const Database = require('better-sqlite3');
const path = require('path');

function migrateLitterId(dbPath) {
  console.log('Running litter_id migration...');
  
  const db = new Database(dbPath);
  db.pragma('foreign_keys = ON');
  
  try {
    // Check if litter_id column already exists
    const tableInfo = db.prepare("PRAGMA table_info(dogs)").all();
    const hasLitterId = tableInfo.some(col => col.name === 'litter_id');
    
    if (hasLitterId) {
      console.log('litter_id column already exists. Skipping migration.');
      db.close();
      return;
    }
    
    // Add litter_id column to dogs table
    db.exec(`
      ALTER TABLE dogs ADD COLUMN litter_id INTEGER;
    `);
    
    // Create index for litter_id
    db.exec(`
      CREATE INDEX IF NOT EXISTS idx_dogs_litter ON dogs(litter_id);
    `);
    
    // Add foreign key relationship (SQLite doesn't support ALTER TABLE ADD CONSTRAINT)
    // So we'll rely on application-level constraint checking
    
    console.log('✓ Added litter_id column to dogs table');
    console.log('✓ Created index on litter_id');
    console.log('Migration completed successfully!');
    
    db.close();
  } catch (error) {
    console.error('Migration failed:', error.message);
    db.close();
    throw error;
  }
}

module.exports = { migrateLitterId };

// Run migration if called directly
if (require.main === module) {
  const dbPath = process.env.DB_PATH || path.join(__dirname, '../../data/breedr.db');
  migrateLitterId(dbPath);
}