const Product = require('../models/Product');
const { validationResult } = require('express-validator');

// @desc    Get all products
// @route   GET /api/products
// @access  Private (all roles, but filtered by company)
exports.getProducts = async (req, res, next) => {
  try {
    let query = {};
    
    // Filter products by company
    if (req.user.role !== 'superadmin') {
      query.companyId = req.user.companyId;
    } else if (req.query.companyId) {
      // Superadmin can filter by company
      query.companyId = req.query.companyId;
    }
    
    const products = await Product.find(query)
      .populate('companyId', 'name')
      .populate('createdBy', 'email');
    
    res.status(200).json({
      success: true,
      count: products.length,
      data: products
    });
  } catch (error) {
    next(error);
  }
};

// @desc    Get single product
// @route   GET /api/products/:id
// @access  Private (all roles, but filtered by company)
exports.getProduct = async (req, res, next) => {
  try {
    const product = await Product.findById(req.params.id)
      .populate('companyId', 'name')
      .populate('createdBy', 'email');
    
    if (!product) {
      return res.status(404).json({
        success: false,
        message: 'Product not found'
      });
    }
    
    // Check if user has access to this product
    if (req.user.role !== 'superadmin' && 
        product.companyId._id.toString() !== req.user.companyId.toString()) {
      return res.status(403).json({
        success: false,
        message: 'Not authorized to access this product'
      });
    }
    
    res.status(200).json({
      success: true,
      data: product
    });
  } catch (error) {
    next(error);
  }
};

// @desc    Create product
// @route   POST /api/products
// @access  Private (all roles, but company is restricted)
exports.createProduct = async (req, res, next) => {
  try {
    const errors = validationResult(req);
    if (!errors.isEmpty()) {
      return res.status(400).json({ 
        success: false, 
        errors: errors.array() 
      });
    }
    
    // Set company ID based on user role
    let companyId;
    
    if (req.user.role === 'superadmin' && req.body.companyId) {
      // Superadmin can specify company
      companyId = req.body.companyId;
    } else {
      // Other roles can only add products to their own company
      companyId = req.user.companyId;
    }
    
    const product = await Product.create({
      ...req.body,
      companyId,
      createdBy: req.user._id
    });
    
    res.status(201).json({
      success: true,
      data: product
    });
  } catch (error) {
    next(error);
  }
};

// @desc    Update product
// @route   PUT /api/products/:id
// @access  Private (all roles, but company is restricted)
exports.updateProduct = async (req, res, next) => {
  try {
    const errors = validationResult(req);
    if (!errors.isEmpty()) {
      return res.status(400).json({ 
        success: false, 
        errors: errors.array() 
      });
    }
    
    let product = await Product.findById(req.params.id);
    
    if (!product) {
      return res.status(404).json({
        success: false,
        message: 'Product not found'
      });
    }
    
    // Check if user has access to this product
    if (req.user.role !== 'superadmin' && 
        product.companyId.toString() !== req.user.companyId.toString()) {
      return res.status(403).json({
        success: false,
        message: 'Not authorized to update this product'
      });
    }
    
    // Prevent changing companyId for non-superadmin users
    if (req.user.role !== 'superadmin' && req.body.companyId && 
        req.body.companyId.toString() !== req.user.companyId.toString()) {
      return res.status(403).json({
        success: false,
        message: 'Not authorized to change company for this product'
      });
    }
    
    product = await Product.findByIdAndUpdate(
      req.params.id,
      req.body,
      { new: true, runValidators: true }
    )
      .populate('companyId', 'name')
      .populate('createdBy', 'email');
    
    res.status(200).json({
      success: true,
      data: product
    });
  } catch (error) {
    next(error);
  }
};

// @desc    Delete product
// @route   DELETE /api/products/:id
// @access  Private (all roles, but company is restricted)
exports.deleteProduct = async (req, res, next) => {
  try {
    const product = await Product.findById(req.params.id);
    
    if (!product) {
      return res.status(404).json({
        success: false,
        message: 'Product not found'
      });
    }
    
    // Check if user has access to this product
    if (req.user.role !== 'superadmin' && 
        product.companyId.toString() !== req.user.companyId.toString()) {
      return res.status(403).json({
        success: false,
        message: 'Not authorized to delete this product'
      });
    }
    
    await product.deleteOne();
    
    res.status(200).json({
      success: true,
      data: {}
    });
  } catch (error) {
    next(error);
  }
};