using System;
using System.Buffers.Binary;
using System.Collections.Generic;
using System.Linq;
using System.Reflection.Metadata;
using System.Threading.Tasks;
using Nyanbyte.Sysnya.Binary;

namespace Nyanbyte.Sysnya.CoreTests.Binary;

public class BinaryMapperTests
{

    private class Dummy
    {
        public short Int16 { get; set; }
        public ushort UInt16 { get; set; }
        public int Int32 { get; set; }
        public uint UInt32 { get; set; }
        public long Int64 { get; set; }
        public ulong UInt64 { get; set; }
    }

    [Fact]
    public void Map32Bit()
    {
        // Given
        Span<byte> bytes = stackalloc byte[8];
        BinaryPrimitives.WriteUInt32BigEndian(bytes, 0xfeedbeef);
        BinaryPrimitives.WriteInt32BigEndian(bytes[4..], 0xbeef);

        BinaryStructMapperBuilder<Dummy> b = new(0, true);

        // When
        var mapper = b.BindU32(p => p.UInt32).BindI32(p => p.Int32).Build();
        var dummy = mapper.Map(bytes.ToArray());

        // Then
        Assert.Equal(0xfeedbeef, dummy.UInt32);
        Assert.Equal(0xbeef, dummy.Int32);
    }

    [Fact]
    public void MapAll()
    {
        // Given
        Span<byte> bytes = stackalloc byte[28];
        BinaryPrimitives.WriteUInt16BigEndian(bytes[0..], 0xbabe);
        BinaryPrimitives.WriteInt16BigEndian(bytes[2..], 0xbf);
        BinaryPrimitives.WriteUInt32BigEndian(bytes[4..], 0xfeedbeef);
        BinaryPrimitives.WriteInt32BigEndian(bytes[8..], 0xbeef);
        BinaryPrimitives.WriteUInt64BigEndian(bytes[12..], 0xbad1dea0babebebe);
        BinaryPrimitives.WriteInt64BigEndian(bytes[20..], 0x1dea0babebebe);

        BinaryStructMapperBuilder<Dummy> b = new(0, true);

        // When
        var mapper = b
            .BindU16(p => p.UInt16).BindI16(p => p.Int16)
            .BindU32(p => p.UInt32).BindI32(p => p.Int32)
            .BindU64(p => p.UInt64).BindI64(p => p.Int64)
        .Build();
        var dummy = mapper.Map(bytes.ToArray());

        // Then
        Assert.Equal(0xbabe, dummy.UInt16);
        Assert.Equal(0xbf, dummy.Int16);
        Assert.Equal(0xfeedbeef, dummy.UInt32);
        Assert.Equal(0xbeef, dummy.Int32);
        Assert.Equal(0xbad1dea0babebebe, dummy.UInt64);
        Assert.Equal(0x1dea0babebebe, dummy.Int64);
    }
}