using System;
using System.Buffers;
using System.IO;
using SharpCompress.Compressors.LZMA;
using Xunit;

namespace SharpCompress.Test.Streams;

public class LzmaStreamTests
{
    [Fact]
    public void TestLzma2Decompress1Byte()
    {
        var properties = new byte[] { 0x01 };
        var compressedData = new byte[] { 0x01, 0x00, 0x00, 0x58, 0x00 };
        var lzma2Stream = new MemoryStream(compressedData);

        var decompressor = new LzmaStream(properties, lzma2Stream, 5, 1);
        Assert.Equal('X', decompressor.ReadByte());
    }

    private static byte[] LzmaData { get; } =
        [
            0x5D,
            0x00,
            0x20,
            0x00,
            0x00,
            0x48,
            0x01,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x80,
            0x24,
            0x18,
            0x2F,
            0xEB,
            0x20,
            0x78,
            0xBA,
            0x78,
            0x70,
            0xDC,
            0x43,
            0x2C,
            0x32,
            0xC9,
            0xC3,
            0x97,
            0x4D,
            0x10,
            0x74,
            0xE2,
            0x20,
            0xBF,
            0x5A,
            0xB4,
            0xB3,
            0xC4,
            0x31,
            0x80,
            0x26,
            0x3E,
            0x6A,
            0xEA,
            0x51,
            0xFC,
            0xE4,
            0x8D,
            0x54,
            0x96,
            0x05,
            0xCC,
            0x78,
            0x59,
            0xAC,
            0xD4,
            0x21,
            0x65,
            0x8F,
            0xA9,
            0xC8,
            0x0D,
            0x9B,
            0xE2,
            0xC2,
            0xF9,
            0x7C,
            0x3C,
            0xDD,
            0x4D,
            0x38,
            0x04,
            0x0B,
            0xF8,
            0x0B,
            0x68,
            0xA5,
            0x93,
            0x6C,
            0x64,
            0xAC,
            0xCF,
            0x71,
            0x68,
            0xE8,
            0x69,
            0x25,
            0xC6,
            0x17,
            0x28,
            0xF1,
            0x7C,
            0xF1,
            0xDC,
            0x47,
            0x51,
            0x4D,
            0x1E,
            0x0E,
            0x0B,
            0x80,
            0x37,
            0x24,
            0x58,
            0x80,
            0xF7,
            0xB4,
            0xAC,
            0x54,
            0xF1,
            0x0F,
            0x7F,
            0x0F,
            0x0F,
            0xF5,
            0x9C,
            0xDE,
            0x54,
            0x4F,
            0xA3,
            0x7B,
            0x20,
            0xC5,
            0xA8,
            0x18,
            0x3B,
            0xED,
            0xDC,
            0x04,
            0xF6,
            0xFB,
            0x86,
            0xE0,
            0xAB,
            0xB6,
            0x87,
            0x99,
            0x92,
            0x43,
            0x7B,
            0x2C,
            0xCC,
            0x31,
            0x83,
            0x90,
            0xFF,
            0xF1,
            0x76,
            0x03,
            0x90
        ];

