//! \file       ArcDAT.cs
//! \date       Sat May 14 02:20:37 2016
//! \brief      'non color' resource archive.
//
// Copyright (C) 2016 by morkt
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
// IN THE SOFTWARE.
//

using System;
using System.Collections.Generic;
using System.ComponentModel.Composition;
using System.IO;
using GameRes.Compression;
using GameRes.Utility;
using GameRes.Formats.Properties;
using GameRes.Formats.Strings;

namespace GameRes.Formats.NonColor
{
    internal class ArcDatEntry : PackedEntry
    {
        public byte[]   RawName;
        public ulong    Hash;
        public int      Flags;
    }

    internal class ArcDatArchive : ArcFile
    {
        public readonly ulong MasterKey;

        public ArcDatArchive (ArcView arc, ArchiveFormat impl, ICollection<Entry> dir, ulong key)
            : base (arc, impl, dir)
        {
            MasterKey = key;
        }
    }

    [Serializable]
    public class Scheme
    {
        public string   Title;
        public ulong    Hash;

        public Scheme(string title)
        {
            Title = title;
            var key = Encodings.cp932.GetBytes(title);
            Hash = Crc64.Compute(key, 0, key.Length);
        }
    }

    [Serializable]
    public class ArcDatScheme : ResourceScheme
    {
        public Dictionary<string, Scheme> KnownSchemes;

        public static ulong GetKey (string title)
        {
            var key = Encodings.cp932.GetBytes (title);
            return Crc64.Compute (key, 0, key.Length);
        }
    }

    public class ArcDatOptions : ResourceOptions
    {
        public string Scheme;
    }

    [Export(typeof(ArchiveFormat))]
    public class DatOpener : ArchiveFormat
    {
        public override string         Tag { get { return "ARC/noncolor"; } }
        public override string Description { get { return "'non color' resource archive"; } }
        public override uint     Signature { get { return 0; } }
        public override bool  IsHierarchic { get { return true; } }
        public override bool      CanWrite { get { return false; } }

        public DatOpener ()
        {
            Extensions = new string[] { "dat" };
        }

        public static readonly string PersistentFileMapName = "NCFileMap.dat";

        public override ArcFile TryOpen (ArcView file)
        {
            if (!file.Name.HasExtension (".dat"))
                return null;
            int count = file.View.ReadInt32 (0) ^ 0x26ACA46E;
            if (!IsSaneCount (count))
                return null;

            var scheme = QueryScheme (file.Name);
            if (null == scheme)
                return null;

            var dir = new List<Entry> (count);
            using (var input = file.CreateStream (4, (uint)count * 0x15))
            {
                foreach (var entry in ReadIndex (input, count, scheme))
                {
                    if (!entry.CheckPlacement (file.MaxOffset))
                        return null;
                    dir.Add (entry);
                }
            }
            return new ArcDatArchive (file, this, dir, scheme.Hash);
        }

        public override Stream OpenEntry (ArcFile arc, Entry entry)
        {
            var darc = arc as ArcDatArchive;
            var dent = entry as ArcDatEntry;
            if (null == darc || null == dent || 0 == dent.Flags || 0 == dent.Size)
                return base.OpenEntry (arc, entry);
            var data = arc.File.View.ReadBytes (entry.Offset, entry.Size);
            if (2 == dent.Flags)
            {
                if (darc.MasterKey != 0)
                    DecryptData (data, (uint)(dent.Hash ^ darc.MasterKey));
                return new ZLibStream (new MemoryStream (data), CompressionMode.Decompress);
            }
            // 1 == dent.Flags
            if (dent.RawName != null && 0 != dent.Flags)
                DecryptWithName (data, dent.RawName);
            return new BinMemoryStream (data, entry.Name);
        }

        internal IEnumerable<ArcDatEntry> ReadIndex (IBinaryStream input, int count, Scheme scheme, uint key = 0)
        {
            int skipped = 0;
            var file_map = ReadFilenameMap (scheme);
            for (int i = 0; i < count; ++i)
            {
                var hash = input.ReadUInt64();
                var entry = new ArcDatEntry
                {
                    Hash   = hash,
                    Flags  = input.ReadByte()   ^ (byte)hash,
                    Offset = input.ReadUInt32() ^ (uint)hash ^ key,
                    Size   = input.ReadUInt32() ^ (uint)hash,
                    UnpackedSize = input.ReadUInt32() ^ (uint)hash,
                };
                entry.IsPacked = 0 != (entry.Flags & 2);
                byte[] raw_name = null;
                if (file_map.TryGetValue (hash, out raw_name))
                {
                    entry.Name = Encodings.cp932.GetString (raw_name);
                    entry.Type = FormatCatalog.Instance.GetTypeFromName (entry.Name);
                    entry.RawName = raw_name;
                }
                if (0 == (entry.Flags & 2))
                {
                    if (null == raw_name)
                    {
//                      System.Diagnostics.Trace.WriteLine ("Unknown hash", hash.ToString ("X16"));
                        ++skipped;
                        continue;
                    }
                    entry.Offset        ^= raw_name[raw_name.Length >> 1];
                    entry.Size          ^= raw_name[raw_name.Length >> 2];
                    entry.UnpackedSize  ^= raw_name[raw_name.Length >> 3];
                }
                if (string.IsNullOrEmpty (entry.Name))
                    entry.Name = hash.ToString ("X16");
                yield return entry;
            }
            if (skipped != 0)
                System.Diagnostics.Trace.WriteLine (string.Format ("Missing {0} names", skipped), "[noncolor]");
        }

