using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Runtime.InteropServices;

namespace ArchiveUnpack
{
    public class PECheck
    {
        public static void Check(Stream s,long startIndex)
        {
            byte[] _DWORDBUFFER = new byte[4];
            byte[] _WORDBUFFER = new byte[2];
            int ReadCount = 0;

            s.Position = startIndex;

            ReadCount = s.Read(_DWORDBUFFER,0,4);
            int DosHeaderMagic = BitConverter.ToInt32(_DWORDBUFFER, 0);


            if (DosHeaderMagic == 9460301)
            {
                Console.WriteLine("Find MZ on " + (s.Position-4).ToString() );
            }
#if DEBUG
            else
            {
                Console.WriteLine(string.Format("Find {0} on {1}.",DosHeaderMagic,s.Position-4));              
            }
#endif

            s.Position = 0;

            PEFormat pefile = new PEFormat();
            DosHeader dh = Read<DosHeader>(s);
            s.Position = dh.e_lfanew;
            NtHeader nh = Read<NtHeader>(s);

            SectionHeader[] shs = new SectionHeader[nh.FileHeader.NumberOfSections];

            for (int i = 0; i < shs.Length; i++)
            {
                shs[i] = Read<SectionHeader>(s);
            }

            int offsetCLRHeader = nh.OptionalHeader.DataDirectory[14].VirtualAddress - shs[0].VirtualAddress + shs[0].PointerToRawData;

            s.Position = offsetCLRHeader;

            CLRHeader clh = Read<CLRHeader>(s);

            int offsetMetaData = clh.MetaData.VirtualAddress - shs[0].VirtualAddress + shs[0].PointerToRawData;

            s.Position = offsetMetaData;

            MetaData md = Read<MetaData>(s);

            NStreamHeader[] streams = new NStreamHeader[md.iStreams];
            Dictionary<string, NStreamHeader> streamheaders = new Dictionary<string, NStreamHeader>();

            for(int i =0;i<md.iStreams;i++)
            {
                streams[i] = new NStreamHeader
                {
                    iOffset = ReadInt(s),
                    iSize = ReadInt(s),
                    
                };

                List<char> chars = new List<char>();

                char c = (char)s.ReadByte();
                while(c>0)
                {
                    chars.Add(c);
                    c = (char)s.ReadByte();
                }

                streams[i].rcName = chars.ToArray();

                ////对齐
                int remain = streams[i].rcName.Length <= 3?3- streams[i].rcName.Length:4 - (streams[i].rcName.Length + 1)  % 4;
                s.Position += remain;

                streamheaders.Add(new string(streams[i].rcName), streams[i] );
            }

            ////获取元字节流的文件偏移
            int offsetStreamData = offsetMetaData + streamheaders["#~"].iOffset;
            s.Position = offsetStreamData;

            NStreamData nsd = Read<NStreamData>(s);

            ////检测有效表的总数

            int index = 0;
            int TableCount = 0;
            while(index < 64)
            {
                int b = (int)(nsd.MaskValid >> index & 1);
                if(b == 1) { TableCount++; }
                TableCheck(b, index);
                index++;
            }

            ////跳过每个表的项目统计
            s.Position += TableCount * 4;

            ////直接读取Module的第一项
            s.Position += 2;
            int nMoudleNameOffset = ReadShort(s);

            ////获取字符串流的文件偏移
            offsetStreamData = offsetMetaData + streamheaders["#Strings"].iOffset;
            s.Position = offsetStreamData;

            ////开始进行读入字符串流
            ////以0开始，先读入一位起始位
            s.ReadByte();
            List<string> Strings = new List<string>();
            while (s.Position<offsetStreamData + streamheaders["#Strings"].iSize)
            {
                Strings.Add(ReadString(s));
            }


            ////测试用，获取Module表第一项的名称
            s.Position = offsetStreamData + nMoudleNameOffset;

            Console.WriteLine(ReadString(s));


            Console.WriteLine("");

        }

        /// <summary>
        /// 检验有效表
        /// </summary>
        /// <param name="对应的二进制位"></param>
        /// <param name="二进制位游标"></param>
        public static void TableCheck(int r,int index)
        {
            if(r == 0)
            {
                return;
            }
            switch(index)
            {
                default:
                    Console.WriteLine("Undefine " + index);
                    break;
                case 0:
                    Console.WriteLine(string.Format("Find Module"));
                    break;
                case 1:
                    Console.WriteLine(string.Format("Find TypeRef"));
                    break;
                case 2:
                    Console.WriteLine(string.Format("Find TypeDef"));
                    break;
                case 3:
                    Console.WriteLine(string.Format("Find FiledPtr"));
                    break;
                case 4:
                    Console.WriteLine(string.Format("Find Filed"));
                    break;
                case 5:
                    Console.WriteLine(string.Format("Find MethodPtr"));
                    break;
                case 6:
                    Console.WriteLine(string.Format("Find MethodDef"));
                    break;
                case 7:
                    Console.WriteLine(string.Format("Find ParamPtr"));
                    break;
                case 8:
                    Console.WriteLine(string.Format("Find Param"));
                    break;
                case 9:
                    Console.WriteLine(string.Format("Find MethodImpl"));
                    break;
                case 10:
                    Console.WriteLine(string.Format("Find MemberRef"));
                    break;
                case 11:
                    Console.WriteLine(string.Format("Find Constant"));
                    break;
                case 12:
                    Console.WriteLine(string.Format("Find CustomAttribute"));
                    break;
                case 13:
                    Console.WriteLine(string.Format("Find FieldMarshal"));
                    break;

