Log Every Email to Daily Files With Rotation

$wpide_mail_log_days = 14; // Days of log files to keep.

$wpide_mail_log_write = function ( $line ) {
    $uploads = wp_upload_dir( null, false );
    $dir     = trailingslashit( $uploads['basedir'] ) . 'wpide-mail-logs';

    if ( ! is_dir( $dir ) ) {
        wp_mkdir_p( $dir );
        file_put_contents( $dir . '/index.php', "<?php\n// Silence is golden.\n" );
        file_put_contents( $dir . '/.htaccess', "Require all denied\nDeny from all\n" );
    }

    $file = sprintf( '%s/mail-%s-%s.log', $dir, gmdate( 'Y-m-d' ), substr( wp_hash( 'mail-log' ), 0, 12 ) );
    file_put_contents( $file, '[' . gmdate( 'c' ) . '] ' . str_replace( array( "\r", "\n" ), ' ', $line ) . "\n", FILE_APPEND | LOCK_EX );
};

add_filter( 'wp_mail', function ( $atts ) use ( $wpide_mail_log_write ) {
    $wpide_mail_log_write( sprintf( 'QUEUED to=%s subject="%s"', implode( ',', (array) $atts['to'] ), wp_strip_all_tags( (string) $atts['subject'] ) ) );

    return $atts;
}, PHP_INT_MAX );

add_action( 'wp_mail_succeeded', function ( $data ) use ( $wpide_mail_log_write ) {
    $wpide_mail_log_write( sprintf( 'SENT to=%s', implode( ',', (array) $data['to'] ) ) );
} );

add_action( 'wp_mail_failed', function ( $error ) use ( $wpide_mail_log_write ) {
    $data = (array) $error->get_error_data();
    $wpide_mail_log_write( sprintf( 'FAILED to=%s error="%s"', isset( $data['to'] ) ? implode( ',', (array) $data['to'] ) : '?', $error->get_error_message() ) );
} );

add_action( 'init', function () {
    if ( ! wp_next_scheduled( 'wpide_mail_log_rotate' ) ) {
        wp_schedule_event( time() + HOUR_IN_SECONDS, 'daily', 'wpide_mail_log_rotate' );
    }
} );

add_action( 'wpide_mail_log_rotate', function () use ( $wpide_mail_log_days ) {
    $uploads = wp_upload_dir( null, false );
    $files   = glob( trailingslashit( $uploads['basedir'] ) . 'wpide-mail-logs/mail-*.log' );

    foreach ( (array) $files as $file ) {
        if ( filemtime( $file ) < time() - $wpide_mail_log_days * DAY_IN_SECONDS ) {
            wp_delete_file( $file );
        }
    }
} );