using System;
using System.Buffers.Binary;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reactive.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging;
using OMODFramework;
using Wabbajack.Common;
using Wabbajack.Common.FileSignatures;
using Wabbajack.Compression.BSA;
using Wabbajack.Compression.BSA.FO4Archive;
using Wabbajack.DTOs.Streams;
using Wabbajack.FileExtractor.ExtractedFiles;
using Wabbajack.IO.Async;
using Wabbajack.Paths;
using Wabbajack.Paths.IO;
using Wabbajack.RateLimiter;

namespace Wabbajack.FileExtractor;

public class FileExtractor
{
    public static readonly SignatureChecker ArchiveSigs = new(FileType.TES3,
        FileType.BSA,
        FileType.BA2,
        FileType.BTAR,
        FileType.ZIP,
        //FileType.EXE,
        FileType.RAR_OLD,
        FileType.RAR_NEW,
        FileType._7Z);

    private static readonly Extension OMODExtension = new(".omod");
    private static readonly Extension FOMODExtension = new(".fomod");

    private static readonly Extension BSAExtension = new(".bsa");

    public static readonly HashSet<Extension> ExtractableExtensions = new()
    {
        new Extension(".bsa"),
        new Extension(".ba2"),
        new Extension(".7z"),
        new Extension(".7zip"),
        new Extension(".rar"),
        new Extension(".zip"),
        new Extension(".btar"),
        OMODExtension,
        FOMODExtension
    };

    private readonly IResource<FileExtractor> _limiter;
    private readonly ILogger<FileExtractor> _logger;
    private readonly TemporaryFileManager _manager;

    private readonly ParallelOptions _parallelOptions;

    public FileExtractor(ILogger<FileExtractor> logger, ParallelOptions parallelOptions, TemporaryFileManager manager,
        IResource<FileExtractor> limiter)
    {
        _logger = logger;
        _parallelOptions = parallelOptions;
        _manager = manager;
        _limiter = limiter;
    }

    public async Task<IDictionary<RelativePath, T>> GatheringExtract<T>(
        IStreamFactory sFn,
        Predicate<RelativePath> shouldExtract,
        Func<RelativePath, IExtractedFile, ValueTask<T>> mapfn,
        CancellationToken token,
        HashSet<RelativePath>? onlyFiles = null,
        Action<Percent>? progressFunction = null)
    {
        if (sFn is NativeFileStreamFactory) _logger.LogInformation("Extracting {file}", sFn.Name);
        await using var archive = await sFn.GetStream();
        var sig = await ArchiveSigs.MatchesAsync(archive);
        archive.Position = 0;


        IDictionary<RelativePath, T> results;

        switch (sig)
        {
            case FileType.RAR_OLD:
            case FileType.RAR_NEW:
            case FileType._7Z:
            case FileType.ZIP:
            {
                if (sFn.Name.FileName.Extension == OMODExtension)
                {
                    results = await GatheringExtractWithOMOD(archive, shouldExtract, mapfn, token);
                }
                else
                {
                    await using var tempFolder = _manager.CreateFolder();
                    results = await GatheringExtractWith7Zip(sFn, shouldExtract,
                        mapfn, onlyFiles, token, progressFunction);
                }

                break;
            }
            case FileType.BTAR:
                results = await GatheringExtractWithBTAR(sFn, shouldExtract, mapfn, token);
                break;

            case FileType.BSA:
            case FileType.BA2:
                results = await GatheringExtractWithBSA(sFn, (FileType) sig, shouldExtract, mapfn, token);
                break;

            case FileType.TES3:
                if (sFn.Name.FileName.Extension == BSAExtension)
                    results = await GatheringExtractWithBSA(sFn, (FileType) sig, shouldExtract, mapfn, token);
                else
                    throw new Exception($"Invalid file format {sFn.Name}");
                break;
            default:
                throw new Exception($"Invalid file format {sFn.Name}");
        }

        if (onlyFiles != null && onlyFiles.Count != results.Count)
            throw new Exception(
                $"Sanity check error extracting {sFn.Name} - {results.Count} results, expected {onlyFiles.Count}");
        return results;
    }

    private async Task<IDictionary<RelativePath,T>> GatheringExtractWithBTAR<T>
        (IStreamFactory sFn, Predicate<RelativePath> shouldExtract, Func<RelativePath,IExtractedFile,ValueTask<T>> mapfn, CancellationToken token)
    {
        await using var strm = await sFn.GetStream();
        var astrm = new AsyncBinaryReader(strm);
        var magic = BinaryPrimitives.ReadUInt32BigEndian(await astrm.ReadBytes(4));
        // BTAR Magic
        if (magic != 0x42544152) throw new Exception("Not a valid BTAR file");
        if (await astrm.ReadUInt16() != 1) throw new Exception("Invalid BTAR major version, should be 1");
        var minorVersion = await astrm.ReadUInt16();
        if (minorVersion is < 2 or > 4) throw new Exception("Invalid BTAR minor version");

