(req.userId!);
            }

            await IncomingAgentService.updateInElevenLabs(
              agent.id,
              updatedAgent.elevenLabsAgentId,
              agent,
              {
                name,
                systemPrompt,
                elevenLabsVoiceId,
                firstMessage: req.body.firstMessage,
                language,
                llmModel,
                temperature: req.body.temperature,
                knowledgeBaseIds,
                transferEnabled,
                transferPhoneNumber,
                detectLanguageEnabled,
                endConversationEnabled,
                appointmentBookingEnabled,
                messagingEmailEnabled,
                messagingWhatsappEnabled,
                messagingWhatsappTemplates: whatsappTemplateNames,
                messagingEmailSelectedTemplate: messagingEmailTemplate || updatedAgent.messagingEmailTemplate || undefined,
                messagingWhatsappSelectedTemplate: messagingWhatsappTemplate || updatedAgent.messagingWhatsappTemplate || undefined,
                messagingWhatsappVariables: messagingWhatsappVariables || updatedAgent.messagingWhatsappVariables || undefined,
                expressiveMode,
                voiceStability,
                voiceSimilarityBoost,
                voiceSpeed,
                turnTimeout,
                databaseAgentId: agent.id,
              }
            );
          } catch (error: any) {
            console.error("Failed to sync Incoming agent to ElevenLabs:", error);
          }
        }

        return res.json(updatedAgent);
      }

      await storage.updateAgent(req.params.id, req.body);
      const updatedAgent = await storage.getAgent(req.params.id);
      if (!updatedAgent) {
        return res.status(500).json({ error: "Failed to retrieve updated agent" });
      }

      res.json(updatedAgent);
    } catch (error: any) {
      console.error("Update agent error:", error);
      res.status(500).json({ error: "Failed to update agent" });
    }
  });

  router.delete("/api/agents/:id", authenticateHybrid, async (req: AuthRequest, res: Response) => {
    try {
      const agent = await storage.getAgent(req.params.id);
      if (!agent || agent.userId !== req.userId) {
        return res.status(404).json({ error: "Agent not found" });
      }

      if (agent.elevenLabsAgentId) {
        try {
          const credential = await ElevenLabsPoolService.getCredentialForAgent(agent.id);
          if (credential) {
            const agentElevenLabsService = new ElevenLabsService(credential.apiKey);
            await agentElevenLabsService.deleteAgent(agent.elevenLabsAgentId);
            console.log(`✅ Deleted agent ${agent.name} from ElevenLabs (${agent.elevenLabsAgentId})`);
          } else {
            await elevenLabsService.deleteAgent(agent.elevenLabsAgentId);
            console.log(`✅ Deleted agent ${agent.name} from ElevenLabs using default credential`);
          }
        } catch (elevenLabsError: any) {
          console.error(`⚠️ Failed to delete from ElevenLabs (will still delete from database):`, elevenLabsError.message);
        }
      }

      if (agent.elevenLabsCredentialId) {
        try {
          await ElevenLabsPoolService.updateAssignmentCount(agent.elevenLabsCredentialId, false);
          console.log(`📊 [Agent Delete] Decremented agent count for credential ${agent.elevenLabsCredentialId}`);
        } catch (countError) {
          console.warn("Failed to update credential agent count:", countError);
        }
      }

      await storage.deleteAgent(req.params.id);
      res.json({ success: true });
    } catch (error: any) {
      console.error("Delete agent error:", error);
      res.status(500).json({ error: "Failed to delete agent" });
    }
  });