    /// <summary>
    /// The decoded data for <see cref="LzmaData"/>.
    /// </summary>
    private static byte[] LzmaResultData { get; } =
        [
            0x01,
            0x00,
            0xFD,
            0x01,
            0x00,
            0x00,
            0x00,
            0x00,
            0xFA,
            0x61,
            0x18,
            0x5F,
            0x02,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x02,
            0x00,
            0x00,
            0x00,
            0x03,
            0x00,
            0x00,
            0x00,
            0x01,
            0x00,
            0x00,
            0x00,
            0x02,
            0x00,
            0xB4,
            0x01,
            0x00,
            0x00,
            0x00,
            0x00,
            0x3D,
            0x61,
            0xE5,
            0x5E,
            0x03,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x12,
            0x00,
            0x00,
            0x00,
            0x02,
            0x00,
            0xB4,
            0x01,
            0x00,
            0x00,
            0x00,
            0x00,
            0xE2,
            0x61,
            0x18,
            0x5F,
            0x04,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x12,
            0x00,
            0x00,
            0x00,
            0x29,
            0x00,
            0x00,
            0x00,
            0x01,
            0x00,
            0xFD,
            0x01,
            0x00,
            0x00,
            0x00,
            0x00,
            0x14,
            0x62,
            0x18,
            0x5F,
            0x01,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x03,
            0x00,
            0x00,
            0x00,
            0x40,
            0x00,
            0x00,
            0x00,
            0x09,
            0x00,
            0x00,
            0x00,
            0x02,
            0x00,
            0xB4,
            0x01,
            0x00,
            0x00,
            0x00,
            0x00,
            0x7F,
            0x61,
            0xE5,
            0x5E,
            0x05,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x3B,
            0x00,
            0x00,
            0x00,
            0xCB,
            0x15,
            0x00,
            0x00,
            0x02,
            0x00,
            0xB4,
            0x01,
            0x00,
            0x00,
            0x00,
            0x00,
            0x7F,
            0x61,
            0xE5,
            0x5E,
            0x06,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x3B,
            0x00,
            0x00,
            0x00,
            0xCB,
            0x15,
            0x00,
            0x00,
            0x02,
            0x00,
            0xB4,
            0x01,
            0x00,
            0x00,
            0x00,
            0x00,
            0x3D,
            0x61,
            0xE5,
            0x5E,
            0x07,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x12,
            0x00,
            0x00,
            0x00,
            0x02,
            0x00,
            0xB4,
            0x01,
            0x00,
            0x00,
            0x00,
            0x00,
            0xFC,
            0x96,
            0x40,
            0x5C,
            0x08,
            0x00,
            0x00,
            0x00,
            0x60,
            0x00,
            0x00,
            0x00,
            0xFF,
            0xFF,
            0xFF,
            0xFF,
            0x00,
            0x00,
            0x00,
            0x00,
            0xF8,
            0x83,
            0x12,
            0x00,
            0xD4,
            0x99,
            0x00,
            0x00,
            0x43,
            0x95,
            0x00,
            0x00,
            0xEB,
            0x7A,
            0x00,
            0x00,
            0x40,
            0x6F,
            0x00,
            0x00,
            0xD2,
            0x6F,
            0x00,
            0x00,
            0x67,
            0x74,
            0x00,
            0x00,
            0x02,
            0x69,
            0x00,
            0x00,
            0x76,
            0x79,
            0x00,
            0x00,
            0x98,
            0x66,
            0x00,
            0x00,
            0x23,
            0x25,
            0x00,
            0x00,
            0x01,
            0x00,
            0xFD,
            0x01,
            0x00,
            0x00,
            0x00,
            0x00,
            0x3B,
            0x2F,
            0xC0,
            0x5F,
            0x09,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x00,
            0x03,
            0x00,
            0x00,
            0x00,
            0x69,
            0x00,
            0x3D,
            0x00,
            0x0A,
            0x00,
            0x00,
            0x00
        ];

    [Fact]
    public void TestLzmaBuffer()
    {
        var input = new MemoryStream(LzmaData);
        using var output = new MemoryStream();
        var properties = new byte[5];
        input.Read(properties, 0, 5);

        var fileLengthBytes = new byte[8];
        input.Read(fileLengthBytes, 0, 8);
        var fileLength = BitConverter.ToInt64(fileLengthBytes, 0);

        var coder = new Decoder();
        coder.SetDecoderProperties(properties);
        coder.Code(input, output, input.Length, fileLength, null);

        Assert.Equal(output.ToArray(), LzmaResultData);
    }

    [Fact]
    public void TestLzmaStreamEncodingWritesData()
    {
        using var inputStream = new MemoryStream(LzmaResultData);
        using MemoryStream outputStream = new();
        using var lzmaStream = new LzmaStream(LzmaEncoderProperties.Default, false, outputStream);
        inputStream.CopyTo(lzmaStream);
        lzmaStream.Close();
        Assert.NotEqual(0, outputStream.Length);
    }

    [Fact]
    public void TestLzmaEncodingAccuracy()
    {
        var input = new MemoryStream(LzmaResultData);
        var compressed = new MemoryStream();
        var lzmaEncodingStream = new LzmaStream(LzmaEncoderProperties.Default, false, compressed);
        input.CopyTo(lzmaEncodingStream);
        lzmaEncodingStream.Close();
        compressed.Position = 0;

        var output = new MemoryStream();
        DecompressLzmaStream(
            lzmaEncodingStream.Properties,
            compressed,
            compressed.Length,
            output,
            LzmaResultData.LongLength
        );

        Assert.Equal(output.ToArray(), LzmaResultData);
    }

    private static void DecompressLzmaStream(
        byte[] properties,
        Stream compressedStream,
        long compressedSize,
        Stream decompressedStream,
        long decompressedSize
    )
    {
        var lzmaStream = new LzmaStream(
            properties,
            compressedStream,
            compressedSize,
            -1,
            null,
            false
        );

        var buffer = ArrayPool<byte>.Shared.Rent(1024);
        long totalRead = 0;
        while (totalRead < decompressedSize)
        {
            var toRead = (int)Math.Min(buffer.Length, decompressedSize - totalRead);
            var read = lzmaStream.Read(buffer, 0, toRead);
            if (read > 0)
            {
                decompressedStream.Write(buffer, 0, read);
                totalRead += read;
            }
            else
            {
                break;
            }
        }
        ArrayPool<byte>.Shared.Return(buffer);
    }
}
