using Newtonsoft.Json;
using System.IO.Compression;

namespace Pilz.IO;

public class EmbeddedFilesContainer
{
    [JsonProperty("CompressedFiles")]
    private readonly Dictionary<string, byte[]> compressedFiles = new Dictionary<string, byte[]>();

    /// <summary>
    /// Returns the names of all embedded files.
    /// </summary>
    [JsonIgnore]
    public IEnumerable<string> AllFileNames
    {
        get => compressedFiles.Keys;
    }

    /// <summary>
    /// Embeds a file to this container.
    /// </summary>
    /// <param name="fileName">The name how it should be called in this container.</param>
    /// <param name="filePath">The file path to the file that should be embedded.</param>
    /// <returns>Returns a <see cref="bool"/> that defines if the file as been embedded successfully.</returns>
    public Task<bool> AddFileAsync(string fileName, string filePath)
    {
        return Task.Run(() => AddFile(fileName, filePath));
    }

    /// <summary>
    /// Embeds a file to this container.
    /// </summary>
    /// <param name="fileName">The name how it should be called in this container.</param>
    /// <param name="filePath">The file path to the file that should be embedded.</param>
    /// <returns>Returns a <see cref="bool"/> that defines if the file as been embedded successfully.</returns>
    public bool AddFile(string fileName, string filePath)
    {
        bool success;
        FileStream fs = null;
        MemoryStream compressed = null;

#if !DEBUG
        try
        {
#endif
            fs = new FileStream(filePath, FileMode.Open, FileAccess.Read);
            compressed = new MemoryStream();
            using (var compressor = new DeflateStream(compressed, CompressionLevel.Optimal, true))
                fs.CopyTo(compressor);
            success = true;
#if !DEBUG
        }
        catch (Exception)
        {
            success = false;
        }
#endif

        if (success)
        {
            var compressedBytes = compressed.ToArray();
            if (compressedFiles.ContainsKey(fileName))
                compressedFiles[fileName] = compressedBytes;
            else
                compressedFiles.Add(fileName, compressedBytes);
        }

        compressed?.Close();
        fs?.Close();

        return success;
    }

    /// <summary>
    /// Removes a file from this container.
    /// </summary>
    /// <param name="fileName">The name how the file is called.</param>
    public void RemoveFile(string fileName)
    {
        if (compressedFiles.ContainsKey(fileName))
            compressedFiles.Remove(fileName);
    }

    /// <summary>
    /// Checks if the given file exists in this container.
    /// </summary>
    /// <param name="fileName">The name how the file is called.</param>
    /// <returns>Returns if the given file exists in this container.</returns>
    public bool HasFile(string fileName)
    {
        return compressedFiles.ContainsKey(fileName);
    }

    /// <summary>
    /// Gets a file from this container as stream.
    /// </summary>
    /// <param name="fileName">The name how the file is called.</param>
    /// <returns>Returns a stream of the file with the given name.</returns>
    public Task<Stream> GetStreamAsync(string fileName)
    {
        return Task.Run(() => GetStream(fileName));
    }

    /// <summary>
    /// Gets a file from this container as stream.
    /// </summary>
    /// <param name="fileName">The name how the file is called.</param>
    /// <returns>Returns a stream of the file with the given name.</returns>
    public Stream GetStream(string fileName)
    {
        Stream decompressed = null;

        if (compressedFiles.ContainsKey(fileName))
        {
            decompressed = new MemoryStream();
            DecompressToStream(decompressed, compressedFiles[fileName]);
        }

        return decompressed;
    }

    /// <summary>
    /// Saves a given file to the users temp directory.
    /// </summary>
    /// <param name="fileName">The name how the file is called.</param>
    /// <returns>Returns the file path to the temp file.</returns>
    public Task<string> GetLocalFilePathAsync(string fileName)
    {
        return Task.Run(() => GetLocalFilePath(fileName));
    }


    /// <summary>
    /// Saves a given file to the users temp directory.
    /// </summary>
    /// <param name="fileName">The name how the file is called.</param>
    /// <returns>Returns the file path to the temp file.</returns>
    public string GetLocalFilePath(string fileName)
    {
        string filePath = string.Empty;

        if (compressedFiles.ContainsKey(fileName))
        {
            filePath = Path.GetTempFileName();

            if (Path.HasExtension(fileName))
                filePath = Path.ChangeExtension(filePath, Path.GetExtension(fileName));

            var decompressed = new FileStream(filePath, FileMode.Create, FileAccess.ReadWrite);
            DecompressToStream(decompressed, compressedFiles[fileName]);
            decompressed.Flush();
            decompressed.Close();
        }

        return filePath;
    }

    private void DecompressToStream(Stream decompressed, byte[] compressedData)
    {
        var compressed = new MemoryStream(compressedData);
        var decompressor = new DeflateStream(compressed, CompressionMode.Decompress, true);
        decompressor.CopyTo(decompressed);
        decompressor.Close();
        compressed.Close();
    }
}