  // ========================================
  // Knowledge Base Routes
  // ========================================

  router.get("/api/knowledge-base", authenticateHybrid, async (req: AuthRequest, res: Response) => {
    try {
      const items = await storage.getUserKnowledgeBase(req.userId!);
      res.json(items);
    } catch (error: any) {
      console.error("Get knowledge base error:", error);
      res.status(500).json({ error: "Failed to get knowledge base" });
    }
  });

  router.post("/api/knowledge-base", authenticateHybrid, async (req: AuthRequest, res: Response) => {
    try {
      const { type, title, content, url, metadata } = req.body;

      if (!type || !title) {
        return res.status(400).json({ error: "Type and title are required" });
      }

      const currentCount = await storage.getUserKnowledgeBaseCount(req.userId!);
      const limits = await storage.getUserEffectiveLimits(req.userId!);
      const maxKnowledgeBases = typeof limits.maxKnowledgeBases === 'number' ? limits.maxKnowledgeBases : 5;

      // Skip limit check if explicitly unlimited (999 or -1)
      if (maxKnowledgeBases !== 999 && maxKnowledgeBases !== -1 && currentCount >= maxKnowledgeBases) {
        return res.status(403).json({
          error: `Knowledge base limit reached (${maxKnowledgeBases}). Upgrade your plan or contact support to increase your limit.`
        });
      }

      const storageSize = content ? content.length : 0;

      const item = await storage.createKnowledgeBaseItem({
        userId: req.userId!,
        type,
        title,
        content: content || null,
        url: url || null,
        fileUrl: null,
        metadata: metadata || null,
        storageSize,
      });

      res.json(item);
    } catch (error: any) {
      console.error("Create knowledge base item error:", error);
      res.status(500).json({ error: "Failed to create knowledge base item" });
    }
  });

  router.post("/api/knowledge-base/upload", authenticateHybrid, upload.single('file'), async (req: AuthRequest, res: Response) => {
    try {
      if (!req.file) {
        return res.status(400).json({ error: "No file uploaded" });
      }

      const currentCount = await storage.getUserKnowledgeBaseCount(req.userId!);
      const limits = await storage.getUserEffectiveLimits(req.userId!);
      const maxKnowledgeBases = typeof limits.maxKnowledgeBases === 'number' ? limits.maxKnowledgeBases : 5;

      // Skip limit check if explicitly unlimited (999 or -1)
      if (maxKnowledgeBases !== 999 && maxKnowledgeBases !== -1 && currentCount >= maxKnowledgeBases) {
        return res.status(403).json({
          error: `Knowledge base limit reached (${maxKnowledgeBases}). Upgrade your plan or contact support to increase your limit.`
        });
      }

      const { name } = req.body;
      const filename = req.file.originalname;

      if (req.file.size > 20 * 1024 * 1024) {
        return res.status(400).json({ error: "File size exceeds 20MB limit" });
      }

      const elevenLabsResult = await elevenLabsService.uploadKnowledgeBaseFile(
        req.file.buffer,
        filename,
        name || filename
      );

      const item = await storage.createKnowledgeBaseItem({
        userId: req.userId!,
        type: 'file',
        title: name || filename,
        content: null,
        url: null,
        fileUrl: filename,
        elevenLabsDocId: elevenLabsResult.id,
        metadata: { filename, mimeType: req.file.mimetype },
        storageSize: req.file.size,
      });

      res.json(item);
    } catch (error: any) {
      console.error("Upload knowledge base file error:", error);
      res.status(500).json({ error: "Failed to upload file" });
    }
  });

  router.post("/api/knowledge-base/url", authenticateHybrid, async (req: AuthRequest, res: Response) => {
    try {
      const { url, name } = req.body;

      if (!url) {
        return res.status(400).json({ error: "URL is required" });
      }

      const currentCount = await storage.getUserKnowledgeBaseCount(req.userId!);
      const limits = await storage.getUserEffectiveLimits(req.userId!);
      const maxKnowledgeBases = typeof limits.maxKnowledgeBases === 'number' ? limits.maxKnowledgeBases : 5;

