// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.Security;
 
namespace System.IO
{
    public sealed partial class DriveInfo
    {
        public DriveType DriveType
        {
            get
            {
                DriveType type;
                int result = Interop.Sys.GetFormatInfoForMountPoint(Name, out type);
                if (result == 0)
                {
                    return type;
                }
                else
                {
                    Interop.ErrorInfo errorInfo = Interop.Sys.GetLastErrorInfo();
 
                    // This is one of the few properties that doesn't throw on failure,
                    // instead returning a value from the enum.
                    switch (errorInfo.Error)
                    {
                        case Interop.Error.ELOOP:
                        case Interop.Error.ENAMETOOLONG:
                        case Interop.Error.ENOENT:
                        case Interop.Error.ENOTDIR:
                            return DriveType.NoRootDirectory;
                        default:
                            return DriveType.Unknown;
                    }
                }
            }
        }
 
        public string DriveFormat
        {
            get
            {
                string format;
                CheckStatfsResultAndThrowIfNecessary(Interop.Sys.GetFormatInfoForMountPoint(Name, out format));
                return format;
            }
        }
 
        public long AvailableFreeSpace
        {
            get
            {
                Interop.Sys.MountPointInformation mpi;
                CheckStatfsResultAndThrowIfNecessary(Interop.Sys.GetSpaceInfoForMountPoint(Name, out mpi));
                return checked((long)mpi.AvailableFreeSpace);
            }
        }
 
        public long TotalFreeSpace
        {
            get
            {
                Interop.Sys.MountPointInformation mpi;
                CheckStatfsResultAndThrowIfNecessary(Interop.Sys.GetSpaceInfoForMountPoint(Name, out mpi));
                return checked((long)mpi.TotalFreeSpace);
            }
        }
 
        public long TotalSize
        {
            get
            {
                Interop.Sys.MountPointInformation mpi;
                CheckStatfsResultAndThrowIfNecessary(Interop.Sys.GetSpaceInfoForMountPoint(Name, out mpi));
                return checked((long)mpi.TotalSize);
            }
        }
 
        private void CheckStatfsResultAndThrowIfNecessary(int result)
        {
            if (result != 0)
            {
                var errorInfo = Interop.Sys.GetLastErrorInfo();
                if (errorInfo.Error == Interop.Error.ENOENT)
                {
                    throw new DriveNotFoundException(SR.Format(SR.IO_DriveNotFound_Drive, Name)); // match Win32
                }
                else
                {
                    throw Interop.GetExceptionForIoErrno(errorInfo);
                }
            }
        }
 
        private static string[] GetMountPoints() => Interop.Sys.GetAllMountPoints();
    }
}