const Conversation = require('../models/Conversation');
const Message = require('../models/Message');
const Joi = require('joi');

// Validation schemas
const createConversationSchema = Joi.object({
  title: Joi.string().min(1).max(100).required()
});

const updateConversationSchema = Joi.object({
  title: Joi.string().min(1).max(100),
  isArchived: Joi.boolean(),
  tags: Joi.array().items(Joi.string().trim())
});

// Create new conversation
exports.createConversation = async (req, res) => {
  try {
    // Validate input
    const { error } = createConversationSchema.validate(req.body);
    if (error) {
      return res.status(400).json({ error: error.details[0].message });
    }

    const { title } = req.body;
    const userId = req.userId;

    const conversation = new Conversation({
      title,
      userId
    });

    await conversation.save();

    res.status(201).json({
      message: 'Conversation created successfully',
      conversation
    });
  } catch (error) {
    console.error('Create conversation error:', error);
    res.status(500).json({ error: 'Internal server error' });
  }
};

// Get user conversations
exports.getConversations = async (req, res) => {
  try {
    const { page = 1, limit = 20, search, archived } = req.query;
    const userId = req.userId;

    // Build query
    const query = { userId };
    
    if (archived !== undefined) {
      query.isArchived = archived === 'true';
    }

    if (search) {
      query.title = { $regex: search, $options: 'i' };
    }

    // Get conversations with pagination
    const conversations = await Conversation.find(query)
      .sort({ lastMessageAt: -1 })
      .limit(limit * 1)
      .skip((page - 1) * limit);

    const total = await Conversation.countDocuments(query);

    res.json({
      conversations,
      pagination: {
        page: parseInt(page),
        limit: parseInt(limit),
        total,
        pages: Math.ceil(total / limit)
      }
    });
  } catch (error) {
    console.error('Get conversations error:', error);
    res.status(500).json({ error: 'Internal server error' });
  }
};

// Get single conversation
exports.getConversation = async (req, res) => {
  try {
    const { conversationId } = req.params;
    const userId = req.userId;

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

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

    res.json({ conversation });
  } catch (error) {
    console.error('Get conversation error:', error);
    res.status(500).json({ error: 'Internal server error' });
  }
};

// Update conversation
exports.updateConversation = async (req, res) => {
  try {
    // Validate input
    const { error } = updateConversationSchema.validate(req.body);
    if (error) {
      return res.status(400).json({ error: error.details[0].message });
    }

    const { conversationId } = req.params;
    const userId = req.userId;
    const updates = req.body;

    const conversation = await Conversation.findOneAndUpdate(
      { _id: conversationId, userId },
      updates,
      { new: true, runValidators: true }
    );

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

    res.json({
      message: 'Conversation updated successfully',
      conversation
    });
  } catch (error) {
    console.error('Update conversation error:', error);
    res.status(500).json({ error: 'Internal server error' });
  }
};

// Delete conversation
exports.deleteConversation = async (req, res) => {
  try {
    const { conversationId } = req.params;
    const userId = req.userId;

    const conversation = await Conversation.findOneAndDelete({
      _id: conversationId,
      userId
    });

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

    // Delete all messages in the conversation
    await Message.deleteMany({ conversationId });

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