      // Skip limit check if explicitly unlimited (999 or -1)
      if (maxKnowledgeBases !== 999 && maxKnowledgeBases !== -1 && currentCount >= maxKnowledgeBases) {
        return res.status(403).json({
          error: `Knowledge base limit reached (${maxKnowledgeBases}). Upgrade your plan or contact support to increase your limit.`
        });
      }

      const elevenLabsResult = await elevenLabsService.addKnowledgeBaseFromUrl(url, name);

      const item = await storage.createKnowledgeBaseItem({
        userId: req.userId!,
        type: 'url',
        title: name || url,
        content: null,
        url: url,
        fileUrl: null,
        elevenLabsDocId: elevenLabsResult.id,
        metadata: { url },
        storageSize: 0,
      });

      res.json(item);
    } catch (error: any) {
      console.error("Add knowledge base URL error:", error);
      res.status(500).json({ error: "Failed to add URL" });
    }
  });

  router.post("/api/knowledge-base/text", authenticateHybrid, async (req: AuthRequest, res: Response) => {
    try {
      const { text, name } = req.body;

      if (!text || !name) {
        return res.status(400).json({ error: "Text and name are required" });
      }

      const currentCount = await storage.getUserKnowledgeBaseCount(req.userId!);
      const limits = await storage.getUserEffectiveLimits(req.userId!);
      const maxKnowledgeBases = typeof limits.maxKnowledgeBases === 'number' ? limits.maxKnowledgeBases : 5;

      // Skip limit check if explicitly unlimited (999 or -1)
      if (maxKnowledgeBases !== 999 && maxKnowledgeBases !== -1 && currentCount >= maxKnowledgeBases) {
        return res.status(403).json({
          error: `Knowledge base limit reached (${maxKnowledgeBases}). Upgrade your plan or contact support to increase your limit.`
        });
      }

      if (text.length > 300000) {
        return res.status(400).json({ error: "Text exceeds 300,000 character limit" });
      }

      const elevenLabsResult = await elevenLabsService.addKnowledgeBaseFromText(text, name);

      const item = await storage.createKnowledgeBaseItem({
        userId: req.userId!,
        type: 'text',
        title: name,
        content: text,
        url: null,
        fileUrl: null,
        elevenLabsDocId: elevenLabsResult.id,
        metadata: null,
        storageSize: text.length,
      });

      res.json(item);
    } catch (error: any) {
      console.error("Add knowledge base text error:", error);
      res.status(500).json({ error: "Failed to add text" });
    }
  });

  router.delete("/api/knowledge-base/:id", authenticateHybrid, async (req: AuthRequest, res: Response) => {
    try {
      const item = await storage.getKnowledgeBaseItem(req.params.id);
      if (!item || item.userId !== req.userId) {
        return res.status(404).json({ error: "Knowledge base item not found" });
      }

      if (item.elevenLabsDocId) {
        try {
          await elevenLabsService.deleteKnowledgeBase(item.elevenLabsDocId);
        } catch (elevenLabsError: any) {
          console.error("Failed to delete from ElevenLabs:", elevenLabsError.message);
        }
      }

      await storage.deleteKnowledgeBaseItem(req.params.id);
      res.json({ success: true });
    } catch (error: any) {
      console.error("Delete knowledge base item error:", error);
      res.status(500).json({ error: "Failed to delete knowledge base item" });
    }
  });

  // ========================================
  // Agent Version History Routes
  // ========================================

  router.get("/api/agents/:agentId/versions", authenticateHybrid, async (req: AuthRequest, res: Response) => {
    try {
      const agent = await storage.getAgent(req.params.agentId);
      if (!agent) {
        return res.status(404).json({ error: "Agent not found" });
      }
      if (agent.userId !== req.userId) {
        return res.status(403).json({ error: "Access denied" });
      }

      const versions = await storage.getAgentVersions(req.params.agentId);
      res.json(versions);
    } catch (error: any) {
      console.error("Get agent versions error:", error);
      res.status(500).json({ error: "Failed to get agent versions" });
    }
  });