        var results = new Dictionary<RelativePath, T>();

        while (astrm.Position < astrm.Length)
        {
            var nameLength = await astrm.ReadUInt16();
            var name = Encoding.UTF8.GetString(await astrm.ReadBytes(nameLength)).ToRelativePath();
            var dataLength = await astrm.ReadUInt64();
            var newPos = astrm.Position + (long)dataLength;
            if (!shouldExtract(name))
            {
                astrm.Position += (long)dataLength;
                continue;
            }

            var result = await mapfn(name, new BTARExtractedFile(sFn, name, astrm, astrm.Position, (long) dataLength));
            results.Add(name, result);
            astrm.Position = newPos;
        }

        return results;
    }

    private class BTARExtractedFile : IExtractedFile
    {
        private readonly IStreamFactory _parent;
        private readonly AsyncBinaryReader _rdr;
        private readonly long _start;
        private readonly long _length;
        private readonly RelativePath _name;

        public BTARExtractedFile(IStreamFactory parent, RelativePath name, AsyncBinaryReader rdr, long startingPosition, long length)
        {
            _name = name;
            _parent = parent;
            _rdr = rdr;
            _start = startingPosition;
            _length = length;
        }

        public DateTime LastModifiedUtc => _parent.LastModifiedUtc;
        public IPath Name => _name;
        public async ValueTask<Stream> GetStream()
        {
            _rdr.Position = _start;
            var data = await _rdr.ReadBytes((int) _length);
            return new MemoryStream(data);
        }

        public bool CanMove { get; set; } = true;
        public async ValueTask Move(AbsolutePath newPath, CancellationToken token)
        {
            await using var output = newPath.Open(FileMode.Create, FileAccess.Read, FileShare.Read);
            _rdr.Position = _start;
            await _rdr.BaseStream.CopyToLimitAsync(output, (int)_length, token);
        }
    }

    private async Task<Dictionary<RelativePath, T>> GatheringExtractWithOMOD<T>
    (Stream archive, Predicate<RelativePath> shouldExtract, Func<RelativePath, IExtractedFile, ValueTask<T>> mapfn,
        CancellationToken token)
    {
        var tmpFile = _manager.CreateFile();
        await tmpFile.Path.WriteAllAsync(archive, CancellationToken.None);
        var dest = _manager.CreateFolder();

        using var omod = new OMOD(tmpFile.Path.ToString());

        var results = new Dictionary<RelativePath, T>();

        omod.ExtractFilesParallel(dest.Path.ToString(), 4, cancellationToken: token);
        if (omod.HasEntryFile(OMODEntryFileType.PluginsCRC))
            omod.ExtractFiles(false, dest.Path.ToString());

        var files = omod.GetDataFiles();
        if (omod.HasEntryFile(OMODEntryFileType.PluginsCRC))
            files.UnionWith(omod.GetPluginFiles());

        foreach (var compressedFile in files)
        {
            var abs = compressedFile.Name.ToRelativePath().RelativeTo(dest.Path);
            var rel = abs.RelativeTo(dest.Path);
            if (!shouldExtract(rel)) continue;

            var result = await mapfn(rel, new ExtractedNativeFile(abs));
            results.Add(rel, result);
        }

        return results;
    }

    public async Task<Dictionary<RelativePath, T>> GatheringExtractWithBSA<T>(IStreamFactory sFn,
        FileType sig,
        Predicate<RelativePath> shouldExtract,
        Func<RelativePath, IExtractedFile, ValueTask<T>> mapFn,
        CancellationToken token)
    {
        var archive = await BSADispatch.Open(sFn, sig);
        var results = new Dictionary<RelativePath, T>();
        foreach (var entry in archive.Files)
        {
            if (token.IsCancellationRequested) break;

            if (!shouldExtract(entry.Path))
                continue;

            var result = await mapFn(entry.Path, new ExtractedMemoryFile(await entry.GetStreamFactory(token)));
            results.Add(entry.Path, result);
        }
        
        _logger.LogInformation("Finished extracting {Name}", sFn.Name);
        return results;
    }

    public async Task<IDictionary<RelativePath, T>> GatheringExtractWith7Zip<T>(IStreamFactory sf,
        Predicate<RelativePath> shouldExtract,
        Func<RelativePath, IExtractedFile, ValueTask<T>> mapfn,
        IReadOnlyCollection<RelativePath>? onlyFiles,
        CancellationToken token,
        Action<Percent>? progressFunction = null)
    {
        TemporaryPath? tmpFile = null;
        await using var dest = _manager.CreateFolder();

