<?php
/**
 * Install database table for Parallax batch requests.
 *
 * @package AIContentByParallax
 */

namespace AIContentByParallax\Database;

defined( 'ABSPATH' ) || exit;

/**
 * Create the batch requests table.
 */
class BatchRequestTableInstaller {

	/**
	 * Schema version. Bump this string whenever the table structure changes so
	 * that maybe_upgrade() re-runs dbDelta() on existing installations.
	 *
	 * @var string
	 */
	private const SCHEMA_VERSION = '1.1.0';

	/**
	 * Option key used to persist the last installed schema version.
	 *
	 * @var string
	 */
	private const VERSION_OPTION = 'ai_content_by_parallax_batch_requests_db_version';

	/**
	 * Install or upgrade the batch requests table.
	 *
	 * @return void
	 */
	public static function install() {
		global $wpdb;
		$table_name      = $wpdb->prefix . 'ai_content_by_parallax_batch_requests';
		$charset_collate = $wpdb->get_charset_collate();

		$sql = "CREATE TABLE $table_name (
			id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
			batch_request_id VARCHAR(64) NOT NULL,
			status VARCHAR(20) NOT NULL DEFAULT 'processing',
			type VARCHAR(21) NOT NULL,
			total_expected INT DEFAULT 0,
			batches_done INT DEFAULT 0,
			metadata LONGTEXT,
			created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
			updated_at DATETIME DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
			PRIMARY KEY (id),
			UNIQUE KEY batch_request_id (batch_request_id),
			KEY idx_status (status),
			KEY idx_created_at (created_at),
			KEY idx_type_status_created (type, status, created_at)
		) $charset_collate;";

		require_once ABSPATH . 'wp-admin/includes/upgrade.php';
		dbDelta( $sql );

		update_option( self::VERSION_OPTION, self::SCHEMA_VERSION );
	}

	/**
	 * Run install() only when the stored schema version is behind the current
	 * one. Safe to call on every request — no-ops when already up to date.
	 *
	 * @return void
	 */
	public static function maybe_upgrade(): void {
		if ( get_option( self::VERSION_OPTION ) !== self::SCHEMA_VERSION ) {
			self::install();
		}
	}
}