<?php
require_once __DIR__ . '/config.php';

echo "Starting database migration...\n";

try {
    $pdo = db();

    // 1. Create migrations table if it doesn't exist
    $pdo->exec("CREATE TABLE IF NOT EXISTS `migrations` (
        `id` INT AUTO_INCREMENT PRIMARY KEY,
        `migration_file` VARCHAR(255) NOT NULL UNIQUE,
        `applied_at` TIMESTAMP DEFAULT CURRENT_TIMESTAMP
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;");

    // 2. Get applied migrations
    $appliedMigrations = $pdo->query("SELECT `migration_file` FROM `migrations`")->fetchAll(PDO::FETCH_COLUMN);

    // 3. Find migration files
    $migrationFiles = glob(__DIR__ . '/migrations/*.sql');
    if (empty($migrationFiles)) {
        echo "No migration files found.\n";
    }

    // 4. Apply pending migrations
    $migrationsApplied = 0;
    foreach ($migrationFiles as $file) {
        $basename = basename($file);
        if (!in_array($basename, $appliedMigrations)) {
            echo "Applying migration: {$basename}...\n";
            
            $sql = file_get_contents($file);
            $pdo->exec($sql);
            
            $stmt = $pdo->prepare("INSERT INTO `migrations` (`migration_file`) VALUES (?)");
            $stmt->execute([$basename]);
            
            echo "  -> Applied successfully.\n";
            $migrationsApplied++;
        } else {
            echo "Skipping already applied migration: {$basename}\n";
        }
    }

    if ($migrationsApplied > 0) {
        echo "\nMigration complete. Applied {$migrationsApplied} new migration(s).\n";
    } else {
        echo "\nDatabase is already up to date.\n";
    }

    // 5. Synchronize inventory table
    echo "\nSynchronizing inventory...\n";
    $stmt = $pdo->query("INSERT INTO inventory (product_id, quantity) 
                         SELECT p.id, 0 FROM products p 
                         LEFT JOIN inventory i ON p.id = i.product_id 
                         WHERE i.product_id IS NULL");
    $newInventoryCount = $stmt->rowCount();
    if ($newInventoryCount > 0) {
        echo "Added {$newInventoryCount} new products to the inventory with a default stock of 0.\n";
    } else {
        echo "Inventory is already in sync with products.\n";
    }

} catch (PDOException $e) {
    die("Database migration failed: " . $e->getMessage() . "\n");
}
?>