  router.get("/api/agents/:agentId/versions/:versionNumber", authenticateHybrid, async (req: AuthRequest, res: Response) => {
    try {
      const agent = await storage.getAgent(req.params.agentId);
      if (!agent) {
        return res.status(404).json({ error: "Agent not found" });
      }
      if (agent.userId !== req.userId) {
        return res.status(403).json({ error: "Access denied" });
      }

      const versionNumber = parseInt(req.params.versionNumber, 10);
      if (isNaN(versionNumber)) {
        return res.status(400).json({ error: "Invalid version number" });
      }

      const version = await storage.getAgentVersionByNumber(req.params.agentId, versionNumber);
      if (!version) {
        return res.status(404).json({ error: "Version not found" });
      }

      res.json(version);
    } catch (error: any) {
      console.error("Get agent version error:", error);
      res.status(500).json({ error: "Failed to get agent version" });
    }
  });

  router.post("/api/agents/:agentId/versions/:versionNumber/rollback", authenticateHybrid, async (req: AuthRequest, res: Response) => {
    try {
      const agent = await storage.getAgent(req.params.agentId);
      if (!agent) {
        return res.status(404).json({ error: "Agent not found" });
      }
      if (agent.userId !== req.userId) {
        return res.status(403).json({ error: "Access denied" });
      }

      const versionNumber = parseInt(req.params.versionNumber, 10);
      if (isNaN(versionNumber)) {
        return res.status(400).json({ error: "Invalid version number" });
      }

      const targetVersion = await storage.getAgentVersionByNumber(req.params.agentId, versionNumber);
      if (!targetVersion) {
        return res.status(404).json({ error: "Version not found" });
      }

      const latestVersion = await storage.getLatestAgentVersion(req.params.agentId);
      const nextVersionNumber = (latestVersion?.versionNumber || 0) + 1;

      const currentSnapshot = {
        name: agent.name,
        type: agent.type,
        voiceTone: agent.voiceTone,
        personality: agent.personality,
        systemPrompt: agent.systemPrompt,
        language: agent.language,
        firstMessage: agent.firstMessage,
        llmModel: agent.llmModel,
        temperature: agent.temperature,
        elevenLabsVoiceId: agent.elevenLabsVoiceId,
        voiceStability: agent.voiceStability,
        voiceSimilarityBoost: agent.voiceSimilarityBoost,
        voiceSpeed: agent.voiceSpeed,
        transferPhoneNumber: agent.transferPhoneNumber,
        transferEnabled: agent.transferEnabled,
        detectLanguageEnabled: agent.detectLanguageEnabled,
        endConversationEnabled: agent.endConversationEnabled,
        knowledgeBaseIds: agent.knowledgeBaseIds,
        maxDurationSeconds: agent.maxDurationSeconds,
        config: agent.config as Record<string, unknown> | null,
      };

      await storage.createAgentVersion({
        agentId: req.params.agentId,
        versionNumber: nextVersionNumber,
        snapshot: currentSnapshot,
        changesSummary: `Snapshot before rollback to version ${versionNumber}`,
        changedFields: [],
        editedBy: req.userId!,
        note: req.body.note || null,
      });

      const targetSnapshot = targetVersion.snapshot as typeof currentSnapshot;
      await storage.updateAgent(req.params.agentId, {
        name: targetSnapshot.name,
        voiceTone: targetSnapshot.voiceTone,
        personality: targetSnapshot.personality,
        systemPrompt: targetSnapshot.systemPrompt,
        language: targetSnapshot.language,
        firstMessage: targetSnapshot.firstMessage,
        llmModel: targetSnapshot.llmModel,
        temperature: targetSnapshot.temperature,
        elevenLabsVoiceId: targetSnapshot.elevenLabsVoiceId,
        voiceStability: targetSnapshot.voiceStability,
        voiceSimilarityBoost: targetSnapshot.voiceSimilarityBoost,
        voiceSpeed: targetSnapshot.voiceSpeed,
        transferPhoneNumber: targetSnapshot.transferPhoneNumber,
        transferEnabled: targetSnapshot.transferEnabled,
        detectLanguageEnabled: targetSnapshot.detectLanguageEnabled,
        endConversationEnabled: targetSnapshot.endConversationEnabled,
        knowledgeBaseIds: targetSnapshot.knowledgeBaseIds,
        maxDurationSeconds: targetSnapshot.maxDurationSeconds,
        config: targetSnapshot.config,
        updatedAt: new Date(),
      });

