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

namespace PFCRip
{
  public class PFCDataRecord
  {
    #region Declarations

    private byte[] _data;
    private Dictionary<ushort, DataSubItem> _subItems;

    #endregion

    #region Constructors / Teardown

    public PFCDataRecord(byte[] data)
    {
      byte[] header = {(byte)'A', (byte)'O', (byte)'L', (byte)'H'};
      byte[] footer = {(byte)'A', (byte)'O', (byte)'L', (byte)'F'};

      _data = data;

      //If we don't have the AOLH and AOLF headers, freak out
      if (_data.Length > 0 && _data.Length < (header.Length + footer.Length))
        throw new InvalidOperationException(String.Format("PFCDataRecord: Invalid length {0}", _data.Length));

      //Verify the header is there
      for (int i = 0; i < header.Length; i++)
        if (header[i] != _data[i])
          throw new InvalidOperationException("PFCDataRecord: Invalid header: " +
            BitConverter.ToString(_data, 0, 4));

      //Verify the footer is there
      for (int i = 0; i < footer.Length; i++)
        if (footer[i] != _data[_data.Length - 4 + i])
          throw new InvalidOperationException("PFCDataRecord: Invalid footer: " +
            BitConverter.ToString(_data, _data.Length - 4 - 1, 4));

      //Parse into individual items
      uint index = (uint)(4 + header.Length);
      _subItems = new Dictionary<ushort, DataSubItem>();
      while (index < _data.Length - footer.Length)
      {
        ushort itemId = LittleEndianConverter.ToUInt16(_data, index); index += 2;
        byte itemType = _data[index]; index++;
        uint size;
        switch (itemType)
        {
          case 0x01:
          case 0x02:
          case 0x03:
          case 0x04:
            {
              size = itemType;
              break;
            }
          default:
            {
              size = LittleEndianConverter.ToUInt32(_data, index); index += 4;
              break;
            }
        }

        var subData = new byte[size];
        for (int i = 0; i < size; i++)
          subData[i] = _data[index + i];
        index += size;
        _subItems.Add(itemId, new DataSubItem(itemId, itemType, subData));
      }
    }

    #endregion

    #region Public Properties

    public Dictionary<ushort, DataSubItem> SubItems
    {
      get
      {
        return _subItems;
      }
    }

    #endregion
  }
}