using System.IO;
using Octodiff.Core;
using Octodiff.Diagnostics;

namespace Wabbajack.Compiler.PatchCache
{
    public class OctoDiff
    {
        public static void Create(byte[] oldData, byte[] newData, Stream output)
        {
            using var signature = CreateSignature(oldData);
            using var oldStream = new MemoryStream(oldData);
            using var newStream = new MemoryStream(newData);
            var db = new DeltaBuilder();
            db.BuildDelta(newStream, new SignatureReader(signature, new NullProgressReporter()), new AggregateCopyOperationsDecorator(new BinaryDeltaWriter(output)));
        }

        private static Stream CreateSignature(byte[] oldData)
        {
            using var oldDataStream = new MemoryStream(oldData);
            var sigStream = new MemoryStream();
            var signatureBuilder = new SignatureBuilder();
            signatureBuilder.Build(oldDataStream, new SignatureWriter(sigStream));
            sigStream.Position = 0;
            return sigStream;
        }
        
        private static void CreateSignature(Stream oldData, Stream sigStream)
        {
            var signatureBuilder = new SignatureBuilder();
            signatureBuilder.Build(oldData, new SignatureWriter(sigStream));
            sigStream.Position = 0;
        }
        
        public static void Create(Stream oldData, Stream newData, Stream signature, Stream output)
        {
            CreateSignature(oldData, signature);
            var db = new DeltaBuilder {ProgressReporter = new NullProgressReporter()};
            db.BuildDelta(newData, new SignatureReader(signature, new NullProgressReporter()), new AggregateCopyOperationsDecorator(new BinaryDeltaWriter(output)));
        }

    }
}