      if (agent.elevenLabsAgentId) {
        try {
          const credential = await ElevenLabsPoolService.getCredentialForAgent(agent.id);
          if (credential) {
            const rollbackElevenLabsService = new ElevenLabsService(credential.apiKey);
            await rollbackElevenLabsService.updateAgent(agent.elevenLabsAgentId, {
              name: targetSnapshot.name,
              first_message: targetSnapshot.firstMessage || undefined,
              prompt: targetSnapshot.systemPrompt || undefined,
              voice_id: targetSnapshot.elevenLabsVoiceId || undefined,
              language: targetSnapshot.language || 'en',
              model: targetSnapshot.llmModel || undefined,
              temperature: targetSnapshot.temperature || undefined,
            });
          }
        } catch (syncError) {
          console.warn("Failed to sync rollback with ElevenLabs:", syncError);
        }
      }

      const updatedAgent = await storage.getAgent(req.params.agentId);

      res.json({
        success: true,
        message: `Rolled back to version ${versionNumber}`,
        agent: updatedAgent,
        previousVersionNumber: nextVersionNumber,
      });
    } catch (error: any) {
      console.error("Rollback agent version error:", error);
      res.status(500).json({ error: "Failed to rollback agent version" });
    }
  });

  // ========================================
  // Voices Routes (Agent-related)
  // ========================================

  router.get("/api/voices", authenticateHybrid, async (req: AuthRequest, res: Response) => {
    try {
      const voices = await storage.getUserVoices(req.userId!);
      res.json(voices);
    } catch (error: any) {
      console.error("Get voices error:", error);
      res.status(500).json({ error: "Failed to get voices" });
    }
  });

  router.post("/api/voices/preview", authenticateHybrid, async (req: AuthRequest, res: Response) => {
    try {
      const { voiceId, text, voiceSettings, modelId, language } = req.body;

      if (!voiceId) {
        return res.status(400).json({ error: "Voice ID is required" });
      }

      const defaultPreviewTexts: Record<string, string> = {
        en: "Hello! This is a preview of how I'll sound. I can adjust my tone and style based on your preferences.",
        es: "¡Hola! Esta es una vista previa de cómo sonaré. Puedo ajustar mi tono y estilo según tus preferencias.",
        fr: "Bonjour ! Voici un aperçu de ma voix. Je peux ajuster mon ton et mon style selon vos préférences.",
        de: "Hallo! Dies ist eine Vorschau meiner Stimme. Ich kann meinen Ton und Stil an Ihre Wünsche anpassen.",
        it: "Ciao! Questa è un'anteprima di come suonerò. Posso adattare il mio tono e stile in base alle tue preferenze.",
        pt: "Olá! Esta é uma prévia de como vou soar. Posso ajustar meu tom e estilo de acordo com suas preferências.",
        ar: "مرحباً! هذه معاينة لصوتي. يمكنني تعديل نبرتي وأسلوبي حسب تفضيلاتك.",
        hi: "नमस्ते! यह मेरी आवाज़ का पूर्वावलोकन है। मैं आपकी पसंद के अनुसार अपनी आवाज़ और शैली बदल सकता हूँ।",
        ja: "こんにちは！これは私の声のプレビューです。あなたの好みに合わせてトーンやスタイルを調整できます。",
        ko: "안녕하세요! 이것은 제 목소리의 미리보기입니다. 귀하의 선호도에 따라 톤과 스타일을 조정할 수 있습니다.",
        zh: "你好！这是我声音的预览。我可以根据你的喜好调整语调和风格。",
        nl: "Hallo! Dit is een voorbeeld van hoe ik zal klinken. Ik kan mijn toon en stijl aanpassen aan uw voorkeuren.",
        pl: "Cześć! To podgląd mojego głosu. Mogę dostosować ton i styl do Twoich preferencji.",
        ru: "Привет! Это предварительный просмотр моего голоса. Я могу настроить тон и стиль в соответствии с вашими предпочтениями.",
        tr: "Merhaba! Bu sesimin bir ön izlemesidir. Tercihlerinize göre tonumu ve tarzımı ayarlayabilirim.",
        uk: "Привіт! Це попередній перегляд мого голосу. Я можу налаштувати тон і стиль відповідно до ваших уподобань.",
      };
      const langKey = language ? language.substring(0, 2).toLowerCase() : "en";
      const previewText = text || defaultPreviewTexts[langKey] || defaultPreviewTexts["en"];

