using System;
using System.IO;
using BinaryObjectScanner.Interfaces;
using SharpCompress.Compressors;
using SharpCompress.Compressors.Deflate;

namespace BinaryObjectScanner.FileType
{
    /// <summary>
    /// BFPK custom archive format
    /// </summary>
    public class BFPK : IExtractable
    {
        /// <inheritdoc/>
#if NET48
        public string Extract(string file, bool includeDebug)
#else
        public string? Extract(string file, bool includeDebug)
#endif
        {
            if (!File.Exists(file))
                return null;

            using (var fs = File.Open(file, FileMode.Open, FileAccess.Read, FileShare.Read))
            {
                return Extract(fs, file, includeDebug);
            }
        }

        /// <inheritdoc/>
#if NET48
        public string Extract(Stream stream, string file, bool includeDebug)
#else
        public string? Extract(Stream stream, string file, bool includeDebug)
#endif
        {
            try
            {
                // Create the wrapper
                var bfpk = SabreTools.Serialization.Wrappers.BFPK.Create(stream);
                if (bfpk == null)
                    return null;

                // Create a temp output directory
                string tempPath = Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString());
                Directory.CreateDirectory(tempPath);

                // Extract all files
                ExtractAll(bfpk, tempPath);

                return tempPath;
            }
            catch (Exception ex)
            {
                if (includeDebug) Console.WriteLine(ex);
                return null;
            }
        }
    
        /// <summary>
        /// Extract all files from the BFPK to an output directory
        /// </summary>
        /// <param name="outputDirectory">Output directory to write to</param>
        /// <returns>True if all files extracted, false otherwise</returns>
        public static bool ExtractAll(SabreTools.Serialization.Wrappers.BFPK item, string outputDirectory)
        {
            // If we have no files
            if (item.Model.Files == null || item.Model.Files.Length == 0)
                return false;

            // Loop through and extract all files to the output
            bool allExtracted = true;
            for (int i = 0; i < item.Model.Files.Length; i++)
            {
                allExtracted &= ExtractFile(item, i, outputDirectory);
            }

            return allExtracted;
        }

        /// <summary>
        /// Extract a file from the BFPK to an output directory by index
        /// </summary>
        /// <param name="index">File index to extract</param>
        /// <param name="outputDirectory">Output directory to write to</param>
        /// <returns>True if the file extracted, false otherwise</returns>
        public static bool ExtractFile(SabreTools.Serialization.Wrappers.BFPK item, int index, string outputDirectory)
        {
            // If we have no files
            if (item.Model.Files == null || item.Model.Files.Length == 0)
                return false;

            // If we have an invalid index
            if (index < 0 || index >= item.Model.Files.Length)
                return false;

            // Get the file information
            var file = item.Model.Files[index];
            if (file == null)
                return false;

            // Get the read index and length
            int offset = file.Offset + 4;
            int compressedSize = file.CompressedSize;

            // Some files can lack the length prefix
            if (compressedSize > item.GetEndOfFile())
            {
                offset -= 4;
                compressedSize = file.UncompressedSize;
            }

            try
            {
                // Ensure the output directory exists
                Directory.CreateDirectory(outputDirectory);

                // Create the output path
                string filePath = Path.Combine(outputDirectory, file.Name ?? $"file{index}");
                using (FileStream fs = File.OpenWrite(filePath))
                {
                    // Read the data block
#if NET48
                    byte[] data = item.ReadFromDataSource(offset, compressedSize);
#else
                    byte[]? data = item.ReadFromDataSource(offset, compressedSize);
#endif
                    if (data == null)
                        return false;

                    // If we have uncompressed data
                    if (compressedSize == file.UncompressedSize)
                    {
                        fs.Write(data, 0, compressedSize);
                    }
                    else
                    {
                        MemoryStream ms = new MemoryStream(data);
                        ZlibStream zs = new ZlibStream(ms, CompressionMode.Decompress);
                        zs.CopyTo(fs);
                    }
                }

                return true;
            }
            catch
            {
                return false;
            }
        }
    }
}