#include <windows.h>
#include <stdio.h>
#include "main.h"
#include "mouse.h"
#include "hook.h"

BOOL Hook_Active;
GETCURSORPOSPROC real_GetCursorPos = GetCursorPos;
CLIPCURSORPROC real_ClipCursor = ClipCursor;
SHOWCURSORPROC real_ShowCursor = ShowCursor;
SETCURSORPROC real_SetCursor = SetCursor;
GETWINDOWRECTPROC real_GetWindowRect = GetWindowRect;
GETCLIENTRECTPROC real_GetClientRect = GetClientRect;
CLIENTTOSCREENPROC real_ClientToScreen = ClientToScreen;
SCREENTOCLIENTPROC real_ScreenToClient = ScreenToClient;
SETCURSORPOSPROC real_SetCursorPos = SetCursorPos;
WINDOWFROMPOINTPROC real_WindowFromPoint = WindowFromPoint;
GETCLIPCURSORPROC real_GetClipCursor = GetClipCursor;
GETCURSORINFOPROC real_GetCursorInfo = GetCursorInfo;
GETSYSTEMMETRICSPROC real_GetSystemMetrics = GetSystemMetrics;
SETWINDOWPOSPROC real_SetWindowPos = SetWindowPos;
MOVEWINDOWPROC real_MoveWindow = MoveWindow;
SENDMESSAGEAPROC real_SendMessageA = SendMessageA;
SETWINDOWLONGAPROC real_SetWindowLongA = SetWindowLongA;

void Hook_PatchIAT(HMODULE hMod, char *moduleName, char *functionName, PROC newFunction)
{
    if (!hMod || hMod == INVALID_HANDLE_VALUE || !newFunction)
        return;

    PIMAGE_DOS_HEADER pDosHeader = (PIMAGE_DOS_HEADER)hMod;
    if (pDosHeader->e_magic != IMAGE_DOS_SIGNATURE)
        return;

    PIMAGE_NT_HEADERS pNTHeaders = (PIMAGE_NT_HEADERS)((DWORD)pDosHeader + (DWORD)pDosHeader->e_lfanew);
    if (pNTHeaders->Signature != IMAGE_NT_SIGNATURE)
        return;

    PIMAGE_IMPORT_DESCRIPTOR pImportDescriptor = (PIMAGE_IMPORT_DESCRIPTOR)((DWORD)pDosHeader +
        (DWORD)(pNTHeaders->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_IMPORT].VirtualAddress));

    if (pImportDescriptor == (PIMAGE_IMPORT_DESCRIPTOR)pNTHeaders)
        return;

    while (pImportDescriptor->FirstThunk)
    {
        char *impModuleName = (char *)((DWORD)pDosHeader + (DWORD)(pImportDescriptor->Name));

        if (_stricmp(impModuleName, moduleName) == 0)
        {
            PIMAGE_THUNK_DATA pFirstThunk = 
                (PIMAGE_THUNK_DATA)((DWORD)pDosHeader + (DWORD)pImportDescriptor->FirstThunk);

            PIMAGE_THUNK_DATA pOrigFirstThunk = 
                (PIMAGE_THUNK_DATA)((DWORD)pDosHeader + (DWORD)pImportDescriptor->OriginalFirstThunk);

            while (pFirstThunk->u1.Function && pOrigFirstThunk->u1.AddressOfData)
            {
                PIMAGE_IMPORT_BY_NAME pImport = 
                    (PIMAGE_IMPORT_BY_NAME)((DWORD)pDosHeader + pOrigFirstThunk->u1.AddressOfData);

                if ((pOrigFirstThunk->u1.Ordinal & IMAGE_ORDINAL_FLAG) == 0 &&
                    _stricmp((const char *)pImport->Name, functionName) == 0)
                {
                    DWORD oldProtect;

                    if (VirtualProtect(&pFirstThunk->u1.Function, sizeof(DWORD), PAGE_READWRITE, &oldProtect))
                    {
                        pFirstThunk->u1.Function = (DWORD)newFunction;
                        VirtualProtect(&pFirstThunk->u1.Function, sizeof(DWORD), oldProtect, &oldProtect);
                    }

                    break;
                }

                pFirstThunk++;
                pOrigFirstThunk++;
            }
        }

        pImportDescriptor++;
    }
}

PROC Hook_HotPatch(PROC function, PROC newFunction)
{
    PROC result = function;

    if (!function)
        return result;

    unsigned short *bytes = (unsigned short *)function;

    if (*bytes == 0x25FF) // JMP DWORD PTR
    {
        char *address = (char *)function;
        DWORD oldProtect;

        if (VirtualProtect(address, 8, PAGE_EXECUTE_READWRITE, &oldProtect))
        {
            if (memcmp(address + 6, (const char[]) { 0xCC, 0xCC }, 2) == 0 ||
                memcmp(address + 6, (const char[]) { 0x90, 0x90 }, 2) == 0)
            {
                memmove(address + 2, address, 6);
                *((WORD *)(&address[0])) = 0xFF8B; // mov edi, edi
            }

