namespace Aaru.Tests.Issues;

using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using Aaru.Checksums;
using Aaru.CommonTypes;
using Aaru.CommonTypes.Enums;
using Aaru.CommonTypes.Interfaces;
using Aaru.CommonTypes.Structs;
using Aaru.Core;
using FluentAssertions;
using Newtonsoft.Json;
using Newtonsoft.Json.Converters;
using NUnit.Framework;
using FileAttributes = Aaru.CommonTypes.Structs.FileAttributes;

/// <summary>This will extract (and discard data) all files in all filesystems detected in an image.</summary>
public abstract class FsExtractHashIssueTest
{
    protected abstract string                     DataFolder       { get; }
    protected abstract string                     TestFile         { get; }
    protected abstract Dictionary<string, string> ParsedOptions    { get; }
    protected abstract bool                       Debug            { get; }
    protected abstract bool                       Xattrs           { get; }
    protected abstract string                     Encoding         { get; }
    protected abstract bool                       ExpectPartitions { get; }
    protected abstract string                     Namespace        { get; }

    [Test]
    public void Test()
    {
        Environment.CurrentDirectory = DataFolder;

        var     filtersList = new FiltersList();
        IFilter inputFilter = filtersList.GetFilter(TestFile);

        Dictionary<string, string> options = ParsedOptions;
        options["debug"] = Debug.ToString();

        Assert.IsNotNull(inputFilter, "Cannot open specified file.");

        Encoding encodingClass = null;

        if(Encoding != null)
            encodingClass = Claunia.Encoding.Encoding.GetEncoding(Encoding);

        PluginBase plugins = GetPluginBase.Instance;

        var imageFormat = ImageFormat.Detect(inputFilter) as IMediaImage;

        Assert.NotNull(imageFormat, "Image format not identified, not proceeding with analysis.");

        Assert.AreEqual(ErrorNumber.NoError, imageFormat.Open(inputFilter), "Unable to open image format");

        List<Partition> partitions = Partitions.GetAll(imageFormat);

        if(partitions.Count == 0)
        {
            Assert.IsFalse(ExpectPartitions, "No partitions found");

            partitions.Add(new Partition
            {
                Description = "Whole device",
                Length      = imageFormat.Info.Sectors,
                Offset      = 0,
                Size        = imageFormat.Info.SectorSize * imageFormat.Info.Sectors,
                Sequence    = 1,
                Start       = 0
            });
        }

        var filesystemFound = false;

        Assert.True(File.Exists($"{TestFile}.unittest.json"));

        var serializer = new JsonSerializer
        {
            Formatting        = Formatting.Indented,
            MaxDepth          = 16384,
            NullValueHandling = NullValueHandling.Ignore
        };

        serializer.Converters.Add(new StringEnumConverter());

        var               sr           = new StreamReader($"{TestFile}.unittest.json");
        FsExtractHashData expectedData = serializer.Deserialize<FsExtractHashData>(new JsonTextReader(sr));

        Assert.NotNull(expectedData);

        Assert.AreEqual(expectedData.Partitions.Length, partitions.Count,
                        $"Excepted {expectedData.Partitions.Length} partitions but found {partitions.Count}");

        for(var i = 0; i < partitions.Count; i++)
        {
            Filesystems.Identify(imageFormat, out List<string> idPlugins, partitions[i]);

            if(idPlugins.Count == 0)
            {
                Assert.IsNull(expectedData.Partitions[i],
                              $"Expected no filesystems identified in partition {i} but found {idPlugins.Count}");

                continue;
            }

            if(expectedData.Partitions[i].Volumes is null)
                continue;

            Assert.AreEqual(expectedData.Partitions[i].Volumes.Length, idPlugins.Count,
                            $"Expected {expectedData.Partitions[i].Volumes.Length} filesystems identified in partition {i} but found {idPlugins.Count}");

            for(var j = 0; j < idPlugins.Count; j++)
            {
                string pluginName = idPlugins[j];

                if(!plugins.ReadOnlyFilesystems.TryGetValue(pluginName, out IReadOnlyFilesystem plugin))
                    continue;

                Assert.IsNotNull(plugin, "Could not instantiate filesystem plugin");

                var fs = (IReadOnlyFilesystem)plugin.GetType().GetConstructor(Type.EmptyTypes)?.Invoke(Array.Empty<object>());

                Assert.IsNotNull(fs, $"Could not instantiate filesystem {pluginName}");

                filesystemFound = true;

                ErrorNumber error = fs.Mount(imageFormat, partitions[i], encodingClass, options, Namespace);

