using System;
using System.Collections.Generic;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Text;

namespace NativeLibraryLoader.Windows
{
    internal class PEFileCheck : IFileCheck
    {
        unsafe MachineType IFileCheck.CheckFile(string path)
        {
            MachineType machineType = MachineType.NoSupport;
            byte[] bytes = System.IO.File.ReadAllBytes(path);
            ImageDosHeader imageDosHeader;
            fixed (void* p = &bytes[0])
            {
                imageDosHeader = Marshal.PtrToStructure<ImageDosHeader>((IntPtr)p);
            }
            fixed (void* p = &bytes[(imageDosHeader.Lfanew >> 16) | (imageDosHeader.Lfanew << 16)])
            {
                ImageNTHeaders imageNTHeaders = Marshal.PtrToStructure<ImageNTHeaders>((IntPtr)(p));
            }
            fixed (void* p = &bytes[((imageDosHeader.Lfanew >> 16) | (imageDosHeader.Lfanew << 16)) + Marshal.SizeOf<ImageNTHeaders>()])
            {
                switch (Unsafe.Read<MagicType>(p))
                {
                    case MagicType.IMAGE_NT_OPTIONAL_HDR32_MAGIC:
                        machineType = MachineType.Bit32;
                        break;
                    case MagicType.IMAGE_NT_OPTIONAL_HDR64_MAGIC:
                        machineType = MachineType.Bit64;
                        break;
                }
            }
            return machineType;
        }

        enum PeMachineType : ushort
        {
            /// <summary>
            /// The content of this field is assumed to be applicable to any machine type
            /// </summary>
            Unknown = 0x0000,
            /// <summary>
            /// Intel 386 or later processors and compatible processors
            /// </summary>
            I386 = 0x014c,
            R3000 = 0x0162,
            /// <summary>
            ///  MIPS little endian
            /// </summary>
            R4000 = 0x0166,
            R10000 = 0x0168,
            /// <summary>
            /// MIPS little-endian WCE v2
            /// </summary>
            WCEMIPSV2 = 0x0169,
            /// <summary>
            /// Alpha AXP
            /// </summary>
            Alpha = 0x0184,
            /// <summary>
            /// Hitachi SH3
            /// </summary>
            SH3 = 0x01a2,
            /// <summary>
            /// Hitachi SH3 DSP
            /// </summary>
            SH3DSP = 0x01a3,
            /// <summary>
            /// Hitachi SH4
            /// </summary>
            SH4 = 0x01a6,
            /// <summary>
            /// Hitachi SH5
            /// </summary>
            SH5 = 0x01a8,
            /// <summary>
            /// ARM little endian
            /// </summary>
            ARM = 0x01c0,
            /// <summary>
            /// Thumb
            /// </summary>
            Thumb = 0x01c2,
            /// <summary>
            /// ARM Thumb-2 little endian
            /// </summary>
            ARMNT = 0x01c4,
            /// <summary>
            /// Matsushita AM33
            /// </summary>
            AM33 = 0x01d3,
            /// <summary>
            /// Power PC little endian
            /// </summary>
            PowerPC = 0x01f0,
            /// <summary>
            /// Power PC with floating point support
            /// </summary>
            PowerPCFP = 0x01f1,
            /// <summary>
            /// Intel Itanium processor family
            /// </summary>
            IA64 = 0x0200,
            /// <summary>
            /// MIPS16
            /// </summary>
            MIPS16 = 0x0266,
            /// <summary>
            /// Motorola 68000 series
            /// </summary>
            M68K = 0x0268,
            /// <summary>
            /// Alpha AXP 64-bit
            /// </summary>
            Alpha64 = 0x0284,
            /// <summary>
            /// MIPS with FPU
            /// </summary>
            MIPSFPU = 0x0366,
            /// <summary>
            /// MIPS16 with FPU
            /// </summary>
            MIPSFPU16 = 0x0466,
            /// <summary>
            /// EFI byte code
            /// </summary>
            EBC = 0x0ebc,
            /// <summary>
            /// RISC-V 32-bit address space
            /// </summary>
            RISCV32 = 0x5032,
            /// <summary>
            /// RISC-V 64-bit address space
            /// </summary>
            RISCV64 = 0x5064,
            /// <summary>
            /// RISC-V 128-bit address space
            /// </summary>
            RISCV128 = 0x5128,
            /// <summary>
            /// x64
            /// </summary>
            AMD64 = 0x8664,
            /// <summary>
            /// ARM64 little endian
            /// </summary>
            ARM64 = 0xaa64,
            /// <summary>
            /// LoongArch 32-bit processor family
            /// </summary>
            LoongArch32 = 0x6232,
            /// <summary>
            /// LoongArch 64-bit processor family
            /// </summary>
            LoongArch64 = 0x6264,
            /// <summary>
            /// Mitsubishi M32R little endian
            /// </summary>
            M32R = 0x9041
        }
        enum CHARACTERISTICS : UInt16
        {
            RELOCS_STRIPPED = 0x1,
            EXECUTABLE_IMAGE = 0x2,
            LINE_NUMS_STRIPPED = 0x4,
            LOCAL_SYMS_STRIPPED = 0x8,
            AGGRESIVE_WS_TRIM = 0x10,
            LARGE_ADDRESS_AWARE = 0x20,
            BYTES_REVERSED_LO = 0x80,
            BIT32_MACHINE = 0x100,
            DEBUG_STRIPPED = 0x200,
            REMOVABLE_RUN_FROM_SWAP = 0x400,
            NET_RUN_FROM_SWAP = 0x800,
            SYSTEM = 0x1000,
            DLL = 0x2000,
            UP_SYSTEM_ONLY = 0x4000,
            BYTES_REVERSED_HI = 0x8000
        }
        enum MagicType : ushort
        {
            IMAGE_NT_OPTIONAL_HDR32_MAGIC = 0x10b,
            IMAGE_NT_OPTIONAL_HDR64_MAGIC = 0x20b
        }
        enum SubSystemType : ushort
        {
            IMAGE_SUBSYSTEM_UNKNOWN = 0,
            IMAGE_SUBSYSTEM_NATIVE = 1,
            IMAGE_SUBSYSTEM_WINDOWS_GUI = 2,
            IMAGE_SUBSYSTEM_WINDOWS_CUI = 3,
            IMAGE_SUBSYSTEM_POSIX_CUI = 7,
            IMAGE_SUBSYSTEM_WINDOWS_CE_GUI = 9,
            IMAGE_SUBSYSTEM_EFI_APPLICATION = 10,
            IMAGE_SUBSYSTEM_EFI_BOOT_SERVICE_DRIVER = 11,
            IMAGE_SUBSYSTEM_EFI_RUNTIME_DRIVER = 12,
            IMAGE_SUBSYSTEM_EFI_ROM = 13,
            IMAGE_SUBSYSTEM_XBOX = 14

