Packager/Packager.cs

using System.Text;

namespace BrikPackager;

public class BrikPackage : IDisposable {
    private readonly byte[] _data;
    private readonly byte _key;

    public BrikPackage(string filePath, byte key) {
        _key = key;
        _data = File.ReadAllBytes(filePath);
        Decode();
    }

    private void Decode() {
        for (int i = 0; i < _data.Length; i++) {
            _data[i] = (byte)(_data[i] ^ _key);
        }
    }

    public List<string> ListEntries() {
        using var ms = new MemoryStream(_data);
        using var archive = ArchiveFactory.Open(ms);
        return archive.Entries.Select(e => e.Key!).ToList();
    }

    public string GetFileContent(string internalPath) {
        using var ms = new MemoryStream(_data);
        using var archive = ArchiveFactory.Open(ms);
        var entry = archive.Entries.FirstOrDefault(e => e.Key == internalPath);
        
        if (entry == null || entry.IsDirectory) return string.Empty;

        using var entryStream = entry.OpenEntryStream();
        using var reader = new StreamReader(entryStream, Encoding.UTF8);
        return reader.ReadToEnd();
    }

    public byte[] GetFileBytes(string internalPath) {
        using var ms = new MemoryStream(_data);
        using var archive = ArchiveFactory.Open(ms);
        var entry = archive.Entries.FirstOrDefault(e => e.Key == internalPath);
        
        if (entry == null) return Array.Empty<byte>();

        using var entryStream = entry.OpenEntryStream();
        using var outMs = new MemoryStream();
        entryStream.CopyTo(outMs);
        return outMs.ToArray();
    }

    public void Unpack(string targetDirectory) {
        if (!Directory.Exists(targetDirectory)) Directory.CreateDirectory(targetDirectory);

        using var ms = new MemoryStream(_data);
        using var archive = ArchiveFactory.Open(ms);
        foreach (var entry in archive.Entries.Where(e => !e.IsDirectory)) {
            entry.WriteToDirectory(targetDirectory, new ExtractionOptions {
                ExtractFullPath = true,
                Overwrite = true
            });
        }
    }

    public void Dispose() {
        Array.Clear(_data, 0, _data.Length);
    }
}

public static class Packager {
    public static void Pack(string sourceFolder, string outputPath, byte key) {
        using var memoryStream = new MemoryStream();
        var writerOptions = new WriterOptions(CompressionType.LZMA); 
        
        using (var writer = WriterFactory.Open(memoryStream, ArchiveType.Zip, writerOptions)) {
            writer.WriteAll(sourceFolder, "*", SearchOption.AllDirectories);
        }

        byte[] data = memoryStream.ToArray();

        for (int i = 0; i < data.Length; i++) {
            data[i] = (byte)(data[i] ^ key);
        }

        File.WriteAllBytes(outputPath, data);
    }
}

public static class MimeHelper {
    public static string GetMimeType(string path) {
        string extension = Path.GetExtension(path).ToLower();
        return extension switch
        {
            ".html" or ".htm" => "text/html",
            ".css"            => "text/css",
            ".js"             => "text/javascript",
            ".png"            => "image/png",
            ".jpg" or ".jpeg" => "image/jpeg",
            ".svg"            => "image/svg+xml",
            ".woff2"          => "font/woff2",
            ".json"           => "application/json",
            _                 => "application/octet-stream",
        };
    }
}