using System;
using System.Collections.Concurrent;
using System.IO;
using BurnOutSharp.Tools;
using LibMSPackN;

namespace BurnOutSharp.FileType
{
    // Specification available at http://download.microsoft.com/download/5/0/1/501ED102-E53F-4CE0-AA6B-B0F93629DDC6/Exchange/%5BMS-CAB%5D.pdf
    public class MicrosoftCAB : IScannable
    {
        /// <inheritdoc/>
        public bool ShouldScan(byte[] magic)
        {
            if (magic.StartsWith(new byte?[] { 0x4d, 0x53, 0x43, 0x46 }))
                return true;

            return false;
        }

        /// <inheritdoc/>
        public ConcurrentDictionary<string, ConcurrentQueue<string>> Scan(Scanner scanner, string file)
        {
            if (!File.Exists(file))
                return null;

            using (var fs = File.OpenRead(file))
            {
                return Scan(scanner, fs, file);
            }
        }

        // TODO: Add stream opening support
        /// <inheritdoc/>
        public ConcurrentDictionary<string, ConcurrentQueue<string>> Scan(Scanner scanner, Stream stream, string file)
        {
            // If the cab file itself fails
            try
            {
                string tempPath = Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString());
                Directory.CreateDirectory(tempPath);

                using (MSCabinet cabfile = new MSCabinet(file))
                {
                    foreach (var sub in cabfile.GetFiles())
                    {
                        // If an individual entry fails
                        try
                        {
                            // The trim here is for some very odd and stubborn files
                            string tempFile = Path.Combine(tempPath, sub.Filename.TrimEnd('.'));
                            sub.ExtractTo(tempFile);
                        }
                        catch { }
                    }
                }

                // Collect and format all found protections
                var protections = scanner.GetProtections(tempPath);

                // If temp directory cleanup fails
                try
                {
                    Directory.Delete(tempPath, true);
                }
                catch { }

                // Remove temporary path references
                Utilities.StripFromKeys(protections, tempPath);

                return protections;
            }
            catch { }

            return null;
        }
    }
}