        internal unsafe void DecryptData (byte[] data, uint key)
        {
            fixed (byte* data8 = data)
            {
                uint* data32 = (uint*)data8;
                for (int i = data.Length/4; i > 0; --i)
                    *data32++ ^= key;
            }
        }

        internal void DecryptWithName (byte[] data, byte[] name)
        {
            int block_length = data.Length / name.Length;
            int n = 0;
            for (int i = 0; i < name.Length-1; ++i)
            for (int j = 0; j < block_length; ++j)
                data[n++] ^= name[i];
        }

        static IDictionary<ulong, Tuple<uint, int>> FileMapIndex = null;

        internal IDictionary<ulong, Tuple<uint, int>> ReadFileMapIndex (BinaryReader idx)
        {
            int scheme_count = idx.ReadInt32();
            idx.BaseStream.Seek (12, SeekOrigin.Current);
            var map = new Dictionary<ulong, Tuple<uint, int>> (scheme_count);
            for (int i = 0; i < scheme_count; ++i)
            {
                ulong   key = idx.ReadUInt64();
                uint offset = idx.ReadUInt32();
                int   count = idx.ReadInt32();
                map[key] = Tuple.Create (offset, count);
            }
            return map;
        }

        Tuple<ulong, Dictionary<ulong, byte[]>> LastAccessedScheme;

        internal IDictionary<ulong, byte[]> ReadFilenameMap (Scheme scheme)
        {
            if (null != LastAccessedScheme && LastAccessedScheme.Item1 == scheme.Hash)
                return LastAccessedScheme.Item2;
            var dir = FormatCatalog.Instance.DataDirectory;
            var lst_file = Path.Combine (dir, PersistentFileMapName);
            var idx_file = Path.ChangeExtension (lst_file, ".idx");
            using (var idx_stream = File.OpenRead (idx_file))
            using (var idx = new BinaryReader (idx_stream))
            {
                if (null == FileMapIndex)
                    FileMapIndex = ReadFileMapIndex (idx);

                Tuple<uint, int> nc_info;
                if (!FileMapIndex.TryGetValue (scheme.Hash, out nc_info))
                    throw new UnknownEncryptionScheme();

                using (var lst_stream = File.OpenRead (lst_file))
                using (var lst = new BinaryReader (lst_stream))
                {
                    var name_map = new Dictionary<ulong, byte[]> (nc_info.Item2);
                    idx_stream.Position = nc_info.Item1;
                    for (int i = 0; i < nc_info.Item2; ++i)
                    {
                        ulong   key = idx.ReadUInt64();
                        uint offset = idx.ReadUInt32();
                        int  length = idx.ReadInt32();
                        lst_stream.Position = offset;
                        name_map[key] = lst.ReadBytes (length);
                    }
                    LastAccessedScheme = Tuple.Create (scheme.Hash, name_map);
                    return name_map;
                }
            }
        }

        public static Dictionary<string, Scheme> KnownSchemes = new Dictionary<string, Scheme>();

        public override ResourceScheme Scheme
        {
            get { return new ArcDatScheme { KnownSchemes = KnownSchemes }; }
            set { KnownSchemes = ((ArcDatScheme)value).KnownSchemes; }
        }

        internal Scheme QueryScheme (string arc_name)
        {
            var title = FormatCatalog.Instance.LookupGame (arc_name);
            if (!string.IsNullOrEmpty (title) && KnownSchemes.ContainsKey (title))
                return KnownSchemes[title];
            var options = Query<ArcDatOptions> (arcStrings.ArcEncryptedNotice);
            Scheme scheme;
            if (string.IsNullOrEmpty (options.Scheme) || !KnownSchemes.TryGetValue (options.Scheme, out scheme))
                return null;
            return scheme;
        }

        public override ResourceOptions GetDefaultOptions ()
        {
            return new ArcDatOptions { Scheme = Settings.Default.NCARCScheme };
        }

        public override object GetAccessWidget ()
        {
            return new GUI.WidgetNCARC();
        }
    }
}