#include "master.h"

F_STRING *get_error_message(void)
{
	DWORD id = GetLastError();
	F_CHAR *msg = error_message(id);
	F_STRING *string = from_u16_string(msg);
	LocalFree(msg);
	return string;
}

/* You must LocalFree() the return value! */
F_CHAR *error_message(DWORD id)
{
	F_CHAR *buffer;
	int index;

	DWORD ret = FormatMessage(
		FORMAT_MESSAGE_ALLOCATE_BUFFER |
		FORMAT_MESSAGE_FROM_SYSTEM,
		NULL,
		id,
		MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
		(LPTSTR)(void *) &buffer,
		0, NULL);
	if(ret == 0)
		return error_message(GetLastError());

	/* strip whitespace from end */
	index = wcslen(buffer) - 1;
	while(index >= 0 && isspace(buffer[index]))
		buffer[index--] = 0;

	return buffer;
}

HMODULE hFactorDll;

void init_ffi(void)
{
	hFactorDll = GetModuleHandle(FACTOR_DLL);
	if(!hFactorDll)
		fatal_error("GetModuleHandle(\"" FACTOR_DLL_NAME "\") failed", 0);
}

void ffi_dlopen(F_DLL *dll)
{
	dll->dll = LoadLibraryEx(alien_offset(dll->path), NULL, 0);
}

void *ffi_dlsym(F_DLL *dll, F_SYMBOL *symbol)
{
	return GetProcAddress(dll ? (HMODULE)dll->dll : hFactorDll, symbol);
}

void ffi_dlclose(F_DLL *dll)
{
	FreeLibrary((HMODULE)dll->dll);
	dll->dll = NULL;
}

bool windows_stat(F_CHAR *path)
{
	BY_HANDLE_FILE_INFORMATION bhfi;
	HANDLE h = CreateFileW(path,
			GENERIC_READ,
			FILE_SHARE_READ,
			NULL,
			OPEN_EXISTING,
			FILE_FLAG_BACKUP_SEMANTICS,
			NULL);

	if(h == INVALID_HANDLE_VALUE)
	{
		// FindFirstFile is the only call that can stat c:\pagefile.sys
		WIN32_FIND_DATA st;
		HANDLE h;

		if(INVALID_HANDLE_VALUE == (h = FindFirstFile(path, &st)))
			return false;
		FindClose(h);
		return true;
	}
	bool ret;
	ret = GetFileInformationByHandle(h, &bhfi);
	CloseHandle(h);
	return ret;
}

void windows_image_path(F_CHAR *full_path, F_CHAR *temp_path, unsigned int length)
{
	snwprintf(temp_path, length-1, L"%s.image", full_path); 
	temp_path[sizeof(temp_path) - 1] = 0;
}

/* You must free() this yourself. */
const F_CHAR *default_image_path(void)
{
	F_CHAR full_path[MAX_UNICODE_PATH];
	F_CHAR *ptr;
	F_CHAR temp_path[MAX_UNICODE_PATH];

	if(!GetModuleFileName(NULL, full_path, MAX_UNICODE_PATH))
		fatal_error("GetModuleFileName() failed", 0);

	if((ptr = wcsrchr(full_path, '.')))
		*ptr = 0;

	snwprintf(temp_path, sizeof(temp_path)-1, L"%s.image", full_path); 
	temp_path[sizeof(temp_path) - 1] = 0;

	if(!windows_stat(temp_path)) {
		unsigned int len = wcslen(full_path);
		F_CHAR magic[] = L"-console";
		unsigned int magic_len = wcslen(magic);

		if(!wcsncmp(full_path + len - magic_len, magic, MIN(len, magic_len)))
			full_path[len - magic_len] = 0;
		snwprintf(temp_path, sizeof(temp_path)-1, L"%s.image", full_path); 
		temp_path[sizeof(temp_path) - 1] = 0;
	}

	return safe_strdup(temp_path);
}

/* You must free() this yourself. */
const F_CHAR *vm_executable_path(void)
{
	F_CHAR full_path[MAX_UNICODE_PATH];
	if(!GetModuleFileName(NULL, full_path, MAX_UNICODE_PATH))
		fatal_error("GetModuleFileName() failed", 0);
	return safe_strdup(full_path);
}


void primitive_existsp(void)
{

	F_CHAR *path = unbox_u16_string();
	box_boolean(windows_stat(path));
}

F_SEGMENT *alloc_segment(CELL size)
{
	char *mem;
	DWORD ignore;

	if((mem = (char *)VirtualAlloc(NULL, getpagesize() * 2 + size,
		MEM_COMMIT, PAGE_EXECUTE_READWRITE)) == 0)
		out_of_memory();

	if (!VirtualProtect(mem, getpagesize(), PAGE_NOACCESS, &ignore))
		fatal_error("Cannot allocate low guard page", (CELL)mem);

	if (!VirtualProtect(mem + size + getpagesize(),
		getpagesize(), PAGE_NOACCESS, &ignore))
		fatal_error("Cannot allocate high guard page", (CELL)mem);

	F_SEGMENT *block = safe_malloc(sizeof(F_SEGMENT));

	block->start = (CELL)mem + getpagesize();
	block->size = size;
	block->end = block->start + size;

	return block;
}

void dealloc_segment(F_SEGMENT *block)
{
	SYSTEM_INFO si;
	GetSystemInfo(&si);
	if(!VirtualFree((void*)(block->start - si.dwPageSize), 0, MEM_RELEASE))
		fatal_error("dealloc_segment failed",0);
	free(block);
}

long getpagesize(void)
{
	static long g_pagesize = 0;
	if (! g_pagesize)
	{
		SYSTEM_INFO system_info;
		GetSystemInfo (&system_info);
		g_pagesize = system_info.dwPageSize;
	}
	return g_pagesize;
}

void sleep_micros(u64 usec)
{
	Sleep((DWORD)(usec / 1000));
}