reason-flow/server/services/chatRouter.js

const groqService = require('./groqService');
const model1Service = require('./model1Service');
const logger = require('../utils/logger');

class ChatRouter {
  constructor() {
    this.systemPrompt = `You are ReasonAI, a specialized engineering assistant. Your role is to:

1. **Identify Engineering Questions**: Determine if a user's message requires an engineering plan or is a simple question/conversation.

2. **Respond Appropriately**:
   - For engineering questions: Indicate that a plan should be generated
   - For simple questions/greetings: Provide helpful responses within your engineering scope
   - For conversation context: Use conversation history to provide relevant responses
   - For out-of-scope questions: Politely redirect to engineering topics

3. **Scope Boundaries**:
   - ✅ Engineering: Civil, mechanical, electrical, chemical, environmental, software engineering
   - ✅ Technical: Calculations, design, analysis, standards, codes, materials
   - ✅ Simple: Greetings, basic engineering concepts, "what is 2+2"
   - ✅ Conversation: Questions about previous messages, context, follow-ups
   - ❌ Out-of-scope: Sports, entertainment, politics, general knowledge outside engineering

4. **Context Awareness**: Use conversation history to provide relevant responses. If user asks about previous messages or context, respond helpfully.

5. Some questiosn might be engineering questions but not every questions requires a plan, if it can be answered straightforwardly, then it doesnt need a plan 

6. **Response Format (STRICT)**: Respond ONLY with a single, minified JSON object. No prose, no code fences, no backticks, no explanations. Use DOUBLE QUOTES for all keys and string values. If unsure, default to simple_response. The JSON schema is:
   {
     "isEngineeringQuestion": boolean,
     "responseType": "plan_needed" | "simple_response" | "out_of_scope",
     "response": "Your response to the user",
     "reasoning": "Why you classified it this way"
   }`;
  }

  async routeMessage(content, context = {}) {
    try {
      const messages = [
        {
          role: 'system',
          content: this.systemPrompt
        }
      ];

      // Add conversation history for context
      if (context.conversationHistory && context.conversationHistory.length > 0) {
        context.conversationHistory.forEach(msg => {
          messages.push({
            role: msg.role,
            content: msg.content
          });
        });
      }

      // Add current message
      messages.push({
        role: 'user',
        content: `Current user message: "${content}"\n\nContext: ${JSON.stringify(context)}\n\nConversation History: ${context.conversationHistory ? JSON.stringify(context.conversationHistory) : 'None'}`
      });

      const response = await groqService.generateResponse(messages, {
        temperature: 0.3,
        max_tokens: 4000
      });

      // Parse the JSON response
      let routingDecision;
      try {
        // Prefer fenced json block if present
        const fence = response.content.match(/```json\s*([\s\S]*?)```/i);
        const raw = fence ? fence[1] : (response.content.match(/\{[\s\S]*\}/) || [null])[0];
        if (!raw) throw new Error('No JSON found in response');

        // Trim whitespace and attempt strict parse
        const candidate = raw.trim();
        routingDecision = JSON.parse(candidate);
      } catch (parseError) {
        // Downgrade to warn to avoid noisy error logs for non-strict JSON
        logger.warn('Routing JSON parse failed; falling back to heuristic classification');
        
        // Smart fallback based on content analysis
        const lowerContent = content.toLowerCase();
        const engineeringKeywords = ['design', 'calculate', 'analyze', 'beam', 'steel', 'concrete', 'structure', 'load', 'stress', 'engineering', 'technical', 'specification', 'code', 'standard'];
        const isEngineering = engineeringKeywords.some(keyword => lowerContent.includes(keyword));
        
        routingDecision = {
          isEngineeringQuestion: isEngineering,
          responseType: isEngineering ? 'plan_needed' : 'simple_response',
          response: isEngineering ? 
            "I'll generate an engineering plan for your request." : 
            "I'm ReasonAI, your engineering assistant. I can help with engineering questions, calculations, and technical problems. How can I assist you today?",
          reasoning: "Fallback routing due to parse error"
        };
      }

      logger.info(`Message routed as: ${routingDecision.responseType}`, {
        content: content.substring(0, 100),
        reasoning: routingDecision.reasoning,
        conversationHistoryLength: context.conversationHistory ? context.conversationHistory.length : 0
      });

      return routingDecision;
    } catch (error) {
      logger.error('Chat routing error:', error);
      
      // Fallback response
      return {
        isEngineeringQuestion: false,
        responseType: 'simple_response',
        response: "I'm ReasonAI, your engineering assistant. I'm here to help with engineering questions and technical problems. How can I assist you today?",
        reasoning: "Routing service error"
      };
    }
  }

  async generateSimpleResponse(content, context = {}) {
    try {
      const messages = [
        {
          role: 'system',
          content: `You are ReasonAI, a friendly engineering assistant. Respond helpfully to the user's message while staying within your engineering scope. Be concise and professional. Consider the conversation history for context.`
        }
      ];

      // Add conversation history for context
      if (context.conversationHistory && context.conversationHistory.length > 0) {
        context.conversationHistory.forEach(msg => {
          messages.push({
            role: msg.role,
            content: msg.content
          });
        });
      }

      // Add current message
      messages.push({
        role: 'user',
        content: content
      });

      const response = await groqService.generateResponse(messages, {
        temperature: 0.7,
        max_tokens: 300
      });

      return response.content;
    } catch (error) {
      logger.error('Simple response generation error:', error);
      return "I'm ReasonAI, your engineering assistant. I can help with engineering questions, calculations, and technical problems. How can I assist you today?";
    }
  }
}

module.exports = new ChatRouter();