                Assert.AreEqual(ErrorNumber.NoError, error, $"Could not mount {pluginName} in partition {i}.");

                Assert.AreEqual(expectedData.Partitions[i].Volumes[j].VolumeName, fs.XmlFsType.VolumeName,
                                $"Excepted volume name \"{expectedData.Partitions[i].Volumes[j].VolumeName}\" for filesystem {j} in partition {i} but found \"{fs.XmlFsType.VolumeName}\"");

                VolumeData volumeData = expectedData.Partitions[i].Volumes[j];

                ExtractFilesInDir("/", fs, Xattrs, volumeData);

                volumeData.Directories.Should().BeEmpty("Expected directories not found:", volumeData.Directories);
                volumeData.Files.Should().BeEmpty("Expected files not found:", volumeData.Files.Keys);
            }
        }

        Assert.IsTrue(filesystemFound, "No filesystems found.");
    }

    static void ExtractFilesInDir(string path, IReadOnlyFilesystem fs, bool doXattrs, VolumeData volumeData)
    {
        if(path.StartsWith('/'))
            path = path[1..];

        ErrorNumber error = fs.ReadDir(path, out List<string> directory);

        Assert.AreEqual(ErrorNumber.NoError, error,
                        string.Format("Error {0} reading root directory {0}", error.ToString()));

        foreach(string entry in directory)
        {
            error = fs.Stat(path + "/" + entry, out FileEntryInfo stat);

            Assert.AreEqual(ErrorNumber.NoError, error, $"Error getting stat for entry {entry}");

            if(stat.Attributes.HasFlag(FileAttributes.Directory))
            {
                if(string.IsNullOrWhiteSpace(path))
                {
                    Assert.True(volumeData.Directories.Contains(entry), $"Found unexpected directory {entry}");
                    volumeData.Directories.Remove(entry);
                }
                else
                {
                    Assert.True(volumeData.Directories.Contains(path + "/" + entry),
                                $"Found unexpected directory {path + "/" + entry}");

                    volumeData.Directories.Remove(path + "/" + entry);
                }

                ExtractFilesInDir(path + "/" + entry, fs, doXattrs, volumeData);

                continue;
            }

            FileData fileData;

            if(string.IsNullOrWhiteSpace(path))
            {
                Assert.IsTrue(volumeData.Files.TryGetValue(entry, out fileData), $"Found unexpected file {entry}");

                volumeData.Files.Remove(entry);
            }
            else
            {
                Assert.IsTrue(volumeData.Files.TryGetValue(path + "/" + entry, out fileData),
                              $"Found unexpected file {path + "/" + entry}");

                volumeData.Files.Remove(path + "/" + entry);
            }

            if(doXattrs)
            {
                error = fs.ListXAttr(path + "/" + entry, out List<string> xattrs);

                Assert.AreEqual(ErrorNumber.NoError, error,
                                $"Error {error} getting extended attributes for entry {path + "/" + entry}");

                Dictionary<string, string> expectedXattrs = fileData.XattrsWithMd5;

                if(error == ErrorNumber.NoError)
                    foreach(string xattr in xattrs)
                    {
                        Assert.IsTrue(expectedXattrs.TryGetValue(xattr, out string expectedXattrMd5),
                                      $"Found unexpected extended attribute {xattr} in file {entry}");

                        expectedXattrs.Remove(xattr);

                        byte[] xattrBuf = Array.Empty<byte>();
                        error = fs.GetXattr(path + "/" + entry, xattr, ref xattrBuf);

                        Assert.AreEqual(ErrorNumber.NoError, error,
                                        $"Error {error} reading extended attributes for entry {path + "/" + entry}");

                        string xattrMd5 = Md5Context.Data(xattrBuf, out _);

                        Assert.AreEqual(expectedXattrMd5, xattrMd5,
                                        $"Invalid checksum for xattr {xattr} for file {path + "/" + entry}");
                    }

                expectedXattrs.Should().
                               BeEmpty($"Expected extended attributes not found for file {path + "/" + entry}:",
                                       expectedXattrs);
            }

            byte[] outBuf = Array.Empty<byte>();

            error = fs.Read(path + "/" + entry, 0, stat.Length, ref outBuf);

            Assert.AreEqual(ErrorNumber.NoError, error, $"Error {error} reading file {path + "/" + entry}");

            string calculatedMd5 = Md5Context.Data(outBuf, out _);

            Assert.AreEqual(fileData.Md5, calculatedMd5, $"Invalid checksum for file {path + "/" + entry}");
        }
    }
}