<?php
/**
 * Error logging for WP Data Optimizer.
 *
 * @package WP_Data_Optimizer
 */

declare(strict_types=1);

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Lightweight error logger — writes to wpdo_errors table and PHP error_log.
 */
class TMDO_Logger {

	/**
	 * Request-scoped correlation id, lazily generated.
	 *
	 * @var string|null
	 */
	private static ?string $trace_id = null;

	/**
	 * Request-scoped UUIDv4 correlation id.
	 *
	 * Every audit row written during one request shares this value so a single
	 * update_*_meta() call can be traced across entity groups.
	 *
	 * @return string UUIDv4.
	 */
	public static function trace_id(): string {
		if ( null === self::$trace_id ) {
			try {
				$bytes = random_bytes( 16 );
			} catch ( \Throwable $e ) {
				$bytes = pack( 'H*', md5( (string) microtime( true ) . wp_generate_password( 16, false ) ) );
			}
			$bytes[6]       = chr( ( ord( $bytes[6] ) & 0x0f ) | 0x40 );
			$bytes[8]       = chr( ( ord( $bytes[8] ) & 0x3f ) | 0x80 );
			self::$trace_id = vsprintf( '%s%s-%s-%s-%s-%s%s%s', str_split( bin2hex( $bytes ), 4 ) );
		}
		return self::$trace_id;
	}

	/**
	 * Log an INFO-level event (event-based signature, used by v2.0.0 engine code).
	 *
	 * Writes only to PHP error_log, and only when debug logging is on; does NOT touch wpdo_errors (which is reserved
	 * for actual errors). Mode changes / cache flushes / audit prunes call here
	 * many times per request — keeping them out of the DB error table.
	 *
	 * @param string $event   Event name (e.g. 'bridge_mode_changed').
	 * @param array  $context Structured context.
	 * @return void
	 */
	public static function info( string $event, array $context = array() ): void {
		// Routine events: only with WP_DEBUG_LOG (filter `tmdo_log_info`), or every
		// CLI run and production request would flood the log.
		if ( ! apply_filters( 'tmdo_log_info', defined( 'WP_DEBUG_LOG' ) && WP_DEBUG_LOG ) ) {
			return;
		}
		self::write_info( $event, $context );
	}

	/**
	 * Write an INFO line to the PHP error log.
	 *
	 * @param string               $event   Event name.
	 * @param array<string, mixed> $context Structured context.
	 * @return void
	 */
	private static function write_info( string $event, array $context ): void {
		error_log( sprintf( '[WPDO][INFO][%s] %s', $event, $context ? wp_json_encode( $context, JSON_UNESCAPED_UNICODE ) : '' ) );
	}

	/**
	 * Log a NOTICE-level event — alias of info() for callers that want a stronger
	 * level intent. Same routing (error_log only).
	 *
	 * @param string $event   Event name.
	 * @param array  $context Structured context.
	 * @return void
	 */
	public static function notice( string $event, array $context = array() ): void {
		self::info( $event, $context );
	}

	/**
	 * Log a WARNING-level event — error_log + wpdo_errors row (for admin visibility).
	 *
	 * Use for "anomaly worth attention but not breaking" (e.g. invalid filter
	 * return, unexpected fallback path). The event_name becomes the `hook` column;
	 * message gets a `[WARN]` prefix to distinguish from hard errors.
	 *
	 * @param string $event   Event name (e.g. 'wpdo_route_decision_invalid_return').
	 * @param array  $context Structured context.
	 * @return void
	 */
	public static function warning( string $event, array $context = array() ): void {
		error_log( sprintf( '[WPDO][WARN][%s] %s', $event, $context ? wp_json_encode( $context, JSON_UNESCAPED_UNICODE ) : '' ) );
		self::error( 'engine', $event, '[WARN] ' . $event, $context );
	}

	/**
	 * Log a DEBUG-level event — only when WP_DEBUG is true; routes to error_log.
	 *
	 * @param string $event   Event name.
	 * @param array  $context Structured context.
	 * @return void
	 */
	public static function debug( string $event, array $context = array() ): void {
		if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
			self::write_info( $event, $context );
		}
	}

	/**
	 * Log a module error.
	 *
	 * @param string $module  Module name (e.g. 'reviews', 'hot_hp_listing').
	 * @param string $hook    The hook or method where the error occurred.
	 * @param string $message Human-readable error message.
	 * @param array  $context Optional extra context (will be JSON-encoded).
	 * @param string $zone    Optional zone identifier (hot/warm/cold/archive).
	 */
	public static function error( string $module, string $hook, string $message, array $context = array(), string $zone = '' ): void {
		global $wpdb;

		error_log( sprintf( '[WPDO][%s][%s] %s', $module, $hook, $message ) );

		$table = TMDO_DB::table( 'wpdo_errors' );
		$wpdb->insert(
			$table,
			array(
				'module'     => sanitize_key( $module ),
				'zone'       => sanitize_key( $zone ),
				'hook'       => substr( sanitize_text_field( $hook ), 0, 255 ),
				'message'    => $message,
				'context'    => $context ? wp_json_encode( $context, JSON_UNESCAPED_UNICODE ) : null,
				'created_at' => current_time( 'mysql', true ),
			),
			array( '%s', '%s', '%s', '%s', '%s', '%s' )
		);
	}

	/**
	 * Return recent errors, optionally filtered by module.
	 *
	 * @param string $module Module name (empty = all modules).
	 * @param int    $limit  Max rows to return.
	 * @return array
	 */
	public static function get_recent( string $module = '', int $limit = 100 ): array {
		global $wpdb;
		$table = TMDO_DB::table( 'wpdo_errors' );

		// phpcs:disable WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- Table name from TMDO_DB::table().
		if ( $module ) {
			return $wpdb->get_results(
				$wpdb->prepare(
					"SELECT * FROM `{$table}` WHERE module = %s ORDER BY id DESC LIMIT %d",
					$module,
					$limit
				),
				ARRAY_A
			) ?: array();
		}

		return $wpdb->get_results(
			$wpdb->prepare( "SELECT * FROM `{$table}` ORDER BY id DESC LIMIT %d", $limit ),
			ARRAY_A
		) ?: array();
		// phpcs:enable WordPress.DB.PreparedSQL.InterpolatedNotPrepared
	}

	/**
	 * Delete errors older than a given number of days.
	 *
	 * @param int $days Keep errors from the last N days.
	 * @return int Number of rows deleted.
	 */
	public static function purge( int $days = 30 ): int {
		global $wpdb;
		$table = TMDO_DB::table( 'wpdo_errors' );

		$now = current_time( 'mysql', true );

		if ( TMDO_IS_SQLITE ) {
			$sql = $wpdb->prepare(
				"DELETE FROM `{$table}` WHERE created_at < datetime(%s, %s)", // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared
				$now,
				"-{$days} days"
			);
		} else {
			$sql = $wpdb->prepare(
				"DELETE FROM `{$table}` WHERE created_at < DATE_SUB(%s, INTERVAL %d DAY)", // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared
				$now,
				$days
			);
		}

		return (int) $wpdb->query( $sql ); // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared
	}
}