fix(#14): Implement database migrations system with baseline migration

backend/migrations/runner.js

@@ -0,0 +1,114 @@
+import mysql from 'mysql2';
+import fs from 'fs/promises';
+import path from 'path';
+import { fileURLToPath } from 'url';
+import config from './config.js';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
+// Create database connection
+const connection = mysql.createConnection(config.connection);
+
+// Ensure migrations table exists
+function ensureMigrationsTable() {
+  const createTableQuery = `
+    CREATE TABLE IF NOT EXISTS ${config.tableName} (
+      id INT AUTO_INCREMENT PRIMARY KEY,
+      name VARCHAR(255) NOT NULL,
+      executed_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+    )
+  `;
+  
+  return new Promise((resolve, reject) => {
+    connection.execute(createTableQuery, (err) => {
+      if (err) reject(err);
+      else resolve();
+    });
+  });
+}
+
+// Get list of already executed migrations
+function getExecutedMigrations() {
+  const query = `SELECT name FROM ${config.tableName} ORDER BY executed_at`;
+  
+  return new Promise((resolve, reject) => {
+    connection.execute(query, (err, results) => {
+      if (err) reject(err);
+      else resolve(results.map(row => row.name));
+    });
+  });
+}
+
+// Execute a migration file
+function executeMigration(migrationName, sqlContent) {
+  return new Promise((resolve, reject) => {
+    connection.execute(sqlContent, (err) => {
+      if (err) reject(err);
+      else {
+        // Log the execution in migrations table
+        const logQuery = `INSERT INTO ${config.tableName} (name) VALUES (?)`;
+        connection.execute(logQuery, [migrationName], (logErr) => {
+          if (logErr) reject(logErr);
+          else resolve();
+        });
+      }
+    });
+  });
+}
+
+// Get all migration files
+async function getMigrationFiles() {
+  try {
+    const files = await fs.readdir(config.migrationsDir);
+    return files
+      .filter(file => file.endsWith('.sql'))
+      .sort((a, b) => a.localeCompare(b));
+  } catch (err) {
+    if (err.code === 'ENOENT') {
+      // Directory doesn't exist, create it
+      await fs.mkdir(config.migrationsDir, { recursive: true });
+      return [];
+    }
+    throw err;
+  }
+}
+
+// Run migrations
+async function runMigrations() {
+  try {
+    await ensureMigrationsTable();
+    const executed = await getExecutedMigrations();
+    const allMigrations = await getMigrationFiles();
+    
+    const pending = allMigrations.filter(name => !executed.includes(name));
+    
+    if (pending.length === 0) {
+      console.log('No pending migrations');
+      return;
+    }
+    
+    console.log(`Running ${pending.length} migrations...`);
+    
+    for (const migrationName of pending) {
+      console.log(`Executing ${migrationName}`);
+      const filePath = path.join(config.migrationsDir, migrationName);
+      const sqlContent = await fs.readFile(filePath, 'utf8');
+      await executeMigration(migrationName, sqlContent);
+    }
+    
+    console.log('All migrations executed successfully');
+  } catch (err) {
+    console.error('Error running migrations:', err);
+    throw err;
+  } finally {
+    connection.end();
+  }
+}
+
+// Run the migrations
+if (process.argv.includes('--run')) {
+  runMigrations().catch(console.error);
+}
+
+export { runMigrations };