/****************************************************************************
 * server.cpp * Example Winsock server                                      *
 ****************************************************************************
 * By: Jonathan Overholt                      http://overholt.org/jonathan/ *
 ****************************************************************************/

#include <windows.h>
#include <stdio.h>
#include <winsock.h>

#pragma comment(lib, "wsock32.lib")

struct MAIN
{
	HINSTANCE hInst;
	HWND hWnd;

	SOCKET Sock;
	sockaddr_in Sin;
} Main;

int InitSocket(int nPort);
int SendData(SOCKET sock, char * lpszData);
LRESULT WINAPI WinProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam);
int HandleData(WPARAM wParam, LPARAM lParam);
int HandleAccept(WPARAM wParam, LPARAM lParam);

int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrev, char * lpCmdLine, int nShowCmd)
{
/* hPrev is NULL unless there's another instance running.
                    We don't want two servers now, do we? */
	if (hPrev)
		return -1;

	Main.hInst = hInst;

	WSAData wsa;
	WSAStartup(MAKEWORD(1, 1), &wsa);

	WNDCLASS wnd;
	wnd.cbClsExtra = 0;
	wnd.cbWndExtra = 0;
	wnd.hbrBackground = (HBRUSH) COLOR_WINDOW;
	wnd.hCursor = LoadCursor(NULL, IDC_ARROW);
	wnd.hIcon = LoadIcon(NULL, IDI_APPLICATION);
	wnd.hInstance = Main.hInst;
	wnd.lpfnWndProc = WinProc;
	wnd.lpszClassName = "GenericServerClass";
	wnd.lpszMenuName = NULL;
	wnd.style = CS_HREDRAW | CS_VREDRAW;

	RegisterClass(&wnd);

	Main.hWnd = CreateWindow("GenericServerClass", "Serving on port 1234...", WS_CAPTION | WS_POPUPWINDOW, 0, 0, 200, 100, NULL, NULL, Main.hInst, NULL);

	if (!Main.hWnd)
		return -2;

	if (!InitSocket(1234))
	{
		char szBuffer[1024];
		
		sprintf(szBuffer, "Error initializing listening socket [%d]", WSAGetLastError());

		MessageBox(Main.hWnd, szBuffer, "Error", MB_OK);
	}

	ShowWindow(Main.hWnd, SW_SHOWNORMAL);

	MSG msg;

	while (GetMessage(&msg, NULL, 0, 0))
	{
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}

	WSACleanup();

	return msg.wParam;

}

int InitSocket(int nPort)
{
	if ((Main.Sock = socket(PF_INET, SOCK_STREAM, 0)) == SOCKET_ERROR)
		return FALSE;

	Main.Sin.sin_family = AF_INET;
	Main.Sin.sin_port = htons(nPort);

	if (bind(Main.Sock, (sockaddr *)&Main.Sin, sizeof(sockaddr_in)) == SOCKET_ERROR)
		return FALSE;

	if (listen(Main.Sock, 200) == SOCKET_ERROR)
		return FALSE;

	WSAAsyncSelect(Main.Sock, Main.hWnd, WM_USER + 1, FD_ACCEPT);

	return TRUE;
}

int SendData(SOCKET sock, char * lpszData)
{
	return send(sock, lpszData, strlen(lpszData), 0);
}

LRESULT WINAPI WinProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
	switch (uMsg)
	{
	case WM_DESTROY:
		PostQuitMessage(0);
		break;

	case WM_USER + 1:
		HandleAccept(wParam, lParam);
		break;

	case WM_USER + 2:
		HandleData(wParam, lParam);
		break;
	}

	return DefWindowProc(hWnd, uMsg, wParam, lParam);
}

int HandleData(WPARAM wParam, LPARAM lParam)
{
	SOCKET sock = (SOCKET)wParam;
	WORD event = LOWORD(lParam);
	WORD error = HIWORD(lParam);

	if (event == FD_CLOSE)
	{
		closesocket(sock);
	}
	else if (event == FD_READ)
	{
		char szBuffer[1024];
		ZeroMemory(szBuffer, 1024);
		recv(sock, szBuffer, 1024, 0);

		MessageBox(Main.hWnd, szBuffer, "Received Data!", MB_OK);

		closesocket(sock);
	}
	return TRUE;
}	

int HandleAccept(WPARAM wParam, LPARAM lParam)
{
	SOCKET sock = (SOCKET)wParam;
	WORD event = LOWORD(lParam);
	WORD error = HIWORD(lParam);
	
	if (event == FD_ACCEPT)
	{
		sockaddr_in NewRemoteSin;
		SOCKET newsock = accept(sock, (sockaddr*)&NewRemoteSin, NULL);

		WSAAsyncSelect(newsock, Main.hWnd, WM_USER + 2, FD_READ | FD_CLOSE);
		
		SendData(newsock, "Hello, welcome to my server.");
	}
	return TRUE;
}