//	Spludlow Software
//	Copyright © Samuel P. Ludlow 2020 All Rights Reserved
//	Distributed under the terms of the GNU General Public License version 3
//	Distributed WITHOUT ANY WARRANTY; without implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE
//	https://www.spludlow.co.uk/LICENCE.TXT
//	The Spludlow logo is a registered trademark of Samuel P. Ludlow and may not be used without permission
//	v1.14

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

using System.IO;

namespace Spludlow.Email
{
	/// <summary>
	/// Read 'AppleDouble' files, normally emailed from a Macintosh
	///	Works with the 'MacBinary' class to create a file that can be extracted on a Macintosh to restore the data fork, File Type, and Creator Code
	///	You dont see as many AppleDoubles these days
	/// </summary>
	public class AppleDouble
	{
		public class AppleEntry
		{
			public uint Id;
			public uint OffSet;
			public uint Length;
		}

		public uint MagicNumber;
		public uint VersionNumber;

		public ushort NumberOfEntries;
		public AppleEntry[] AppleEntries;

		public byte[] DataFork;
		public byte[] ResourceFork;

		public string FileName;
		public byte[] FileNameData;

		public byte[] FileType;
		public byte[] CreatorCode;

		public byte[] DateInfo;

		public uint CreationDate;
		public uint ModificationDate;
		public uint BackUpDate;
		public uint AccessDate;

		public AppleDouble()
		{
		}

		public void Load(string filename)
		{
			using (BinaryReader headReader = new BinaryReader(new FileStream(filename, FileMode.Open)))
			{
				this.MagicNumber = Spludlow.Io.BinaryIO.ReadUInt32(headReader, true);
				this.VersionNumber = Spludlow.Io.BinaryIO.ReadUInt32(headReader, true);

				headReader.ReadBytes(16);

				this.NumberOfEntries = Spludlow.Io.BinaryIO.ReadUInt16(headReader, true);

				this.AppleEntries = new AppleEntry[this.NumberOfEntries];

				for (int index = 0; index < this.NumberOfEntries; ++index)
				{
					AppleEntry appleEntry = new AppleEntry();
					appleEntry.Id = Spludlow.Io.BinaryIO.ReadUInt32(headReader, true);
					appleEntry.OffSet = Spludlow.Io.BinaryIO.ReadUInt32(headReader, true);
					appleEntry.Length = Spludlow.Io.BinaryIO.ReadUInt32(headReader, true);
					this.AppleEntries[index] = appleEntry;
				}

				foreach (AppleEntry appleEntry in this.AppleEntries)
				{
					byte[] entryData = new byte[appleEntry.Length];
					headReader.BaseStream.Seek(appleEntry.OffSet, SeekOrigin.Begin);
					headReader.Read(entryData, 0, entryData.Length);

					switch (appleEntry.Id)
					{
						case 0:
							break;

						case 1:     //Data Fork 1 Data fork
							this.DataFork = entryData;
							break;

						case 2:     //Resource Fork 2 Resource fork
							this.ResourceFork = entryData;
							break;

						case 3:     //Real Name 3 File’s name as created on home file system
							this.FileName = System.Text.Encoding.ASCII.GetString(entryData);
							this.FileNameData = entryData;
							break;

						case 4:     //Comment 4 Standard Macintosh comment
							break;

						case 5:     //Icon, B&W 5 Standard Macintosh black and white icon
							break;

						case 6:     //Icon, Color 6 Macintosh color icon
							break;

						case 7:     // Not defined
							break;

						case 8:     //File Dates Info 8 File creation date, modification date, and so on
							if (entryData.Length != 16)
								throw new ApplicationException("Apple Single/Double Date section is not 16 bytes");

							this.CreationDate = Spludlow.Io.BinaryIO.ReadUInt32(entryData, 0, true);
							this.ModificationDate = Spludlow.Io.BinaryIO.ReadUInt32(entryData, 4, true);
							this.BackUpDate = Spludlow.Io.BinaryIO.ReadUInt32(entryData, 8, true);
							this.AccessDate = Spludlow.Io.BinaryIO.ReadUInt32(entryData, 12, true);
							break;

						case 9:     //Finder Info 9 Standard Macintosh Finder information

							this.FileType = new byte[4];
							this.FileType[0] = entryData[0];
							this.FileType[1] = entryData[1];
							this.FileType[2] = entryData[2];
							this.FileType[3] = entryData[3];

							this.CreatorCode = new byte[4];
							this.CreatorCode[0] = entryData[4];
							this.CreatorCode[1] = entryData[5];
							this.CreatorCode[2] = entryData[6];
							this.CreatorCode[3] = entryData[7];

							break;

						case 10:        //Macintosh File Info 10 Macintosh file information, attributes, and so on
							break;

						case 11:        //ProDOS File Info 11 ProDOS file information, attributes, and so on
							break;

						case 12:        //MS-DOS File Info 12 MS-DOS file information, attributes, and so on
							break;

						case 13:        //Short Name 13 AFP short name
							break;

						case 14:        //AFP File Info 14 AFP file information, attributes, and so on
							break;

						case 15:        //Directory ID 15 AFP directory ID
							break;

						default:
							break;
					}

				}
			}

			if (this.FileType == null)
				this.FileType = Encoding.ASCII.GetBytes("    ");

			if (this.CreatorCode == null)
				this.CreatorCode = Encoding.ASCII.GetBytes("    ");

			if (this.ResourceFork == null)
				this.ResourceFork = new byte[0];

			if (this.DataFork == null)
				this.DataFork = new byte[0];
		}
	}
}