﻿/*  MapleLib - A general-purpose MapleStory library
 * Copyright (C) 2009, 2010, 2015 Snow and haha01haha01
   
 * This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

 * This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

 * You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.*/

using System;
using System.Collections;
using System.IO;
using MapleLib.MapleCryptoLib;

namespace MapleLib.WzLib.Util
{
	public class WzTool
	{

		public static Hashtable StringCache = new Hashtable();

		public static UInt32 RotateLeft(UInt32 x, byte n)
		{
			return (UInt32)(((x) << (n)) | ((x) >> (32 - (n))));
		}

		public static UInt32 RotateRight(UInt32 x, byte n)
		{
			return (UInt32)(((x) >> (n)) | ((x) << (32 - (n))));
		}

		public static int GetCompressedIntLength(int i)
		{
			if (i > 127 || i < -127)
				return 5;
			return 1;
		}

		public static int GetEncodedStringLength(string s)
		{
			int len = 0;
			if (string.IsNullOrEmpty(s))
				return 1;
			bool unicode = false;
			foreach (char c in s)
				if (c > 255)
					unicode = true;
			if (unicode)
			{
				if (s.Length > 126)
					len += 5;
				else
					len += 1;
				len += s.Length * 2;
			}
			else
			{
				if (s.Length > 127)
					len += 5;
				else
					len += 1;
				len += s.Length;
			}
			return len;
		}

		public static int GetWzObjectValueLength(string s, byte type)
		{
			string storeName = type + "_" + s;
			if (s.Length > 4 && StringCache.ContainsKey(storeName))
			{
				return 5;
			}
			else
			{
				StringCache[storeName] = 1;
				return 1 + GetEncodedStringLength(s);
			}
		}

		public static T StringToEnum<T>(string name)
		{
			try
			{
				return (T)Enum.Parse(typeof(T), name);
			}
			catch
			{
				return default(T);
			}
		}

		public static byte[] GetIvByMapleVersion(WzMapleVersion ver)
		{
			switch (ver)
			{
				case WzMapleVersion.EMS:
					return CryptoConstants.WZ_MSEAIV;//?
				case WzMapleVersion.GMS:
					return CryptoConstants.WZ_GMSIV;
                case WzMapleVersion.BMS:
				case WzMapleVersion.CLASSIC:
				default:
					return new byte[4];
			}
		}

        private static int GetRecognizedCharacters(string source)
        {
            int result = 0;
            foreach (char c in source)
                if (0x20 <= c && c <= 0x7E)
                    result++;
            return result;
        }

        private static double GetDecryptionSuccessRate(string wzPath, WzMapleVersion encVersion, ref short? version)
        {
            WzFile wzf;
            if (version == null)
                wzf = new WzFile(wzPath, encVersion);
            else
                wzf = new WzFile(wzPath, (short)version, encVersion);
            wzf.ParseWzFile();
            if (version == null) version = wzf.Version;
            int recognizedChars = 0;
            int totalChars = 0;
            foreach (WzDirectory wzdir in wzf.WzDirectory.WzDirectories)
            {
                recognizedChars += GetRecognizedCharacters(wzdir.Name);
                totalChars += wzdir.Name.Length;
            }
            foreach (WzImage wzimg in wzf.WzDirectory.WzImages)
            {
                recognizedChars += GetRecognizedCharacters(wzimg.Name);
                totalChars += wzimg.Name.Length;
            }
            wzf.Dispose();
            return (double)recognizedChars / (double)totalChars;
        }

        public static WzMapleVersion DetectMapleVersion(string wzFilePath, out short fileVersion)
        {
            Hashtable mapleVersionSuccessRates = new Hashtable();
            short? version = null;
            mapleVersionSuccessRates.Add(WzMapleVersion.GMS, GetDecryptionSuccessRate(wzFilePath, WzMapleVersion.GMS, ref version));
            mapleVersionSuccessRates.Add(WzMapleVersion.EMS, GetDecryptionSuccessRate(wzFilePath, WzMapleVersion.EMS, ref version));
            mapleVersionSuccessRates.Add(WzMapleVersion.BMS, GetDecryptionSuccessRate(wzFilePath, WzMapleVersion.BMS, ref version));
            fileVersion = (short)version;
            WzMapleVersion mostSuitableVersion = WzMapleVersion.GMS;
            double maxSuccessRate = 0;
            foreach (DictionaryEntry mapleVersionEntry in mapleVersionSuccessRates)
                if ((double)mapleVersionEntry.Value > maxSuccessRate)
                {
                    mostSuitableVersion = (WzMapleVersion)mapleVersionEntry.Key;
                    maxSuccessRate = (double)mapleVersionEntry.Value;
                }
            if (maxSuccessRate < 0.7 && File.Exists(Path.Combine(Path.GetDirectoryName(wzFilePath), "ZLZ.dll")))
                return WzMapleVersion.GETFROMZLZ;
            else return mostSuitableVersion;
        }

        public const int WzHeader = 0x31474B50; //PKG1

        public static bool IsListFile(string path)
        {
            BinaryReader reader = new BinaryReader(File.OpenRead(path));
            bool result = reader.ReadInt32() != WzHeader;
            reader.Close();
            return result;
        }

        private static byte[] Combine(byte[] a, byte[] b)
        {
            byte[] result = new byte[a.Length + b.Length];
            Array.Copy(a, 0, result, 0, a.Length);
            Array.Copy(b, 0, result, a.Length, b.Length);
            return result;
        }
	}
}