            VirtualProtect(address, 8, oldProtect, &oldProtect);
        }
    }

    if (*bytes == 0xFF8B) // mov edi, edi
    {
        char *address = ((char *)function) - 5;
        DWORD oldProtect;

        if (VirtualProtect(address, 7, PAGE_EXECUTE_READWRITE, &oldProtect))
        {
            if (memcmp(address, (const char[]) { 0xCC, 0xCC, 0xCC, 0xCC, 0xCC }, 5) == 0 ||
                memcmp(address, (const char[]) { 0x90, 0x90, 0x90, 0x90, 0x90 }, 5) == 0)
            {
                address[0] = 0xE9; // long jump
                *((DWORD *)(&address[1])) = ((char *)newFunction) - address - 5;
                *((WORD *)(&address[5])) = 0xF9EB; // short jump to our long jump

                result = (PROC)(((char *)function) + 2);
            }

            VirtualProtect(address, 7, oldProtect, &oldProtect);
        }
    }

    return result;
}

void Hook_TryHotPatch(char *moduleName, char *functionName, PROC newFunction, PROC *function)
{
    FARPROC org = GetProcAddress(GetModuleHandle(moduleName), functionName);
    if (ddraw->hotPatch && org)
    {
        *function = Hook_HotPatch(org, newFunction);

        if (*function == org) // hotpatch failed...
            Hook_PatchIAT(GetModuleHandle(NULL), moduleName, functionName, newFunction);
    }
    else
    {
        Hook_PatchIAT(GetModuleHandle(NULL), moduleName, functionName, newFunction);
    }
}

void Hook_Init()
{
    if (!Hook_Active)
    {
        Hook_Active = TRUE;

        Hook_TryHotPatch("user32.dll", "GetCursorPos", (PROC)fake_GetCursorPos, (PROC *)&real_GetCursorPos);
        Hook_TryHotPatch("user32.dll", "ClipCursor", (PROC)fake_ClipCursor, (PROC *)&real_ClipCursor);
        Hook_TryHotPatch("user32.dll", "ShowCursor", (PROC)fake_ShowCursor, (PROC *)&real_ShowCursor);
        Hook_TryHotPatch("user32.dll", "SetCursor", (PROC)fake_SetCursor, (PROC *)&real_SetCursor);
        Hook_TryHotPatch("user32.dll", "GetWindowRect", (PROC)fake_GetWindowRect, (PROC *)&real_GetWindowRect);
        Hook_TryHotPatch("user32.dll", "GetClientRect", (PROC)fake_GetClientRect, (PROC *)&real_GetClientRect);
        Hook_TryHotPatch("user32.dll", "ClientToScreen", (PROC)fake_ClientToScreen, (PROC *)&real_ClientToScreen);
        Hook_TryHotPatch("user32.dll", "ScreenToClient", (PROC)fake_ScreenToClient, (PROC *)&real_ScreenToClient);
        Hook_TryHotPatch("user32.dll", "SetCursorPos", (PROC)fake_SetCursorPos, (PROC *)&real_SetCursorPos);
        Hook_TryHotPatch("user32.dll", "GetClipCursor", (PROC)fake_GetClipCursor, (PROC *)&real_GetClipCursor);
        Hook_TryHotPatch("user32.dll", "WindowFromPoint", (PROC)fake_WindowFromPoint, (PROC *)&real_WindowFromPoint);
        Hook_TryHotPatch("user32.dll", "GetCursorInfo", (PROC)fake_GetCursorInfo, (PROC *)&real_GetCursorInfo);
        Hook_TryHotPatch("user32.dll", "GetSystemMetrics", (PROC)fake_GetSystemMetrics, (PROC *)&real_GetSystemMetrics);
        Hook_TryHotPatch("user32.dll", "SetWindowPos", (PROC)fake_SetWindowPos, (PROC *)&real_SetWindowPos);
        Hook_TryHotPatch("user32.dll", "MoveWindow", (PROC)fake_MoveWindow, (PROC *)&real_MoveWindow);
        Hook_TryHotPatch("user32.dll", "SendMessageA", (PROC)fake_SendMessageA, (PROC *)&real_SendMessageA);
        Hook_TryHotPatch("user32.dll", "SetWindowLongA", (PROC)fake_SetWindowLongA, (PROC *)&real_SetWindowLongA);

        //Hook_PatchIAT(GetModuleHandle(NULL), "user32.dll", "GetCursorPos", (PROC)fake_GetCursorPos);
    }
}