      if (previewText.length > 500) {
        return res.status(400).json({ error: "Preview text cannot exceed 500 characters" });
      }

      const credential = await ElevenLabsPoolService.getUserCredential(req.userId!);
      if (!credential) {
        return res.status(500).json({ error: "No available ElevenLabs API keys" });
      }

      const previewService = new ElevenLabsService(credential.apiKey);

      const audioBuffer = await previewService.generateVoicePreview({
        voiceId,
        text: previewText,
        voiceSettings,
        modelId,
      });

      res.setHeader('Content-Type', 'audio/mpeg');
      res.setHeader('Content-Length', audioBuffer.length);
      res.setHeader('Cache-Control', 'no-cache');

      res.send(audioBuffer);
    } catch (error: any) {
      console.error("Voice preview error:", error);
      res.status(500).json({ error: "Failed to generate voice preview" });
    }
  });

  // ========================================
  // OpenAI Voice Preview Route
  // ========================================

  router.post("/api/openai/voices/preview", authenticateHybrid, async (req: AuthRequest, res: Response) => {
    try {
      const { voiceId, text, speed } = req.body;

      if (!voiceId) {
        return res.status(400).json({ error: "Voice ID is required" });
      }

      const validVoices = ["alloy", "echo", "shimmer", "ash", "ballad", "coral", "sage", "verse", "cedar", "marin"];
      if (!validVoices.includes(voiceId)) {
        return res.status(400).json({ error: `Invalid voice. Must be one of: ${validVoices.join(", ")}` });
      }

      const previewText = text || "Hello! This is a preview of how I'll sound. I can adjust my tone and style based on your preferences.";

      if (previewText.length > 500) {
        return res.status(400).json({ error: "Preview text cannot exceed 500 characters" });
      }

      const credential = await OpenAIPoolService.getLeastLoadedCredential();
      if (!credential) {
        return res.status(500).json({ error: "No available OpenAI API keys" });
      }

      const response = await fetch("https://api.openai.com/v1/audio/speech", {
        method: "POST",
        headers: {
          "Authorization": `Bearer ${credential.apiKey}`,
          "Content-Type": "application/json",
        },
        body: JSON.stringify({
          model: "tts-1",
          input: previewText,
          voice: voiceId,
          response_format: "mp3",
          speed: speed || 1.0,
        }),
      });

      if (!response.ok) {
        const errorText = await response.text();
        console.error("OpenAI TTS error:", errorText);
        return res.status(500).json({ error: "Failed to generate voice preview" });
      }

      const audioBuffer = Buffer.from(await response.arrayBuffer());

      res.setHeader('Content-Type', 'audio/mpeg');
      res.setHeader('Content-Length', audioBuffer.length);
      res.setHeader('Cache-Control', 'no-cache');

      res.send(audioBuffer);
    } catch (error: any) {
      console.error("OpenAI voice preview error:", error);
      res.status(500).json({ error: "Failed to generate voice preview" });
    }
  });

  return router;
}