// Simple SQL Generator Function
const generateSelectQuery = ({
  table,
  columns = ['*'],
  where = {},
  orderBy,
  limit
}) => {
  let query = `SELECT ${columns.join(', ')} FROM ${table}`;
  
  // Add WHERE clause
  const conditions = Object.entries(where)
    .map(([key, value]) => `${key} = ?`)
    .join(' AND ');
  
  if (conditions) {
    query += ` WHERE ${conditions}`;
  }
  
  // Add ORDER BY
  if (orderBy) {
    query += ` ORDER BY ${orderBy}`;
  }
  
  // Add LIMIT
  if (limit) {
    query += ` LIMIT ${limit}`;
  }
  
  return {
    query,
    params: Object.values(where)
  };
};

// Usage Example
const result = generateSelectQuery({
  table: 'users',
  columns: ['id', 'name', 'email'],
  where: {
    status: 'active',
    role: 'admin'
  },
  orderBy: 'created_at DESC',
  limit: 10
});

console.log(result);
// Output:
// {
//   query: "SELECT id, name, email FROM users WHERE status = ? AND role = ? ORDER BY created_at DESC LIMIT 10",
//   params: ['active', 'admin']
// }

const generateInsertQuery = (table, data) => {
  const columns = Object.keys(data);
  const values = Object.values(data);
  const placeholders = new Array(columns.length).fill('?').join(', ');
  
  const query = `
    INSERT INTO ${table} 
    (${columns.join(', ')}) 
    VALUES (${placeholders})
  `;
  
  return {
    query: query.trim(),
    params: values
  };
};

// Usage
const insertData = {
  name: 'John Doe',
  email: 'john@example.com',
  status: 'active'
};

const insert = generateInsertQuery('users', insertData);
console.log(insert);

const generateUpdateQuery = (table, data, where) => {
  const updates = Object.keys(data)
    .map(key => `${key} = ?`)
    .join(', ');
    
  const conditions = Object.keys(where)
    .map(key => `${key} = ?`)
    .join(' AND ');
  
  const query = `
    UPDATE ${table}
    SET ${updates}
    WHERE ${conditions}
  `;
  
  return {
    query: query.trim(),
    params: [...Object.values(data), ...Object.values(where)]
  };
};

// Usage
const updateResult = generateUpdateQuery(
  'users',
  { status: 'inactive', updated_at: new Date() },
  { id: 123 }
);

const mysql = require('mysql2/promise');
const { generateSelectQuery } = require('./queryGenerator');

const pool = mysql.createPool({
  host: 'localhost',
  user: 'user',
  password: 'password',
  database: 'mydb'
});

app.get('/users', async (req, res) => {
  try {
    const { query, params } = generateSelectQuery({
      table: 'users',
      where: req.query
    });
    
    const [rows] = await pool.execute(query, params);
    res.json(rows);
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});