        TemporaryPath? spoolFile = null;
        AbsolutePath source;
        
        var job = await _limiter.Begin($"Extracting {sf.Name}", 0, token);
        try
        {
            if (sf.Name is AbsolutePath abs)
            {
                source = abs;
            }
            else
            {
                spoolFile = _manager.CreateFile(sf.Name.FileName.Extension);
                await using var s = await sf.GetStream();
                await spoolFile.Value.Path.WriteAllAsync(s, token);
                source = spoolFile.Value.Path;
            }

            _logger.LogInformation("Extracting {Source}", source.FileName);


            var initialPath = "";
            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
                initialPath = @"Extractors\windows-x64\7z.exe";
            else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
                initialPath = @"Extractors\linux-x64\7zz";
            else if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
                initialPath = @"Extractors\mac\7zz";

            var process = new ProcessHelper
                {Path = initialPath.ToRelativePath().RelativeTo(KnownFolders.EntryPoint)};

            if (onlyFiles != null)
            {
                //It's stupid that we have to do this, but 7zip's file pattern matching isn't very fuzzy
                IEnumerable<string> AllVariants(string input)
                {
                    var forward = input.Replace("\\", "/");
                    yield return $"\"{input}\"";
                    yield return $"\"\\{input}\"";
                    yield return $"\"{forward}\"";
                    yield return $"\"/{forward}\"";
                }

                tmpFile = _manager.CreateFile();
                await tmpFile.Value.Path.WriteAllLinesAsync(onlyFiles.SelectMany(f => AllVariants((string) f)),
                    token);
                process.Arguments = new object[]
                {
                    "x", "-bsp1", "-y", $"-o\"{dest}\"", source, $"@\"{tmpFile.Value.ToString()}\"", "-mmt=off"
                };
            }
            else
            {
                process.Arguments = new object[] {"x", "-bsp1", "-y", $"-o\"{dest}\"", source, "-mmt=off"};
            }

            _logger.LogInformation("{prog} {args}", process.Path, process.Arguments);

            var totalSize = source.Size();
            var lastPercent = 0;
            job.Size = totalSize;

            var result = process.Output.Where(d => d.Type == ProcessHelper.StreamType.Output)
                .ForEachAsync(p =>
                {
                    var (_, line) = p;
                    if (line == null)
                        return;

                    if (line.Length <= 4 || line[3] != '%') return;

                    if (!int.TryParse(line[..3], out var percentInt)) return;

                    var oldPosition = lastPercent == 0 ? 0 : totalSize / lastPercent;
                    var newPosition = percentInt == 0 ? 0 : totalSize / percentInt;
                    var throughput = newPosition - oldPosition;
                    job.ReportNoWait((int) throughput);
                    
                    progressFunction?.Invoke(Percent.FactoryPutInRange(lastPercent, 100));
                    
                    lastPercent = percentInt;
                }, token);

            var exitCode = await process.Start();


            /*
            if (exitCode != 0)
            {
                Utils.ErrorThrow(new _7zipReturnError(exitCode, source, dest, ""));
            }
            else
            {
                Utils.Status($"Extracting {source.FileName} - done", Percent.One, alsoLog: true);
            }*/

            
            job.Dispose();
            var results = await dest.Path.EnumerateFiles()
                .PMapAll(async f =>
                {
                    var path = f.RelativeTo(dest.Path);
                    if (!shouldExtract(path)) return ((RelativePath, T)) default;
                    var file = new ExtractedNativeFile(f);
                    var mapResult = await mapfn(path, file);
                    f.Delete();
                    return (path, mapResult);
                })
                .Where(d => d.Item1 != default)
                .ToDictionary(d => d.Item1, d => d.Item2);

            return results;
        }
        finally
        {
            job.Dispose();
            
            if (tmpFile != null) await tmpFile.Value.DisposeAsync();

            if (spoolFile != null) await spoolFile.Value.DisposeAsync();
        }
    }

    public async Task ExtractAll(AbsolutePath src, AbsolutePath dest, CancellationToken token,
        Predicate<RelativePath>? filterFn = null, Action<Percent>? updateProgress = null)
    {
        filterFn ??= _ => true;
        await GatheringExtract(new NativeFileStreamFactory(src), filterFn, async (path, factory) =>
        {
            var abs = path.RelativeTo(dest);
            abs.Parent.CreateDirectory();
            await using var stream = await factory.GetStream();
            await abs.WriteAllAsync(stream, token);
            return 0;
        }, token, progressFunction: updateProgress);
    }
}