using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SentinelKernel.FAT.Listing
{
  public class MyFatFile : Cosmos.System.Filesystem.Listing.File
  {
    public readonly MyFatFileSystem FileSystem;
    public readonly UInt64 FirstClusterNum;

    // Size is UInt32 because FAT doesn't support bigger.
    // Dont change to UInt64
    public MyFatFile(MyFatFileSystem aFileSystem, string aName, UInt32 aSize, UInt64 aFirstCluster)
      : base(aFileSystem, aName, aSize)
    {
      FileSystem = aFileSystem;
      FirstClusterNum = aFirstCluster;
    }

    //TODO: Seperate out the file mechanics from the Listing class
    // so a file can exist without a listing instance
    public List<UInt64> GetFatTable()
    {
      uint xBytesPerCluster = (FileSystem.SectorsPerCluster * FileSystem.BytesPerSector);
      ulong numberOfClusters = (Size / xBytesPerCluster);
      var xListCapacity = (int)numberOfClusters;
      var xResult = new List<UInt64>();//xListCapacity
      UInt64 xClusterNum = FirstClusterNum;

      byte[] xSector = new byte[FileSystem.BytesPerSector];
      UInt32? xSectorNum = null;

      UInt32 xNextSectorNum;
      UInt32 xNextSectorOffset;
      do
      {
        if (FileSystem == null)
        {
          Console.WriteLine("$this is null! (1)");
        }
        FileSystem.GetFatTableSector(xClusterNum, out xNextSectorNum, out xNextSectorOffset);
        if (FileSystem == null)
        {
          Console.WriteLine("$this is null! (2)");
        }
        if (xSectorNum.HasValue == false || xSectorNum != xNextSectorNum)
        {
          if (FileSystem == null)
          {
            Console.WriteLine("$this is null! (3)");
          }
          var nextSectorNum = (ulong)xNextSectorNum;
          if (this == null)
          {
            Console.WriteLine("$this is null!");
          }
          if (FileSystem == null)
          {
            Console.WriteLine("$this.FileSystem is null");
          }
          FileSystem.ReadFatTableSector(nextSectorNum, xSector);
          xSectorNum = xNextSectorNum;
        }

        xResult.Add(xClusterNum);
        if (FileSystem == null)
        {
          Console.WriteLine("$this.FileSystem is null (2)");
        }
        var xFS = FileSystem;
        if (xFS == null)
        {
          Console.WriteLine("xFS is null (2)");
        }
        xClusterNum = xFS.GetFatEntry(xSector, xClusterNum, xNextSectorOffset);
      } while (!FileSystem.FatEntryIsEOF(xClusterNum));

      return xResult;
    }

  }
}