using System;
using System.Runtime.InteropServices;
using System.Text;

namespace ScreenConnect;

public abstract class DeflateCoder : CriticalFinalizerDisposableObject, IMultiCallCoder, ICoder, IDisposable
{
	private unsafe Native.libz.z_stream_s* nativeStream;

	private DeflateWrapper wrapper;

	public unsafe int UnusedBitTakenCount => nativeStream->data_type & 0x3F;

	public bool AreInputOutputCursorsAlwaysSynced => false;

	public unsafe long TotalInputByteCount => nativeStream->total_in.ToInt64();

	public unsafe long TotalOutputByteCount => nativeStream->total_out.ToInt64();

	protected DeflateCoder(DeflateWrapper wrapper)
	{
		this.wrapper = wrapper;
	}

	protected unsafe override void Dispose(bool disposing)
	{
		if (nativeStream != null)
		{
			try
			{
				End((IntPtr)nativeStream);
			}
			catch
			{
			}
			Marshal.FreeHGlobal((IntPtr)nativeStream);
			nativeStream = null;
		}
	}

	protected unsafe void Initialize()
	{
		int num = 15;
		if (wrapper == DeflateWrapper.None)
		{
			num *= -1;
		}
		else if (wrapper == DeflateWrapper.Gzip)
		{
			num += 16;
		}
		int num2 = Marshal.SizeOf(typeof(Native.libz.z_stream_s));
		nativeStream = (Native.libz.z_stream_s*)(void*)Marshal.AllocHGlobal(num2);
		Extensions.ZeroMemory(nativeStream, num2);
		fixed (byte* bytes = Encoding.UTF8.GetBytes("1.0.0"))
		{
			Extensions.AssertNativeResultZero(Initialize((IntPtr)nativeStream, bytes, num2, num));
		}
	}

	public unsafe CoderProcessResult Process(byte* inputData, int inputCount, byte* outputData, int outputCount, CoderFlushType flushType, out int inputTaken, out int outputProduced)
	{
		nativeStream->next_in = inputData;
		nativeStream->avail_in = (uint)inputCount;
		nativeStream->next_out = outputData;
		nativeStream->avail_out = (uint)outputCount;
		int result = Process((IntPtr)nativeStream, flushType);
		inputTaken = inputCount - (int)nativeStream->avail_in;
		outputProduced = outputCount - (int)nativeStream->avail_out;
		return (CoderProcessResult)result;
	}

	protected unsafe abstract int Initialize(IntPtr stream, byte* version, int streamSize, int windowBits);

	protected abstract int Process(IntPtr stream, CoderFlushType flushType);

	protected abstract int End(IntPtr stream);
}