<?php
/**
 * Performance Profiler — captures REST API timing and DB query data.
 *
 * @package Advanced_REST_API_DevTools
 */

defined( 'ABSPATH' ) || exit;

class Aradt_Profiler {

	/**
	 * Profiling data store.
	 *
	 * @var array
	 */
	private static $profile_data = array();

	/**
	 * Register profiling hooks.
	 * Called dynamically per-request, not globally.
	 */
	public static function start_profiling() {
		global $wpdb;

		// Enable query logging if not already.
		if ( ! defined( 'SAVEQUERIES' ) ) {
			// Can't define at runtime, but we can still read $wpdb->queries.
			// In production, SAVEQUERIES should be defined in wp-config.php for full data.
		}

		self::$profile_data = array(
			'start_time'       => microtime( true ),
			'start_queries'    => isset( $wpdb->queries ) ? count( $wpdb->queries ) : 0,
			'memory_start'     => memory_get_usage( true ),
		);
	}

	/**
	 * End profiling and return results.
	 *
	 * @return array Profiling data.
	 */
	public static function end_profiling() {
		global $wpdb;

		$end_time    = microtime( true );
		$end_queries = isset( $wpdb->queries ) ? count( $wpdb->queries ) : 0;
		$memory_end  = memory_get_usage( true );

		$total_time = round( ( $end_time - self::$profile_data['start_time'] ) * 1000, 2 );
		$query_count = $end_queries - self::$profile_data['start_queries'];

		// Calculate total DB time from queries if available.
		$db_time = 0;
		$query_details = array();

		if ( isset( $wpdb->queries ) && is_array( $wpdb->queries ) ) {
			$relevant_queries = array_slice( $wpdb->queries, self::$profile_data['start_queries'] );
			foreach ( $relevant_queries as $q ) {
				$db_time += isset( $q[1] ) ? (float) $q[1] : 0;
				$query_details[] = array(
					'sql'    => isset( $q[0] ) ? substr( $q[0], 0, 200 ) : '',
					'time'   => isset( $q[1] ) ? round( (float) $q[1] * 1000, 2 ) : 0,
					'caller' => isset( $q[2] ) ? substr( $q[2], 0, 150 ) : '',
				);
			}
		}

		$db_time_ms = round( $db_time * 1000, 2 );

		return array(
			'total_time_ms'    => $total_time,
			'db_queries'       => $query_count,
			'db_time_ms'       => $db_time_ms,
			'php_time_ms'      => round( $total_time - $db_time_ms, 2 ),
			'memory_used_mb'   => round( ( $memory_end - self::$profile_data['memory_start'] ) / 1048576, 2 ),
			'memory_peak_mb'   => round( memory_get_peak_usage( true ) / 1048576, 2 ),
			'query_details'    => array_slice( $query_details, 0, 50 ), // Cap for display.
		);
	}

	/**
	 * Get server environment info for the profiler panel.
	 *
	 * @return array
	 */
	public static function get_server_info() {
		global $wp_version;

		return array(
			'php_version'    => phpversion(),
			'wp_version'     => $wp_version,
			'server'         => isset( $_SERVER['SERVER_SOFTWARE'] ) ? sanitize_text_field( wp_unslash( $_SERVER['SERVER_SOFTWARE'] ) ) : 'Unknown',
			'mysql_version'  => self::get_mysql_version(),
			'memory_limit'   => ini_get( 'memory_limit' ),
			'max_exec_time'  => ini_get( 'max_execution_time' ),
			'savequeries'    => defined( 'SAVEQUERIES' ) && SAVEQUERIES,
			'wp_debug'       => defined( 'WP_DEBUG' ) && WP_DEBUG,
		);
	}

	/**
	 * Get MySQL version.
	 *
	 * @return string
	 */
	private static function get_mysql_version() {
		global $wpdb;
		return $wpdb->get_var( 'SELECT VERSION()' ) ?? 'Unknown'; // phpcs:ignore WordPress.DB.DirectDatabaseQuery
	}
}