const express = require('express');
const router = express.Router();
const jwt = require('jsonwebtoken');
const Recipe = require('../models/Recipe');

// Middleware to authenticate JWT token
function authenticateToken(req, res, next) {
  const authHeader = req.headers['authorization'];
  const token = authHeader && authHeader.split(' ')[1];
  
  if (!token) {
    return res.status(401).json({ error: 'Access token required' });
  }
  
  jwt.verify(token, process.env.JWT_SECRET, (err, decoded) => {
    if (err) {
      return res.status(403).json({ error: 'Invalid or expired token' });
    }
    req.userId = decoded.userId;
    next();
  });
}

// Get ingredient suggestions for autocomplete
router.get('/ingredients/suggestions', async (req, res) => {
  try {
    const { q } = req.query; // Search query
    
    if (!q || q.length < 2) {
      return res.json([]);
    }
    
    // Aggregate unique ingredient names from all recipes
    const suggestions = await Recipe.aggregate([
      { $unwind: '$ingredients' },
      { 
        $match: { 
          'ingredients.name': { 
            $regex: q, 
            $options: 'i' 
          } 
        } 
      },
      { 
        $group: { 
          _id: { $toLower: '$ingredients.name' },
          name: { $first: '$ingredients.name' },
          count: { $sum: 1 }
        } 
      },
      { $sort: { count: -1, name: 1 } },
      { $limit: 10 },
      { 
        $project: { 
          _id: 0, 
          name: 1, 
          count: 1 
        } 
      }
    ]);
    
    res.json(suggestions);
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// Get unit suggestions for a specific ingredient
router.get('/ingredients/units', async (req, res) => {
  try {
    const { ingredient } = req.query;
    
    if (!ingredient) {
      return res.json([]);
    }
    
    // Find units used with this specific ingredient
    const unitSuggestions = await Recipe.aggregate([
      { $unwind: '$ingredients' },
      { 
        $match: { 
          'ingredients.name': { 
            $regex: ingredient, 
            $options: 'i' 
          } 
        } 
      },
      { 
        $group: { 
          _id: { $toLower: '$ingredients.unit' },
          unit: { $first: '$ingredients.unit' },
          count: { $sum: 1 },
          avgAmount: { $avg: '$ingredients.amount' }
        } 
      },
      { $sort: { count: -1, unit: 1 } },
      { $limit: 8 },
      { 
        $project: { 
          _id: 0, 
          unit: 1, 
          count: 1,
          avgAmount: { $round: ['$avgAmount', 2] }
        } 
      }
    ]);
    
    res.json(unitSuggestions);
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// Get all recipes
router.get('/', async (req, res) => {
  try {
    const { category, difficulty, search } = req.query;
    let filter = {};
    
    if (category) filter.category = category;
    if (difficulty) filter.difficulty = difficulty;
    if (search) {
      filter.$or = [
        { title: { $regex: search, $options: 'i' } },
        { description: { $regex: search, $options: 'i' } }
      ];
    }
    
    const recipes = await Recipe.find(filter).sort({ createdAt: -1 });
    res.json(recipes);
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// Get recipe by ID
router.get('/:id', async (req, res) => {
  try {
    const recipe = await Recipe.findById(req.params.id);
    if (!recipe) {
      return res.status(404).json({ error: 'Recipe not found' });
    }
    res.json(recipe);
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

// Create new recipe (protected route)
router.post('/', authenticateToken, async (req, res) => {
  try {
    const recipe = new Recipe({
      ...req.body,
      createdBy: req.userId // Add user ID to track who created the recipe
    });
    await recipe.save();
    res.status(201).json(recipe);
  } catch (error) {
    res.status(400).json({ error: error.message });
  }
});

// Update recipe
router.put('/:id', async (req, res) => {
  try {
    const recipe = await Recipe.findByIdAndUpdate(
      req.params.id,
      req.body,
      { new: true, runValidators: true }
    );
    if (!recipe) {
      return res.status(404).json({ error: 'Recipe not found' });
    }
    res.json(recipe);
  } catch (error) {
    res.status(400).json({ error: error.message });
  }
});

// Delete recipe
router.delete('/:id', async (req, res) => {
  try {
    const recipe = await Recipe.findByIdAndDelete(req.params.id);
    if (!recipe) {
      return res.status(404).json({ error: 'Recipe not found' });
    }
    res.json({ message: 'Recipe deleted successfully' });
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

module.exports = router;