using System.IO;

namespace WebDesktopBackend.Extentions {
    public static class DirectoryInfoExtentions {
        /// <summary>
        /// Returns the size of the Directory (from: https://stackoverflow.com/a/32364847)
        /// </summary>
        /// <param name="directoryInfo">The Directory</param>
        /// <param name="recursive">When set to true, the Functions includes also Subdirectories</param>
        /// <returns>The size of the Directory</returns>
        public static long GetDirectorySize(this DirectoryInfo directoryInfo, bool recursive = true) {
            var startDirectorySize = default(long);
            if (directoryInfo == null || !directoryInfo.Exists)
                return startDirectorySize; //Return 0 while Directory does not exist.

            //Add size of files in the Current Directory to main size.
            foreach (var fileInfo in directoryInfo.GetFiles())
                System.Threading.Interlocked.Add(ref startDirectorySize, fileInfo.Length);

            if (recursive) //Loop on Sub Direcotries in the Current Directory and Calculate it's files size.
                System.Threading.Tasks.Parallel.ForEach(directoryInfo.GetDirectories(), (subDirectory) =>
                    System.Threading.Interlocked.Add(ref startDirectorySize, GetDirectorySize(subDirectory, recursive)));

            return startDirectorySize;  //Return full Size of this Directory.
        }
    }
}