const express = require('express');
const router = express.Router();
const db = require('../database');

// Get monthly categories by year and month
router.get('/:year/:month', (req, res) => {
  const { year, month } = req.params;
  
  const query = `
    SELECT mc.*, c.name as card_name, c.bank, cat.name as category_name
    FROM monthly_categories mc
    JOIN cards c ON mc.card_id = c.id
    JOIN categories cat ON mc.category_id = cat.id
    WHERE mc.year = ? AND mc.month = ?
    ORDER BY c.name, cat.name
  `;
  
  db.all(query, [year, month], (err, rows) => {
    if (err) {
      console.error(err);
      res.status(500).json({ error: 'Database error' });
    } else {
      res.json(rows);
    }
  });
});

// Create monthly category assignment
router.post('/', (req, res) => {
  const { card_id, category_id, month, year, cashback_percent } = req.body;
  
  if (!card_id || !category_id || !month || !year || cashback_percent === undefined) {
    return res.status(400).json({ error: 'All fields are required' });
  }

  db.run(
    `INSERT OR REPLACE INTO monthly_categories 
     (card_id, category_id, month, year, cashback_percent) 
     VALUES (?, ?, ?, ?, ?)`,
    [card_id, category_id, month, year, cashback_percent],
    function(err) {
      if (err) {
        console.error(err);
        res.status(500).json({ error: 'Database error' });
      } else {
        res.status(201).json({ 
          id: this.lastID,
          card_id,
          category_id,
          month,
          year,
          cashback_percent
        });
      }
    }
  );
});

// Delete monthly category assignment
router.delete('/:id', (req, res) => {
  const { id } = req.params;
  
  db.run('DELETE FROM monthly_categories WHERE id = ?', [id], function(err) {
    if (err) {
      console.error(err);
      res.status(500).json({ error: 'Database error' });
    } else if (this.changes === 0) {
      res.status(404).json({ error: 'Assignment not found' });
    } else {
      res.json({ message: 'Assignment deleted successfully' });
    }
  });
});

// Get available categories for a card in a specific month/year
router.get('/available/:card_id/:year/:month', (req, res) => {
  const { card_id, year, month } = req.params;
  
  const query = `
    SELECT c.* FROM categories c
    WHERE c.id NOT IN (
      SELECT mc.category_id 
      FROM monthly_categories mc 
      WHERE mc.card_id = ? AND mc.year = ? AND mc.month = ?
    )
    ORDER BY c.name
  `;
  
  db.all(query, [card_id, year, month], (err, rows) => {
    if (err) {
      console.error(err);
      res.status(500).json({ error: 'Database error' });
    } else {
      res.json(rows);
    }
  });
});

module.exports = router;