using DiscUtils;
using DiscUtils.Ntfs;
using DiscUtils.Partitions;
using DiscUtils.Streams;
using SvdCli.Storage;
using System;
using System.IO;

namespace SvdCli.DiskUtils
{
    internal static class FsMaker
    {
        public static void MakeNtfsRamDisk(ISvdStorage storage, bool createTempFolder)
        {
            storage.Init();
            using var sss = new SvdStorageStream(storage);
            using VirtualDisk disk = new DiscUtils.Raw.Disk(sss, Ownership.None);
            BiosPartitionTable.Initialize(disk, WellKnownPartitionType.WindowsNtfs);
            var volMgr = new VolumeManager(disk);

            using var destNtfs = NtfsFileSystem.Format(volMgr.GetLogicalVolumes()[0], "RamDIsk", new NtfsFormatOptions());
            if (createTempFolder) destNtfs.CreateDirectory("Temp");
        }

        private class SvdStorageStream : Stream
        {
            private readonly ISvdStorage _storage;

            public SvdStorageStream(ISvdStorage storage) => _storage = storage;

            public override int Read(byte[] buffer, int offset, int count)
            {
                var read = _storage.Read(buffer, Position, offset, count);
                Position += read;
                return read;
            }

            public override void Write(byte[] buffer, int offset, int count)
            {
                _storage.Write(buffer, Position, offset, count);
                Position += count;
            }

            public override void Flush() => _storage.Flush();

            public override long Seek(long offset, SeekOrigin origin)
            {
                switch (origin)
                {
                    case SeekOrigin.Begin:
                        Position = offset;
                        break;

                    case SeekOrigin.Current:
                        Position += offset;
                        break;

                    case SeekOrigin.End:
                        Position = Length + offset;
                        break;

                    default:
                        throw new ArgumentOutOfRangeException(nameof(origin), origin, null);
                }

                return Position;
            }

            public override void SetLength(long value)
            {
            }

            public override bool CanRead => true;
            public override bool CanSeek => true;
            public override bool CanWrite => true;
            public override long Length => _storage.BlockSize * (long)_storage.BlockCount;
            public override long Position { get; set; }
        }
    }
}