using System;
using System.Runtime.InteropServices;
using System.Text;

namespace LANCommander.Interposer
{
    internal static class NativeMethods
    {
        // Process access rights
        internal const uint PROCESS_CREATE_THREAD = 0x0002;
        internal const uint PROCESS_VM_OPERATION = 0x0008;
        internal const uint PROCESS_VM_READ = 0x0010;
        internal const uint PROCESS_VM_WRITE = 0x0020;
        internal const uint PROCESS_QUERY_INFORMATION = 0x0400;

        // Memory allocation
        internal const uint MEM_COMMIT = 0x00001000;
        internal const uint MEM_RESERVE = 0x00002000;
        internal const uint MEM_RELEASE = 0x00008000;
        internal const uint PAGE_READWRITE = 0x04;

        // Process creation
        internal const uint CREATE_SUSPENDED = 0x00000004;
        internal const uint CREATE_UNICODE_ENVIRONMENT = 0x00000400;

        // File mapping
        internal const uint FILE_MAP_WRITE = 0x0002;

        [DllImport("kernel32.dll", SetLastError = true)]
        internal static extern IntPtr OpenProcess(uint dwDesiredAccess, bool bInheritHandle, uint dwProcessId);

        [DllImport("kernel32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        internal static extern bool CloseHandle(IntPtr hObject);

        [DllImport("kernel32.dll", SetLastError = true)]
        internal static extern IntPtr VirtualAllocEx(
            IntPtr hProcess, IntPtr lpAddress, UIntPtr dwSize,
            uint flAllocationType, uint flProtect);

        [DllImport("kernel32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        internal static extern bool VirtualFreeEx(
            IntPtr hProcess, IntPtr lpAddress, UIntPtr dwSize, uint dwFreeType);

        [DllImport("kernel32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        internal static extern bool WriteProcessMemory(
            IntPtr hProcess, IntPtr lpBaseAddress, byte[] lpBuffer,
            UIntPtr nSize, out UIntPtr lpNumberOfBytesWritten);

        [DllImport("kernel32.dll", SetLastError = true)]
        internal static extern IntPtr CreateRemoteThread(
            IntPtr hProcess, IntPtr lpThreadAttributes, UIntPtr dwStackSize,
            IntPtr lpStartAddress, IntPtr lpParameter,
            uint dwCreationFlags, IntPtr lpThreadId);

        [DllImport("kernel32.dll", SetLastError = true)]
        internal static extern uint WaitForSingleObject(IntPtr hHandle, uint dwMilliseconds);

        [DllImport("kernel32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        internal static extern bool GetExitCodeThread(IntPtr hThread, out uint lpExitCode);

        [DllImport("kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
        internal static extern IntPtr GetModuleHandleW(string lpModuleName);

        [DllImport("kernel32.dll", CharSet = CharSet.Ansi, SetLastError = true, ExactSpelling = true)]
        internal static extern IntPtr GetProcAddress(IntPtr hModule, string lpProcName);

        [DllImport("kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        internal static extern bool CreateProcessW(
            string lpApplicationName,
            StringBuilder lpCommandLine,
            IntPtr lpProcessAttributes,
            IntPtr lpThreadAttributes,
            bool bInheritHandles,
            uint dwCreationFlags,
            IntPtr lpEnvironment,
            string lpCurrentDirectory,
            ref STARTUPINFO lpStartupInfo,
            out PROCESS_INFORMATION lpProcessInformation);

        [DllImport("kernel32.dll", SetLastError = true)]
        internal static extern uint ResumeThread(IntPtr hThread);

        [DllImport("kernel32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        internal static extern bool TerminateProcess(IntPtr hProcess, uint uExitCode);

        [DllImport("kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
        internal static extern IntPtr CreateFileMappingW(
            IntPtr hFile, IntPtr lpFileMappingAttributes,
            uint flProtect, uint dwMaximumSizeHigh, uint dwMaximumSizeLow,
            string lpName);

        [DllImport("kernel32.dll", SetLastError = true)]
        internal static extern IntPtr MapViewOfFile(
            IntPtr hFileMappingObject, uint dwDesiredAccess,
            uint dwFileOffsetHigh, uint dwFileOffsetLow, UIntPtr dwNumberOfBytesToMap);

        [DllImport("kernel32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        internal static extern bool UnmapViewOfFile(IntPtr lpBaseAddress);

        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
        internal struct STARTUPINFO
        {
            public int cb;
            public string lpReserved;
            public string lpDesktop;
            public string lpTitle;
            public int dwX;
            public int dwY;
            public int dwXSize;
            public int dwYSize;
            public int dwXCountChars;
            public int dwYCountChars;
            public int dwFillAttribute;
            public int dwFlags;
            public short wShowWindow;
            public short cbReserved2;
            public IntPtr lpReserved2;
            public IntPtr hStdInput;
            public IntPtr hStdOutput;
            public IntPtr hStdError;
        }

        [StructLayout(LayoutKind.Sequential)]
        internal struct PROCESS_INFORMATION
        {
            public IntPtr hProcess;
            public IntPtr hThread;
            public uint dwProcessId;
            public uint dwThreadId;
        }
    }
}