using System;
using System.IO;
using AMWD.Common.Packing.Tar.Interfaces;
using AMWD.Common.Packing.Tar.Utils;

namespace AMWD.Common.Packing.Tar
{
	/// <summary>
	/// Writes a tar (see GNU tar) archive to a stream.
	/// </summary>
	/// <remarks>
	/// Copied from: <see href="https://github.com/ygoe/DotnetMakeDeb/blob/v1.1.0/DotnetMakeDeb/Tar/TarWriter.cs">DotnetMakeDeb</see>
	/// </remarks>
	public class TarWriter : LegacyTarWriter
	{
		/// <summary>
		/// Initilizes a new instance of the <see cref="TarWriter"/> class.
		/// </summary>
		/// <param name="outStream">The stream to write the archive to.</param>
		public TarWriter(Stream outStream)
			: base(outStream)
		{ }

		/// <summary>
		/// Writes an entry header (file, dir, ...) to the archive.
		/// </summary>
		/// <param name="name">The name.</param>
		/// <param name="lastModificationTime">The last modification time.</param>
		/// <param name="count">The number of bytes.</param>
		/// <param name="userId">The user id.</param>
		/// <param name="groupId">The group id.</param>
		/// <param name="mode">The access mode.</param>
		/// <param name="entryType">The entry type.</param>
		protected override void WriteHeader(string name, DateTime lastModificationTime, long count, int userId, int groupId, int mode, EntryType entryType)
		{
			var tarHeader = new UsTarHeader()
			{
				FileName = name,
				Mode = mode,
				UserId = userId,
				GroupId = groupId,
				SizeInBytes = count,
				LastModification = lastModificationTime,
				EntryType = entryType,
				UserName = Convert.ToString(userId, 8),
				GroupName = Convert.ToString(groupId, 8)
			};
			OutStream.Write(tarHeader.GetHeaderValue(), 0, tarHeader.HeaderSize);
		}

		/// <summary>
		/// Writes an entry header (file, dir, ...) to the archive.
		/// Hashes the username and groupname down to a HashCode.
		/// </summary>
		/// <param name="name">The name.</param>
		/// <param name="lastModificationTime">The last modification time.</param>
		/// <param name="count">The number of bytes.</param>
		/// <param name="userName">The username.</param>
		/// <param name="groupName">The group name.</param>
		/// <param name="mode">The access mode.</param>
		/// <param name="entryType">The entry type.</param>
		protected virtual void WriteHeader(string name, DateTime lastModificationTime, long count, string userName, string groupName, int mode, EntryType entryType)
		{
			WriteHeader(
				name: name,
				lastModificationTime: lastModificationTime,
				count: count,
				userId: userName.GetHashCode(),
				groupId: groupName.GetHashCode(),
				mode: mode,
				entryType: entryType);
		}

		/// <summary>
		/// Writes a file to the archive.
		/// </summary>
		/// <param name="name">The file name.</param>
		/// <param name="dataSizeInBytes">The filesize in bytes.</param>
		/// <param name="userName">The username.</param>
		/// <param name="groupName">The group name.</param>
		/// <param name="mode">The access mode.</param>
		/// <param name="lastModificationTime">The last modification time.</param>
		/// <param name="writeDelegate">The write handle.</param>
		public virtual void Write(string name, long dataSizeInBytes, string userName, string groupName, int mode, DateTime lastModificationTime, WriteDataDelegate writeDelegate)
		{
			var writer = new DataWriter(OutStream, dataSizeInBytes);
			WriteHeader(name, lastModificationTime, dataSizeInBytes, userName, groupName, mode, EntryType.File);
			while (writer.CanWrite)
			{
				writeDelegate(writer);
			}
			AlignTo512(dataSizeInBytes, false);
		}

		/// <summary>
		/// Writes a file to the archive.
		/// </summary>
		/// <param name="data">The file stream to add to the archive.</param>
		/// <param name="dataSizeInBytes">The filesize in bytes.</param>
		/// <param name="fileName">The file name.</param>
		/// <param name="userId">The user id.</param>
		/// <param name="groupId">The group id.</param>
		/// <param name="mode">The access mode.</param>
		/// <param name="lastModificationTime">The last modification time.</param>
		public void Write(Stream data, long dataSizeInBytes, string fileName, string userId, string groupId, int mode,
						  DateTime lastModificationTime)
		{
			WriteHeader(fileName, lastModificationTime, dataSizeInBytes, userId, groupId, mode, EntryType.File);
			WriteContent(dataSizeInBytes, data);
			AlignTo512(dataSizeInBytes, false);
		}
	}
}