        }
        enum DllCharacteristicsType : ushort
        {
            RES_0 = 0x0001,
            RES_1 = 0x0002,
            RES_2 = 0x0004,
            RES_3 = 0x0008,
            IMAGE_DLL_CHARACTERISTICS_DYNAMIC_BASE = 0x0040,
            IMAGE_DLL_CHARACTERISTICS_FORCE_INTEGRITY = 0x0080,
            IMAGE_DLL_CHARACTERISTICS_NX_COMPAT = 0x0100,
            IMAGE_DLLCHARACTERISTICS_NO_ISOLATION = 0x0200,
            IMAGE_DLLCHARACTERISTICS_NO_SEH = 0x0400,
            IMAGE_DLLCHARACTERISTICS_NO_BIND = 0x0800,
            RES_4 = 0x1000,
            IMAGE_DLLCHARACTERISTICS_WDM_DRIVER = 0x2000,
            IMAGE_DLLCHARACTERISTICS_TERMINAL_SERVER_AWARE = 0x8000
        }
        [StructLayout(LayoutKind.Sequential, Pack = 1, Size = 64)]
        struct ImageDosHeader
        {
            public UInt16 Magic;
            public UInt16 Cblp;
            public UInt16 Cp;
            public UInt16 Crlc;
            public UInt16 Minalloc;
            public UInt16 Maxalloc;
            public UInt16 SS;
            public UInt16 SP;
            public UInt16 CSum;
            public UInt16 IP;
            public UInt16 CS;
            public UInt16 Lfarlc;
            public UInt16 Ovno;
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 4)]
            public UInt16[] Res;
            public UInt16 OemId;
            public UInt16 OemInfo;
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 10)]
            public UInt16[] Res2;
            public UInt32 Lfanew;
        }
        [StructLayout(LayoutKind.Sequential, Pack = 1)]
        struct ImageNTHeaders
        {
            public UInt32 Signature;
            public ImageFileHeader ImageFileHeader;
        }
        [StructLayout(LayoutKind.Sequential, Pack = 1)]
        struct ImageFileHeader
        {
            public PeMachineType Machine;
            public UInt16 NumberOfSections;
            public UInt32 TimeDateStamp;
            public UInt32 PointerToSymbolTable;
            public UInt32 NumberOfSymbols;
            public UInt16 SizeOfOptionalHeader;
            public CHARACTERISTICS Characteristics;
        }

    }
}