Improve disk space error message clarity

src/helper/Site_Backup_Restore.php

@@ -631,11 +631,44 @@ private function pre_backup_check() {
 		EE::debug( 'Free space: ' . $free_space );
 
 		if ( $site_size > $free_space ) {
-			EE::error( 'Not enough disk space to take backup. Please free up some space and try again.' );
+			$error_message = $this->build_disk_space_error_message( 'backup', $site_size, $free_space );
+
 			$this->fs->remove( EE_BACKUP_DIR . '/' . $this->site_data['site_url'] . '.lock' );
+			EE::error( $error_message );
 		}
 	}
 
+	/**
+	 * Build a disk space error message for backup/restore operations.
+	 *
+	 * @param string $operation   The operation name ('backup' or 'restore').
+	 * @param int $required_space The required disk space in bytes.
+	 * @param int $free_space     The available free space in bytes.
+	 *
+	 * @return string The formatted error message.
+	 */
+	private function build_disk_space_error_message( $operation, $required_space, $free_space ) {
+		$additional_space    = $required_space - $free_space;
+		$required_formatted  = $this->format_bytes( $required_space );
+		$available_formatted = $this->format_bytes( $free_space );
+		$needed_formatted    = $this->format_bytes( $additional_space );
+
+		return sprintf(
+			"Not enough disk space to take %s.\n" .
+			"Required: %s (%s bytes)\n" .
+			"Available: %s (%s bytes)\n" .
+			"Additional space needed: %s (%s bytes)\n" .
+			"Please free up some space and try again.",
+			$operation,
+			$required_formatted,
+			number_format( $required_space ),
+			$available_formatted,
+			number_format( $free_space ),
+			$needed_formatted,
+			number_format( $additional_space )
+		);
+	}
+
 	private function check_and_install( $command, $name ) {
 		$status = EE::exec( "command -v $command" );
 		if ( ! $status ) {
@@ -669,9 +702,32 @@ private function pre_restore_check() {
 		EE::debug( 'Remote backup size: ' . $remote_size );
 
 		$free_space = disk_free_space( EE_BACKUP_DIR );
+		if ( false === $free_space ) {
+			EE::error( 'Unable to determine free disk space for backup directory.' );
+		}
 
 		if ( $remote_size > $free_space ) {
-			EE::error( 'Not enough disk space to restore backup. Please free up some space and try again.' );
+			$required_space      = $remote_size;
+			$additional_space    = $required_space - $free_space;
+			$required_formatted  = $this->format_bytes( $required_space );
+			$available_formatted = $this->format_bytes( $free_space );
+			$needed_formatted    = $this->format_bytes( $additional_space );
+
+			$error_message = sprintf(
+				"Not enough disk space to restore backup.\n" .
+				"Required: %s (%s bytes)\n" .
+				"Available: %s (%s bytes)\n" .
+				"Additional space needed: %s (%s bytes)\n" .
+				"Please free up some space and try again.",
+				$required_formatted,
+				number_format( $required_space ),
+				$available_formatted,
+				number_format( $free_space ),
+				$needed_formatted,
+				number_format( $additional_space )
+			);
+
+			EE::error( $error_message );
 		}
 
 
@@ -728,6 +784,18 @@ private function pre_restore_check() {
 	}
 
 
+	private function format_bytes( $bytes, $precision = 2 ) {
+		$units = [ 'B', 'KB', 'MB', 'GB', 'TB' ];
+
+		$bytes = max( $bytes, 0 );
+		$pow   = floor( ( $bytes ? log( $bytes ) : 0 ) / log( 1024 ) );
+		$pow   = min( $pow, count( $units ) - 1 );
+
+		$size = $bytes / pow( 1024, $pow );
+
+		return round( $size, $precision ) . ' ' . $units[ $pow ];
+	}
+
 	private function dir_size( string $directory ) {
 		$size = 0;