<?php
/**
 * Schema and migrations.
 *
 * @package Enrollment_Verifier_Logger
 */

defined( 'ABSPATH' ) || exit;

/**
 * Database schema management. Never drops data.
 */
class EVLFL_Database {

	const VERSION_OPTION = 'evlfl_db_version';

	/**
	 * Table name (prefix-aware).
	 *
	 * @return string
	 */
	public static function table_name() {
		global $wpdb;
		return $wpdb->prefix . 'ld_enrollment_logs';
	}

	/**
	 * Run install/migrations when the stored version differs.
	 *
	 * @return void
	 */
	public static function maybe_upgrade() {
		if ( get_option( self::VERSION_OPTION ) !== EVLFL_DB_VERSION ) {
			try {
				self::install();
			} catch ( \Throwable $e ) {
				if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
					error_log( 'EVL migration failed: ' . $e->getMessage() ); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
				}
			}
		}
	}

	/**
	 * Create/update the table (idempotent) and run version migrations.
	 *
	 * @return void
	 */
	public static function install() {
		global $wpdb;
		require_once ABSPATH . 'wp-admin/includes/upgrade.php';

		$from    = (string) get_option( self::VERSION_OPTION, '0' );
		$table   = self::table_name();
		$collate = $wpdb->get_charset_collate();

		$sql = "CREATE TABLE {$table} (
  id bigint(20) unsigned NOT NULL AUTO_INCREMENT,
  user_id bigint(20) unsigned NOT NULL,
  course_id bigint(20) unsigned NOT NULL,
  action varchar(20) NOT NULL,
  source varchar(50) NOT NULL DEFAULT 'unknown',
  event_trigger varchar(100) NOT NULL DEFAULT 'unknown',
  actor_type varchar(30) NOT NULL DEFAULT 'unknown',
  actor_id bigint(20) unsigned DEFAULT NULL,
  status varchar(20) NOT NULL DEFAULT 'unknown',
  verification_reason text DEFAULT NULL,
  confidence varchar(20) NOT NULL DEFAULT 'unknown',
  event_time datetime NOT NULL,
  related_event_id bigint(20) unsigned DEFAULT NULL,
  metadata longtext DEFAULT NULL,
  created_at datetime NOT NULL,
  PRIMARY KEY  (id),
  KEY event_time (event_time),
  KEY user_event (user_id,event_time),
  KEY course_event (course_id,event_time),
  KEY action_event (action,event_time),
  KEY source_event (source,event_time),
  KEY status_event (status,event_time)
) {$collate};";

		dbDelta( $sql );

		// Future schema changes: add version => callable entries; they run once, in order.
		$migrations = array();
		foreach ( $migrations as $version => $callback ) {
			if ( version_compare( $from, (string) $version, '<' ) && is_callable( $callback ) ) {
				call_user_func( $callback );
			}
		}

		// Settings are a small array read on every request, so they are autoloaded; creating the
		// option up front also avoids a "missing option" database lookup on each page load.
		add_option( EVLFL_Settings::OPTION, array(), '', true );

		update_option( self::VERSION_OPTION, EVLFL_DB_VERSION, false );
	}
}