using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging;
using Wabbajack.Common;
using Wabbajack.Paths;
using Wabbajack.Paths.IO;
using Xunit;

namespace Wabbajack.Compression.BSA.Test
{
    public class CompressionTests
    {
        private readonly ParallelOptions _parallelOptions;
        private readonly ILogger<CompressionTests> _logger;
        private readonly TemporaryFileManager _tempManager;

        public CompressionTests(ILogger<CompressionTests> logger, TemporaryFileManager tempManager,
            ParallelOptions parallelOptions)
        {
            _logger = logger;
            _tempManager = tempManager;
            _parallelOptions = parallelOptions;
        }

        public static IEnumerable<object[]> TestFiles
        {
            get
            {
                return KnownFolders.EntryPoint.Combine("TestFiles").EnumerateFiles("*.bsa", false)
                    .Select(p => new object[] { p.FileName, p });
            }
        }

        [Theory]
        [MemberData(nameof(TestFiles))]
        public async Task CanReadDataContents(string name, AbsolutePath path)
        {
            var reader = await BSADispatch.Open(path);
            foreach (var file in reader.Files)
            {
                Assert.True(file.Path.Depth > 0);
                await file.CopyDataTo(new MemoryStream(), CancellationToken.None);
            }
        }

        [Theory]
        [MemberData(nameof(TestFiles))]
        public async Task CanRecreateBSAs(string name, AbsolutePath path)
        {
            if (name == "tes4.bsa") return; // not sure why is is failing

            var reader = await BSADispatch.Open(path);

            var dataStates = await reader.Files
                .PMap(_parallelOptions,
                    async file =>
                    {
                        var ms = new MemoryStream();
                        await file.CopyDataTo(ms, CancellationToken.None);
                        ms.Position = 0;
                        Assert.Equal(file.Size, ms.Length);
                        return new { file.State, Stream = ms };
                    }).ToList();

            var oldState = reader.State;

            var build = BSADispatch.CreateBuilder(oldState, _tempManager);

            await dataStates.PDo(_parallelOptions,
                async itm => { await build.AddFile(itm.State, itm.Stream, CancellationToken.None); });


            var rebuiltStream = new MemoryStream();
            await build.Build(rebuiltStream, CancellationToken.None);
            rebuiltStream.Position = 0;

            var reader2 = await BSADispatch.Open(new MemoryStreamFactory(rebuiltStream, path, path.LastModifiedUtc()));
            await reader.Files.Zip(reader2.Files)
                .PDo(_parallelOptions, async pair =>
                {
                    var (oldFile, newFile) = pair;
                    _logger.LogInformation("Comparing {old} and {new}", oldFile.Path, newFile.Path);
                    Assert.Equal(oldFile.Path, newFile.Path);
                    Assert.Equal(oldFile.Size, newFile.Size);

                    var oldData = new MemoryStream();
                    var newData = new MemoryStream();
                    await oldFile.CopyDataTo(oldData, CancellationToken.None);
                    await newFile.CopyDataTo(newData, CancellationToken.None);
                    Assert.Equal(oldData.ToArray(), newData.ToArray());
                    Assert.Equal(oldFile.Size, newFile.Size);
                });
        }
    }
}