const { Conversation, Message, Plan, User } = require('../models');
const logger = require('../utils/logger');
const model1Service = require('../services/model1Service');
const chatRouter = require('../services/chatRouter');

const createConversation = async (req, res) => {
  try {
    const { title } = req.body;
    const userId = req.user.userId;

    const conversation = await Conversation.create({
      user_id: userId,
      title: title || 'New Conversation',
      status: 'active'
    });

    logger.info(`New conversation created: ${conversation.id}`);

    res.status(201).json({
      success: true,
      data: { conversation }
    });
  } catch (error) {
    logger.error('Create conversation error:', error);
    res.status(500).json({
      success: false,
      error: 'Internal server error'
    });
  }
};

const getConversations = async (req, res) => {
  try {
    const userId = req.user.userId;
    const { page = 1, limit = 10, status } = req.query;

    const whereClause = { user_id: userId };
    if (status) whereClause.status = status;

    const conversations = await Conversation.findAndCountAll({
      where: whereClause,
      include: [
        {
          model: Message,
          limit: 1,
          order: [['created_at', 'DESC']]
        }
      ],
      order: [['created_at', 'DESC']],
      limit: parseInt(limit),
      offset: (parseInt(page) - 1) * parseInt(limit)
    });

    res.json({
      success: true,
      data: {
        conversations: conversations.rows,
        pagination: {
          page: parseInt(page),
          limit: parseInt(limit),
          total: conversations.count,
          pages: Math.ceil(conversations.count / limit)
        }
      }
    });
  } catch (error) {
    logger.error('Get conversations error:', error);
    res.status(500).json({
      success: false,
      error: 'Internal server error'
    });
  }
};

const getConversation = async (req, res) => {
  try {
    const { conversationId } = req.params;
    const userId = req.user.userId;

    const conversation = await Conversation.findOne({
      where: {
        id: conversationId,
        user_id: userId
      },
      include: [
        {
          model: Message,
          order: [['created_at', 'ASC']]
        },
        {
          model: Plan,
          order: [['created_at', 'DESC']]
        }
      ]
    });

    if (!conversation) {
      return res.status(404).json({
        success: false,
        error: 'Conversation not found'
      });
    }

    res.json({
      success: true,
      data: { conversation }
    });
  } catch (error) {
    logger.error('Get conversation error:', error);
    res.status(500).json({
      success: false,
      error: 'Internal server error'
    });
  }
};

const sendMessage = async (req, res) => {
  try {
    const { conversationId, content, messageType = 'text' } = req.body;
    const userId = req.user.userId;

    // Verify conversation belongs to user
    const conversation = await Conversation.findOne({
      where: {
        id: conversationId,
        user_id: userId
      }
    });

    if (!conversation) {
      return res.status(404).json({
        success: false,
        error: 'Conversation not found'
      });
    }

    // Create user message
    const userMessage = await Message.create({
      conversation_id: conversationId,
      role: 'user',
      content,
      message_type: messageType
    });

    // Get conversation history for context
    const conversationHistory = await Message.findAll({
      where: { conversation_id: conversationId },
      order: [['created_at', 'DESC']],
      limit: 20 // Last 20 messages for context
    });

    // Create properly ordered conversation history for context
    const orderedHistory = conversationHistory.reverse().map(msg => ({
      role: msg.role,
      content: msg.content,
      message_type: msg.message_type,
      timestamp: msg.created_at
    }));

    // Route the message to determine response type
    const routingDecision = await chatRouter.routeMessage(content, {
      conversationId,
      userId,
      timestamp: new Date().toISOString(),
      conversationHistory: orderedHistory
    });

    let assistantMessage;

    if (routingDecision.responseType === 'plan_needed' && routingDecision.isEngineeringQuestion) {
      // Generate engineering plan using MODEL1
      try {
        const planData = await model1Service.generatePlan(content, {
          conversationId,
          userId,
          timestamp: new Date().toISOString()
        });

