SCRIPT: How to check database files allocated free disk space?

SELECT DB_NAME() AS DbName,
    name AS FileName,
    type_desc,
    size/128.0 AS CurrentSizeMB,
    size/128.0 - CAST(FILEPROPERTY(name, 'SpaceUsed') AS INT)/128.0 AS FreeSpaceMB,
       max_size/128.0 AS MaxSizeMB,
    CAST(CAST((((size/128.0 - CAST(FILEPROPERTY(name, 'SpaceUsed') AS INT)/128.0) * 100) / (size/128.0)) AS DECIMAL(10, 2)) AS VARCHAR(100)) + ' %' AS [Free Space Percentage],
       physical_name
FROM sys.database_files
ORDER BY name