                case 14:
                    Console.WriteLine(string.Format("Find DeclSecurity"));
                    break;
                case 15:
                    Console.WriteLine(string.Format("Find ClassLayout"));
                    break;
                case 16:
                    Console.WriteLine(string.Format("Find FieldLayout"));
                    break;
                case 17:
                    Console.WriteLine(string.Format("Find StandAloneSig"));
                    break;
                case 18:
                    Console.WriteLine(string.Format("Find EventMap"));
                    break;
                case 19:
                    Console.WriteLine(string.Format("Find EventPtr"));
                    break;
                case 20:
                    Console.WriteLine(string.Format("Find Event"));
                    break;
                case 21:
                    Console.WriteLine(string.Format("Find PropertyMap"));
                    break;
                case 22:
                    Console.WriteLine(string.Format("Find PropertyPtr"));
                    break;
                case 23:
                    Console.WriteLine(string.Format("Find Property"));
                    break;
                case 24:
                    Console.WriteLine(string.Format("Find MethodSemantics"));
                    break;
                case 25:
                    Console.WriteLine(string.Format("Find MethodImpl"));
                    break;
                case 26:
                    Console.WriteLine(string.Format("Find ModuleRef"));
                    break;
                case 27:
                    Console.WriteLine(string.Format("Find TypeSpec"));
                    break;
                case 28:
                    Console.WriteLine(string.Format("Find ImplMap"));
                    break;
                case 29:
                    Console.WriteLine(string.Format("Find FiledRVA"));
                    break;
                case 30:
                    Console.WriteLine(string.Format("Find ENCLog"));
                    break;
                case 31:
                    Console.WriteLine(string.Format("Find ENCMap"));
                    break;
                case 32:
                    Console.WriteLine(string.Format("Find AssemblyRef"));
                    break;
                case 33:
                    Console.WriteLine(string.Format("Find AssemblyProcessor"));
                    break;
                case 34:
                    Console.WriteLine(string.Format("Find AssemblyOS"));
                    break;
                case 35:
                    Console.WriteLine(string.Format("Find Assembly"));
                    break;
                case 36:
                    Console.WriteLine(string.Format("Find AssemblyRefProcessor"));
                    break;
                case 37:
                    Console.WriteLine(string.Format("Find AssemblyRefOS"));
                    break;
                case 38:
                    Console.WriteLine(string.Format("Find File"));
                    break;
                case 39:
                    Console.WriteLine(string.Format("Find ExportedType"));
                    break;
                case 40:
                    Console.WriteLine(string.Format("Find ManifestResource"));
                    break;
                case 41:
                    Console.WriteLine(string.Format("Find NestedClass"));
                    break;
                case 42:
                    Console.WriteLine(string.Format("Find GenericParam"));
                    break;
                case 43:
                    Console.WriteLine(string.Format("Find MethodSpec"));
                    break;
                case 44:
                    Console.WriteLine(string.Format("Find GenericParamConstraint"));
                    break;
            }
        }

        public static string ReadString(Stream s)
        {
            string r = "";
            char c;
            do
            {
                c = (char)s.ReadByte();
                if (c > 0) { r += c; }
            } while (c > 0);

            return r;
        }

        public static int ReadShort(Stream s)
        {
            byte[] buffer = ReadBytes(s, 2);
            return BitConverter.ToInt16(buffer, 0);
        }

        public static int ReadInt(Stream s)
        {
            byte[] buffer = ReadBytes(s, 4);
            return BitConverter.ToInt32(buffer,0);
        }

        public static byte[] ReadBytes(Stream s, int count)
        {
            byte[] data = new byte[count];
            s.Read(data, 0, count);
            return data;
        }

        public static T Read<T>(Stream s ) where T : struct
        {
            try
            {
                int _SIZE = Marshal.SizeOf(typeof(T));
                byte[] data = ReadBytes(s,_SIZE);
                IntPtr ptr = Marshal.AllocHGlobal(data.Length);
                Marshal.Copy(data, 0, ptr, data.Length);

                //Marshal.FreeHGlobal(ptr);

                return (T)Marshal.PtrToStructure(ptr, typeof(T));
            }
            catch (Exception e)
            {
                Console.WriteLine(string.Format("{0}.Read {1} fail.{2}", "PECheck", typeof(T), e.Message));
                return default(T);
            }
        }
    }
}