        // Save the plan to database
        const plan = await Plan.create({
          conversation_id: conversationId,
          title: planData.title,
          description: planData.description,
          steps: planData.steps,
          status: 'draft',
          tools_required: planData.toolsRequired || [],
          estimated_duration: planData.estimatedDuration,
          complexity_score: planData.complexityScore,
          metadata: {
            safetyConsiderations: planData.safetyConsiderations,
            qualityChecks: planData.qualityChecks,
            processingTime: planData.processingTime,
            tokensUsed: planData.tokensUsed,
            model: planData.model
          }
        });

        // Create assistant message with plan
        assistantMessage = await Message.create({
          conversation_id: conversationId,
          plan_id: plan.id,
          role: 'assistant',
          content: planData.rawContent || `# ${planData.title}\n\n${planData.description}\n\n## Steps:\n${planData.steps.map((step, index) => `${index + 1}. ${step}`).join('\n')}`,
          message_type: 'plan',
          metadata: {
            modelType: 'MODEL1',
            processingTime: planData.processingTime,
            tokensUsed: planData.tokensUsed,
            routingDecision: routingDecision.reasoning
          }
        });

        logger.info(`MODEL1 plan generated: ${plan.id} for conversation: ${conversationId}`);
      } catch (error) {
        logger.error('MODEL1 plan generation failed:', error);
        
        // Fallback to simple response if plan generation fails
        const fallbackResponse = await chatRouter.generateSimpleResponse(content, {
          conversationHistory: orderedHistory
        });
        assistantMessage = await Message.create({
          conversation_id: conversationId,
          role: 'assistant',
          content: fallbackResponse,
          message_type: 'text',
          metadata: {
            error: error.message,
            modelType: 'FALLBACK',
            routingDecision: routingDecision.reasoning
          }
        });
      }
    } else {
      // Generate simple conversational response
      const responseContent = routingDecision.response || await chatRouter.generateSimpleResponse(content, {
        conversationHistory: orderedHistory
      });
      
      assistantMessage = await Message.create({
        conversation_id: conversationId,
        role: 'assistant',
        content: responseContent,
        message_type: 'text',
        metadata: {
          modelType: 'REASONAI',
          routingDecision: routingDecision.reasoning,
          responseType: routingDecision.responseType
        }
      });

      logger.info(`Simple response generated for conversation: ${conversationId}`, {
        responseType: routingDecision.responseType,
        reasoning: routingDecision.reasoning
      });
    }

    logger.info(`Message sent in conversation: ${conversationId}`);

    res.json({
      success: true,
      data: { userMessage, assistantMessage }
    });
  } catch (error) {
    logger.error('Send message error:', error);
    res.status(500).json({
      success: false,
      error: 'Internal server error'
    });
  }
};

const updateConversation = async (req, res) => {
  try {
    const { conversationId } = req.params;
    const { title, status } = req.body;
    const userId = req.user.userId;

    const conversation = await Conversation.findOne({
      where: {
        id: conversationId,
        user_id: userId
      }
    });

    if (!conversation) {
      return res.status(404).json({
        success: false,
        error: 'Conversation not found'
      });
    }

    const updateData = {};
    if (title) updateData.title = title;
    if (status) updateData.status = status;

    await conversation.update(updateData);

    logger.info(`Conversation updated: ${conversationId}`);

    res.json({
      success: true,
      data: { conversation }
    });
  } catch (error) {
    logger.error('Update conversation error:', error);
    res.status(500).json({
      success: false,
      error: 'Internal server error'
    });
  }
};

const deleteConversation = async (req, res) => {
  try {
    const { conversationId } = req.params;
    const userId = req.user.userId;

    const conversation = await Conversation.findOne({
      where: {
        id: conversationId,
        user_id: userId
      }
    });

    if (!conversation) {
      return res.status(404).json({
        success: false,
        error: 'Conversation not found'
      });
    }

    await conversation.destroy();

    logger.info(`Conversation deleted: ${conversationId}`);

    res.json({
      success: true,
      message: 'Conversation deleted successfully'
    });
  } catch (error) {
    logger.error('Delete conversation error:', error);
    res.status(500).json({
      success: false,
      error: 'Internal server error'
    });
  }
};

module.exports = {
  createConversation,
  getConversations,
  getConversation,
  sendMessage,
  updateConversation,
  deleteConversation
};